Next Article in Journal
Waste Foundry Sand as an Alternative Material in Road Construction
Next Article in Special Issue
Winery Residues Transformed into Biochar and Co-Applied with Trichoderma Increase Grape Productivity and Soil Quality
Previous Article in Journal
An Examination of the Emissions, Cost, and Time of Intermodal Transportation
Previous Article in Special Issue
Effects of Reclaimed Water Irrigation on Soil Properties and the Composition and Diversity of Microbial Communities in Northwest China
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Sustainability
Volume 17
Issue 6
10.3390/su17062369
sustainability-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

The Potential of Hydroxyapatite for the Remediation of Lead-Contaminated Territories: A Case Study of Soils in Primorsky Krai

by
Svetlana Novikova
1,2,
Andrei Gilev
2,
Anastasia Brikmans
2,
Igor Priymak
1,
Daria Shlyk
1,
Olga Nesterova
2 and
Andrei Egorin
1,*
1
Institute of Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159 Prosp. 100-Letiya Vladivostoka, Vladivostok 690022, Russia
2
Far Eastern Climate Smart Lab, Far Eastern Federal University, Vladivostok 690922, Russia
*
Author to whom correspondence should be addressed.
Sustainability 2025, 17(6), 2369; https://doi.org/10.3390/su17062369
Submission received: 22 January 2025 / Revised: 3 March 2025 / Accepted: 4 March 2025 / Published: 7 March 2025
(This article belongs to the Special Issue Soil Pollution, Soil Ecology and Sustainable Land Use)
Browse Figures
Versions Notes

Abstract

Finding ways to enhance the resilience of soil ecosystems in the context of heavy metal contamination remains an important and urgent challenge. This work is devoted to assessing the impact of the soil composition in Primorsky Krai on the efficiency of using hydroxyapatite to decrease lead intake into plants. The physicochemical characteristics of Luvic Anthrosol and Gleyic Cambisol and their absorption properties with respect to lead have been studied. Adsorption, distribution of forms, and biotesting were carried out under lead saturation of soils conditions. It has been found that soil composition determines sorption properties and the proportion of mobile lead. The high organic carbon content in Gleyic Cambisol explains its high adsorption capacity and low content of water-soluble lead fraction. The addition of hydroxyapatite reduces the water solubility of lead in Luvic Anthrosol by three orders of magnitude and in the ion mobile form by one order. The capacity of hydroxyapatite decreases by more than thirty times when added to Luvic Anthrosol. With a ratio of hydroxyapatite/soil 0.2, oat germination increases by 18.7%, average seedling length increases by 7 cm, and lead uptake into tissues decreases by 83%.

1. Introduction

The stability of soil ecosystems is a crucial prerequisite for maintaining soil fertility and ecological integrity. The entry of pollutants into the soil as a result of anthropogenic activity leads to degradation and disrupts the stable functioning of these ecosystems. Such disturbances disrupt the critical ecological functions provided by soils, resulting in the death of organisms in trophic networks and a decrease in overall biodiversity.
Soil pollution by heavy metals is a serious environmental problem of modern times. The content of metals in soils can be increased due to natural factors, such as the geological composition of parent rocks and volcanic activity [1,2]. Anthropogenic activities also contribute to this problem [3,4]. Urban soils become polluted through the deposition of dust and aerosols and by industrial activity, as well as by the use of fertilizer and paint [5,6,7]. Lead is released from car paint and exhaust fumes. In agricultural areas, pollution occurs through atmospheric transport and the combustion of fuel and due to the use of fertilizers and plant protection chemicals [8,9,10,11].
According to research, areas of the world that are most contaminated with heavy metals include Linfen, Shenyang in China; Haina in the Dominican Republic; Ranipet in India; Mailuu-Suu in Kyrgyzstan; and cities in Zambia that are near lead and cadmium mines [12,13]. In Russia, the issue of heavy metal soil contamination is a serious problem, particularly in Primorsky Krai (Primorye Territory). The eastern coast of the region has experienced a prolonged environmental crisis due to the activities of industries such as the Mining and Chemical Company “BOR” LLC, the lead plant in the village of Rudnaya Pristan, and the Khrustalnensky mining and processing plant [14,15]. These facilities created persistent geochemical abnormalities, especially in Dalnegorsk, where there were systematic excesses that exceeded the hygiene standards (since 2007–2014) for heavy metals in the soil, affecting the Terney District [16]. Residential areas, agricultural land, and garden plots here are located in zones of high and medium pollution, with a significant portion of the population living in the sanitary protection zone of class 1 hazardous enterprises [14].
The main sources of toxic elements are tailing ponds containing lead, cadmium, and copper, as well as other heavy metals [15]. In the village of Rudnaya Pristan, soil contamination is associated with natural factors and a century-old history of lead mining and processing [16]. Lead concentrations around tailings dams exceed permissible levels by 18 times [17], and in the area influenced by the third tailing dump of the Khrustalnensky mining and processing plant, soil, sediment, and vegetation pollution exceed background levels by 1.5–32 times over a distance up to 5 km [15,18]. From 2012 to 2018, lead concentrations in slurry waters from the Kavalerovsky District and the Rudnaya River exceeded regional background levels by 619 and 1280 times, respectively, which is associated with the oxidation of sulfide minerals [19].
Coal mining operations, such as the Lipovtsy coal field mine No. 4, further amplify the problem: soils adjacent to waste dumps exhibit lead levels as high as 22.09 mg/kg, with elevated concentrations persisting even at considerable distances [20]. Soil degradation driven by pollution manifests through reduced fertility within a 1–2 km radius of tailings ponds, alongside disrupted soil structure and suppressed vegetation growth [17]. Lead bioaccumulation in plants reaches 2–30 times permissible thresholds, causing teratological deformities, impaired reproductive capacity, and pollen sterility (reaching 25% in heavily contaminated zones) [15,18]. The threat to agriculture is acute; for example, soybean yields directly depend on the concentrations of lead and cadmium in the soil [21].
Environmental contamination extends beyond industrial areas. In Vladivostok, urban soil is polluted with chromium, copper, zinc, and lead, and the situation is exacerbated by topsoil degradation [22]. In Ussurisk and its surrounding area, plant tissue exhibits abnormally high concentrations of lead [23]. The concentration of heavy metals in the sediments of the Ussuri River is increasing due to anthropogenic impact, which creates risks for wetlands [24]. Elevated levels of lead have been detected near Ussuriysk, in the Razdoly River, although the source of contamination remains unknown [25]. A government report from 2022 Primorsky territory linked transport infrastructure with lead pollution: in Nakhodka and Partizansk, the average regional values were exceeded, while the proportion of soil samples exceeding regulatory limits increased from 13.1% in 2020 to 25% in 2022 [26].
Thus, the long-term effects of heavy metals on ecosystems and human health necessitate the implementation of innovative techniques to restore soil coverage and reduce pollution. In order to restore ecological functions and reduce pollution levels to acceptable levels, it is essential to carry out soil remediation. A safe, technically feasible solution is to introduce additives that reduce levels of water-soluble, exchangeable forms of lead (immobilization), which reduces its availability.
Liming of soils reduces the bioavailability of Pb and Cd [12]. The use of lime fertilizers or composite additives reduces the content of Pb and Cd in rice sprouts and grains [27]. Additives based on oyster shells and eggshells reduce the concentration of Cd by 63–77% and Pb by 47–75% in corn sprouts. The addition of CaO and MgO reduces the bioavailability of Cd, Cu, and Pb. However, an assessment of long-term stability is necessary for limestone fertilizer [28]. At high dosages (5–10 wt.%), this can negatively affect plant growth due to a decrease in the availability of essential trace elements such as Fe, Mn, Zn, Cu, and B [29] and an increase in the proportion of mobile forms of heavy metals [30]. The addition of fly ash to contaminated soils reduces the bioavailability of Pb in rape seed [31] and rice [32] by forming insoluble hydroxide compounds and increasing soil pH [32]. However, fly ash can itself be a potential source of contamination [33,34] and can pose a risk to soil, water, and plants [35]. Despite the effectiveness of liming and its availability, its effects are only temporary, as soil pH decreases over time. For this reason, it is essential to continuously monitor, as when soil becomes acidic Pb becomes more bioavailable in its gross form.
The presence of ion-exchange groups in compost allows it to effectively bind heavy metals such as Pb, Cu, Cd, and Ni [36]. Animal-derived compost reduces the bioavailability of Pb by forming low-solubility phosphate minerals, thereby improving plant growth and microbial activity [37]. The addition of 10% compost reduces Pb availability by about 92% but increases arsenic mobility.
Commercial compost has been demonstrated to reduce arsenic absorption in clay soils, diminishing its overall positive impact as an additive [38]. Biochar is a popular material that is used as a complex soil additive, improving soil quality and adsorbing heavy metals, including Pb [39,40,41]. It has been shown that the bioavailability of Pb in soil treated with biochar is reduced due to the formation of two specific minerals, chlorpyromorphite (Pb5(PO4)3Cl) and hydroxypyromorphite (Pb5(PO4)3(OH)) [42].
Despite the numerous advantages, biochar tends to “age”, which is manifested in changes in its properties due to external factors [43]. These changes affect the elemental composition, aromatic group, specific surface area, morphology, pH, and ion exchange capacity [44]. The aging of biochar can increase the mobile and water-soluble fraction of Pb in the soil due to acidification, and also the amount of Pb involved in the formation of contaminated colloidal particles which enter the groundwater [44]. The effectiveness of using biochar for immobilizing pollutants depends on several factors: the type of plant, the type of biochar used, the climate, and the soil conditions [3].
Aluminosilicate materials, such as bentonite, have been shown to reduce the mobility of Pb by more than 40% compared to a control experiment [45]. Bentonite has been successfully used to immobilize Cd and Pb in contaminated floodplain soils [31]. Zeolite increases soil pH and reduces concentrations of Cd and Pb in rice grains by 27.9% and 63.5%, respectively [46]. Expanded clay can also be used as a soil additive [47]. The addition of gibbsite or iron crumbs reduces the mobility of Pb in soil [48,49]. The disadvantage of these materials is their low selectivity for Pb. Manganese oxides are more effective at immobilizing Pb than iron oxides [50,51]. However, manganese oxides are sensitive to redox potential, which can change the properties of the additive due to the reduction of Mn(IV) to Mn(II) [52,53].
Apatites, hydroxyapatites, diammonium phosphate, and phosphate-based rocks have been successfully used as additives to immobilize heavy metals, such as Pb. The use of phosphate additives causes the precipitation of pyromorphite, which is a mineral that has poor solubility over a wide pH range and under various redox conditions [54,55]. The use of organic fertilizers with a high phosphorus content, such as poultry waste, can lead to the immobilization of Pb into PbCO3, followed by its transformation into chlorpyromorphite [56]. However, the excessive application of certain types of phosphate fertilizers, such as triple superphosphate and phosphorite, may increase the uptake of Cd by plants due to a reduction in soil pH [57].
Additives based on hydroxyapatite (HAP), a substance that is insoluble and nontoxic, can be used to immobilize Pb in soils [58]. Hydroxyapatite is used for purifying water from pesticides [59], heavy metals [60], and radionuclides [61]. Hydroxyapatite does not exhibit the disadvantages associated with other soil additives and has a high selectivity for Pb. As a result, alkaline and alkaline earth cation have a minimal impact on the efficiency of Pb extraction from water solutions [62,63]. Hydroxyapatite can be used independently or in combination with biochar to enhance selectivity [64,65,66]. However, the characteristics of these complex soil additives are determined by the properties of the biochar, which depend on the type of raw materials, pyrolysis conditions, and other factors [67]. The addition of nanoscale hydroxyapatite into soil reduces the percentage of water soluble Pb by 72% and Cd by 90% [58]. Hydroxyapatite can be used to immobilize Pb and Cd in the long-term, when combined with biochar and bentonite [68]. The combination of HAP, bentonite, and biochar, as a soil additive, has been shown to effectively reduce the uptake of Cd and Pb by edible plant parts [69].
Nanocomposites based on natural polymers (chitosan, alginate, and cellulose) have been developed to reduce lead bioavailability. High efficiency is achieved due to the large specific surface area and presence of additional amino and hydroxyl functional groups. The biodegradable and low-toxicity nature of these polymers reduces their negative impact on the environment [70]. Hybrid systems with fungal hyphae (Aspergillus niger) with n-HFP/n-HFS nanoparticles reduce the water-soluble fraction of lead by 63% and the bioavailable fraction by 60%. Hyphae prevent the aggregation of nanoparticles and transform mobile metal forms into more stable ones. However, this method requires a lengthy equilibrium period of 42 days and is difficult to implement in heterogeneous soils [71]. ANHP biocomposite (hydroxyapatite + biochar) immobilizes lead due to the formation of stable minerals and fungal hyphae fixation. Fungal hyphae also prevent the aggregation of HAP nanoparticles and increase the stability of the composites. The immobilization efficiency of lead is 42.6%, which is higher than that of pure HAP. ANHP biocomposite can be used for high lead concentrations (2548–6120 mg/kg), but its effectiveness depends on the fungal type [72]. Modified biochar (montmorillonite + chitosan) reduces lead mobility by 73% with the addition of 10%. It improves soil porosity but requires an assessment of its long-term impact on ecosystems [73].
Despite great success, the use of nanomaterials is associated with a number of limitations: scaling difficulties, high cost of synthesis, the negative impact of metal nanoparticles on the soil microbiota, and competition with the agricultural sphere (for example, the use of corn for PLA production). Although nanomaterials based on natural polymers for soil lead purification are a promising area, their implementation requires technology optimization and environmental risk assessment [70].
The aim of this study is to investigate the potential of hydroxyapatite in reducing the concentration of bioavailable Pb in the soil of Primorsky Krai. Due to its several advantages, such as high selectivity, stability, and biocompatibility, the use of hydroxyapatite-based additives appears to be the most promising approach for restoring soils in Primorsky Krai contaminated with Pb.

2. Materials and Methods

2.1. Materials and Reagents

The study is devoted to analyzing the effectiveness of hydroxyapatite (HAP) in reducing the bioavailability of lead in contaminated soils of Primorsky Krai, as well as assessing the role of soil composition in the success of remediation measures. In the experimental part, model lead solutions were prepared using lead(II) nitrate(Pb(NO3)2), which was also used to saturate soil samples during the investigation of metal form distribution depending on the soil-to-hydroxyapatite ratio. Control of ionic strength in the model solutions during adsorption experiments was ensured by adding sodium nitrate (NaNO3). To characterize the physicochemical parameters of the soils, including organic carbon and humus content, analyses were conducted using sulfuric acid (H2SO4), sodium pyrophosphate (Na4P2O7), sodium hydroxide (NaOH), and potassium permanganate (KMnO4).
Hydroxyapatite was synthesized via a chemical precipitation method, with ammonium hydrogen phosphate ((NH4)2HPO4) and calcium chloride tetrahydrate (CaCl2 × 4H2O) used as precursors. pH adjustment during synthesis was performed using ammonium hydroxide (NH4OH). All chemical reagents meeting the “chemically pure” qualification were obtained from NevaReaktiv LLC and used without further purification.

2.2. Sampling and Preparation of Soils

Two types of soil were studied in Primorski Krai: Gleyi Cambisols (common in urban recreation areas) and Luvic Anthrosol (predominantly in arable land) [74]. Luvic Anthrosols were selected in May of 2022 at the Primorskaya Vegetable Experimental Station of VNIIO, LLC (Surazhevka, Russia). Gleyi Cambisols were collected in July of 2019 from Cape Vyatlina (Russky Island). Samples were collected using the envelope method (5 points) from the top horizon (0–5 cm) of 2 kg of each type. The size of the envelope was 5 × 5 m. The samples were then dried, cleaned, and crushed, and fractions of 0.25–1.0 mm and 2.0 mm isolated.

2.3. Evaluation of the Main Soil Characteristics

The moisture content of soil samples was determined by repeating the experiment three times with drying to a constant weight [75]. Moisture content (W, wt.%) was calculated using Formula (1):
W = A − B B − C × 100 ,
where A is the weight of the initial soil sample with a vial (g), B is the weight of the dried soil sample with a vial (g), and C is the weight of the vial (g).
The density of the solid phase of soil (ps) was determined using the pycnometric method [76]. An amount of 10 g of soil was placed in a pycnometer, filled with distilled water, and kept for 10–12 h. The suspension was then boiled for 30–60 min, cooled, and brought to the desired mark with water. The weight of the suspension was measured, and the ps value (g/cm3) was calculated using Formula (2).
p s = v s v s + P W 1 − P W 2 × d H 2 O ,
where Vs is the weight of the air-dried soil sample (g), PW1 is the weight of the vial with water (g), PW2 is the weight of the vial with water and soil (g), and dH2O is the density of water at a given temperature (g/cm3).
The granulometric analysis of soil was carried out according to standard methodology [77]. Sampling was conducted taking into account density of solid phase and temperature of water.
The determination of the pH of water (pH(H2O)) and salt extracts at 1 M concentration of KCl (pH(KCl)) was carried out in accordance with GOST 26423-85 [78]. Soil extracts were prepared by mixing 25 mL of water with 10 g of the sample, followed by stirring. After 5 min, the pH value of the resulting aqueous extract was measured. To determine the pH of a salt extract, 1 M of KCl solution was added, and the pH measurement was taken after 24 h.
Organic carbon content (C(org)%) as a percentage of air-dry soil was determined using Formula (3):
C o r g = a − b × n × 0.03 × 100 p ,
where a is the amount of Mohr’s salt used to titrate 10 mL of the chromium mixture in a blank experiment (mL) and b is the amount of molarity of Mohr’s salt used in the titration of excess chromium in the soil experiment (mL). n is the molar concentration of the Mohr’s salt solution, determined by titrating it with a 0.05 N solution of KMnO4 and 0.003 is the weight of 1 milligram equivalent of carbon. p is the weight of the soil sample (g) and 100 represents the factor for converting the analysis results to 100 g of soil.
The group composition of humus was determined using the method of Kononova and Belchikova [79], which involves the extraction of humic and fulvic acids. To 5 g of soil, 100 mL of a mixture of Na4P2O7 (0.1 M) and NaOH (0.1 M) was added, incubated for 12 h in a sealed flask, and then filtered. To determine the total carbon of humic and fulvic acids (C1), an aliquot of the extract was neutralized with 1 M H2SO4, evaporated to dryness, and the carbon content was measured using wet burning methods [80]. C1 was calculated using Formula (3), where p1 represents the sample weight corresponding to the aliquot volume of the original extract (g).
For analyzing the carbon of humic acids (C(hum)), an aliquot of the pyrophosphate extract was neutralized with H2SO4, heated to 80 °C, cooled, and incubated for 12 h. The humic acid gel was separated using a “blue ribbon” filter, dissolved in 0.05 M NaOH, and the carbon content was determined by method [80]. C(hum) was calculated using Formula (3), where p2 denotes the sample weight corresponding to the aliquot volume of the pyrophosphate extract (g).
The carbon content of fulvic acid (C(fulvo)) in alkaline extracts is calculated from the difference between the total carbon content of humic substance and the carbon of humic acid (Formula (4)):
C f u l v o = C 1 − C h u m ,

2.4. Synthesis of Hydroxyapatite

Hydroxyapatite was prepared according to the method described in [81]. A 0.25 M solution of (NH4)2HPO4 was mixed with 0.5 M CaCl2 for 60 min with continuous stirring at room temperature. The molar ratio of Ca/P in the final mixture was 1.67. The pH of the mixture was maintained at pH 12 using concentrated NH4OH. The completed mixture was heated to a boil with continuous stirring and then kept for one day. The precipitate was separated from the solution using filtration, and washed with hot distilled water under vacuum. The material was then dried at 150 °C for six hours and calcined at 400 °C in an air atmosphere.

2.5. Adsorption Experiments

The process of Pb adsorption on HAP and soil samples was carried out under static conditions. Air-dried samples were placed in plastic tubes and 50 mL of the solution was added. After that, the mixture was shaken for a specified period. At the end of the test, the solution was separated from the sample by centrifugation at 4000 rpm. The value of the static exchange capacity (SEC) was calculated using Formula (5).
S E C = C o − C t * V s m H A P ,
where Co is the concentration of Pb in the initial solution (mg/L), Ct is the residual equilibrium concentration of Pb in the solution (mg/L), Vs is the volume of the solution (L), and mHAP is the HAP weight (g).
The adsorption isotherm was obtained by putting HAP or soil samples into contact with a series of solutions with various concentrations of Pb. To control the ionic strength, NaNO3 with a concentration of 0.01 M was added to the model solutions.
The standard Freundlich Equation (6), Langmuir Equation (7), and Sips Equation (8) were used to describe sorption isotherms.
Γ = K f * C e m ,
Γ = G m a x * K l * C e 1 + K l * C e ,
Γ = G m a x * K l f * C e m 1 + K l f * C e m ,
where Gmax is the maximum sorption capacity (mmol/g); Ce is the equilibrium concentration of Pb (mmol/L); and Kf is the Freundlich constant. It characterizes the relative adsorption capacity. It represents the value of the adsorption at an equilibrium concentration of unity and Kl and Klf are the constants of adsorption equilibrium, which characterize binding energy between adsorbent and adsorbate, and m is the index of heterogeneity of exchange centers, which characterizes changes in heat of adsorption, depending on degree of filling.

2.6. Determination of Pb Forms in Soil Samples

To evaluate the ability of HAP to reduce the proportion of mobile and water-soluble forms of Pb, we used an approach based on complete saturation of soil samples. We took into account calculated maximum adsorption values (Equations (7) and (8)). When maximum soil saturation was reached, Pb concentrations exceeded established standards significantly. This simplified and improved the accuracy of analysis by eliminating the need for further sample concentration steps.
The evaluation of the efficacy of HAP for the distribution of Pb concentration in Luvic Anthrosols has been evaluated in the following studies:
“Experiment A”: an assessment of HAP effectiveness when Pb enters soil that has not been contaminated.
“Experiment B”: evaluation of HAP effectiveness in soil already contaminated with Pb.
In “Experiment A”, the ability of HAP to reduce the available forms of lead in uncontaminated soils was studied. Soil samples (5 g, <0.25 mm fraction) were treated with HAP and then incubated with a lead nitrate solution (0.016 M, 50 mL, 7 days). The lead concentration required to fully saturate the soil samples was calculated using previously determined maximum adsorption capacity values (Gmax). After centrifugation, lead forms were analyzed. For Gleyic Cambisols, only this scenario was investigated.
In “Experiment B”, the effect of HAP on already contaminated soils was evaluated. Samples (100 g) were saturated with Pb by incubation with a lead nitrate solution (0.058 M, 250 mL, 7 days), followed by drying. Then, 5 g of contaminated soil was treated with HAP and incubated with 0.01 M NaNO3 (7 days). Lead forms were analyzed similarly.
The proportion of the water-soluble fraction was determined according to RD 52.18.286-91 (water extraction, 60 min) [82], while mobile forms were assessed using RD 52.18.289–2022 with ammonium-acetate buffer (AAB) [83].

2.7. Biological Testing

Biotesting was conducted in accordance with GOST R ISO 18763-2019 [84]. Soil samples were sieved to a 2–3 mm fraction, placed in Petri dishes (50 g each), and seeded with 100 oat (Avena sativa) seeds. The experiment was carried out under natural lighting in 4 series, each with three replicates (Table 1). An experiment without the addition of lead or HAP was used as the control group.
In experiments H(10) and H(20), HAP was mixed with soil mechanically and distributed into Petri dishes in layers of 5–7 mm. All samples (except controls) were treated with lead at a concentration of 1.25 g: 50% on the first day and the rest on days 4–5. The dishes were closed for 48 h to allow germination of seeds, then moistened periodically with distilled water. After 2 weeks, the germination rate was evaluated, as well as biomass, sprout lengths, and lead concentrations in plant tissue.
Lead content in plant tissue was determined using a method described in [85]. Dried plant samples were washed at 525 ± 25 °C, and ash residue was dissolved in 15 mL of HNO3 (1:1), heated in a water bath for 30 min, filtered (“white ribbon” filter), and adjusted to 50 mL final volume. Lead concentration was then measured by atomic absorption spectrometry.
The effects of lead and HAP were quantified by calculating the difference in mean values between control groups (control, H(0)) and experimental groups (H(10) and H(20)). Statistical significance was determined using Student t-test (p < 0.05) and Welch test was used for unequal variances. Due to the non-normal distribution of data (Shapiro–Wilk test, p < 0.001), sprout length was compared using Mann–Whitney U-test (p < 0.05). To minimize variability (likely caused by uneven HAP and lead distribution), replicates under identical conditions were compared. Outliers (p < 0.05) were excluded, and remaining data were pooled.
The phytoeffect size (PhyE) was calculated using Formula (9):
P h y E = L c o n t r − L e f f L c o n t r × 100 ,
Lcontr is the average sprout length (mm) in the control group. When assessing the effect of lead, a control without its addition was used. To assess the effect of lead in the presence of HAP, negative control was used (without HAP, experiment H(0)); Leff is the average sprout length (mm) in the experimental group with the addition of HAP.

2.8. Equipment and Software

The study used: a pH meter “FiveEasy F20” (Mettler Toledo, Greifensee, Switzerland) with a plastic electrode LE438 to measure the acidity of aqueous and salt extracts; atomic absorption spectrometers SOLAAR M6 (Thermo Scientific, Waltham, MA, USA) to determine the concentration of lead (Pb) in solutions, and AA6800 (Shimadzu, Kyoto, Japan) for analysis of Pb in plant tissues; D8 ADVANCE diffractometer (Bruker, Berlin, Germany) for phase analysis in the range of 2θ 3–85° (step 0.02°, exposure time 0.6 s/point). The phase composition was identified using the Qualx 2.0 program [86] based on the Crystallography Open Database (COD, version SQLITE3, May 2022). Statistical data processing, including the Shapiro–Wilk (normality assessment) and Mann–Whitney (sample comparison) criteria, was performed in the GNU PSPP program (GNU PSPP ver. 2.0.1. for Linux, GNU General public licence).

3. Results

Table 2 presents the results of a comprehensive analysis of the characteristics of soil samples that were significant for the study.
The pH values for Luvic Anthrosol and Gleyc Cambisol are markedly different. For Gleysic Cambisol, pH(H2O), and especially pH(KCl), is characterized by an acidic environment, indicating the presence of many protonated functional groups, corresponding to its classification criteria [74].
According to the results, the surface horizon of Gleyic Cambisols contains 46.0% sand and 9.0% clay, which can be classified as “Sandy clay”, according to the Ferre triangle [87]. Luvic Anthrosols contains 23.5% sand and 13.0% fine clay fraction and can be classified as “Clay”.
Table 3 shows the results of a comparative analysis of the group composition of humus, which demonstrates significant differences between the studied soil types.
Figure 1 shows the X-ray diffraction patterns of the original soil samples. The samples are characterized by the presence of quartz as the main mineral component, as well as muscovite aluminosilicate, belonging to the mica group, and albite, belonging to the feldspar group.
Figure 2 shows the isotherms of Pb adsorption by the studied soils. According to Giles, the sorption isotherm can be classified as L-type, indicating a high affinity for Pb under the studied conditions. The adsorption isotherms are well described by the Sips equations (R2 > 0.99).
Figure 3 illustrates the X-ray diffraction patterns of the synthesized hydroxyapatite before and after the adsorption of lead. The X-ray pattern of the initial sample clearly exhibits peaks that correspond to the hydroxyapatite phase, indicating successful synthesis. This approach was subsequently employed to produce additional batches of hydroxyapatite.
Work was carried out to evaluate the adsorption characteristics of HAP in relation to lead. Figure 4 shows adsorption isotherms for lead by HAP in 0.01 M NaNO3 and in ammonium acetate buffer. As can be seen, HAP has a high maximum adsorption capacity and adsorption equilibrium constant in NaNO3 solution.
To study the distribution patterns of lead forms, depending on soil type, experiments were conducted. The results were presented in the form of diagrams showing the distribution of lead under conditions of maximum soil saturation (Figure 5). For Luvic Anthrosols, results from experiments A and B were presented.
Figure 6 shows the results of the distribution of water-soluble and mobile forms of lead depending on the HAP/soil ratio in semi-logarithmic coordinates. The experimental data are fairly well described (R2 > 0.9) by a linear regression equation that can be used to predict the effect of reducing bioavailable lead forms when HAP is added.
Table 4 shows the calculated parameters for the linear equations. B is the logarithm of water-soluble or mobile Pb in soil without HAP. A is the slope of the line that characterizes the increase in efficiency of HAP with increasing content.
The adsorption capacity of HAP to lead during long-term exposure to Luvic Anthrosols was estimated. Figure 7 shows the relationship between the SEC value and the amount of added HAP. The experiment lasted for 14 days.
Laboratory studies were conducted to evaluate the effectiveness of HAP as an additive for reducing lead uptake into plant tissue using oats (Avena sativa) as an example. Table 5 shows the results of the effect of adding lead and HAP on oat growth, formation, and lead accumulation in tissue.
Figure 8 shows the results of statistical analysis of the data obtained during the laboratory experiment to investigate the effect of the application of HAP and dose on the germination, growth, and weight of sprouts, as well as the lead content in oat tissues (Avena Sativa).

4. Discussion

The presence of increased clay content in Luvic Anthrosols (Table 2) is explained by plowing, during which the upper horizon, enriched in organic matter, is mixed with the lower horizon, which is enriched in aluminosilicate minerals. The increase in humus in Gleyic Cambisols (Table 3) is associated with the enrichment of the upper horizons with plant litter due to the small biological cycle. A genetic feature of this type of soil in Primorsky Krai is the high content of fulvic acids in humus. Fulvic acids have active adsorption centers in the form of carboxyl and hydroxyl functional groups [88,89], which explains their low hydrogen index compared to Luvic Anthrosols.
The adsorption isotherms of lead by soils are close to the Sips model, which indicates complete saturation of the monomolecular layer in the concentration range. However, significant heterogeneity of adsorption centers is observed, which is associated with the variety of adsorption-active components (oxides, silicates, aluminosilicates, and high-molecular organic compounds) in the soil. Gleyic Cambisols have a higher maximum capacity (Gmax) than Luvic Anthrosols, which is explained by the increased content of organic substances, in particular fulvic acids. Lee et al. [90] showed that soils with a high content of organic matter adsorb lead better. The main active centers are associated with organic matter, and metal oxides do not play a significant role in lead adsorption by soils [90]. Zhao et al. [91] showed that solid organic matter plays a significant role in lead adsorption through interaction with phenolic and carboxylate functional groups. However, minerals reduce the affinity of lead compared to humic acid [91]. Coutinho et al. [92] showed, using Histosols as an example, that lead has a greater affinity for soil compared to copper. Lead adsorbs non-specifically to fulvic acid, which is enriched in aliphatic structures. Compared with Gleyic Cambisols, Luvic Anthrosols are characterized by a higher adsorption equilibrium constant (K), which may indicate that adsorption occurs on an inorganic part with a higher affinity for Pb compared to organic components. Lead can adsorb on feldspar, which is described in the literature as a material for extracting heavy metals [93,94,95].
The process of lead absorption by HAP involves the dissolution of Ca10(PO4)6(OH)2 and the precipitation of a hydroxypyromorphite with the composition of Ca8.51Pb1.49(PO4)6(OH)2. This is caused by an ion exchange reaction between Ca and Pb ions. The molar ratio of Ca to Pb in the solid phase decreases until a pure HAP structure is reached [96,97]. However, the final product in our experiment was lead phosphate (Figure 3, curve 2). The adsorption equilibrium constant (K) for HAP is 28 and 207 times higher than the values for Gleyic Cambisols and Luvic Anthrosols, respectively (Figure 4a). This suggests that HAP will significantly reduce the bioavailable fractions of Pb by irreversibly binding to form lead phosphate. However, in ammonium acetate buffer, the efficiency of Pb extraction decreases and the experimental values are described by Freundlich’s equation (Figure 4b). This is due to the increase in the ionic strength of the solution and the competing effects of K+ and NH4+ ions. The results indicate that HAP is effective in reducing the fraction of water-soluble lead forms, but less effective for mobile forms.
The diagrams of Pb forms’ distribution in soil samples at maximum saturation (Figure 5) showed some features. For Luvic Anthrosols, the proportion of the water-soluble form is 2.8% and 5.4% for “Experiment A” and “Experiment B”, respectively. For Gleyic Cambisols, the proportion of water-soluble form does not exceed 0.15%, which is consistent with the adsorption isotherm data (Figure 4). To analyze the results in detail, the distribution of water-soluble and mobile forms of Pb depending on the HAP/soil ratio was plotted in semi-logarithmic coordinates (Figure 6) with subsequent linear regression. It was found that, for Luvic Anthrosols, a decrease in the proportion of the water-soluble form of Pb with an increase in the HAP content can reach three orders of magnitude in both experiments. For Gleyic Cambisols, the effect of HAP application on reducing the water-soluble fraction is less pronounced and does not exceed two orders of magnitude. The value of A is more than 1.5 times lower than that of Luvic Anthrosols (Table 4). Thus, Gleyic Cambisols are characterized by a higher degree of Pb binding, which is reflected in a decrease in the content of the water-soluble fraction compared to Luvic Anthrosols. Therefore, the effect of applying HAP to reduce the content of the water-soluble form of Pb will be more pronounced in the case of Luvic Anthrosols and less pronounced in the case of Gleyic Cambisols. In comparison with Luvic Anthrosols, the proportion of the mobile fraction is reduced in Gleyic Cambisols by more than 5%. This indicates their high ability to adsorb Pb. The values for parameter A are similar for both soil types, indicating the presence of sites that can adsorb Pb through ion exchange.
An unexpected result was the decrease in the capacity of HAP for Pb when added to Luvic Anthrosols (Figure 7). The absorption capacity of HAP decreased more than 30 times compared to the calculated maximum capacity (Figure 4). This is probably due to the negative impact of the soil components (iron, manganese, etc.) blocking the adsorption centers of HAP.
The results of the experiment show that adding Pb to irrigation water decreases seed germination and sprout length, as well as biomass (Figure 8). The introduction of Pb has a negative effect on plant growth, decreasing the average length of sprouts by 110 cm with a phytoeffect of −88.3. Preliminary application of HAP to the soil generally has a stimulating effect, affecting plant growth through strong binding of lead and reducing its availability to the root system. By adding HAP to soil and increasing its content, the negative effect of Pb on plant growth decreases. However, only the results of seed germination and sprout length in experiment H(20) are reliable (p > 0.05). When HAP was added at a concentration of 20%, the germination of oat seeds increased by 18.7%, sprout length increased by 7 mm, and the phytoeffect was 131.7 compared to experiment H(0).
There is no statistical significance in estimating the mass of root and above-ground parts of plants. Although the magnitude of effect indicates an increase in biomass when HAP is added (Figure 8b), the addition of lead in irrigation water has a more negative effect on above-ground plant parts (p < 0.01) than on root systems.
The greatest positive effect of the HAP application was observed when assessing the uptake of Pb into plant tissue. So, compared to H(0), the decrease in the Pb content of plant tissue was 66% for H(10) and 83% for H(20) (p < 0.05).

5. Conclusions

The physicochemical properties of Luvic Anthrosols and Gleyic Cambisols, including the content of physical clay, humus and its type, and the adsorption characteristics towards lead, were evaluated. Gleyic Cambisols are characterized by a fulvic humus type and a higher maximum capacity (1.8 times), possibly due to Pb adsorption on fulvic acids. Luvic Anthrosols contain more physical clay and have a higher affinity for lead, which is reflected in a higher value of the adsorption equilibrium constant (7.2 times higher than that of Gleyic Cambisols).
The adsorption properties of the synthesized hydroxyapatite were characterized in a 0.01 M NaNO3 solution, and the maximum adsorption capacity for Pb was 1500 ± 100 mg/g. The Langmuir adsorption equilibrium constant was calculated to be 110 ± 10. When hydroxyapatite was introduced into soil, its capacity decreased by more than a factor of 30, probably due to mineral soil components, such as iron and manganese. The forms of Pb in the studied soil samples were evaluated under conditions of maximum saturation. Gleyic Cambisols have a reduced content of the water-soluble fraction of Pb of more than 20 times. The mass fraction of the mobile fraction of Pb for both samples is comparable.
The introduction of hydroxyapatite into the soil reduces the proportion of the water-soluble fraction of lead; for Luvic Anthrosols, the positive effect can be up to three orders of magnitude. The decrease in mobile Pb does not exceed one order of magnitude when the mass ratio of HAP to soil is 0.2.
The toxic effect of lead at a mass ratio of 0.2 hydroxyapatite to soil is reduced, manifesting in an increase in germination of 18.7% and an increase in sprout length of 7 mm. The proportion of Pb in oat tissue is reduced by 83% and the phytoeffect effect is 131.7 compared to a control sample without HAP.

Author Contributions

Conceptualization, A.E.; methodology, A.E., A.G., S.N. and A.B.; validation, A.E. and S.N.; formal analysis, A.E. and S.N.; investigation, A.E., S.N., A.G., I.P. and D.S.; data curation, A.E.; writing—original draft preparation, A.E.; and writing—review and editing, A.E., O.N. and A.B. All authors have read and agreed to the published version of the manuscript.

Funding

Work on the synthesis of hydroxyapatite, the study of the adsorption properties of hydroxyapatite and soil samples in relation to lead, and the assessment of the distribution of lead forms in soil samples were carried out within the framework of the State Order of the Institute of Chemistry of the Far Eastern Branch of the Russian Academy of Sciences, project No. FWFN (0205)-2025-0002. Work on the assessment of the basic characteristics of soil samples, biotesting using oats, and assessment of lead intake into plant tissues were carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation, project No. FZNS-2025-0004. “Assessment of the sequestration potential of coastal marine ecosystems”.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Acknowledgments

Equipment of CUC “Far Eastern Center of Structural Investigations” was used in this work.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Li, J.-S.; Beiyuan, J.; Tsang, D.C.W.; Wang, L.; Poon, C.S.; Li, X.-D.; Fendorf, S. Arsenic-Containing Soil from Geogenic Source in Hong Kong: Leaching Characteristics and Stabilization/Solidification. Chemosphere 2017, 182, 31–39. [Google Scholar] [CrossRef] [PubMed]
  2. Cui, J.; Zhao, Y.; Li, J.; Beiyuan, J.; Tsang, D.C.W.; Poon, C.; Chan, T.; Wang, W.; Li, X. Speciation, Mobilization, and Bioaccessibility of Arsenic in Geogenic Soil Profile from Hong Kong. Environ. Pollut. 2018, 232, 375–384. [Google Scholar] [CrossRef] [PubMed]
  3. O’Connor, D.; Peng, T.; Zhang, J.; Tsang, D.C.W.; Alessi, D.S.; Shen, Z.; Bolan, N.S.; Hou, D. Biochar Application for the Remediation of Heavy Metal Polluted Land: A Review of in Situ Field Trials. Sci. Total Environ. 2018, 619–620, 815–826. [Google Scholar] [CrossRef]
  4. Hou, D.; Li, F. Complexities Surrounding China’s Soil Action Plan. Land Degrad. Dev. 2017, 28, 2315–2320. [Google Scholar] [CrossRef]
  5. Luo, X.; Yu, S.; Zhu, Y.; Li, X. Trace Metal Contamination in Urban Soils of China. Sci. Total Environ. 2012, 421–422, 17–30. [Google Scholar] [CrossRef]
  6. Davis, H.T.; Marjorie Aelion, C.; McDermott, S.; Lawson, A.B. Identifying Natural and Anthropogenic Sources of Metals in Urban and Rural Soils Using GIS-Based Data, PCA, and Spatial Interpolation. Environ. Pollut. 2009, 157, 2378–2385. [Google Scholar] [CrossRef] [PubMed]
  7. Lee, C.S.; Li, X.; Shi, W.; Cheung, S.C.; Thornton, I. Metal Contamination in Urban, Suburban, and Country Park Soils of Hong Kong: A Study Based on GIS and Multivariate Statistics. Sci. Total Environ. 2006, 356, 45–61. [Google Scholar] [CrossRef]
  8. Yang, Q.; Li, Z.; Lu, X.; Duan, Q.; Huang, L.; Bi, J. A Review of Soil Heavy Metal Pollution from Industrial and Agricultural Regions in China: Pollution and Risk Assessment. Sci. Total Environ. 2018, 642, 690–700. [Google Scholar] [CrossRef] [PubMed]
  9. Shaheen, S.M.; Tsadilas, C.D.; Rinklebe, J. Immobilization of Soil Copper Using Organic and Inorganic Amendments. J. Plant Nutr. Soil Sci. 2015, 178, 112–117. [Google Scholar] [CrossRef]
  10. Nicholson, F.A.; Smith, S.R.; Alloway, B.J.; Carlton-Smith, C.; Chambers, B.J. An Inventory of Heavy Metals Inputs to Agricultural Soils in England and Wales. Sci. Total Environ. 2003, 311, 205–219. [Google Scholar] [CrossRef]
  11. Luo, W.; Lu, Y.; Giesy, J.P.; Wang, T.; Shi, Y.; Wang, G.; Xing, Y. Effects of Land Use on Concentrations of Metals in Surface Soils and Ecological Risk around Guanting Reservoir, China. Environ. Geochem. Health 2007, 29, 459–471. [Google Scholar] [CrossRef] [PubMed]
  12. Shakoor, M.B.; Ali, S.; Farid, M.; Farooq, M.A.; Tauqeer, H.M.; Iftikhar, U.; Hannan, F.; Bharwana, S.A. Heavy Metal Pollution, a Global Problem and Its Remediation by Chemically Enhanced Phytoremediation: A Review. J. Biodivers. Environ. Sci. 2013, 3, 12–20. [Google Scholar]
  13. Vodyanitskiy, Y.N. Modern trends in soil pollution by heavy metals. Agrochemistry 2013, 88–96. Available online: https://www.elibrary.ru/item.asp?id=20250698 (accessed on 14 February 2025). (In Russian).
  14. Rastanina, N.K. Negative Environmental Impact Of Man–Made Facilities of a Closed Tin Ore Enterprise in Primorsky Krai on the Example of Khrustalnensky Gok. Eur. Sci. Forum Collect. Artic. III Int. Sci. Pract. Conf. Petrozavodsk 2020, 205–208. Available online: https://www.elibrary.ru/item.asp?id=42593195 (accessed on 14 February 2025). (In Russian).
  15. Khanchuk, A.I.; Krupskaya, L.T.; Zvereva, V.P. Ecological Problems of Development of Tin Ore Resources in Primorie and Priamurie. Geogr. Nat. Resour. 2012, 33, 45–49. [Google Scholar] [CrossRef]
  16. Yakunina, G.A.; Salomatova, L.P.; Kostenko, M.Y.; Shiyanova, E.A.; Kravtsova, V.M. Hygienic assessment of the soil condition in the territories of the Dalnegorsk urban district and the Terneysky municipal district. Health Med. Ecol. Nauka 2015, 62, 100–105. (In Russian) [Google Scholar]
  17. Krupskaya, L.T.; Zvereva, V.P.; Volobueva, N.G. Providing Stable Development of Technogenic Systems Formed during Mineral Exploration in the Far Eastern Federal District. Appl. Mech. Mater. 2014, 644–650, 5379–5382. [Google Scholar] [CrossRef]
  18. Krupskaya, L.T.; Zvereva, V.P.; Kirienko, O.A.; Imranova, E.L.; Volobueva, N.G. Using an Comprehensive Method for Evaluation of Environment State in a Zone of Influence of a Tailing Dam. Russ. J. Gen. Chem. 2016, 86, 3012–3014. [Google Scholar] [CrossRef]
  19. Huang, Y.; Wang, L.; Wang, W.; Li, T.; He, Z.; Yang, X. Current Status of Agricultural Soil Pollution by Heavy Metals in China: A Meta-Analysis. Sci. Total Environ. 2019, 651, 3034–3042. [Google Scholar] [CrossRef]
  20. Arefieva, O.D.; Tregubova, V.G.; Gruschakova, N.V.; Starozhilov, V.T. Properties of Soils of Abandoned Coal Mine Industrial Areas (Primorsky Krai, Russia). J. Geosci. Environ. Prot. 2018, 6, 78. [Google Scholar] [CrossRef]
  21. Lopatina, A.A. Influence of Lead and Cadmium on Soybean Yield and Quality; Bulletin of the Krasnoyarsk State Agrarian University: Krasnoyarsk, Russia, 2017; pp. 160–166. (In Russian) [Google Scholar]
  22. Zharikova, E.A. Heavy metals in urban soils: Assessment of content and environmental risk // Proceedings of Tomsk Polytechnic University. Georesour. Eng. 2021, 332, 164–173. (In Russian) [Google Scholar]
  23. Soboleva, E.; Kovekovdova, L. Lead in soils and plants of the city of Ussurisk and the Ussurisky District. Res. Russ. 2003, 6, 2188–2195. (In Russian) [Google Scholar]
  24. Gao, C.; Lin, Q.; Bao, K.; Zhao, H.; Zhang, Z.; Xing, W.; Lu, X.; Wang, G. Historical Variation and Recent Ecological Risk of Heavy Metals in Wetland Sediments along Wusuli River, Northeast China. Environ. Earth Sci. 2014, 72, 4345–4355. [Google Scholar] [CrossRef]
  25. Shulkin, V.; Bogdanova, N. Concentration of Metals in the Rivers of the South Part of Primorski Krai, Russia. In Proceedings of the Climate Variability and Human Activities in Relation to Notheast Asia and Their Land-Ocean Interactions and Their Implications for Coastal Zone Management, Nanjing, China, 4–8 December 2004; pp. 28–36. [Google Scholar]
  26. Government of Primorsky Krai. Reports on The Environmental Situation in the Region. Available online: https://primorsky.ru/upload/Экoлoгический%20дoклад%20за%202022%20-публикация.pdf (accessed on 14 February 2025).
  27. Hamid, Y.; Tang, L.; Hussain, B.; Usman, M.; Gurajala, H.K.; Rashid, M.S.; He, Z.; Yang, X. Efficiency of Lime, Biochar, Fe Containing Biochar and Composite Amendments for Cd and Pb Immobilization in a Co-Contaminated Alluvial Soil. Environ. Pollut. 2020, 257, 113609. [Google Scholar] [CrossRef]
  28. Lim, J.E.; Ahmad, M.; Lee, S.S.; Shope, C.L.; Hashimoto, Y.; Kim, K.-R.; Usman, A.R.A.; Yang, J.E.; Ok, Y.S. Effects of Lime-Based Waste Materials on Immobilization and Phytoavailability of Cadmium and Lead in Contaminated Soil. CLEAN-Soil Air Water 2013, 41, 1235–1241. [Google Scholar] [CrossRef]
  29. Holland, J.E.; Bennett, A.E.; Newton, A.C.; White, P.J.; McKenzie, B.M.; George, T.S.; Pakeman, R.J.; Bailey, J.S.; Fornara, D.A.; Hayes, R.C. Liming Impacts on Soils, Crops and Biodiversity in the UK: A Review. Sci. Total Environ. 2018, 610–611, 316–332. [Google Scholar] [CrossRef]
  30. Mahar, A.; Wang, P.; Ali, A.; Guo, Z.; Awasthi, M.K.; Lahori, A.H.; Wang, Q.; Shen, F.; Li, R.; Zhang, Z. Impact of CaO, Fly Ash, Sulfur and Na2S on the (Im)Mobilization and Phytoavailability of Cd, Cu and Pb in Contaminated Soil. Ecotoxicol. Environ. Saf. 2016, 134, 116–123. [Google Scholar] [CrossRef] [PubMed]
  31. Shaheen, S.M.; Rinklebe, J. Impact of Emerging and Low Cost Alternative Amendments on the (Im)Mobilization and Phytoavailability of Cd and Pb in a Contaminated Floodplain Soil. Ecol. Eng. 2015, 74, 319–326. [Google Scholar] [CrossRef]
  32. Gu, H.-H.; Qiu, H.; Tian, T.; Zhan, S.-S.; Deng, T.-H.-B.; Chaney, R.L.; Wang, S.-Z.; Tang, Y.-T.; Morel, J.-L.; Qiu, R.-L. Mitigation Effects of Silicon Rich Amendments on Heavy Metal Accumulation in Rice (Oryza Sativa L.) Planted on Multi-Metal Contaminated Acidic Soil. Chemosphere 2011, 83, 1234–1240. [Google Scholar] [CrossRef]
  33. Ma, W.; Tai, L.; Qiao, Z.; Zhong, L.; Wang, Z.; Fu, K.; Chen, G. Contamination Source Apportionment and Health Risk Assessment of Heavy Metals in Soil around Municipal Solid Waste Incinerator: A Case Study in North China. Sci. Total Environ. 2018, 631–632, 348–357. [Google Scholar] [CrossRef]
  34. Shaheen, S.M.; Rinklebe, J.; Selim, M.H. Impact of Various Amendments on Immobilization and Phytoavailability of Nickel and Zinc in a Contaminated Floodplain Soil. Int. J. Environ. Sci. Technol. 2015, 12, 2765–2776. [Google Scholar] [CrossRef]
  35. Ram, L.C.; Masto, R.E. Fly Ash for Soil Amelioration: A Review on the Influence of Ash Blending with Inorganic and Organic Amendments. Earth-Sci. Rev. 2014, 128, 52–74. [Google Scholar] [CrossRef]
  36. Milojković, J.; Pezo, L.; Stojanović, M.; Mihajlović, M.; Lopičić, Z.; Petrović, J.; Stanojević, M.; Kragović, M. Selected Heavy Metal Biosorption by Compost of Myriophyllum Spicatum—A Chemometric Approach. Ecol. Eng. 2016, 93, 112–119. [Google Scholar] [CrossRef]
  37. Katoh, M.; Kitahara, W.; Yagi, R.; Sato, T. Suitable Chemical Properties of Animal Manure Compost to Facilitate Pb Immobilization in Soil. Soil Sediment Contam. Int. J. 2014, 23, 523–539. [Google Scholar] [CrossRef]
  38. Mehmood, T.; Bibi, I.; Shahid, M.; Niazi, N.K.; Murtaza, B.; Wang, H.; Ok, Y.S.; Sarkar, B.; Javed, M.T.; Murtaza, G. Effect of Compost Addition on Arsenic Uptake, Morphological and Physiological Attributes of Maize Plants Grown in Contrasting Soils. J. Geochem. Explor. 2017, 178, 83–91. [Google Scholar] [CrossRef]
  39. Ahmad, M.; Ok, Y.S.; Kim, B.-Y.; Ahn, J.-H.; Lee, Y.H.; Zhang, M.; Moon, D.H.; Al-Wabel, M.I.; Lee, S.S. Impact of Soybean Stover- and Pine Needle-Derived Biochars on Pb and As Mobility, Microbial Community, and Carbon Stability in a Contaminated Agricultural Soil. J. Environ. Manag. 2016, 166, 131–139. [Google Scholar] [CrossRef]
  40. Ahmad, M.; Ok, Y.S.; Rajapaksha, A.U.; Lim, J.E.; Kim, B.-Y.; Ahn, J.-H.; Lee, Y.H.; Al-Wabel, M.I.; Lee, S.-E.; Lee, S.S. Lead and Copper Immobilization in a Shooting Range Soil Using Soybean Stover- and Pine Needle-Derived Biochars: Chemical, Microbial and Spectroscopic Assessments. J. Hazard. Mater. 2016, 301, 179–186. [Google Scholar] [CrossRef]
  41. Moon, D.H.; Park, J.-W.; Chang, Y.-Y.; Ok, Y.S.; Lee, S.S.; Ahmad, M.; Koutsospyros, A.; Park, J.-H.; Baek, K. Immobilization of Lead in Contaminated Firing Range Soil Using Biochar. Environ. Sci. Pollut. Res. 2013, 20, 8464–8471. [Google Scholar] [CrossRef]
  42. Herath, I.; Iqbal, M.C.M.; Al-Wabel, M.I.; Abduljabbar, A.; Ahmad, M.; Usman, A.R.A.; Sik Ok, Y.; Vithanage, M. Bioenergy-Derived Waste Biochar for Reducing Mobility, Bioavailability, and Phytotoxicity of Chromium in Anthropized Tannery Soil. J. Soils Sediments 2017, 17, 731–740. [Google Scholar] [CrossRef]
  43. Liu, Y.; Chen, J. Effect of Ageing on Biochar Properties and Pollutant Management. Chemosphere 2022, 292, 133427. [Google Scholar] [CrossRef]
  44. Wang, L.; O’Connor, D.; Rinklebe, J.; Ok, Y.S.; Tsang, D.C.W.; Shen, Z.; Hou, D. Biochar Aging: Mechanisms, Physicochemical Changes, Assessment, And Implications for Field Applications. Environ. Sci. Technol. 2020, 54, 14797–14814. [Google Scholar] [CrossRef] [PubMed]
  45. Usman, A.R.A.; Kuzyakov, Y.; Lorenz, K.; Stahr, K. Remediation of a Soil Contaminated with Heavy Metals by Immobilizing Compounds. J. Plant Nutr. Soil Sci. 2006, 169, 205–212. [Google Scholar] [CrossRef]
  46. Zhao, H.; Huang, X.; Liu, F.; Hu, X.; Zhao, X.; Wang, L.; Gao, P.; Li, X.; Ji, P. Potential of Using a New Aluminosilicate Amendment for the Remediation of Paddy Soil Co-Contaminated with Cd and Pb. Environ. Pollut. 2021, 269, 116198. [Google Scholar] [CrossRef] [PubMed]
  47. Li, C.; Song, B.; Chen, Z.; Liu, Z.; Yu, L.; Zhi, Z.; Zhao, Y.; Wei, H.; Song, M. Immobilization of Heavy Metals in Ceramsite Prepared Using Contaminated Soils: Effectiveness and Potential Mechanisms. Chemosphere 2023, 310, 136846. [Google Scholar] [CrossRef]
  48. Houben, D.; Pircar, J.; Sonnet, P. Heavy Metal Immobilization by Cost-Effective Amendments in a Contaminated Soil: Effects on Metal Leaching and Phytoavailability. J. Geochem. Explor. 2012, 123, 87–94. [Google Scholar] [CrossRef]
  49. Rajapaksha, A.U.; Ahmad, M.; Vithanage, M.; Kim, K.-R.; Chang, J.Y.; Lee, S.S.; Ok, Y.S. The Role of Biochar, Natural Iron Oxides, and Nanomaterials as Soil Amendments for Immobilizing Metals in Shooting Range Soil. Environ. Geochem. Health 2015, 37, 931–942. [Google Scholar] [CrossRef]
  50. Feng, X.H.; Zhai, L.M.; Tan, W.F.; Liu, F.; He, J.Z. Adsorption and Redox Reactions of Heavy Metals on Synthesized Mn Oxide Minerals. Environ. Pollut. 2007, 147, 366–373. [Google Scholar] [CrossRef]
  51. Dong, D.; Nelson, Y.M.; Lion, L.W.; Shuler, M.L.; Ghiorse, W.C. Adsorption of Pb and Cd onto Metal Oxides and Organic Material in Natural Surface Coatings as Determined by Selective Extractions: New Evidence for the Importance of Mn and Fe Oxides. Water Res. 2000, 34, 427–436. [Google Scholar] [CrossRef]
  52. Tournassat, C.; Charlet, L.; Bosbach, D.; Manceau, A. Arsenic(III) Oxidation by Birnessite and Precipitation of Manganese(II) Arsenate. Environ. Sci. Technol. 2002, 36, 493–500. [Google Scholar] [CrossRef]
  53. Tang, Y.; Webb, S.M.; Estes, E.R.; Hansel, C.M. Chromium(III) Oxidation by Biogenic Manganese Oxides with Varying Structural Ripening. Environ. Sci. Process. Impacts 2014, 16, 2127–2136. [Google Scholar] [CrossRef]
  54. Cao, X.; Ma, L.Q.; Chen, M.; Singh, S.P.; Harris, W.G. Impacts of Phosphate Amendments on Lead Biogeochemistry at a Contaminated Site. Environ. Sci. Technol 2002, 36, 5296–5304. [Google Scholar] [CrossRef] [PubMed]
  55. Kumpiene, J.; Lagerkvist, A.; Maurice, C. Stabilization of As, Cr, Cu, Pb and Zn in Soil Using Amendments—A Review. Waste Manag. 2008, 28, 215–225. [Google Scholar] [CrossRef] [PubMed]
  56. Hashimoto, Y.; Matsufuru, H.; Takaoka, M.; Tanida, H.; Sato, T. Impacts of Chemical Amendment and Plant Growth on Lead Speciation and Enzyme Activities in a Shooting Range Soil: An X-Ray Absorption Fine Structure Investigation. J. Environ. Qual. 2009, 38, 1420–1428. [Google Scholar] [CrossRef]
  57. Shaheen, S.M.; Shams, M.S.; Khalifa, M.R.; El-Dali, M.A.; Rinklebe, J. Various Soil Amendments and Environmental Wastes Affect the (Im)Mobilization and Phytoavailability of Potentially Toxic Elements in a Sewage Effluent Irrigated Sandy Soil. Ecotoxicol. Environ. Safety 2017, 142, 375–387. [Google Scholar] [CrossRef] [PubMed]
  58. He, M.; Shi, H.; Zhao, X.; Yu, Y.; Qu, B. Immobilization of Pb and Cd in Contaminated Soil Using Nano-Crystallite Hydroxyapatite. Procedia Environ. Sci. 2013, 18, 657–665. [Google Scholar] [CrossRef]
  59. Sghaier, R.B.; Labidi, A.; Abdallah, M.A.; Latrous, L.; Megriche, A. Green Magnetic Snail Shell Hydroxyapatite Sorbent for Reliable Solid-Phase Extraction of Pesticides from Water Samples. J. Sep. Sci. 2023, 46, 2300290. [Google Scholar] [CrossRef] [PubMed]
  60. Alali, A.F.; Almojil, S.F.; Almohana, A.I.; Anqi, A.E.; Rajhi, A.A.; Alamri, S.; Dhahad, H.A. Hydroxyapatite@Mn–Fe Composite as a Reusable Sorbent for Removal of Nile Blue Dye and Cr(VI) from Polluted Water. Environ. Sci. Pollut. Res. 2023, 30, 18419–18437. [Google Scholar] [CrossRef]
  61. Rosskopfová, O.; Viglašová, E.; Galamboš, M.; Daňo, M.; Tóthová, D. The Removal of Pertechnetate from Aqueous Solution by Synthetic Hydroxyapatite: The Role of Reduction Reagents and Organic Ligands. Int. J. Environ. Res. Public Health 2023, 20, 3227. [Google Scholar] [CrossRef]
  62. Dong, L.; Zhu, Z.; Qiu, Y.; Zhao, J. Removal of Lead from Aqueous Solution by Hydroxyapatite/Magnetite Composite Adsorbent. Chem. Eng. J. 2010, 165, 827–834. [Google Scholar] [CrossRef]
  63. Long, Y.; Jiang, J.; Hu, J.; Hu, X.; Yang, Q.; Zhou, S. Removal of Pb(Ⅱ) from Aqueous Solution by Hydroxyapatite/Carbon Composite: Preparation and Adsorption Behavior. Colloids Surf. A Physicochem. Eng. Asp. 2019, 577, 471–479. [Google Scholar] [CrossRef]
  64. Zuo, W.; Song, B.; Shi, Y.; Zupanic, A.; Guo, S.; Huang, H.; Jiang, L.; Yu, Y. Using Bacillus Thuringiensis HM-311@hydroxyapatite@biochar Beads to Remediate Pb and Cd Contaminated Farmland Soil. Chemosphere 2022, 307, 135797. [Google Scholar] [CrossRef]
  65. Ahmed, W.; Xu, T.; Mahmood, M.; Núñez-Delgado, A.; Ali, S.; Shakoor, A.; Qaswar, M.; Zhao, H.; Liu, W.; Li, W.; et al. Nano-Hydroxyapatite Modified Biochar: Insights into the Dynamic Adsorption and Performance of Lead (II) Removal from Aqueous Solution. Environ. Res. 2022, 214, 113827. [Google Scholar] [CrossRef] [PubMed]
  66. Xiao, J.; Hu, R.; Chen, G. Micro-Nano-Engineered Nitrogenous Bone Biochar Developed with a Ball-Milling Technique for High-Efficiency Removal of Aquatic Cd(II), Cu(II) and Pb(II). J. Hazard. Mater. 2020, 387, 121980. [Google Scholar] [CrossRef]
  67. Gupta, S.; Sireesha, S.; Sreedhar, I.; Patel, C.M.; Anitha, K.L. Latest Trends in Heavy Metal Removal from Wastewater by Biochar Based Sorbents. J. Water Process Eng. 2020, 38, 101561. [Google Scholar] [CrossRef]
  68. Zhang, D.; Ding, A.; Li, T.; Wu, X.; Liu, Y.; Naidu, R. Immobilization of Cd and Pb in a Contaminated Acidic Soil Amended with Hydroxyapatite, Bentonite, and Biochar. J. Soils Sediments 2021, 21, 2262–2272. [Google Scholar] [CrossRef]
  69. Zhang, D.; Li, T.; Ding, A.; Wu, X. Effects of an Additive (Hydroxyapatite–Bentonite–Biochar) on Cd and Pb Stabilization and Microbial Community Composition in Contaminated Vegetable Soil. RSC Adv. 2021, 11, 12200–12208. [Google Scholar] [CrossRef]
  70. Matei, E.; Predescu, A.M.; Râpă, M.; Țurcanu, A.A.; Mateș, I.; Constantin, N.; Predescu, C. Natural Polymers and Their Nanocomposites Used for Environmental Applications. Nanomaterials 2022, 12, 1707. [Google Scholar] [CrossRef]
  71. Liao, Q.; He, L.; Tu, G.; Yang, Z.; Yang, W.; Tang, J.; Cao, W.; Wang, H. Simultaneous Immobilization of Pb, Cd and As in Soil by Hybrid Iron-, Sulfate- and Phosphate-Based Bio-Nanocomposite: Effectiveness, Long-Term Stability and Bioavailablity/Bioaccessibility Evaluation. Chemosphere 2021, 266, 128960. [Google Scholar] [CrossRef] [PubMed]
  72. Yang, Z.; Liang, L.; Yang, W.; Shi, W.; Tong, Y.; Chai, L.; Gao, S.; Liao, Q. Simultaneous Immobilization of Cadmium and Lead in Contaminated Soils by Hybrid Bio-Nanocomposites of Fungal Hyphae and Nano-Hydroxyapatites. Environ. Sci. Pollut. Res. 2018, 25, 11970–11980. [Google Scholar] [CrossRef]
  73. Arabyarmohammadi, H.; Darban, A.K.; van der Zee, S.E.A.T.M.; Abdollahy, M.; Ayati, B. Fractionation and Leaching of Heavy Metals in Soils Amended with a New Biochar Nanocomposite. Environ. Sci. Pollut. Res. 2018, 25, 6826–6837. [Google Scholar] [CrossRef]
  74. Soil Maps and Databases|FAO SOILS PORTAL|Food and Agriculture Organization of the United Nations. Available online: https://www.fao.org/soils-portal/data-hub/soil-maps-and-databases/en/ (accessed on 14 February 2025).
  75. Interstate Standard (GOST) 5180-2015. Soils. Laboratory Methods for Determination of Physical Characteristics. Interstate Counc. Stand. Metrol. Certif. (ISC). 2015. Available online: https://docs.cntd.ru/document/1200126371 (accessed on 14 February 2025). (In Russian).
  76. Interstate standard (GOST) 25100-2011. Soils. Classification. Interstate Counc. Stand. Metrol. Certif. (ISC). 2013. Available online: https://docs.cntd.ru/document/1200095052 (accessed on 14 February 2025). (In Russian).
  77. Burt, R.; United States, National Soil Survey Center (U.S.); National Soil Survey Laboratory (U.S.). Soil Survey Investigations Report No. 42, Version 4.0. In Soil Survey Laboratory Methods Manual; Natural Resources Conservation Service: Washington, DC, USA, 2004. Available online: https://www.nrcs.usda.gov/sites/default/files/2023-01/SSIR42.pdf (accessed on 14 February 2025). (In Russian)
  78. Interstate Standard (GOST) 26423-85. Soils. Methods for Determination of Specific Electric Conductivity, pH and Solid Residue of Water Extract. Interstate Counc. Stand. Metrol. Certif. (ISC). 1985. Available online: https://docs.cntd.ru/document/1200023484 (accessed on 14 February 2025). (In Russian).
  79. Bakina, L.G.; Orlova, N.E. Special features of humus acids extraction from soils by sodium pyrophosphate solutions of different alkalinity. Eurasian Soil Sci. 2012, 45, 392–398. [Google Scholar] [CrossRef]
  80. Walkley, A. An Examination of Methods for Determining Organic Carbon and Nitrogen in Soils. J. Agric. Sci. 1935, 25, 598–609. [Google Scholar] [CrossRef]
  81. Vysotskaja, E.V.; Tarasevich, Y.I.; Klimova, G.M.; Kuzmenko, L.N. Synthesis of Hydroxyapatite and Use for Removal of Heavy Metals from Aqueous Solutions. J. Chem. Technol. Water 2002, 24, 535–546. [Google Scholar]
  82. Guidance Document RD 52.18.286-91. Methodological Guidelines. The Method of Measuring the Mass Fraction of Water-Soluble Forms Of Metals (Copper, Lead, Zinc, Nickel, Cadmium, Cobalt, Chromium, Manganese) in Soil Samples by Atomic Absorption Analysis. USSR State Committee for Hydrometeorology. 1991. Available online: https://docs.cntd.ru/document/1200048597 (accessed on 14 February 2025). (In Russian).
  83. Guidance Document RD 52.18.289–2022. Mass Fraction of Mobile Forms of Metals in Soil and Soil Samples. Measurement Procedure by Atomic Absorption Spectrometry. Ministry of Natural Resources and Ecology of the Russian Federation Federal. Federal Service for Hydrometeorology and Environmental Monitoring 2023. Available online: http://mgmtmo.ru/edumat/rd/52.18.289_2022.pdf (accessed on 14 February 2025). (In Russian).
  84. National Standard of The Russian Federation GOST R ISO 18763-2019. Soil Quality. Determination of the Toxic Effects of Pollutants on Germination and Early Growth of Higher Plants. Fed. Agency Tech. Regul. Metrol. Russ. Fed. 2019. Available online: https://docs.cntd.ru/document/1200166928 (accessed on 14 February 2025). (In Russian).
  85. Guidelines for the Determination of Heavy Metals In Farmland Soils And Crop Production (2nd Edition, Revised and Supplemented). Minist. Agric. Russ. Fed. Cent. Inst. Agric. Agrochem. Serv. 1992. Available online: https://docs.cntd.ru/document/1200078918 (accessed on 14 February 2025). (In Russian).
  86. Altomare, A.; Corriero, N.; Cuocci, C.; Falcicchio, A.; Moliterni, A.; Rizzi, R. QUALX2.0: A Qualitative Phase Analysis Software Using the Freely Available Database POW_COD. J. Appl. Cryst. 2015, 48, 598–603. [Google Scholar] [CrossRef]
  87. Shein, E.V.; Zaidelman, F.R.; Karpachevsky, L.O.; Berezin, P.N.; Smagin, A.V.; Zubkova, T.A.; Guber, A.K.; Manucharov, A.S.; Chernomorchenko, N.I.; Sidorova, M.A. Theories and Methods of Soil Physics; “Grif i K”: Moscow, Russia, 2007; ISBN 978-5-8125-0921-7. (In Russian) [Google Scholar]
  88. Islam, M.A.; Morton, D.W.; Johnson, B.B.; Angove, M.J. Adsorption of Humic and Fulvic Acids onto a Range of Adsorbents in Aqueous Systems, and Their Effect on the Adsorption of Other Species: A Review. Sep. Purif. Technol. 2020, 247, 116949. [Google Scholar] [CrossRef]
  89. Ritchie, J.D.; Perdue, E.M. Proton-Binding Study of Standard and Reference Fulvic Acids, Humic Acids, and Natural Organic Matter. Geochim. Cosmochim. Acta 2003, 67, 85–96. [Google Scholar] [CrossRef]
  90. Lee, S.-Z.; Chang, L.; Yang, H.-H.; Chen, C.-M.; Liu, M.-C. Adsorption Characteristics of Lead onto Soils. J. Hazard. Mater. 1998, 63, 37–49. [Google Scholar] [CrossRef]
  91. Zhao, Q.; Qiu, Y.; Lan, T.; Li, J.; Li, B.; Wu, Z.; Chen, L.; Liu, R.; Zhou, Y.; Wu, W. Comparison of Lead Adsorption Characteristics onto Soil-Derived Particulate Organic Matter versus Humic Acid. J Soils Sediments 2021, 21, 2589–2603. [Google Scholar] [CrossRef]
  92. Coutinho, I.B.; Barros de Souza, C.d.; Lima, E.S.A.; García, A.C.; Pereira, M.G.; Valladares, G.S.; Do Amaral Sobrinho, N.M.B. Roles of Soil Organic Matter and Humic Substance Structure in Cu and Pb Adsorption in Histosols. Soil Sediment Contam. Int. J. 2021, 30, 148–162. [Google Scholar] [CrossRef]
  93. Chardon, E.S.; Bosbach, D.; Bryan, N.D.; Lyon, I.C.; Marquardt, C.; Römer, J.; Schild, D.; Vaughan, D.J.; Wincott, P.L.; Wogelius, R.A.; et al. Reactions of the Feldspar Surface with Metal Ions: Sorption of Pb(II), U(VI) and Np(V), and Surface Analytical Studies of Reaction with Pb(II) and U(VI). Geochim. Cosmochim. Acta 2008, 72, 288–297. [Google Scholar] [CrossRef]
  94. Olu-Owolabi, B.I.; Diagboya, P.N.; Unuabonah, E.I.; Alabi, A.H.; Düring, R.-A.; Adebowale, K.O. Fractal-like Concepts for Evaluation of Toxic Metals Adsorption Efficiency of Feldspar-Biomass Composites. J. Clean. Prod. 2018, 171, 884–891. [Google Scholar] [CrossRef]
  95. Farquhar, M.L.; Vaughan, D.J.; Hughes, C.R.; Charnock, J.M.; England, K.E.R. Experimental Studies of the Interaction of Aqueous Metal Cations with Mineral Substrates: Lead, Cadmium, and Copper with Perthitic Feldspar, Muscovite, and Biotite. Geochim. Cosmochim. Acta 1997, 61, 3051–3064. [Google Scholar] [CrossRef]
  96. Bailliez, S.; Nzihou, A.; Bèche, E.; Flamant, G. Removal of Lead (Pb) by Hydroxyapatite Sorbent. Process Saf. Environ. Prot. 2004, 82, 175–180. [Google Scholar] [CrossRef]
  97. Mavropoulos, E.; Rossi, A.M.; Costa, A.M.; Perez, C.A.C.; Moreira, J.C.; Saldanha, M. Studies on the Mechanisms of Lead Immobilization by Hydroxyapatite. Environ. Sci. Technol. 2002, 36, 1625–1629. [Google Scholar] [CrossRef]
Sustainability 17 02369 g001
Figure 1. X-ray diffraction patterns of soil samples: (a) Luvic Anthrosols and (b) Gleyic Cambisols.
Figure 1. X-ray diffraction patterns of soil samples: (a) Luvic Anthrosols and (b) Gleyic Cambisols.
Sustainability 17 02369 g001
Sustainability 17 02369 g002
Figure 2. Isotherms of Pb adsorption: (a) Gleyic Cambisols and (b) Luvic Anthrosols.
Figure 2. Isotherms of Pb adsorption: (a) Gleyic Cambisols and (b) Luvic Anthrosols.
Sustainability 17 02369 g002
Sustainability 17 02369 g003
Figure 3. X-rays patterns of HAP: 1—original sample and 2—lead-saturated.
Figure 3. X-rays patterns of HAP: 1—original sample and 2—lead-saturated.
Sustainability 17 02369 g003
Sustainability 17 02369 g004
Figure 4. Isotherms of lead adsorption on HAP: (a) 0.01 M NaNO3 solution and (b) ammonium acetate buffer.
Figure 4. Isotherms of lead adsorption on HAP: (a) 0.01 M NaNO3 solution and (b) ammonium acetate buffer.
Sustainability 17 02369 g004
Sustainability 17 02369 g005
Figure 5. Diagrams of the distribution of lead forms in soils: (a) Luvic Anthrosols, “experiment A”; (b) Luvic Anthrosols, “experiment B”; and (c) Gleyic Cambisols.
Figure 5. Diagrams of the distribution of lead forms in soils: (a) Luvic Anthrosols, “experiment A”; (b) Luvic Anthrosols, “experiment B”; and (c) Gleyic Cambisols.
Sustainability 17 02369 g005
Sustainability 17 02369 g006
Figure 6. Dependence of the proportion of the lead fraction on the HAP/soil mass ratio: (a) Luvic Anthrosols, “Experiment A”; (b) Luvic Anthrosols, “Experiment B”; and (c) Gleyic Cambisols.
Figure 6. Dependence of the proportion of the lead fraction on the HAP/soil mass ratio: (a) Luvic Anthrosols, “Experiment A”; (b) Luvic Anthrosols, “Experiment B”; and (c) Gleyic Cambisols.
Sustainability 17 02369 g006
Sustainability 17 02369 g007
Figure 7. Effect of HAP content in soil on SEC value.
Figure 7. Effect of HAP content in soil on SEC value.
Sustainability 17 02369 g007
Sustainability 17 02369 g008
Figure 8. Effects of lead and HAP on: (a) germination; (b) the length of the sprouts; (c) the mass of sprouts (1) and roots (2); (d) the lead content in oat tissue; asterisks indicate statistically significant differences from the control level at * p < 0.05; and vertical shading is the Student’s test, oblique shading is the Mann–Whitney test, and solid shading is the Welch test.
Figure 8. Effects of lead and HAP on: (a) germination; (b) the length of the sprouts; (c) the mass of sprouts (1) and roots (2); (d) the lead content in oat tissue; asterisks indicate statistically significant differences from the control level at * p < 0.05; and vertical shading is the Student’s test, oblique shading is the Mann–Whitney test, and solid shading is the Welch test.
Sustainability 17 02369 g008
Table 1. Experimental legend.
Table 1. Experimental legend.
LegendAddition of PbHAP/Soil Mass Ratio
ControlNo0
H(0)Yes0
H(10)Yes0.1
H(20)Yes0.2
Table 2. Characteristics of soil samples.
Table 2. Characteristics of soil samples.
IndicatorSoil
Luvic AnthrosolsGleyic Cambisols
pH(H2O)6.27 ± 0.165.23 ± 0.03
pH(KCl)5.66 ± 0.074.35 ± 0.16
Solid phase density (g/cm3)2.322.39
Content of granulometric fraction (%)2–0.05 mm23.546
0.05–0.002 mm63.545
<0.002 mm13.09
Classification of soils based on granulometric compositionClaySandy clay
Humidity (W)2.2 ± 0.11.6 ± 0.2
Table 3. The content of total and organic carbon (%), as well as the group composition of humus in soil samples.
Table 3. The content of total and organic carbon (%), as well as the group composition of humus in soil samples.
SampleHumusC(org)C1C(hum)C(fulvo)
Luvic Anthrosols4.27 ± 0.132.48 ± 0.080.83 ± 0.060.49 ± 0.050.34 ± 0.01
Gleyic Cambisols14.28 ± 0.088.28 ± 0.041.72 ± 0.040.51 ± 0.071.20 ± 0.14
Table 4. Parameters of the linear equation describing the dependence of logarithmic fraction of lead on the content of HAP in soil.
Table 4. Parameters of the linear equation describing the dependence of logarithmic fraction of lead on the content of HAP in soil.
The Form of Lead in the SoilExperimentParameters of the Linear Equation
BAR2
Water-solubleLuvic Anthrosols,
«Experiment A»		−1.6 ± 0.1−15 ± 10.995
Luvic Anthrosols,
«Experiment B»		−1.6 ± 0.2−18 ± 30.981
Gleyic Cambisols−3.1 ± 0.1−10 ± 10.997
MobileLuvic Anthrosols,
«Experiment A»		−0.10 ± 0.02−3.5 ± 0.30.991
Luvic Anthrosols,
«Experiment B»		−0.14 ± 0.01−3.6 ± 0.20.996
Gleyic Cambisols−0.17 ± 0.01−3.6 ± 0.10.998
Table 5. Results of evaluation of the effects of lead and HAP supplementation on oat growth after 14 days.
Table 5. Results of evaluation of the effects of lead and HAP supplementation on oat growth after 14 days.
ExperimentGermination Rate (%)Weight of Roots(g)Weight of Sprouts (g)Length of Sprouts (mm)Lead Content in Tissues (mg/g)
Control49 ± 166.1 ± 2.63.8 ± 2.8101.3 ± 10.90
H(0)26 ± 173.7 ± 2.80.2 ± 0.212.1 ± 1.85.04 ± 1.06
H(10)39 ± 214.3 ± 2.00.4 ± 0.719.6 ± 4.31.71 ± 0.33
H(20)44 ± 114.7 ± 0.51.5 ± 2.027.8 ± 6.10.82 ± 0.26
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Novikova, S.; Gilev, A.; Brikmans, A.; Priymak, I.; Shlyk, D.; Nesterova, O.; Egorin, A. The Potential of Hydroxyapatite for the Remediation of Lead-Contaminated Territories: A Case Study of Soils in Primorsky Krai. Sustainability 2025, 17, 2369. https://doi.org/10.3390/su17062369

AMA Style

Novikova S, Gilev A, Brikmans A, Priymak I, Shlyk D, Nesterova O, Egorin A. The Potential of Hydroxyapatite for the Remediation of Lead-Contaminated Territories: A Case Study of Soils in Primorsky Krai. Sustainability. 2025; 17(6):2369. https://doi.org/10.3390/su17062369

Chicago/Turabian Style

Novikova, Svetlana, Andrei Gilev, Anastasia Brikmans, Igor Priymak, Daria Shlyk, Olga Nesterova, and Andrei Egorin. 2025. "The Potential of Hydroxyapatite for the Remediation of Lead-Contaminated Territories: A Case Study of Soils in Primorsky Krai" Sustainability 17, no. 6: 2369. https://doi.org/10.3390/su17062369

APA Style

Novikova, S., Gilev, A., Brikmans, A., Priymak, I., Shlyk, D., Nesterova, O., & Egorin, A. (2025). The Potential of Hydroxyapatite for the Remediation of Lead-Contaminated Territories: A Case Study of Soils in Primorsky Krai. Sustainability, 17(6), 2369. https://doi.org/10.3390/su17062369

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop