Toxics

Research

14 pages, 1799 KiB

Open AccessArticle

Fractionation and Characterization of Metallic Elements in Soils in Land Use Systems

by Farid Ul Haq, Faridullah Faridullah, Muhammad Irshad, Aziz Ur Rahim Bacha, Farhan Hafeez, Zahid Ullah, Akhtar Iqbal, Awais Arifeen, Iqra Nabi, Abdulwahed Fahad Alrefaei and Mikhlid H. Almutairi

Toxics 2024, 12(2), 110; https://doi.org/10.3390/toxics12020110 - 28 Jan 2024

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Abstract

Land use has a great impact on soil dynamics. The soils of various land use systems in Central Karakoram have been under immense pressure in the recent past due to certain anthropogenic activities such as land use practices and land use cover changes. [...] Read more.

Land use has a great impact on soil dynamics. The soils of various land use systems in Central Karakoram have been under immense pressure in the recent past due to certain anthropogenic activities such as land use practices and land use cover changes. These influences have an impact on the spatial distribution of metallic elements (MEs) in the soils of various land uses. Herein, we investigated the occurrence of the MEs, copper (Cu), zinc (Zn), and nickel (Ni), in soils of various land uses such as the permafrost, pasture, forest, and agricultural lands of the Central Karakorum region. The MEs were extracted in exchangeable, adsorbed, organically bound, carbonated, precipitated, and residual forms. The concentrations of MEs showed a significant dependence on the extraction method used, and the extraction trend followed the order of EDTA > HNO₃ > KNO₃ > NaOH > H₂O. Zn showed the highest concentration compared to Ni and Cu in all extractions, whereas the land uses’ ME concentration followed the order of agricultural land > permafrost > forest > pasturelands. The highest values of total Zn, Ni, and Cu were 712 ± 01 mg/kg, 656 ± 02 mg/kg, and 163 ± 02 mg/kg, respectively, in agricultural soil. The ME concentration showed significant variations between different land uses, and the highest concentration was noted in agricultural soil. Zn was found to be a dominant ME compared to Ni and Cu. We believe this effort will provide opportunities for scholars to investigate MEs around the globe. Full article

(This article belongs to the Special Issue Monitoring Heavy Metal Pollution for Environmental Health and Safety)

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19 pages, 3446 KiB

Open AccessArticle

Trace Metal Accumulation in Rats Exposed to Mine Waters: A Case Study, Bor Area (Serbia)

by Ion Valeriu Caraba, Marioara Nicoleta Caraba, Delia Hutanu, Adrian Sinitean, Gabi Dumitrescu and Roxana Popescu

Toxics 2023, 11(12), 960; https://doi.org/10.3390/toxics11120960 - 25 Nov 2023

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Abstract

Zinc (Zn), copper (Cu), iron (Fe), manganese (Mn), cadmium (Cd), and lead (Pb) levels were measured in the Bor City water supply system (control) and two watercourses exposed to mining wastewaters, i.e., the Lutarica River (one site) and the Kriveljska River (two sites). [...] Read more.

Zinc (Zn), copper (Cu), iron (Fe), manganese (Mn), cadmium (Cd), and lead (Pb) levels were measured in the Bor City water supply system (control) and two watercourses exposed to mining wastewaters, i.e., the Lutarica River (one site) and the Kriveljska River (two sites). The same parameters were determined in the brain, heart, lungs, stomach, liver, spleen, kidneys, and testes of male Wistar rats given water from these sources for 2 months. Water Cu, Fe, Cd, and Pb were outside the safe range, excepting the reference site. Significant impacts on intra-organ metal homeostasis were detected, especially in the brain, stomach, kidneys, and testes. The dynamics and magnitude of these changes (versus controls) depended on the target organ, analyzed metal, and water origin. The greatest number of significant intra-organ associations between essential and non-essential metals were found for Cd-Zn, Cd-Cu, and Cd-Mn. A regression analysis suggested the kidneys as the most relevant organ for monitoring water manganese, and the stomach and brain for lead. These results highlight the environmental risks associated with mining wastewaters from the Bor area and could help scientists in mapping the spatial distribution and severity of trace metal contamination in water sources. Full article

(This article belongs to the Special Issue Monitoring Heavy Metal Pollution for Environmental Health and Safety)

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20 pages, 2993 KiB

Open AccessArticle

The Effects and Mechanisms of pH and Dissolved Oxygen Conditions on the Release of Arsenic at the Sediment–Water Interface in Taihu Lake

by Liqing Zeng, Changzhou Yan, Fan Yang, Zhuo Zhen, Jiaming Yang, Jielun Chen, Yujie Huang, Yuhui Xiao and Wen Zhang

Toxics 2023, 11(11), 890; https://doi.org/10.3390/toxics11110890 - 30 Oct 2023

Cited by 1 | Viewed by 1249

Abstract

The pH and dissolved oxygen (DO) conditions are important environmental factors that control the migration of arsenic (As) at the sediment–water interface. This study investigates the distribution differences of reactive iron, manganese, and arsenic at the sediment–water interface under anaerobic and aerobic conditions [...] Read more.

The pH and dissolved oxygen (DO) conditions are important environmental factors that control the migration of arsenic (As) at the sediment–water interface. This study investigates the distribution differences of reactive iron, manganese, and arsenic at the sediment–water interface under anaerobic and aerobic conditions at different pH levels. The strong buffering capacity of sediment to water pH results in a shift towards neutral pH values in the overlying water under different initial pH conditions. The level of DO becomes a key factor in the release of As from sediment, with lower DO environments exhibiting higher release quantities and rates of As compared to high DO environments. Under low DO conditions, the combined effects of ion exchange and anaerobic reduction lead to the most significant release of As, particularly under pH 9.5 conditions. The formation of amorphous ferrous sulfide compounds under low DO conditions is a significant factor contributing to increased arsenic concentration in the interstitial water. Therefore, the re-migration of endogenous arsenic in shallow lake sediments should consider the combined effects of multiple driving forces. Full article

(This article belongs to the Special Issue Monitoring Heavy Metal Pollution for Environmental Health and Safety)

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16 pages, 2743 KiB

Open AccessArticle

Heavy Metals in Surface Sediment of Plateau Lakes in Tibet, China: Occurrence, Risk Assessment, and Potential Sources

by Qiongyuan Su, Asfandyar Shahab, Liangliang Huang, Muhammad Ubaid Ali, Yanan Cheng, Jiahuan Yang, Hao Xu, Zhicheng Sun, Qi Zou, Zhongbing Chen and Bin Kang

Toxics 2023, 11(10), 804; https://doi.org/10.3390/toxics11100804 - 23 Sep 2023

Cited by 2 | Viewed by 1171

Abstract

Tibetan Plateau lakes have high ecological value and play a crucial role in maintaining ecological balance. This research aimed to study the pollution characteristics, ecological risk, and potential sources of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in [...] Read more.

Tibetan Plateau lakes have high ecological value and play a crucial role in maintaining ecological balance. This research aimed to study the pollution characteristics, ecological risk, and potential sources of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in the surface sediments of 12 Tibetan Plateau lakes. The results of the toxicity risk index (TRI) showed that only Gongzhu Tso (28.09) and La’ ang Tso (20.25) had heavy metals that could pose a very high risk of toxicity to aquatic organisms. Hg posed the highest potential ecological risk to aquatic organisms. Based on the results of multiple analyses, we inferred that the contents of Cr, Cu, Hg, and Ni in sediments of Tibetan lakes were influenced by industrial and agricultural development; Cd, Pb, and Zn were influenced by transport and atmospheric transport; and As was derived from geothermal activity and rock weathering. Full article

(This article belongs to the Special Issue Monitoring Heavy Metal Pollution for Environmental Health and Safety)

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20 pages, 1854 KiB

Open AccessArticle

Human Health Risk Assessment of Arsenic and Other Metals in Herbal Products Containing St. John’s Wort in the Metropolitan Area of Mexico City

by Patricia Rojas, Elizabeth Ruiz-Sánchez, Carolina Rojas, Betzabeth A. García-Martínez, Arely M. López-Ramírez, Laura Osorio-Rico, Camilo Ríos and Aldo Arturo Reséndiz-Albor

Toxics 2023, 11(9), 801; https://doi.org/10.3390/toxics11090801 - 21 Sep 2023

Cited by 1 | Viewed by 1505

Abstract

Consumption of St. John’s wort plant is high worldwide due to its various medicinal properties. However, herbal products containing St. John’s wort may be contaminated with toxic metals. This is often related to contamination of both water and the atmosphere, lack of proper [...] Read more.

Consumption of St. John’s wort plant is high worldwide due to its various medicinal properties. However, herbal products containing St. John’s wort may be contaminated with toxic metals. This is often related to contamination of both water and the atmosphere, lack of proper cultivation methods, and inadequate plant storage conditions, as well as a lack of stricter sanitary supervision. A safety assessment of copper (Cu), lead (Pb), cadmium (Cd) and arsenic (As) content in 23 products containing St. John’s wort (pharmaceutical herbal products, food supplements and traditional herbal remedies) sold in the metropolitan area of Mexico City was conducted. The analysis of metals was determined using a graphite-furnace atomic absorption spectrometer. All herbal products were contaminated with Cu, Pb, Cd and As. The pharmaceutical herbal items showed less contamination by metals. The daily human intake (DHI) values for Pb exceeded the permissible limits in the group of traditional herbal remedies. The DHI calculation for As exceeded the permitted intake values for all items in the group of traditional herbal remedies, five food supplements and one pharmaceutical herbal product. The hazard indicator calculation of the non-carcinogenic cumulative risk values for traditional herbal remedies was greater than 1, suggesting a risk to human health. Full article

(This article belongs to the Special Issue Monitoring Heavy Metal Pollution for Environmental Health and Safety)

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18 pages, 5671 KiB

Open AccessArticle

Risk Assessment of Heavy Metals in Sediment Samples from the Mae Chaem River, Chiang Mai, Thailand

by Sawaeng Kawichai, Tippawan Prapamontol, Teetawat Santijitpakdee and Susira Bootdee

Toxics 2023, 11(9), 780; https://doi.org/10.3390/toxics11090780 - 14 Sep 2023

Cited by 1 | Viewed by 1565

Abstract

Heavy metals are significant environmental pollutants that are recognized as posing a potential health hazard to human beings. We investigated the concentrations of the heavy metals As, Cd, Cr, Cu, Ni, Pb, and Zn in surface sediments collected from the Mae Chaem River [...] Read more.

Heavy metals are significant environmental pollutants that are recognized as posing a potential health hazard to human beings. We investigated the concentrations of the heavy metals As, Cd, Cr, Cu, Ni, Pb, and Zn in surface sediments collected from the Mae Chaem River in Chiang Mai, Thailand, during the dry season in 2021. The mean concentrations of heavy metals in sediments were, in decreasing order, Zn > Cr > As > Pb > Ni > Cu > Cd. The mean values of As, Cd, Cr, and Cu were determined to be 32.5 ± 18.3, 0.33 ± 0.07, 45.8 ± 11.9, and 21.9 ± 7.42 mg Kg⁻¹, respectively. These levels are higher than their standard levels in Thailand, namely 10.0, 0.16, 45.5, and 21.5 mg Kg⁻¹, respectively. Principal component analysis (PCA) revealed that the primary origins of heavy metal contamination are predominantly attributed to residential settlements and agricultural areas. The hazard quotient (HQ) was used to estimate the non-carcinogenic risk of exposure to heavy-metal-bound surface sediments for both children and adults. The results showed that the HQ values for both groups were less than 1.0 (HQ < 1.0), indicating no risk. Moreover, assessment of the long-term risk for ingestion of toxic metals indicated no risk (<10⁻⁶) based on the lifetime cancer risk (LCR). However, the LCR values of As and Cr were 5.3 × 10⁻⁶ and 2.5 × 10⁻⁶, respectively, demonstrating the most elevated LCR among the hazardous metals in terms of children’s exposure. Therefore, it is possible that children living in agricultural areas and participating in activities around the study area may be exposed to elevated concentrations of As and Cr. Full article

(This article belongs to the Special Issue Monitoring Heavy Metal Pollution for Environmental Health and Safety)

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23 pages, 7254 KiB

Open AccessArticle

Distribution, Site-Specific Water Quality Criteria, and Ecological Risk Assessment of Heavy Metals in Surface Water in Fen River, China

by Huixian Li, Yue Li, Guanghui Guo, Yang Li, Ruiqing Zhang, Chenglian Feng and Yahui Zhang

Toxics 2023, 11(8), 704; https://doi.org/10.3390/toxics11080704 - 15 Aug 2023

Cited by 5 | Viewed by 1453

Abstract

Due to a lack of toxicity reference values that match the regional environmental characteristics, the ecological risk of metals in water bodies cannot be accurately assessed. The Fen River is the second-largest tributary of the Yellow River in China, and the sustainability of [...] Read more.

Due to a lack of toxicity reference values that match the regional environmental characteristics, the ecological risk of metals in water bodies cannot be accurately assessed. The Fen River is the second-largest tributary of the Yellow River in China, and the sustainability of this area is threatened by heavy metal pollution caused by intensive industrial and agricultural activities. In this study, site-specific water quality criteria (WQCs) for heavy metals in the Fen River were derived considering toxicity data from native aquatic organisms and regional water quality factors (e.g., water hardness). Short-term WQCs for Mn, Cu, Cd, Zn, Cr, Pb, and Ni were 2026.15, 98.62, 10.02, 63.07, 6.06, 166.74, and 132.73 μg/L, respectively, and long-term WQCs were 166.53, 29.71, 2.18, 19.29, 4.15, 6.38, and 14.76 μg/L, respectively. The distribution characteristics of these metals during the wet season in 2020 were explored, and their average concentrations in the river water did not exceed the environmental quality standards for surface water in China but were higher than the world average levels. Cr was the main pollutant in the sampling sites of Yaodu region, Hongdong Shitan, Xiao River, and Duanchun River, as was Pb in Duanchun River. Based on the site-specific WQCs, using hazardous quotient (HQ) and margin of safety (MOS₁₀) approaches, a high risk of Pb was identified in the Duanchun River, and a medium risk of Cr might occur at midstream and downstream of Yaodu and Xiaodian. The results will provide a reference basis for heavy metal pollution control and water quality management in the Fen River. Full article

(This article belongs to the Special Issue Monitoring Heavy Metal Pollution for Environmental Health and Safety)

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10 pages, 504 KiB

Open AccessArticle

Improved Calculations of Heavy Metal Toxicity Coefficients for Evaluating Potential Ecological Risk in Sediments Based on Seven Major Chinese Water Systems

by Yu Cao, Ruimin Wang, Yanyan Liu, Yongjie Li, Lifen Jia, Qingxiang Yang, Xiangpeng Zeng, Xinlei Li, Qiang Wang, Ruifei Wang and Luqman Riaz

Toxics 2023, 11(8), 650; https://doi.org/10.3390/toxics11080650 - 27 Jul 2023

Cited by 1 | Viewed by 1432

Abstract

Several methods have been used to assess heavy metal contamination in sediments. However, an assessment that considers both composite heavy metal speciation and concentration is necessary to accurately study ecological risks. This study improved the potential ecological risk index method and calculated the [...] Read more.

Several methods have been used to assess heavy metal contamination in sediments. However, an assessment that considers both composite heavy metal speciation and concentration is necessary to accurately study ecological risks. This study improved the potential ecological risk index method and calculated the toxicity coefficients of seven heavy metals: Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni), Lead (Pb), and Zinc (Zn). The newly calculated toxicity coefficients were validated by using previously published heavy metal distribution data of the Henan section of the Yellow River. The calculation procedure is based on the principle that the abundance of heavy metals in the environment and their bioavailable forms affect the toxicity of heavy metals. The toxicity coefficients for the seven heavy metals were calculated as follows: As = 10, Cd = 20, Cr = 5, Cu = 2, Ni = 5, Pb = 5, Zn = 1. Ecological risk assessment of the Henan section of the Yellow River using the improved toxicity coefficients revealed that the ecological risk of Cd and total heavy metals is higher than previous calculations, reaching the strength and moderate risk levels, respectively. The improved potential ecological risk index method is more sensitive to heavy metal pollution and thus provides a better indication of ecological risk. This is a necessary improvement to provide more accurate pollution assessments. Full article

(This article belongs to the Special Issue Monitoring Heavy Metal Pollution for Environmental Health and Safety)

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