Plasticizers and Bisphenols in Sicilian Lagoon Bivalves, Water, and Sediments: Environmental Risk in Areas with Different Anthropogenic Pressure

Abstract

Plasticizers and bisphenols are contaminants of concern in the environment, particularly in aquatic ecosystems. Bivalve molluscs are effective bioindicators due to their benthic nature, their ability to filter water, and their capacity to bioaccumulate persistent pollutants. This study analyzes plasticizers and bisphenols in three native clam species (Ruditapes decussatus, Cerastoderma glaucum, and Polititapes aureus) from two Sicilian lagoons under different levels of anthropogenic pressure: the urbanized Capo Peloro lagoon (Ganzirri Lake) and the less impacted Oliveri–Tindari lagoon. The clams, together with water and sediment samples, were collected in winter 2023. Both groups of clams from the two sampling areas contained phthalates such as DMP, DEP, DiBP, and DEHP, as well as non-phthalate plasticizers such as DEHT, DBA, DEA, and DEHA. The sum of non-phthalate plasticizers (NPPs) was consistently higher than the sum of phthalates in all clam samples, confirming the emerging trend of NPPs. This trend was also observed in the water and sediment samples, regardless of the sampling area. The presence of structural analogues of bisphenol A (BPA) highlights the growing prevalence of BPA-like structures in aquatic environments. Given the increasing evidence of widespread and persistent contamination of aquatic environments by plasticizers and bisphenols, it is evident that these substances pose a significant threat to ecosystems and human health.

1. Introduction

The exponential growth in global plastic production, coupled with inadequate waste management practices, has resulted in the widespread dissemination of plastic debris across diverse ecosystems [1,2]. This environmental burden is particularly critical in aquatic environments, where plastic litter undergoes fragmentation and degradation processes, releasing a variety of associated chemical additives into surrounding waters [3,4,5]. Among the most concerning compounds are phthalic acid esters (PAEs) and non-phthalate plasticizers (NPPs), which are intentionally incorporated into polymeric materials to enhance their flexibility, processability, and durability. These substances are not chemically bound to the polymer matrix, making them susceptible to gradual release throughout the life cycle of plastic products. Their release into the environment is through various mechanisms such as volatilization, leaching, abrasion, and environmental dispersion (e.g., wastewater, atmospheric deposition, runoff) [6,7,8].

Alongside the plasticizers, bisphenols (BPs), including structural analogues, constitute another class of contaminants of emerging concern, with distinct chemical behavior and sources of environmental release. Unlike plasticizers, BPs are used as monomers in polycarbonate and epoxy resins, becoming chemically bound in the polymer matrix. However, residual monomers and degradation products can be released over time, particularly under harsh conditions (e.g., elevated temperature, alkaline or acidic pH, saline media) [9,10,11,12].

Coastal zones, rivers, lakes, and estuaries serve as complex and dynamic interfaces where these pollutants accumulate, making them critical areas for environmental monitoring [13].

Due to their widespread use and continuous environmental release, the PAEs, NPPs, and BPs are regarded as pseudo-persistent pollutants. However, their constant input into the environment often exceeds their degradation rates [14]. As a result, they are persistently detected in various environmental compartments, including water, sediment, soil, and biota, particularly in marine invertebrates and fish [15,16,17,18,19,20,21].

PAEs are widely acknowledged for their ecotoxicological relevance and potential adverse effects on human health. In aquatic ecosystems, these compounds can negatively impact various organisms, including invertebrates and fish, by disrupting endocrine signaling pathways, impairing reproductive functions, and inducing developmental and behavioral anomalies. Their pronounced lipophilicity promotes bioaccumulation and potential trophic transfer, thereby raising concerns about cascading effects at the ecosystem level [22,23,24]. From a human health perspective, PAEs have been associated with a range of adverse outcomes, including neurotoxicity, carcinogenicity, reproductive and developmental toxicity, attention deficits, asthma, and autism. They are well-established endocrine-disrupting chemicals (EDCs) and have been shown to interfere with hormone-regulated physiological processes through various mechanisms of action [25,26,27]. NPPs such as terephthalates, adipates, and sebacates have gained attention as alternative plasticizing agents. Although often considered safer or more biodegradable substitutes, emerging evidence indicates they may still pose potential environmental and human health risks [28,29,30].

Similarly, BPs, particularly bisphenol A (BPA) and its structural analogues, exhibit both environmental and human health toxicity. In the environment, BPs can impact aquatic organisms by affecting reproduction, development, and oxidative stress pathways [31,32]. In humans, chronic exposure to BPs has been linked to endocrine disruption, reproductive dysfunction, metabolic disorders (such as obesity and insulin resistance), immune dysregulation, and neurodevelopmental disturbances [33,34,35].

Due to growing concerns about the environmental and health risks posed by PAEs, NPPs, and BPs, global regulatory frameworks have started to act. The European REACH regulation (Regulation (EC) No. 1907/2006) has implemented measures to limit the production and use of specific PAEs, classifying them as substances toxic to reproduction (Repr. 1B) and substances of very high concern (SVHC) due to their negative effects on human health and the environment. For instance, di(2-ethylhexyl) phthalate (DEHP) is classified as toxic for reproduction and as an endocrine disruptor. Dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), and diisobutyl phthalate (DiBP) have also been identified as toxic to reproduction. As a result, the use of DEHP, DBP, BBP, and DiBP is restricted to 0.1% or more by weight in plasticized materials of toys and childcare articles.

Restrictions on major PAEs have also been imposed in the United States, Canada, Japan, and South Korea, in products for children, medical devices, cosmetics, and personal care products. However, despite the restrictions on traditional PAEs, significant gaps remain in the regulation of non-phthalate plasticizers and alternative bisphenols. Many of these are also recognized as EDCs and have been linked to a range of health issues, including obesity, reproductive, neurological, and developmental problems. For example, BPF has shown a higher ecological risk compared to BPA and BPS [36].

Therefore, it is crucial to implement more comprehensive global regulatory measures and intensify monitoring programs, including continuous monitoring of concentrations in various environmental compartments and organisms, with particular attention to seasonal and spatial variations.

In light of these concerns, the aim of the present study was to determine the levels of PAEs, NPPs, and BPs in samples of the three native clam species (Ruditapes decussatus, Cerastoderma glaucum, Polititapes aureus) collected from two Sicilian transitional water environments characterized by different levels of anthropogenic pressure: the Capo Peloro lagoon (specifically Ganzirri Lake), an urbanized brackish system vulnerable to pollution, and the Oliveri–Tindari lagoon, a relatively less disturbed environment. To provide a comprehensive picture of contaminant distribution, samples of water and sediments from the same lagoons were also included in the study. The ultimate goal is to assess the potential for human exposure to plasticizers and bisphenols through seafood consumption, and to provide the scientific evidence necessary for future environmental monitoring.

2. Materials and Methods

2.1. Sampling Locations and Collection

Sampling was conducted during the winter months (from late January to early February 2023) in two distinct coastal lagoon systems located in northeastern Sicily, Italy (Figure 1 and Figure 2). In Ganzirri Lake, belonging to the Capo Peloro (CP) lagoon, three endemic clam species (Ruditapes decussatus, Cerastoderma glaucum, and Paphia aureus) were collected. In the Oliveri–Tindari lagoon, C. glaucum was sampled from the Lago Verde (LV) basin, while R. decussatus and P. aureus were obtained from the Porto Vecchio (PV) basin. A total of 18 samples of clams (500 g each) were collected from each lagoon, with 6 samples per species, resulting in a total of 36 clam samples. Only live, active specimens that were not in the breeding phase and met the commercial size criteria (2.5–3.0 cm for R. decussatus and P. aureus, and 2.0–2.5 cm for C. glaucum) were selected. After being collected, the samples were transported to the laboratory and immediately frozen at −20 °C for storage. Prior to analysis, the samples were thawed, and the clams were manually shucked by severing the adductor muscle with a lancet. The soft tissues were then freeze-dried for 72 h, homogenized, and stored in a desiccator until further analysis.

Additionally, 3 surface water samples and 3 sediment samples were collected at each site (Capo Peloro, Porto Vecchio, and Lago Verde), resulting in a total of 9 surface water and 9 sediment samples. All samples were collected in situ in glass bottles, transported to the laboratory, and immediately frozen at −20 °C. Prior to analysis, sediment samples were oven-dried for 48 h and homogenized. Water samples were stored frozen until analysis.

The Capo Peloro lagoon, a brackish system, is located at the Strait of Messina’s northern opening, comprising the lakes Ganzirri and Faro connected by canals. The lagoon is a protected reserve (Regional Administrative Order n. 437/44 of 2001) in an urbanized area subject to human activities, including modern mussel farming in Faro Lake and traditional clam culturing in Ganzirri Lake. This gives it the special status of an “oriented reserve.” However, the open sea is far away, and the water is not often exchanged. This makes Capo Peloro vulnerable to pollution from human activities [37]. Ganzirri Lake has a maximum depth of 7 m, with temperatures ranging from 13.80 to 29.43 °C, salinity from 30.56 to 35.24 PSU, and oxygen saturation is always above 100% [38,39].

The Oliveri–Tindari lagoon is on Sicily’s Tyrrhenian coast, near the towns of Oliveri and Patti in the Messina province. At present, the lagoon complex comprises four distinct basins: Marinello, Mergolo della Tonnara, Porto Vecchio, and Lago Verde, characterized by depths varying between 3 m and 5 m. The lagoon is one of the last examples of a brackish coastal environment in northeastern Sicily. It is relatively undisturbed by human activity except for tourism. The lagoon is protected under Regional Administrative Order n. 745/44 of 1998 [37]. The temperature, salinity, and oxygen saturation intervals for the two basins are as follows: in the Lago Verde, which hosted the C. glaucum population, the temperature ranged from 11.56 to 26.98 °C, salinity varied between 21.94 and 27.07 PSU, and oxygen saturation ranged from 82.78 to 123.81%; in the Porto Vecchio, which hosted the P. aureus and R. decussatus populations, the temperature ranged from 11.94 to 26.89 °C, salinity varied between 31.29 and 37.56 PSU, and oxygen saturation ranged from 88.95 to 131.87% [40].

2.2. Chemicals and Standard Solution

The following analytical standards, all with certified purity ≥99%, were purchased from Sigma-Aldrich (Steinheim, Germany). Plasticizers included di-methyl adipate (DMA), di-ethyl adipate (DEA), di-isobutyl adipate (DiBA), di-n-butyl adipate (DBA), bis-(2-ethylhexyl) adipate (DEHA), bis(2-methoxyethyl) adipate (DMEA), di-methyl phthalate (DMP), di-ethyl phthalate (DEP), di-propyl phthalate (DPrP), di-butyl phthalate (DBP), di-isooctyl phthalate (DiHepP), di-cyclohexyl phthalate (DcHexP), bis-(2-ethylhexyl) phthalate (DEHP), di-phenyl phthalate (DPhP), di-isononyl phthalate (DiNP), bis(2-methoxyethyl) phthalate (DMEP), benzyl butyl phthalate (BBP); diisobutyl phthalate (DiBP), benzyl benzoate (BB), bis-(2-ethylhexyl) terephthalate (DEHT) and di(2-ethylhexyl) sebacate (DEHS); Bisphenol analogs included 4′-sulfonyldiphenol (BPS), 4,4′-methylenediphenol (BPF), 1,1-bis(4-hydroxyphenyl)ethane (BPE), 4,4′-(propan-2,2-diyl)diphenol (BPA), 4-[2-(4-hydroxyphenyl)butan-2-yl]phenol (BPB), 2,2-Bis(4-hydroxyphenyl)hexafluoropropane (BPAF), 1,1-bis(4-hydroxyphenyl)-1-phenyl-ethane (BPAP), 1,1-bis(4-hydroxyphenyl)-cyclohexane (BPZ), and 1,4-bis(2-(4-hydroxyphenyl)-2-propyl)benzene (BPP).

Isotopically labelled standards used as internal standards (ISs) included DBP-d₄ and DEHP-d₄ (100 ng/μL in nonane), as well as ¹³C₁₂-BPA and ¹³C₁₂-BPS (purity ≥ 99%), all purchased from Cambridge Isotope Laboratories Inc. (Andover, MA, USA).

All solvents for analysis were of analytical grade and were purchased from Merck (Darmstadt, Germany). The salts used for extraction (sodium chloride and magnesium sulphate) and the reagents used for purification (primary and secondary amines (PSAs) and C18 sorbent) were purchased from Fluka in Milan, Italy.

Stock solutions of plasticizers were prepared at a concentration of 1000 mg/L in n-hexane, while stock solutions of bisphenols were prepared at 100 mg/L in acetonitrile. Working solutions for analytical purposes were subsequently obtained by appropriate dilutions of the stock solutions. All solutions were stored at 4 °C in a refrigerator until use.

2.3. Sample Preparation

A single extraction protocol was applied to all matrices to allow the simultaneous isolation of both plasticizers and bisphenols from each sample. In each case, the samples (5 g for clams and sediments, and 5 mL for surface water) were first spiked with internal standards and then 5.0 mL of acetonitrile and QuEChERS salts (2 g NaCl and 1 g MgSO₄) were added; the mixtures were vortexed and centrifuged. The supernatant was subjected to dispersive solid-phase extraction (d-SPE) using 0.25 mg MgSO₄, 0.1 mg PSA, and 0.1 mg C18, and the extract was filtered through a 0.22 µm PTFE membrane filter. The resulting extract was used directly for the LC-MS/MS analysis of bisphenols and for GC-MS analysis of plasticizers [41].

2.4. LC-MS/MS Analysis of Bisphenols

Bisphenol analysis was performed using a high-performance liquid chromatography system coupled to a triple quadrupole mass spectrometer (LCMS-8040, Shimadzu Corporation (Kyoto, Japan)) equipped with an electrospray ionization (ESI) source. An Agilent Zorbax SB-C18 column (5 μm, 4.6 × 250 mm), maintained at 30 °C, was used for chromatographic separation.

The mobile phases for the determination of bisphenol analogues consisted of ultrapure water (solvent A) and acetonitrile (solvent B). The flow rate was set to 0.7 mL/min, and the injection volume was 20 μL. A linear gradient was applied as follows: 0–7 min, 20–40% B; 7–25 min, 40–90% B; 25–35 min, 90–20% B. The mass spectrometer operated in multiple reaction monitoring (MRM) mode with negative electrospray ionization (ESI⁻). Instrumental parameters were as follows: nebulizing gas pressure 770 KPa, drying gas flow 15.0 L/min, DL temperature 250 °C, and CID gas 230 KPa.

All further methodological details, including qualitative and quantitative transitions, linearity, limits of detection (LOD), limits of quantification (LOQ), recovery, and precision, are reported in Table S1 of the Supplementary Material. Acetonitrile and water were tested for BPs and were found to be free of residues, confirming the absence of background contamination. In addition, procedural blanks were analyzed with each sample set.

2.5. GC-MS Analysis of Plasticizers

The analysis of plasticizers was performed using a Shimadzu GCMS-TQ8030 triple quadrupole mass spectrometer (Shimadzu, Kyoto, Japan), equipped with a Supelco SLB-5 MS capillary column (30 m × 0.25 mm i.d., 0.25 μm film thickness). The oven temperature program was as follows: initial temperature 60 °C; ramp from 60 to 190 °C at 8 °C/min with a 5 min hold; from 190 to 240 °C at 8 °C/min with another 5 min hold; and finally from 240 to 315 °C at 8 °C/min. Helium was used as the carrier gas at a constant linear velocity of 34.6 cm/s. The transfer line and injector temperatures were set at 280 °C and 250 °C, respectively. Injections were performed in splitless mode for 60 s, followed by a split ratio of 1:15; the injection volume was 1 μL.

The acquisition was performed in full scan electron ionization (EI) mode, with ionization energy set at 70 eV and an emission current of 250 μA, over a mass range of 40–400 amu. Additionally, Single Ion Monitoring (SIM) mode was applied using three characteristic mass fragments for each target plasticizer as reported in Table S1, together with the method validation parameters. Sample analyses were performed in batches, incorporating procedural blanks and certified reference standards for quality assurance.

2.6. Statistical Analysis

Statistical processing was carried out using SPSS software (v13.0, SPSS Inc., Chicago, IL, USA). Two separate multivariate datasets were considered. The first dataset was structured as a 36 × 16 matrix, containing the concentration values of 13 plasticizers and 3 bisphenols measured in 36 individual clam samples. The second dataset, which comprised water and sediment samples, was organized as an 18 × 16 array. This included nine surface water samples and nine sediment samples, all of which contained the same analytes. For values below the limit of quantification (LOQ), half the value of the limit of detection (LOD/2) was used as a surrogate. The non-parametric Mann–Whitney U test was used to assess the statistical significance of differences in clam samples according to their geographic origin (Capo Peloro and Porto Vecchio–Lago Verde). By contrast, a one-way ANOVA with a Kruskal–Wallis post hoc test was employed to evaluate the significance of contamination differences between water and sediment samples from different areas. Differences were considered statistically significant at p < 0.01 in the clam dataset and p < 0.05 in the water and sediment dataset. All data matrices were subjected to z-score normalization and subsequently subjected to principal component analysis (PCA).

Finally, linear regression analysis and Pearson’s correlation coefficient were used to examine the relationships between all the analytes in the environmental compartments and organisms.

2.7. Assessment of Dietary Intake of Plasticizers and Bisphenols from Clam Consumption

The European Food Safety Authority (EFSA) has conducted extensive risk assessments to establish tolerable daily intake (TDI) levels for various plasticizers.

According to the most recent evaluations from EFSA in 2019, the TDI for a group of phthalates, including DEHP, DBP, BBP, and DINP, has been set at 0.05 mg/kg body weight (bw) per day, while DIDP has a TDI of 0.15 mg/kg bw per day [42]. Additionally, in 2003, the World Health Organization (WHO) set a higher TDI for DEP at 5.00 mg/kg bw per day [43].

A TDI of 0.3 mg/kg bw/day for DEHA was established by the EU Scientific Committee on Food (SCF) in 1997. Although this value has not been updated by EFSA, it is still considered valid in the current European regulatory frameworks [44]. DEHS also has a TDI set at 2 mg/kg bw, established by the SCF in 1978 [45].

For BPA, the EFSA’s 2023 review significantly lowered the TDI to 0.2 ng/kg bw per day, compared to the previous value of 4 µg/kg bw per day established in 2015, due to growing concerns regarding the toxicity of the substance even at low concentrations [46].

Based on the findings of our study, the intake of plasticizers was calculated by assuming the molluscs consumption of 13.92 g per capita per day. The estimation also considers an average adult body weight of 60 kg and assumes 100% gastrointestinal absorption. The daily intake value of 13.92 g was derived from the annual per capita consumption of molluscs in Italy, reported as 5.08 kg in 2022 by the Food and Agriculture Organization of the United Nations [37]. This Italian value is approximately 2.5 times higher than the European average [37].

The estimated exposure levels obtained in this study were then compared with the corresponding TDIs for each compound to perform a risk assessment.

3. Results and Discussion

3.1. Occurrence of PAEs and NPPs in Clam, Water, and Sediments

Twelve PAE congeners (DMP, DEP, DPrP, DiBP, DBP, DMEP, BBP, DHepP, DcHexP, DEHP, DPhP, and DiNP) and nine NPP congeners (DMA, DEA, DiBA, DBA, BB, DMEA, DEHA, DEHT, and DEHS) were analyzed in clam, water, and sediment samples, and the results obtained are presented in Figure 3 and Figure 4 (and in Tables S2 and S3 of the Supplemental Materials).

The congeners DMP, DEP, DiBP, DEHP, DEHT, DEA, DBA, and DEHA were detected in all clam samples, while DBP and DMEP were only detected in clams from the Oliveri–Tindari area, and BBP, DMA, and DiBA were only detected in clam samples from the Capo Peloro area.

Significantly higher values (p < 0.01) of DMP (40.4 ± 9.12 vs. 28.3 ± 9.22 µg/kg), DiBP (59.74 ± 15.67 vs. 44.38 ± 10.41 µg/kg), DEHT (342.74 ± 163.79 vs. 172.4 ± 58.87 µg/kg), and DEA (58.61 ± 11.53 vs. 38.9 ± 5.66 µg/kg) and DBA (2377.1 ± 729.76 vs. 1045.0 ± 393.27 µg/kg) were found in clams from the Oliveri–Tindari area.

Averaging concentrations of 32.95 µg/kg, 61.66 µg/kg, and 40.72 µg/kg, respectively, BBP, DMA, and DiBA were triaged in the Capo Peloro clam samples.

The same congeners found in the clam samples were found in almost all of the analyzed waters and sediments. In particular, the waters of Porto Vecchio and Capo Peloro had significantly higher concentrations of DEP (p < 0.05), while significantly lower concentrations of this plasticizer were found in the waters of Lago Verde and all the analyzed sediments. Conversely, the waters of Porto Vecchio and Lago Verde had higher concentrations of DBP, DMEP, and DMA, whereas the waters of Capo Peloro had concentrations of these plasticizers that were always below the limit of quantification (LOQ). Significantly higher values of DEHP were found in the waters of Lago Verde and Capo Peloro and in the Capo Peloro sediments only. Significantly higher concentrations (p < 0.05) of DMA (present at both sites), DBP, and DEA were found only in the Porto Vecchio sediment, while DEHA was found only in the Lago Verde and Porto Vecchio sediment. The plasticizer with higher concentrations than all others determined was DEHT, which in Porto Vechhio waters and sediments reached concentrations of 1974.9 ± 526.86 µg/L and 2054.2 ± 565.33 µg/kg, respectively. No concentrations of DiBA or DBA were found in any of the analyzed water or sediment samples. The results obtained in this study are in accord with previous studies on mollusc sediment and waters of marine environments. For example, a study investigating the presence of microplastics and levels of plasticizers in bivalves, fish, and holothurians [47] showed that the highest levels were found in the soft tissues of bivalves, with DEHP being the most prevalent compound. By contrast, the highest levels of DBP were found in fish and holothurians. The overall risk to fish was found to be lower. A study conducted in Lazio, Italy, analyzed mussels taken from 12 coastal sites between March and April 2023 [48]. The results showed Phthalates (seven total compounds) with concentrations ranging from 57.5 to 131.5 ng/g, with DiBP being the most prevalent, followed by DBP and DEP.

Analytical screening in this study revealed the presence of plasticizer compounds in all clam samples, as well as in almost all water and sediment samples. This finding suggests that they are widely distributed in marine environments, as shown by several recent studies [8,31,47,49,50].

DBA and DEHT were the compounds that showed the highest level of contamination in the clams, and DEHT also showed the highest level of water and sediment contamination. Phthalates are the predominant plasticizers, accounting for 80–85% of the global market for plasticizers used in polyvinyl chloride (PVC) plastics.

Although phthalates currently dominate the plasticizer market, the range of alternative or emerging plasticizers is expanding. Since the global regulation of phthalates began, emerging plasticizers have become more prevalent.

These substances have complex chemical compositions, characterized mainly by functional groups such as sebacate, adipate, and terephthalate. Unlike traditional phthalates, emerging plasticizers are not chemically bound to the polymer and can easily be released into the environment, resulting in a ‘pseudo-persistence’ effect. Plasticizers can be released from products over varying time scales (e.g., months, years, or decades) and transported in multiple environmental matrices (e.g., air, water, soil, and biota) before eventually leading to human exposure through inhalation, absorption, or ingestion. Adipates, such as DBA, DiBA, and DEHA, are non-phthalate plasticizers that are increasingly being found in various aquatic matrices, as confirmed by the following studies. Furthermore, DEHT, which is also considered an emerging plasticizer, was found to be the most frequently detected non-phthalate plasticizer in sentinel aquatic matrices, such as molluscs. In our previous study, we analyzed the presence of plasticizers (phthalates and DEHT) in sediments and biota from the coast of Mahdia in Tunisia. Various marine compartments were examined, including sediments, seagrasses, and mussels [17].

DEHT was the most widespread and frequently detected congener, with concentrations reaching 1.181 mg/kg in sediments, 1.121 mg/kg in seagrasses, and 1.86 mg/kg in mussels. These results suggest that DEHT may cross the food chain and accumulate in marine ecosystems. Higher levels in biota also indicate their potential for bioaccumulation. The presence of adipates has been detected in the soft tissue of mussels (Mytilus galloprovincialis) and clams (Ruditapes decussatus) in various Mediterranean coastal areas and European lagoons. Although adipate concentrations are generally lower than those of the more common phthalates (e.g., DEHP), they are still detectable at levels of ng/g or ng/kg of dry or wet weight. Accumulation correlates with the presence of microplastics and suspended particulate matter, with filter-feeding molluscs being directly exposed to adsorption. For example, other authors have analyzed samples of M. galloprovincialis collected from various sites along the Italian Tyrrhenian coast, including urban, port, and marine reserve areas [51]. They detected DEHA in the mussels, with average concentrations ranging from 10 to 50 ng/g of wet weight, indicating moderate bioaccumulation. Other authors conducted a survey investigating adipate plasticizer contamination in native freshwater molluscs, with a particular focus on the Corbicula fluminea bivalve, which is commonly found in Italian rivers and lakes. The data revealed DEHA concentrations ranging from 5 to 30 ng/g of dry weight. Contamination was highest at sites near urban and industrial discharges [52].

DEHT can also be released into the aquatic environment through industrial discharges, urban wastewater, and the degradation of plastics.

As filter feeders, clams can absorb DEHT from suspended particulate matter, water, and sediments. Preliminary studies in Europe have detected DEHT in the soft tissue of clams collected in coastal and lagoon areas, albeit generally at lower concentrations than those of more common phthalates, such as DEHP.

Currently, few studies are dedicated specifically to DEHT in native Italian clams, and these are often included in broader investigations on plasticizers. Some investigations of Mediterranean marine molluscs have detected DEHT at levels ranging from a few ng/g to around 20–40 ng/g wet weight, suggesting moderate bioaccumulation.

Our study confirms the emerging trend of plasticizers. As can be seen in Table S2 of the Supplementary Materials, the sum of non-phthalate plasticizers (NPPs) was consistently higher than the sum of phthalates in all clam samples (1378.9 ± 387.04 µg/kg vs. 146.3 ± 15.30 µg/kg, respectively). This trend was also observed in water and sediment, regardless of the sampling area. Filter-feeding molluscs, such as mussels, clams, and holothurians, demonstrate significant bioaccumulation capacities and are exposed to documented toxic effects, even at low environmental concentrations. This has direct implications for cellular, reproductive, and immune function. Data collected in this and other studies show that contamination is no longer limited to industrial sites; it also affects marine protected areas, lagoons, and freshwater environments. In this context, it is clear that monitoring programs need to be extended and standardized to include historical contaminants such as DEHP as well as substitute substances such as DEHT and adipates. Investigations should also be extended to include understudied but potentially vulnerable native freshwater and lagoon molluscs, and multidisciplinary methodologies integrating chemical analyses and biomarkers of effect should be applied to assess the real impact of these contaminants.

3.2. Occurrence of BPs in Clam, Water, and Sediments

Nine BPs (BPS, BPA, BPF, BPZ, BPB, BPP, BPE, BPAF, BPAP) were analyzed in clam, water, and sediment samples, and the results obtained are presented in Figure 5 and in Tables S2 and S3 of the Supplementary Materials.

BPA was detected in all clam and water samples from both the Capo Peloro and Oliveri–Tindari areas. However, it was not detected in any sediment samples. Significantly higher values of BPA (72.1 ± 9.84 vs. 8.60 ± 2.20 µg/kg) were found in clams from the Capo Peloro area.

The analogs BPS and BPF were only detected in clam samples from Capo Peloro, with average concentrations of 7.10 µg/kg and 3.31 µg/kg, respectively. Furthermore, only BPS was found in water samples (64.53 ± 18.19 µg/L) from the Capo Peloro area.

Findings from the present work agree with earlier research conducted on marine molluscs, sediments, and waters. The study, focusing on bivalves, fish, and holothurians [47] reported that, in addition to high levels of DEHP, soft tissues of bivalves also contained elevated concentrations of BPS and BPF. In the same study conducted in Lazio, Italy [48], bisphenols were detected in mussels at concentrations ranging from 0.73 to 219 ng/g, with BPS prevailing over BPA and BPAF.

The same literature survey carried out for plasticizers also highlighted that bisphenols were consistently detected, confirming their widespread occurrence in marine environments [8,31,47,49,50].

What has already been highlighted for plasticizers should also be extended to bisphenol analogs (such as BPS, BPF, and others), by including them in monitoring programs of native mollusc species inhabiting vulnerable environments.

3.3. PCA and Pearson Correlation Analysis

PCA analysis was performed using only the variables that were found to differ significantly between the sample groups, and on the normalized dataset. The suitability of the dataset was checked in advance. For the first dataset, the Kaiser–Meyer–Olkin measure revealed a value of 0.881, which is higher than the recommended minimum of 0.600. The Bartlett’s test of sphericity showed a chi-squared value of 1285.565 (at a p-level of less than 0.01), which also supports the suitability of the correlation matrix. According to Kaiser’s criterion, only principal components (PCs) with eigenvalues greater than one were retained. Three PCs with respective eigenvalues of 10.229, 0.920, and 0.627 were therefore extracted, explaining up to 90.581% of the total variance (78.683% PC1, 7.077% PC2, and 4.821% PC3, respectively), as shown in Figure 6. No variables with low saturation were identified in any of the components, and all communalities were ≥0.630. Therefore, the extracted PCs satisfactorily reproduced all the original variables. Figure 6 shows the results of the principal component analysis (PCA) of the levels of plasticizers and bisphenols in the analyzed clam species, revealing variations between sampling sites. In particular, the 3D score plots show that two groups, separated by the PC2 plane, are clearly distinct. The clams from the Capo Peloro area showed a high positive correlation on the PC1 axis for BPA, BPS, BPF, and BBP. Conversely, a high negative correlation was observed for DMP, DBP, DiBP, DMEP, DEHT, DBA, and DEA for the Lago Verde–Porto Vecchio sampling area group on the PC1 axis.

Pearson’s correlation was used to evaluate the correlation between the levels of plasticizers in clams, water, and sediment. Figure 7 shows the results for significant correlations for Capo Peloro, Lago Verde, and Porto Vecchio. The analysis of Capo Peloro data revealed the following correlations: highly positive correlations between water and sediment for DEHP (0.995) and DiBP (0.979); positive correlations between clam and sediment for DEP (0.373); and clam with both water (0.464) and sediment (0.442) for DiBP. Meanwhile, the following correlations were observed: highly negative correlations between water and sediment for DEP (−0.978); and not highly negative between clam and water for DEP (−0.386); and clam with both water and sediment for DEHP (−0.643 and −0.675, respectively). Analysis of the Porto Vecchio data revealed positive correlations: between water and sediment for DEHT (0.990 with p < 0.001); between clams and sediment (0.814 with p < 0.05). Finally, analysis of the Lago Verde data revealed one positive correlations between clams and water for both DMP (0.495) and DiBP (0.090), while highly negative correlations were observed between water and sediment for DMP (−0.994) and between clams and sediment for DiBP (−0.948); moreover, a not highly negative correlation was observed between clam and sediment for DMP (−0.511) and between water and sediment for DiBP (−0.247). Only one significant correlation (−0.998, with p < 0.001) was found for DMA concentrations (water/sediment).

Although it would seem logical to expect higher contamination levels in Ganzirri Lake, given its more urbanized environment and proximity to the Strait of Messina, experimental data indicate that clams from the Oliveri–Tindari lagoon have higher concentrations of plasticizers. This phenomenon can be explained by a series of ecotoxicological and environmental factors. Ganzirri Lake has a continuous water exchange with the Strait of Messina, which leads to a dilution of contaminants and their partial dispersion towards the sea. In contrast, the Oliveri–Tindari lagoon is a more enclosed basin with limited water renewal; therefore, the contaminants introduced tend to concentrate locally and remain available for longer periods to filtering organisms. Clams have a high bioaccumulation capacity. However, in closed systems, such as the Oliveri–Tindari lagoon, the concentration of contaminants in the filtered water can be higher. This leads to greater accumulation of contaminants in the clams’ tissues. Despite the higher external input of contaminants in Lake Ganzirri, dilution and dispersion mechanisms effectively reduce the concentration available to organisms.

The clams mirrored the differences in environmental contamination between Ganzirri Lake and the Oliveri–Tindari lagoon. These findings confirm that bivalve molluscs can serve as reliable indicators of the presence and relative levels of chemical pollutants in aquatic ecosystems, supporting their use as bioindicators in environmental monitoring and risk assessment programs.

3.4. Human Health Risk Assessment from Contaminants in Clam Consumption

The potential human health risks associated with the consumption of three native clam species (Ruditapes decussatus, Cerastoderma glaucum, Polititapes aureus) from two Sicilian lagoons with different anthropogenic pressures were assessed by comparing the estimated intake of bisphenols and plasticizers with their respective Tolerable Daily Intake (TDI) levels. This assessment considered a daily consumption of 13.92 g of molluscs per capita, based on the national average, and an adult body weight of 60 kg, with the assumption of complete gastrointestinal absorption.

The findings indicate varying levels of risk based on the specific contaminant, with detailed results provided in

Table 1. Tolerable daily intake (TDI) levels for plasticizers and BPA and human health risk assessment in clam consumption.

		Ruditapes decussatus		Cerastoderma glaucum		Polititapes aureus
		Capo Peloro	Porto Vecchio	Capo Peloro	Lago Verde	Capo Peloro	Porto Vecchio
BPA	Mean value (µg/kg)	66.63	8.25	72.69	7.95	76.86	9.59
	Amount ingested (ng)	927.44	114.84	1011.82	110.62	1069.82	133.49
	% of TDI (0.2 ng/kgbw/d)	7729	957	8432	922	8915	1112
DEP	Mean value (µg/kg)	20.74	22.75	21.98	25.31	21.82	26.61
	Amount ingested (mg)	0.00029	0.00032	0.00030	0.00035	0.00030	0.00037
	% of TDI (5 mg/kgbw/d)	0.00010	0.00011	0.00010	0.00012	0.00010	0.00012
Sum of DBP + BBP + DEHP	Mean value (µg/kg)	49.64	41.36	58.49	41.93	48.31	34.97
	Amount ingested (mg)	0.00069	0.00058	0.00081	0.00058	0.00067	0.00049
	% of TDI (0.05 mg/kgbw/d)	0.023	0.019	0.027	0.019	0.022	0.016
DEHA	Mean value (µg/kg)	23.94	20.94	16.69	21.78	19.96	19.53
	Amount ingested (mg)	0.00033	0.00029	0.00023	0.00030	0.00028	0.00027
	% of TDI (0.3 mg/kgbw/d)	0.002	0.002	0.001	0.002	0.002	0.002

. Notably, BPA levels exceeded the TDI by a substantial margin across all clam species and sampling sites. However, a comparison of the data reveals a difference in the range of TDI exceedance between the two areas: clams collected from Ganzirri Lake showed BPA TDI percentages ranging from 7729% to 8915%, whereas those from the Oliveri–Tindari lagoon ranged between 922% and 1112%. This suggests a higher level of concern associated with the consumption of clams from Ganzirri Lake in terms of BPA exposure. Studies in Italy, Europe, and globally have reported BPA in molluscs and other seafood, generally below regulatory limits. Recently, EFSA drastically lowered the tolerable daily intake to 0.2 ng/kg bw/day due to adverse effects at low doses, particularly on the immune, reproductive, and metabolic systems. In response, EU Regulation 2024/3190 prohibits the use and marketing of BPA and other hazardous bisphenols in food contact materials. All bisphenols will now require safety evaluation and authorization before use. These developments highlight the need for continuous monitoring of BPA and related compounds in aquatic environments.

Exposure to plasticizers such as DEP, DEHA, and the combined phthalates DBP, BBP, and DEHP through the consumption of the analyzed clams appears to be of minimal concern. Estimated intakes of DEP ranged from 0.00010% to 0.00012% of its TDI, while DEHA ranged from 0.001% to 0.002%. Similarly, the combined intake of DBP, BBP, and DEHP accounted for only 0.016% to 0.027% of their group TDI. These values indicate that, for all compounds considered, the levels of exposure through clam consumption remain well below thresholds of toxicological relevance. However, it is important to emphasize that risk assessment based solely on the %TDI of single contaminants may underestimate the actual health concern. Simultaneous exposure to plasticizers and bisphenols may result in additive or even synergistic effects, a phenomenon known as the “cocktail effect.” Although the individual compounds may be present below their respective toxicological thresholds, their combined action can still represent a health concern. Since plasticizers and bisphenols share common endocrine pathways, their concurrent exposure may lead to enhanced effects, with risks greater than those estimated when evaluating each compound in isolation.

4. Conclusions

The presence of numerous micropollutants, such as phthalates, bisphenols, and their alternatives, can cause environmental disturbances and threaten the maintenance of aquatic ecosystems and public health. The increasing levels of plastic pollution and presence of plasticizers and bisphenols in the marine environment are a serious concern, so it is essential to increase monitoring to study and compare contamination levels. In our study, we monitored the presence of 21 phthalate and non-phthalate plasticizer congeners, as well as nine bisphenols, in water and sediment samples collected from the Lakes Oliveri–Tindari and Capo Peloro area. Given the filtering nature of clams, our results confirm contamination by plasticizers and bisphenols. The presence of phthalates such as DMP, DEP, DiBP, and DEHP, as well as non-phthalate plasticizers such as DEHT, DBA, DEA, and DEHA, was evident in both areas. The presence of structural analogues of bisphenol A (BPA) highlights the increasing prevalence of these BPA-like structures in aquatic environments. In conclusion, while exposure to DEP, the sum of DBP + BBP + DEHP, and DEHA from consuming these clams remains well within tolerable limits and poses minimal or negligible risk, BPA contamination represents a critical concern. The levels of BPA ingested through these clams exceed the updated TDI by orders of magnitude, indicating a significant potential health risk that requires attention. In light of growing evidence of widespread and persistent contamination of aquatic environments by plasticizers and bisphenols, these substances clearly pose a substantial threat to ecosystem health and food safety. Despite the apparently lower anthropogenic pressure, the sites of the Oliveri–Tindari lagoon show higher contamination by plasticizers because the basin is closed and poorly diluted, and the sediments act as a reservoir of contaminants. In contrast, in Ganzirri, the water exchange with the Strait reduces the bioavailability of plasticizers, despite the higher inputs associated with greater anthropogenic activity. These findings support the use of shellfish as bioindicators in regular monitoring programs. Integrating such measures would help manage human exposure and track environmental contamination.