Microplastics accumulation and human health risk assessment of heavy metals in Marcia opima and Lingula anatina, Phuket

Distribution and diversity of microplastics along the aquatic food web in the largest mangrove reserve of China

Knowledge of microplastics (MPs) in consumers at different trophic levels and with different feeding strategies in mangroves is essential to evaluate pathways and ecological effects from exposure to MPs. We conducted a comprehensive study on the distribution of MPs along the food web in the largest natural mangrove reserve in China, and applied diversity index of MPs, D'(MP), in terms of color, size, shape and type, to investigate complexity of MPs through the trophic cascades. The highest abundance of total MPs occurred at 5.7 ± 2.6 items/individual in fish, followed by 4.8 ± 1.9, 3.2 ± 0.5, 2.2 ± 0.9 items/individual in crabs, bivalves and shrimps, respectively. There was a correlation between the abundance of MPs in the gastrointestinal tracts (GITs) or soft tissues of organisms and trophic levels (r = 0.47, p < 0.01), while microplastic abundance were also correlated with body wet weights. The abundance and diversity of MPs in mangrove organisms were influenced by their feeding behaviors and living habitats, as consumers through indirect ingestion had significantly higher abundance of MPs than discriminate feeders. For MPs in their GITs, crabs had the highest shape D'(MP), but the lowest size D'(MP) and color D'(MP), while fish had highest color D'(MP), but significantly lower shape D'(MP). Our application of diversity index of MPs to mangrove ecosystem for the first time reveals a rather complicated distribution of MPs along the aquatic food web, demonstrating an urgent need for measures to reduce the discharge of MPs into mangrove and develop a remediation strategy.

The effect of educational intervention based on the mobile application on women's knowledge, attitude, and practice on microplastics and health: study protocol for a randomized controlled trial

BACKGROUND

The pervasive issue of microplastic (MP) contamination is undeniable. The primary solution to this global problem lies in significantly reducing the amount of plastic entering the environment. Addressing such a large-scale issue is no easy feat. However, a necessary strategy involves public education. In parallel, a randomized controlled trial (RCT) aims to evaluate the effect of interventional education via a mobile phone application on improving women's knowledge, attitude, and practice regarding the health effects of MPs.

METHODS

This randomized controlled trial includes three phases. In the first phase, a questionnaire assessing women's knowledge, attitudes, and practices (KAP) regarding microplastics will be developed and validated. In phase two, educational content for the mobile application "PlastiWise" will be created based on behavior change constructs. In phase three, a two-arm, parallel-design RCT will be conducted with 136 women aged 18 years and older who own smartphones, have basic literacy skills, and provide informed consent. Participants will be recruited through an online call disseminated via social media platforms and health system networks in Iran. They will be randomly assigned to an intervention group (n = 68) receiving the educational program through the app or a control group (n = 68). The sample size was calculated using G*Power software to ensure sufficient power (80%) with an alpha level of 0.05, factoring in a 15% dropout rate. Primary outcome data (KAP scores) will be collected at baseline, immediately post-intervention, and 8 weeks post-intervention using self-reported questionnaires. Data analysis will include descriptive statistics and inferential tests, such as independent t-tests and paired t-tests, to assess group differences and within-group changes over time.

DISCUSSION

Implementing an educational intervention on knowledge, attitude, and practice (KAP) about MPs using a mobile application will be a first in Iran. This research is expected to benefit Iranian women by contributing evidence on factors that might influence the effectiveness of educational training related to MP consumption. TRIAL STATUS : Protocol version 1, 2024-07-12. The enrolment of participants began on 2024-09-22. The recruitment is estimated to be completed by 2024-11-21. TRIAL REGISTRATION : Iranian Clinical Trial Register IRCT20240529061941N1. https://irct.behdasht.gov.ir/user/trial/77069/view . Date is July 12, 2024.

Heavy metal contamination in marine fish from the Andaman sea: Influence of habitat and health risk assessment

This study investigates Hg, Cd, Cu, Zn, and Pb concentrations in 324 fish samples from 43 species, including two cephalopod species, in the Andaman Sea. The fish were categorized into pelagic and demersal groups. The findings revealed average heavy metal concentrations in the order: Zn > Cu > Hg > Pb > Cd, with pelagic fish showing higher levels than demersal fish. Certain larger pelagic fish had mercury concentrations above prescribed limits, posing possible health hazards, even though they are less commonly consumed by humans. Cd and Pb levels in certain species exceeded regulatory thresholds of 0.05-1 μg/g and 0.3 μg/g, respectively, while Cu and Zn remained within safe limits. Although the overall cancer risk was low, the Target Hazard Quotient (THQ) and Hazard Index (HI) values surpassed 1, indicating significant health risks from consuming species such as Alopias superciliosus, Isurus oxyrinchus, Lepturacanthus savala, Makaira mazara, and Sphyraena barracuda. These findings underscore the need for ongoing monitoring and public advisories to mitigate health risks.

Ecological and health implications of heavy metal bioaccumulation in Thai Fauna: A systematic review

Heavy metals pose significant threats to ecosystems and human health due to their persistence and bioaccumulation. In Thailand, rapid industrialization, extensive agriculture, and urban development have exacerbated heavy metal pollution in both aquatic and terrestrial ecosystems. This systematic review, conducted according to PRISMA guidelines, evaluates study designs and methodologies to assess heavy metal bioaccumulation in Thai fauna, with a focus on ecological and health impacts. The review reveals that fish, particularly from families like Cyprinidae and Cichlidae, account for 42.11 % of studies, with species such as swamp eel, Henicorhynchus siamensis, Arius maculatus, Osteogeneiosus militaris, Puntioplites proctozystron, and Channa striata showing significant bioaccumulation. Molluscs (31.58 %), including Tegillarca granosa and Filopaludina martensi, serve as critical bioindicators of aquatic pollution due to their filter-feeding habits. Amphibians and crustaceans, like Fejervarya limnocharis and Fenneropenaeus merguiensis, also demonstrate vulnerability to heavy metal contamination. Key contamination hotspots include urban waterways in Bangkok, industrial discharges in Songkhla Lake, and mining sites in Loei Province, highlighting widespread environmental and health impacts. Despite extensive research, gaps remain, particularly concerning benthic scavengers and detritivores, which are vital for ecosystem functions. The review underscores the need for targeted monitoring and mitigation, including stricter regulations on industrial discharges, improved waste treatment, and better management of agricultural runoff. While metals like cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn) are well-studied, further research on less-examined metals and species-specific bioaccumulation patterns is crucial to enhancing environmental management, supporting biodiversity conservation, and improving ecosystem resilience in Thailand.

First-of-Its-Kind: Nationwide meta-analysis of microplastic pollution and risk assessment in Thailand

Thailand ranks as the sixth largest contributor to global microplastic pollution, which is exacerbated by extensive plastic use. Despite rising concerns, no comprehensive review is available on microplastic contamination and its potential risk in Thailand. This review synthesised data on microplastic abundance and characteristics within the country from 118 peer-reviewed publications (2017-2024). We found predominant microplastic presence in crustaceans (1.69-160.15 items/g), followed by Mollusca (0.03-9.5 items/g) and fishes (0.01-28.17 items/g), with higher abundances in wastewater (4 × 102 to 6.09 × 105 items/m3) compared to that in freshwater (1.44-2.92 × 106 items/m3) and seawater (2.70 × 10-1 to 6.25 × 104 items/m3). Marine sediments (48.3-2.13 × 104 items/kg) also showed significantly higher microplastic concentrations than terrestrial sediments (3-2.92 × 103 items/kg). Predominant microplastics were identified as fibers (59.36% and 35.05% for biological and environmental samples, respectively) and fragments (24.14%, 30.68%) in blue (25.95%, 18.64%), and colourless/transparent (20.01%, 14.47%), primarily composed of polyethylene terephthalate (19.46%, 9.19%), nylon (3.23%, 9.99%), polypropylene (19.78%, 24.23%), and polyethylene (14.81%, 11.66%). The potential ecological risk was low in all ecosystems except for wastewater. Shrimp and fish were more susceptible to microplastics compared to other studies in the region. Additionally, the sources, transport, and pathways of microplastic pollution in Thailand's aquatic territories and the current measures and policies implemented by the government to address plastic pollution are discussed. This review has compiled up-to-date insights into the prevalence, distribution, and risks associated with microplastics, which is instrumental in formulating effective strategies for contaminant control and ultimately reducing plastic pollution.

Potential risks of accumulated microplastics in shells and soft tissues of cultured hard clams (Meretrix taiwanica) and associated metals

Microplastics (MPs) pose risks to both aquatic ecosystems and human health. This study investigated MPs in the shells and soft tissues of hard clams (Meretrix taiwanica) cultured in the inland waters of Taiwan. This study further developed two novel risk indices for assessing the potential ecological and health consequences of MPs. Moreover, the metal concentrations in the clam's soft tissues and the associated consumption health risks were investigated. Clamshells contained significant amounts of MPs with an average abundance of 16.6 ± 6.9 MPs/ind., which was higher than in the soft tissues (2.7 ± 1.7 MPs/ind.). The distribution and sizes of MPs in shells and soft tissues were similar, primarily small-sized (<2 mm, >99 %), blue (>65 %), and fibrous (>99 %). Dominant MP polymer types included rayon (83.5 %), polyethylene terephthalate (11.8 %), and polyacrylonitrile (3.6 %). The proposed MP potential ecological risk index indicates a higher potential ecological MP risk in soft tissues (302-423) than in shells (270-278) of the clams. The MP potential hazard risk index showed that the risk of exposure to MP through shellfish consumption decreased with age. The total hazard index (THI) value suggested negligible health hazards from metal exposure through shellfish consumption. Moreover, there was no significant correlation between MPs and metal concentrations in soft tissues, suggesting that metals bound to MPs contribute minimally to the total accumulated metals in clam's soft tissues. This study confirms the presence of MPs in clam shells and provides a novel tool to assess the potential ecological and health risks associated with MPs in shellfish.

The effect of environmental health education on microplastic pollution awareness

OBJECTIVE

The aim of this research is to investigate the effect of environmental health education given at the ninth-grade level on the microplastic pollution awareness level of students.

METHODS

This pretest-posttest experimental study with a randomized control group was conducted between 2022 and 2023 in three high schools in a province in eastern Turkey. The sample of the study consisted of 90 ninth-grade students (experimental group: 45, control group: 45), and the sample magnitude was determined by power analysis. Tools such as the "Personal Information Form" and "Microplastic Pollution Awareness Scale (MPAS)" were used to collect data. Training was given to the experimental group as a nursing intervention in a total of four sessions at 15-day intervals. No intervention was applied to the individuals in the control group.

RESULTS

While no significant difference was observed in the MPAS total score in the control group according to the pretest and posttest mean scores, a significant difference was observed in the MPAS total score in the experimental group (p < 0.05). When the posttest mean scores of the experimental and control groups were examined, it was observed that the posttest mean scores of the experimental group were higher than the posttest mean scores of the control group and there was a statistically significant difference (p < 0.05).

CONCLUSION

It was observed that the microplastic pollution awareness level of the experimental group students who received environmental health training increased significantly. The issue of environmental health should be integrated into the education curriculum in schools and students' awareness levels should be increased.

Microplastics in retail shellfish from a seafood market in eastern Thailand: Occurrence and risks to human food safety

This study aimed to investigate the presence of microplastics in three economically essential shellfish species: green mussels, cockles and spotted babylon. The average abundance of microplastics ranged from 2.41 to 2.84 particles/g wet weight. The predominant shape was fiber, with colors ranging from black-grey to transparent. The size of the microplastics discovered was <1.0 mm. Polystyrene and polyethylene were the most detected types in mussels and cockles, while linen was the predominant type in spotted babylon. The Thai population's estimated annual intake (EAI) of microplastics through shellfish consumption ranged from 20.23 to 1178.42 particles/person/year. The potential human health risks were evaluated using the polymer hazard index (PHI), which led to risk categories III-IV. These findings, along with others from the literature, indicate that shellfish consumption may pose risks to human health, depending on the species consumed and the origin of the specimens.

Occurrence characteristics and risk assessment of microplastics in agricultural soils in the loess hilly gully area of Yan' an, China

Large amounts of microplastics accumulated in the soil of agricultural fields with the rapid development of mulch agriculture. The enrichment of microplastics endangered the growth of crops and food security, and it also posed ecological risks. In this study, we investigated microplastics in a typical agriculture area of Yan' an City, in the loess hilly gully area of China. The characteristics of microplastics including their abundances, sizes, and types were measured through laser direct infrared spectrometer. The potential sources of microplastics were analyzed and the risk of soil microplastic pollution was evaluated. It was elaborated that the average abundances of microplastics in soil, water, and fertilizer were 4505 ± 435 n·kg-1, 91 ± 27 n·L-1, and 39,629 ± 10,114 n·kg-1, respectively. Microplastics with particle sizes < 100 μm accounted for >90 %. The smaller the particle size, the higher the content of microplastics. The top three polymers were polyethylene (PE, 37.4 %), polyethylene terephthalate (PET, 15.0 %), and ethylene vinyl acetate (EVA, 8.9 %), respectively. Agricultural mulch, plastic film, domestic waste, surface water irrigation, and organic compost were probably the potential sources of soil microplastics. The ecological risk evaluation showed that overall sampling sites had a minor ecological risk of microplastic pollution based on their abundance, while the polymer type showed a relatively high ecological risk for the investigated agricultural soils. Polyvinylchloride (PVC) and polymethylmethacrylate (PMMA) contribute considerably to the ecological risk, and their inputs to the farmland environment should be strictly limited. There was no significant carcinogenic risk to humans. This study would provide the basic reference for the current situation and risk assessment of farmland soil microplastics pollution in the loess hilly gully area of China.

Environmental fate, aging, toxicity and potential remediation strategies of microplastics in soil environment: Current progress and future perspectives

Microplastics (MPs) are small plastic debris (<5 mm) that result from the fragmentation of plastic due to physical and physiochemical processes. MPs are emerging pollutants that pose a significant threat to the environment and human health, primarily due to their pervasive presence and potential bioaccumulation within the food web. Despite their importance, there is a lack of comprehensive studies on the fate, toxicity, and aging behavior of MPs. Therefore, this review aims to address this gap by providing a cohesive understanding of several key aspects. Firstly, it summarizes the sources and fate of MPs, highlighting their ubiquitous presence and the potential pathways through which they enter ecosystems. Secondly, it evaluates the aging process of MPs and the factors influencing it, including the morphological and physiological changes observed in crops and the release of pollutants from aged MPs, which can have detrimental effects on the environment and human health. Furthermore, the impacts of aging MPs on various processes are discussed, such as the mobilization of other pollutants in the environment. The influence of aged MPs on the soil environment, particularly their effect on heavy metal adsorption, is examined. Finally, the review explores strategies for the prevention technologies and remediation of MPs, highlighting the importance of developing effective approaches to tackle this issue. Overall, this review aims to contribute to our understanding of MPs, their aging process, and their impacts on the environment and human health. It underscores the urgency of addressing the issue of MPs and promoting research and remediation efforts to mitigate their adverse effects.

Heavy metal bioaccumulation and risk assessment in fishery resources from the Gulf of Thailand

The muscle tissues of 19 fish species, two crab species, and one shrimp species collected from the Gulf of Thailand (GoT) were analyzed to determine the levels of heavy metals, including Cu, Zn, Fe, Mn, Ni, Pb, Cd, and Hg. The results revealed that the mean concentrations of the heavy metals, in descending order, were Zn > Cu > Fe > Cd > Hg > Mn > Pb > Ni. Among the examined metals, zinc was found to be the most prevalent in fish tissues. Based on the risk assessment indices, the estimated average daily doses (ADD) of the heavy metals were found to be below the provisional tolerable daily intake (PTDI) recommended by the joint Committee of the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) on food contaminants. The results of the target cancer risk analysis revealed no related cancer risk from the consumption of the fishes considered for the study. However, the target hazard quotient (THQ) values exceeded the threshold of 1 (THQ > 1) specifically for mercury in Gymnothorax spp. and Terapon spp. Furthermore, the calculated hazard index (HI) values for fish muscles were all below 1, indicating that there is no significant health risk for humans at the current consumption rates, except in Terapon species for both normal and habitual consumers. Notably, habitual consumers of Gymnothorax species showed the highest HI value (>1), suggesting potential long-term effects on human health when consuming larger quantities of these fishes.

Co-exposure of microplastics and heavy metals in the marine environment and remediation techniques: a comprehensive review

Microplastics (MPs) and heavy metals are significant pollutants in the marine environment, necessitating effective remediation strategies to prevent their release into the sea through sewage and industrial effluent. This comprehensive review explores the current understanding of the co-exposure of MPs and heavy metal-enriched MPs, highlighting the need for effective remediation methods. Various mechanisms, including surface ion complexation, hydrogen bonding, and electrostatic forces, contribute to the adsorption of heavy metals onto MPs, with factors like surface area and environmental exposure duration playing crucial roles. Additionally, biofilm formation on MPs alters their chemical properties, influencing metal adsorption behaviors. Different thermodynamic models are used to explain the adsorption mechanisms of heavy metals on MPs. The adsorption process is influenced by various factors, including the morphological characteristics of MPs, their adsorption capacity, and environmental conditions. Additionally, the desorption of heavy metals from MPs has implications for their bioavailability and poses risks to marine organisms, emphasizing the importance of source reduction and remedial measures. Hybrid approaches that combine both conventional and modern technologies show promise for the efficient removal of MPs and heavy metals from marine environments. This review identifies critical gaps in existing research that should be addressed in future studies including standardized sampling methods to ensure accurate data, further investigation into the specific interactions between MPs and metals, and the development of hybrid technologies at an industrial scale. Overall, this review sheds light on the adsorption and desorption mechanisms of heavy metal-enriched MPs, underscoring the necessity of implementing effective remediation strategies.

Microplastics and trace metals in river sediment: Prevalence and correlation with multiple factors

Microplastics (MPs), which are ubiquitous, are no longer novel emerging pollutants, yet our knowledge of them is insufficient. This study investigates the prevalence of MPs and trace metals in sediment belonging to Ma River, Vietnam, and their interaction with various parameters, including nutrients such as total carbon (TC), total nitrogen (TN), and total phosphorus (TP), grain sizes, and MPs in surface water. The study revealed that the abundance of MPs in sediment (MPs/S) is relatively high (i.e., 1328.3 ± 1925.5 items.kg-1 dry weight), while the concentration of MPs in surface water (MPs/W) was relatively low (i.e., 57.3 ± 55.8 items.m-3) compared to other areas. Notably, the study found that arsenic and cadmium concentrations exceeded baseline levels, indicating their anthropogenic origin. To interpret the relationship between MPs/S, metals, and the aforementioned parameters, principal component analysis and Pearson correlation analyses were employed. The results demonstrated a significant correlation between metals and nutrients, as well as small grain sizes such as clay and silt. It was observed that the majority of metals displayed co-occurrence with one another but showed weak associations with the levels of MPs present in both water and sediment. Additionally, a weak correlation was observed between MPs/W and MPs/S. In conclusion, these findings suggest that the distribution and behavior of MPs and trace metals in aquatic systems are influenced by multiple factors, including nutrient levels, grain size, and other chemical and physical characteristics of the environment. While certain metals may have natural sources, others may result from human activities such as mining, industrial discharge, and wastewater treatment plants. As a result, understanding the sources and aspects of metal contamination are critical for determining their relationship with MPs and developing effective strategies for mitigating their impact on aquatic ecosystems.