Lifetime bioaccumulation, gender difference, tissue distribution, and parental transfer of organophosphorus plastic additives in freshwater fish

Toxicity comparison and risk assessment of two chlorinated organophosphate flame retardants (TCEP and TCPP) on Polypedates megacephalus tadpoles

Tris(2-chloroethyl) phosphate (TCEP) and tris(1‑chloro-2-propyl) phosphate (TCPP) are widely used as chlorinated organophosphate flame retardants (OPFRs) due to their fire-resistance capabilities. However, their extensive use has led to their permeation and pollution in aquatic environments. Using amphibians, which are non-model organisms, to test the toxic effects of OPFRs is relatively uncommon. This study examined the acute and chronic toxicity differences between TCEP and TCPP on Polypedates megacephalus tadpoles and evaluated the potential ecological risks to tadpoles in different aquatic environments using the risk quotient (RQ). In acute toxicity assay, the tadpole survival rates decreased with increased exposure time and concentrations, with TCEP exhibiting higher LC50 values than TCPP, at 305.5 mg/L and 70 mg/L, respectively. In the chronic assay, prolonged exposure to 300 μg/L of both substances resulted in similar adverse effects on tadpole growth, metamorphosis, and hepatic antioxidant function. Based on RQ values, most aquatic environments did not pose an ecological risk to tadpoles. However, the analysis showed that wastewater presented higher risks than rivers and drinking water, and TCPP posed a higher potential risk than TCEP in all examined aquatic environments. These findings provide empirical evidence to comprehend the toxicological effects of OPFRs on aquatic organisms and to assess the safety of aquatic environments.

Understanding Interface Exchanges for Assessing Environmental Sorption of Additives from Microplastics: Current Knowledge and Perspectives

Although the impacts of plastic pollution have long been recognized, the presence, pervasiveness, and ecotoxicological consequences of microplastic-i.e., plastic particles < 5 mm-contamination have only been explored over the last decade. Far less focus has been attributed to the role of these materials and, particularly, microplastics, as vectors for a multitude of chemicals, including those (un)intentionally added to plastic products, but also organic pollutants already present in the environment. Owing to the ubiquitous presence of microplastics in all environmental matrices and to the diverse nature of their chemical and physical characteristics, thoroughly understanding the mechanistic uptake/release of these compounds is inherently complex, but necessary in order to better assess the potential impacts of both microplastics and associated chemicals on the environment. Herein, we delve into the known processes and factors affecting these mechanisms. We center the discussion on microplastics and discuss some of the most prominent ecological implications of the sorption of this multitude of chemicals. Moreover, the key limitations of the currently available literature are described and a prospective outlook for the future research on the topic is presented.

Microplastic pollution in terrestrial ecosystems: Global implications and sustainable solutions

Microplastic (MPs) pollution has become a global environmental concern with significant impacts on ecosystems and human health. Although MPs have been widely detected in aquatic environments, their presence in terrestrial ecosystems remains largely unexplored. This review examines the multifaceted issues of MPs pollution in terrestrial ecosystem, covering various aspects from additives in plastics to global legislation and sustainable solutions. The study explores the widespread distribution of MPs worldwide and their potential antagonistic interactions with co-occurring contaminants, emphasizing the need for a holistic understanding of their environmental implications. The influence of MPs on soil and plants is discussed, shedding light on the potential consequences for terrestrial ecosystems and agricultural productivity. The aging mechanisms of MPs, including photo and thermal aging, are elucidated, along with the factors influencing their aging process. Furthermore, the review provides an overview of global legislation addressing plastic waste, including bans on specific plastic items and levies on single-use plastics. Sustainable solutions for MPs pollution are proposed, encompassing upstream approaches such as bioplastics, improved waste management practices, and wastewater treatment technologies, as well as downstream methods like physical and biological removal of MPs. The importance of international collaboration, comprehensive legislation, and global agreements is underscored as crucial in tackling this pervasive environmental challenge. This review may serve as a valuable resource for researchers, policymakers, and stakeholders, providing a comprehensive assessment of the environmental impact and potential risks associated with MPs.

Assessment of Daily Exposure to Organophosphate Esters through PM2.5 Inhalation, Dust Ingestion, and Dermal Contact

Inhalation of airborne fine particulate matter (PM2.5), dust ingestion, and dermal contact with dust are important pathways for human exposure to different contaminants, such as organophosphate esters (OPE), compounds that are widely used as flame retardants and plasticizers. There are limited studies assessing the extent of the contamination of OPE in indoor airborne PM2.5. This study offers a novel approach by examining various indoor environments, such as homes, workplaces, and means of transport, where people typically spend their daily lives. The goal is to provide a comprehensive assessment of daily exposure to these pollutants. Both PM2.5 and dust samples were collected in order to determine the concentration levels of 17 different OPEs. Fifteen OPEs in PM2.5 and 16 in dust samples were detected. Concentration levels in indoor air ranged from 4.37 to 185 ng/m3 (median 24.4 ng/m3) and from 3.02 to 36.9 μg/g for the dust samples (median 10.2 μg/g). Estimated daily intakes (EDIs) of OPEs were calculated for adults, yielding median values of 3.97 ng/(kg bw × day) for EDIInhalation, 5.89 ng/(kg bw × day) for EDIDermal, and 1.75 ng/(kg bw × day) for EDIIngestion. Such levels lie below human health threshold risk limits, although in some cases they could be only 2 times below the threshold for carcinogenic risk, with a main contribution from tris(2-chloroethyl) phosphate (TCEP). Given this threshold proximity, additional exposure to these chemicals from other pathways, such as food ingestion, gas phase exposure, and/or inhalation of coarser particles (PM10-2.5), could therefore lead to health limit exceedances.

Profile, Tissue Distribution, and Time Trend of Bisphenol Plastic Additives in Freshwater Wildlife of the Pearl River Ecosystem, China

Plastic-related contaminants in the environment have attracted increasing attention, with plastic pollution becoming a serious issue globally. The present study investigated the potential bioaccumulation and biotransfer of bisphenol (BP) compounds that are widely added in various products such as plastics and other products in a freshwater ecosystem, China. Among commonly applied 14 BP analogues, bisphenol A (BPA), bisphenol F (BPF), and bisphenol S (BPS) were predominant, representing 64%-100% of the total concentrations of BPs (ΣBPs) in freshwater wildlife. Both the concentrations and analogue profiles in the fish showed seasonal differences and species dependence. Higher BP concentrations were observed in fish collected during the dry season than the wet season. Higher percentages of non-BPA analogues (e.g., BPS and BPF) were observed in fish collected during the wet season. Pelagic species accumulated notably higher levels of BPs than midwater and bottom species. The liver generally contained the highest ΣBPs, followed successively by the swim bladder, belly fat, and dorsal muscle. The analogue profile also showed some differences among tissues, varying by species and season. Lower ΣBPs but higher percentages of non-BPA analogues were observed in female than male common carp. Time trends of the BPA concentration in fish varied by species, probably related to habitats and diets of the fish. Habitats, feeding behaviors, and trophic transfer may have significant impacts on exposure of wildlife to BPs in natural ecosystems. The BPs did not demonstrate strong potential for bioaccumulation. More research is warranted about metabolism and transgenerational transfer of BPs in wildlife to fully reveal the bioaccumulation and consequently ecological risks of these chemicals in the environment. Environ Toxicol Chem 2023;42:2130-2142. © 2023 SETAC.

Novel insights on toxicology of ochratoxin A contaminated diets to skin: Residues, mucus disruption and barrier impairment in teleost model grass carp (Ctenopharyngodon idella)

Ochratoxin A (OTA), a notorious pollutant widely present worldwide, seriously pollutes aquafeeds. This paper aims to explore the toxicity effects of OTA by the way of diet on the skin barrier in grass carp (Ctenopharyngodon idella). Results were shown as follows in the skin: (1) OTA increased the mRNA abundances of uptake transporter proteins (e.g., OAT3) and decreased efflux transporter proteins (e.g., ABCG2), which caused the accumulation of OTA in the skin of grass carp. (2) OTA upregulated the gene expression related to ROS production by enhancing the NOX (1, 2, 4) signaling pathway and decreased the ability to ROS elimination with downregulation of GPx1 (a,b), Trx by inhibiting the PGC1-α/Nrf2 signaling pathway, which caused oxidative damage to the skin. (3) OTA exacerbated apoptosis in the skin by upregulating the expression of apoptosis-related proteins mediated by ways of endoplasmic reticulum stress and mitochondrial apoptosis. Moreover, OTA down-regulated the mRNA and protein abundances of tight junction-related proteins by inhibiting the MLCK signaling pathway, which in turn disrupted the tight junctions. (4) OTA reduced the number of mucous cup cells and decreased f LZ activities and IgM contents, and finally down-regulated the mRNA abundances of mucin (2, 3), LEAP-2 (A, B), and β-defensin (1, 2, 3), which in turn resulted in impairing skin chemical barrier. Moreover, based on the antimicrobial-related indexes (LZ activities and IgM contents), the OTA-safe upper doses were 814.827 and 813.601 μg/kg.

Bioaccumulation of organophosphorus flame retardants in marine organisms in Liaodong Bay and their potential ecological risks based on species sensitivity distribution

Although organophosphorus flame retardants (OPFRs) in aquatic environments have received increasing concern, little information is available on their bioaccumulation and trophic transfer in marine food webs. Consequently, the risks of OPFRs to marine ecosystems are unknown. In this study, seven OPFR compounds in marine biological samples collected from Liaodong Bay, Bohai Sea, were analyzed to evaluate their level and biological amplification effect in the marine food web. The total OPFRs of marine organisms in Liaodong Bay ranged from 2.60 to 776 ng/g ww, and lipids were critical factors affecting the concentration of OPFRs in marine species. Tris (2-ethylhexyl) phosphate (TEHP) and tris(1-chloro-2-propyl) phosphate (TCIPP) were the OPFRs most frequently detected in marine species. Still, tris(2-chloroethyl) phosphate (TCEP) was dominant in most marine species (16/24), and the content of chlorinated OPFRs was highest. At the same time, alkyl OPFRs and aryl OPFRs accounted for the same proportion. No correlation between OPFR concentration and the trophic level was observed in marine organisms from Liaodong Bay. It was shown in the results of the species sensitivity distribution that TCIPP in Chinese seawater does not pose a potential ecological risk to marine species. However, much work remains to be done on accumulating information and the ecological risks of OPFRs in different marine food webs.

Melanin interference toxicity or transgenerational toxicity of organic UV filter ethylhexyl salicylate on zebrafish

With the improvement of human health awareness, the production and usage of sunscreens have increased dramatically, and their active ingredients, organic ultraviolet (UV) filters (OUVFs), have the potential to induce melanin abnormalities in aquatic organisms due to their UV-absorbing properties as they enter the aquatic environment directly with the washing of skin during water activities. In this paper, the melanin interference toxicity or transgenerational toxicity effects of typical OUVFs ethylhexyl salicylate (EHS) on zebrafish (Danio rerio) were investigated based on transcriptomic sequencing technology. Results showed that EHS induced significant enrichment of the melanin-related pathway cAMP signaling pathway in parental skin tissue through UV absorption, with sensitive genes identified as melanocortin 1 receptor, protein kinase A catalytic subunit beta a, calcium/calmodulin-dependent protein kinase II delta 2, adenylate cyclase 1 and G protein subunit alpha I a. qRT-PCR verification results showed that EHS may inhibit the expression of the melanin master regulator microphthalmia-associated transcription factor a (mitfa) and its induced signaling cascade mitf-tyrosinase (tyr)-dopachrome tautomerase (dct)-tyrosinase related protein 1 (tyrp1) by inducing abnormal expression of the above sensitive genes, thereby reducing melanogenesis. After reproduction, the melanin interference effect of EHS on the parents can be carried over to offsprings through maternal inheritance of abnormally expressed mitfa and parental transfer of pollutants, as evidenced by significant enrichment of melanogenesis pathway, abnormal expression of sensitive genes mitfa, tyr, dct and tyrp1b and significant decreases in melanin content and spinal melanin area. These findings revealed the specific melanin interference toxicity of OUVFs with UV-absorbing properties, facilitating a comprehensive ecological risk assessment of OUVFs and providing scientific support for the management of new pollutants.

Riverine Plastic Pollution in Asia: Results from a Bibliometric Assessment

Rivers are important ecosystems, vital to the livelihoods of hundreds of millions of humans and other species. Despite their environmental, social, and economic importance, current use of rivers is unsustainable, due to a combination of solid waste and high levels of pollutants. Plastic materials are among the most predominant of such pollutants. Based on the need for additional research in this area, this study examines pressures put to rivers and explores trends related to riverine plastic pollution, with a focus on Asia. Apart from the bibliometric analysis, and relying on the collected information, examples describing the drivers of riverine plastic pollution in a sample of Asian countries are described, outlining the specific problem and its scope. Among some of the results obtained from it, mention can be made to the fact that much of the literature focuses on plastic pollution as a whole and less on one of its most significant ramifications, namely microplastics. Additionally, there is a need related to data availability on riverine plastic data and improving the understanding of transport mechanisms in relation to riverine plastic emission into the ocean. The results from this study illustrate the significance of the problems posed by plastic waste to Asian rivers and point out the fact that there are still significant gaps in respect of regulations and standards, which prevent improvements that are highlighted in this study. Based on the results of this bibliometric assessment, specific measures via which levels of riverine plastic pollution may be reduced are presented, bringing relevant new insights on this topic beyond the existing reviews.

Microplastic pollution in Larimichthys polyactis in the coastal area of Jiangsu, China

We investigated microplastics (MPs) pollution in 349 Larimichthys polyactis specimens from the coastal area of Jiangsu Province, China. The MP abundance in L. polyactis was 1.03 ± 1.04 items/individual and 0.95 ± 0.92 items/10 g (wet weight). The MP abundance in specimens from the Haizhou Bay fishing ground was slightly higher than that in specimens from the Lvsi fishing ground. Spearman's correlation showed that MP abundance was positively correlated with body length when expressed as items/individual, but not items/10 g. The abundance in the gastrointestinal tract was slightly higher than that in the gills, but the differences were not significant for either measurement index. The MPs predominantly ingested by L. polyactis were <1 mm, fibrous, blue and had a cellophane composition. The MP pollution in L. polyactis in the coast of Jiangsu Province is at a medium to low level, as compared with other regions of China.