Perfluorooctane sulfonic acid (PFOS) is a persistent environmental pollutant. Exposure to PFOS has been associated with abnormal fetal development. The long non-coding RNA (lncRNA) has been showed to play a role in fetal growth restriction (FGR), preeclampsia (PE) and other pregnancy complications. Whether the lncRNA contributes to PFOS-induced toxicity in the placenta remains unknown. In this study, we investigated the function of lncRNA MEG3 and its derived miR-770 in PFOS-induced placental toxicity. Pregnant mice received gavage administration of different concentrations of PFOS (0.5, 2.5, and 12.5 mg/kg/day) from GD0 to GD17, and HTR-8/SVneo cells were treated with PFOS in the concentrations of 0, 10⁻¹, 1, 10 μM. We found that expression levels of miR-770 and its host gene MEG3 were reduced in mice placentas and HTR-8/SVneo cells with exposure of PFOS. A significant hypermethylation was observed at MEG3 promoter in placentas of mice gestational-treated with PFOS. We also confirmed that MEG3 and miR-770 overexpression alleviated the cell growth inhibition induced by PFOS. Furthermore, PTX3 (Pentraxin 3) was identified as the direct target of miR-770 and it was enhanced after PFOS exposure. In summary, our results suggested that MEG3 alleviate PFOS-induced placental cell inhibition through MEG3/miR-770/PTX3 axis.

Thallium, a highly toxic heavy metal and priority pollutant, has been widely reported to cause neurodevelopmental toxicity in animals. However, accessible epidemiological studies concerning the neurodevelopmental toxicity of early-life thallium exposure in humans are limited. In a prospective birth cohort including 2164 mother-child pairs, we explored the effect of prenatal serum thallium exposure on cognitive development among preschool-aged children born in Ma'anshan, Anhui, China. Serum thallium concentrations were measured in the first trimester, second trimester, third trimester, and cord blood by inductively coupled plasma mass spectrometry (ICP-MS). Child cognitive development was appraised by the Chinese version of the Wechsler Preschool and Primary Scale of Intelligence-Fourth Edition (WPPSI-IV) at 4.5 years old. Multiple informants generalized estimating equations (GEEs) were fit to jointly estimate the association between the four repeated measurements of thallium concentrations and the preschool-aged children's cognitive test scores. After adjusting for potential confounders, the visual spatial index (VSI) was 1.45 points lower in the highest tertile of serum thallium during the first trimester than in the lowest tertile (p for trend = 0.04). Moreover, children in the highest tertile of serum thallium during the third trimester had a significantly lower full-scale intelligence quotient (FSIQ) (β = −1.51, 95% CI: −2.68, −0.35), VSI (β = −1.79, 95% CI: −3.16, −0.42), fluid reasoning index (FRI) (β = −1.41, 95% CI: −2.73, −0.10), and processing speed index (PSI) (β = −1.47, 95% CI: −2.71, −0.24) scores than the children in the lowest tertile. When performing stratified analysis by child sex, the associations of first- and third-trimester thallium concentrations with cognitive test scores were more prominent in boys than in girls. Our findings revealed that maternal serum thallium exposure during the first and third trimesters, but not other periods, had detrimental effects on preschoolers' cognitive development, and these effects showed sex differences.

This study reports the results obtained from toxicological analyses of different types of baits referred to the laboratory of the Toxicology Area (Faculty of Veterinary Medicine, Cáceres, Spain) over a 17-year period (2002–2018). These baits were suspicious materials found in the environment of the region of Extremadura (Western Spain), where such malpractices are a problem to be addressed, as wide livestock farming and hunting activities are combined with a significant wealth of wildlife (especially birds of prey). A total of 246 baits, including 32 commercial chemical products to be used in baits, were analysed. Samples from 183 cases were received and classified according to the material used for their preparation and the toxic substance found. Overall, the most common bait consisted of meat preparations (56.3% of cases) intended to eliminate predators considered ‘annoying’ for livestock and hunting practices, such as carnivores and scavengers. It should be noted that contact baits (as fenthion-impregnated perches) were also detected (7.6%). Regarding the substances detected, anticholinesterase compounds (organophosphates and carbamates) were the most commonly used substances for the preparation of baits (detected in 85.3% of positive baits). Moreover, 8% of the positive baits presented more than one toxic substance in their composition. Due to the types of toxic compounds and the methods used to prepare the baits, this study shows that the malicious use of highly toxic substances in the environment to kill wildlife is a common and current issue and poses a serious risk to different species.

Contaminant vulnerability in the critical zones like groundwater (GW)-seawater (SW) continuum along the entire Gujarat coast was investigated for the first time through an extensive water monitoring survey. The prime focus of the study was to evaluate whether or not: i) seawater intrusion induced metal load translates to toxicity; ii) in the coastal groundwater, metal distribution follows the pattern of other geogenic and anthropogenic contaminants like NO₃- and F-; and iii) what future lies ahead pertaining to metal fate in association with saturation conditions of the coastal aquifers. The spatial distribution of contaminants depicts that the Gulf of Khambhat area is highly contaminated. Ecological risk assessment (ERA) indicates that the Gujarat coast is experiencing a high ecological risk compared to the southeast coast of India. Investigation results revealed that metals, pH, NO₃, and CO₃ are more vulnerable at the SW-GW mixing interface. An increase in pH is reflected in fewer ionic species of metals in the GW. Salinity ingress due to seawater intrusion (SWI) reduces the toxicities of all trace metals except Cu, attributed to the increase of Ca in GW, leading to dissociation of CuCO₃. Reactive species are dominant for Zn and Cd; and M-CO₃ ligands are dominant for Cu and Pb owing to the undersaturation of dolomite and calcite in the aquifer system. SWI tends to increase the metal load but the toxicity of metals varies with the density of industries, anthropogenic activities, changes in the mixing-induced saturation conditions, and intensive salt production across the coast. Multivariate analysis confirmed that the hydrogeochemical processes change due to GW-SW mixing and dictates over natural weathering. The ecological risk index (ERI) for the Arabian sea is experiencing moderate (300 ≥ ERI>150) to high ecological risk (ERI >600). Children population is likely to encounter a high health risk through ingestion and dermal exposure than adults. Overall, the study emphasizes the complexity of toxicity-related health impacts on coastal communities and suggests the dire need for frequent water monitoring along the coastal areas for quick realization of sustainable development goals.

We present a comprehensive review of the sediment quality triad (SQT) assessment studies in Korea. The bibliographic analysis was applied to evaluate how approaches in sediment assessment have evolved. A meta-analysis was performed, to evaluate potential risks of sedimentary persistent toxic substances (PTSs) reported in Korean coastal waters. Within the framework, we identified and discussed current status and spatiotemporal trends in contamination of both classic and emerging PTSs over the recent decadal period. Out of 26 target regions in Korea, five hotspots (Sihwa, Masan, Ulsan, Taean, and Gwangyang) of concern could be identified. Four of those regions have been designated as Specially-Managed Sea Area under the implementation of Total Pollution Load Management System in Korea, except for Taean coast (oil spill site). Meantime, we could identify three stepwise research phases based on a bibliographic analysis; Phase 1 (1995–2008), Phase 2 (2009–2015), and Phase 3 (2016–2020). It is noteworthy that a technical evolution of the SQT assessment by the phase was featured. It was also evidenced that in-depth studies adopting multiple lines of evidence (LOEs) became prevailed upon approaching Phase 3. In a quantitative manner, the toxicity explanatory power of target PTSs increased by about 10% in Phase 3 compared to the earlier phases. The meta-analysis using ratio-to-mean value method applied for the data set having all three LOEs indicated general improvement of sediment qualities in the hotspots. However, their associations quite varied across regions and years, reflecting a dynamicity in oceanographic settings and/or heterogeneity in toxicological effect or benthic community response. At present, SQT assessment adopting the increased LOEs generally supports better assessment. In conclusion, we suggest that future SQT studies globally should reaffirm the utility of the “multiple LOEs approach”, focusing on the identification and management of causative toxicants that driving negative ecological impacts on marine ecosystems.

Percolation of water through oily sludge during storage and handling of the sludge can cause soil and groundwater contamination. In this study, oily sludge from a refinery was equilibrated with water to obtain the water-soluble fraction (WSF) of oily sludge. The WSF had dissolved organic carbon (DOC) of 166 mg/L. Human cell line-based toxicity assay revealed IC₅₀ of 41 mg/L indicating its toxic nature. The predominant compounds in WSF of oily sludge included isomers of methyl, dimethyl and trimethyl quinolines and naphthalenes along with phenol derivatives and other polynuclear aromatic hydrocarbons (PAHs). Biodegradation of WSF of oily sludge was studied using a consortium of Rhodococcus ruber, Bacillus sp. and Bacillus cereus isolated from the refinery sludge. The consortium of the three strains resulted in 70% degradation over 15 days with a first-order degradation rate of 0.161 day⁻¹. Further analysis of the WSF was performed using the stir-bar sorptive extraction (SBSE) followed by GCxGC-TOF MS employing a PDMS Twister. The GCxGC analysis showed that Bacillus cereus was capable of degrading the quinoline, phenol and naphthalene derivatives in WSF of oily sludge at a faster rate compared to pyridine and benzoquinoline derivatives. Quinoline, phenol, biphenyl, naphthalene, pyridine and benzoquinolines derivatives in the WSF of oily sludge were reduced by 87%, 92%, 88%, 77%, 40% and 62%, respectively with respect to the controls. The WSF of oily sludge contained, n-alkanes, ranging from n-C12 to n-C18 which were removed within 2 days of biodegradation.

Under intensive human activity, sewage discharge causes eutrophication-driven cyanobacteria blooms as well as nanomaterial pollution. In biological control of harmful cyanobacteria, top-down effect of protozoan has great potentials for removing cyanobacterial populations, degrading cyanotoxins, and improving phytoplankton community. ZnO nanoparticles as a kind of emerging contaminants have attracted increasing attention because of wide application and their high bio-toxicity effects on reducing the ingestion of aquatic animals including Paramecium, thereby possibly disturbing top-down control of cyanobacteria. Therefore, this study investigated the effects of ZnO nanoparticles at environmental-relevant concentrations on the protozoan Paramecium removing toxic Microcystis. Results showed Paramecium effectively eliminated all the Microcystis, despite exposure to ZnO nanoparticles. However, their ingestion rate was significantly reduced at more than 0.1 mg L⁻¹ ZnO nanoparticles, thereby delaying Microcystis removal. Nevertheless, at 0.1 mg L⁻¹ ZnO nanoparticles, the time to Microcystis extinction decreased compared to the group without ZnO nanoparticles, because Microcystis populations were reduced under this circumstance, while ingestion rate of Paramecium was unaffected. Furthermore, ZnO nanoparticles obviously accumulated in food vacuoles of Paramecium, and the size of nanoparticles aggregates and zinc concentrations in Paramecium were increased with ZnO nanoparticles concentrations. At the end of experiment, these food vacuoles were not dissipated. Overall, these findings suggest that ZnO nanoparticles impair protozoan top-down effects through reducing Microcystis and ingestion rate as well as disturbing functions of their digestive organelles, and highlight the need to consider the interfering effects of environmental pollutants on cyanobacterial removal efficiency by protozoans in natural waters.

Mangroves play a vital role in protecting the coastal community from the climate change effect and in the restoration of the coastal ecosystem. This research has been designed to determine the spatial and seasonal changes of potentially toxic elements’ (PTEs) concentration in sediments and their potential source contribution among the different human-driven processes in Sundarbans, Bangladesh. Different pollution evaluation indices, random forest (RF) model, conditional inference tree (CIT), self-organizing map (SOM), geographical information system (GIS), and principal component analysis (PCA) were used for the interpretation of sources and risk assessment of PTEs. The mean concentration of PTEs both in winter and monsoon seasons has fallen below the threshold effect level but exceeded the rare effect level of marine sediments quality standards. Results showed that the PTEs were significantly enriched (EF > 1.00 < 70.00) in sediments, whereas the Cd enrichment (7.00% samples) was very alarming (EF = 60–70). Except for Zn and Cd, other PTEs were enriched in 30–60% samples. The highest geoaccumulation and contamination factors for Cd were observed in 46–72% of samples. The ecological risk (ER) factors showed similar results where Cd showed strong to very strong factors (ER = 110–2218) in 80% of samples. The CIT explained the natural/geogenic and anthropogenic sources of pollution, where the higher CIT values for Cd indicated industrial, aquaculture, and coal-based thermal powerplant. The RF model provided that shrimp firms, power plants, industry, and seaport were recognized as the influential sources for Zn, Pb, Cr, Cd, and As in sediments. Though Pb and As were found as the most significant pollutants, Cd was identified as a severe threat to ecology and public health. Based on CIT, RF, SOM and PCA the order of PTEs in mangroves sediment were:industrial/urban > aquaculture/shrimpfirm > powerplant > seaportoperation > tourism > geogenic/natural. The present study will help the policymakers for effective and sustainable management of the mangrove ecosystem.

Numerous applications exist for graphene-based materials, such as graphene oxide (GO) nanosheets. Increased concentrations of GO nanosheets in the environment have the potential to have a large negative effect on the aquatic environment, with consequences for benthic organisms, such as polychaetes. The polychaete Hediste diversicolor mobilises the sediments, hence altering the availability of contaminants and the nutrients biogeochemical cycle. As such, this study proposes to assess the effects of different GO nanosheet concentrations on the behaviour, feeding activity, mucus production, regenerative capacity, antioxidant status, biochemical damage and metabolism of H. diversicolor. This study evidenced that H. diversicolor exposed to GO nanosheets had a significantly lower ability to regenerate their bodies, took longer to feed and burrow into the sediment and produced more mucus. Membrane oxidative damage (lipid peroxidation) increased in exposed specimens. The increased metabolic rate (ETS) evidenced a higher energy expenditure in exposed organisms (high use of ready energy sources – soluble sugars) to fight the toxicity induced by GO nanosheets, such as SOD activity. The increase in SOD activity was enough to reduce reactive oxygen species (ROS) induced by GO on cytosol at the lowest concentrations, avoiding the damage on proteins (lower PC levels), but not on membranes (LPO increase). This study revealed that the presence of GO nanosheets, even at the lower levels tested, impaired behavioural, physiological, and biochemical traits in polychaetes, suggesting that the increase of this engineered nanomaterial in the environment can disturb these benthic organisms, affecting the H. diversicolor population. Moreover, given the important role of this group of organisms in coastal and estuarine food webs, the biogeochemical cycle of nutrients, and sediment oxygenation, there is a real possibility for repercussions into the estuarine community.

Bensulfuron-methyl (BSM) residues in soil threaten the rotation of BSM-sensitive crops. Microbial biofilms formed on crop roots could improve the ability of microbes to survive and protect crop roots. However, the research on biofilms with the purpose of mitigating or even eliminating BSM damage to sensitive crops is very limited. In this study, one BSM-degrading bacterium, Hansschlegelia zhihuaiae S113, colonized maize roots by forming a biofilm. Root exudates were associated with increased BSM degradation efficiency with strain S113 in rhizosphere soil relative to bulk soil, so the interactions among BSM degradation, root exudates, and biofilms may provide a new approach for the BSM-contaminated soil bioremediation. Root exudates and their constituent organic acids, including fumaric acid, tartaric acid, and l-malic acid, enhanced biofilm formation with 13.0–22.2% increases, owing to the regulation of genes encoding proteins responsible for cell motility/chemotaxis (fla/che cluster) and materials metabolism, thus promoting S113 population increases. Additionally, root exudates were also able to induce exopolysaccharide production to promote mature biofilm formation. Complete BSM degradation and healthy maize growth were found in BSM-contaminated rhizosphere soil treated with wild strain S113, compared to that treated with loss-of-function mutants ΔcheA-S113 (89.3%, without biofilm formation ability) and ΔsulE-S113 (22.1%, without degradation ability) or sterile water (10.7%, control). Furthermore, the biofilm mediated by organic acids, such as l-malic acid, exhibited a more favorable effect on BSM degradation and maize growth. These results showed that root exudates and their components (such as organic acids) can induce the biosynthesis of the biofilm to promote BSM degradation, emphasizing the contribution of root biofilm in reducing BSM damage to maize.