Coastal marine microalgae are exposed to anthropogenic pollutants, including pesticides from aquaculture/agriculture/household uses. Some microalgae species, such asPhaeodactylum tricornutum,can induce and accumulate UV-absorbing compounds (UACs) upon ultraviolet radiation (UVR) exposure to prevent deleterious effects. Tolerance mechanisms activated by natural stressors might also protect organisms from anthropogenic stressors. This work assesses the effects of the insecticide cypermethrin (Cyp) and UVR in the marine microalgae P tricornutum. Considering the pro-oxidant properties of both stressors and UACs' induction in P tricornutum, lethal and sublethal effects of Cyp were tested in cultures with and without UVR acclimation. After a 24-h exposure to 10μg L-1 of technical Cyp or culture medium, UACs, growth, glutathione-S-transferase activity (GST), sulfhydryl groups (SH-g), and lipid peroxidation (LPO) were analyzed. Results showed differences in terms of growth between Cyp and Cyp + UVR pre-exposure. UACs' content was induced after UVR acclimation and diminished after 24h of growth in control and UVR pre-treated cultures, while levels remained constant under Cyp exposure. A single Cyp exposure exerted GST induction, SH-g depletion, and LPO increments. In UVR-acclimatized treatments, oxidative stress responses showed similar or more pronounced effects than the single chemical exposure, suggesting a potential additive effect of the UVR acclimation. The contrasting effects of Cyp + UVR observed between growth and biochemical responses suggest different compensatory mechanisms that need to be further investigated. Also, it highlights the need to include both lethal and sublethal endpoints to understand microalgae's tolerance and its significance in the multiple stressors' context.

This study presents a comprehensive application of the probabilistic risk assessment methodology for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), which are two types of perfluoroalkyl acids frequently studied in recent years. The exposure characteristics of PFOA and PFOS in Chinese surface water on a nationwide scale were summarized. Individual predicted no-effect concentration (PNEC) and the sensitivities for taxonomic groups of primary producers, invertebrates, and vertebrates were derived by the species sensitivity distributions method. Both hazard quotients (HQs) and joint probability curves were calculated to assess the risks to aquatic organisms. Among seven Chinese river basins, the mean concentrations of PFOA and PFOS in the Yangtze River Basin were the highest (58ng/L and 22ng/L, respectively), while the lowest concentrations (< 1ng/L) were in the Songhua River Basin. The acute PNEC value was 2.43mg/L for PFOA and 0.96mg/L for PFOS, and the chronic PNEC value was 0.0067mg/L for PFOA and 0.0012mg/L for PFOS, respectively. The sensitivities of different taxonomic groups revealed higher sensitivity of primary producers for PFOA and higher sensitivity of invertebrates for PFOS. The acute HQs of PFOA and PFOS were less than 1. The probabilities of exposure concentrations exceeding 5th percentile toxicity value of the chronic data for all aquatic organisms were 1.65% for PFOA and 1.23% for PFOS, respectively, suggesting a low probability of effects to aquatic organisms. Compared with the risk scenarios worldwide, the ecological risks for chronic effects decreased in the order of PFOS (worldwide) > PFOA (China) > PFOS (China) > PFOA (worldwide).

Imazethapyr is an herbicide that is used in a variety of crops worldwide, including soybean and corn. The aim of the present study was to evaluate the biomarkers responses of adult Leptodactylus latinasus exposed to the formulation Pivot®H (10.59% imazethapyr) in the laboratory at concentrations and under conditions that simulate two potential field exposure scenarios: an immersion in field runoff (Scenario 1: 10mg/L) and a direct exposure to the droplets emitted by spray noozles (Scenario 2: 1000mg/L). In both scenarios, the experimental procedure involved completely immersing the frogs over a period of 15s. Different endpoints were evaluated at several ecotoxicological levels 48 and 96h after the herbicide exposure. These included individual (biometric indices and behavior alterations), histological (liver pigments and lesions), biochemical (catalase, glutathione system and cholinesterase activities) and genotoxic effects (micronuclei induction and nuclear abnormalities). Forty-eight hours after imazethapyr exposure, frogs submitted to Scenario 1 presented an inhibition of liver glutathione-S-transferase activity, whereas histological alterations and increased hepatic cholinesterase levels were observed in frogs exposed under Scenario 2. Ninety-six hours after exposure to the imazethapyr formulation, frogs from the Scenario 1 treatment presented a decrease in liver melanin and hemosiderin, increased hepatic catalase activity and micronuclei induction. For their part, frogs exposed to Scenario 2 presented a decrease in the hepatosomatic index, an increase in liver alterations, melanin reduction and micronuclei induction. The multivariate analysis enables correlations to be made between biomarkers of different organizational level in exposed anurans. Our result indicates that real exposure to imazethapyr formulations under field conditions may pose a risk to Leptodactylus latinasus populations living in the agroecosystems.

Khetri Copper Belt, Rajasthan, is anthropogenically active and geologically belongs to the Delhi super-group. A study was designed to understand the geochemical processes controlling the elemental mobility in the groundwater. Sampling sites were divided into three zones, i.e. copper, quartzite and granite mine zones depending on the type of mineral excavated. A total of 32 representative groundwater samples were collected and analysed for heavy metals and radionuclide (U) using ICP-MS. A maximum U concentration (average 87 µgL-1) is observed in the quartzite mine zone, and minimum (average 13 µgL-1) is found in the copper mine zone samples. A high concentration of U (maximum of 430 µgL-1) in groundwater is attributed to mineral dissolution due to geogenic and anthropogenic activities. Despite the presence of Jaspura and Gothra granitoid in the copper mine zone, the abundance of U is low suggesting the scavenging of U by sulphides or iron oxides. Additionally, at the confluence of two geological groups, Fe concentration is found high with a low concentration of U which further confirms scavenging of U. It is evident from the results that in the absence of iron-bearing sulphides, U concentration in groundwater would be very high compared to the current concentration. It also indicates low concentration of U in the copper mine zone is due to dissolution of Fe sulphide-rich waste. The present study recommends further research to understand the feasibility of mining waste for the removal of U contamination from groundwater.

The aquifer flowing beneath the Yucatan Peninsula, México, is one of the largest in the world and is in direct contact with the surface through "cenotes" (sinkholes) that have been documented to be contaminated with various classes of pollutants. The objective of this study was to evaluate the environmental status of the Great Mayan Aquifer through a review of data published on pollution of the cenotes. Approximately 1000 known georeferenced cenotes on the Yucatan Peninsula were geographically located. A map was generated using the geographic information system software. High-resolution satellite images were processed to complement the "QuickMap Services" and the formatting service of the Environmental Systems Research Institute. From the literature, 173 cenotes were identified as being sampled for various pollutants, and of these, one or more classes of pollutants were detected in 160 (i.e., greater than 92%) of the cenotes. Pollutants reported to be present included bacteria and viruses of human origin, fecal sterols, polycyclic aromatic hydrocarbons (PAHs), pesticides, pharmaceuticals, illicit drugs and personal care products. From the review of the literature, only 13 cenotes were reported to be free of the target pollutants. From this study, it can be concluded that the aquifer system with the Yucatan Peninsula is vulnerable to contamination from pollutants originating from wastewater, as well as surface runoff and infiltration from urban and agricultural lands.

Dragonflies (Order Odonata) often are considered to be biosentinels of environmental contamination, e.g., heavy metals and/or persistent organic pollutants (POPs). Dragonflies (n = 439) belonging to 15 species of 8 genera were collected from an abandoned mercury (Hg) mining region in China to investigate the bioaccumulation of total Hg (THg) and methylmercury (MeHg). THg and MeHg concentrations in dragonflies varied widely within ranges of 0.06-19mg/kg (average: 1.5 ± 2.2mg/kg) and 0.02-5.7mg/kg (average: 0.75 ± 0.65mg/kg), respectively. THg and MeHg were positively correlated with bodyweight (THg: r2 = 0.10, P = 0.000; MeHg: r2 = 0.09, P = 0.000). Significant variations were observed among species, with the highest MeHg value (in Orthetrum triangulare) was fivefold higher than the lowest (in Pantala flavescens). These variations were consistent with those of nitrogen isotope (δ15N) values, indicating that increased δ15N, i.e., trophic levels, may reflect increased exposure and uptake of biomagnifying MeHg in dragonflies. A toxicologicalrisk assessment found hazard quotients for specialist dragonfly-consuming birds of up to 7.2, which is 2.4 times greater than the permissible limit of 3, suggesting a potential toxicological risk of exposure.

The northeastern United States receives elevated mercury (Hg) deposition from United States and global emissions, making it critical to understand the fate of Hg in watersheds with a variety of aquatic habitats and land use types, such as the Finger Lakes region of New York State. Bats are valuable and important organisms to study chronic Hg exposure, because they are at risk of sublethal effects from elevated Hg exposure. The objectives of this study were to: (1) determine total Hg (THg) and methylmercury (MeHg) concentrations in big brown bats(Eptesicus fuscus) of the Finger Lakes region; (2) assess whether morphometric, temporal, or spatial factors predict bat Hg concentrations; and (3) investigate the role of trophic position and diet represented by stable isotopes of carbon and nitrogen in explaining variations in bat Hg concentrations. We found comparable THg and MeHg concentrations to previous studies (THg range 1-45ppm, MeHg range 0.5-38ppm) in big brown bat fur collected throughout the Finger Lakes region. On average, MeHg made up 81% of THg in bat fur. Fifteen percent of our samples showed higher THg than a proposed toxicity threshold of 10ppm. Together, dominant land cover and % wetland cover explained bat THg in the Finger Lakes. Trophic position (i.e., δ15N) was strongest in predicting bat THg in forests but was a weaker predictor of Hg bioaccumulation in bats from agricultural and urban areas. The range of Hg concentrations found in this study warrants further examination into the potential toxicological impacts of Hg to wildlife and the role of land use in Hg exposure to terrestrial organisms of the Finger Lakes.

The thyroid hormones, thyroxine (T4) and triiodothyronine (T3), are required to regulate complex developmental processes in vertebrates and are highly sensitive to endocrine-disrupting compounds. Previous studies demonstrate that dioctyl sodium sulfosuccinate (DOSS), a common constituent of pharmaceuticals, cosmetics, and food products, disrupts canonical signaling of adipocyte differentiation by binding a nuclear hormone receptor in the same superfamily as thyroid hormone (TH) receptors. The present study was designed to determine whether DOSS is capable of disrupting TH signaling using the American bullfrog, Rana (Lithobates) catesbeiana-a cosmopolitan frog species that undergoes TH-dependent metamorphosis to transition from an aquatic tadpole to a terrestrial juvenile frog. Premetamorphic R. catesbeiana tadpoles were injected with 2pmol/g body weight T3 or 10pmol/g body weight T4 to induce precocious metamorphosis, then exposed for 48h to environmentally or clinically relevant DOSS concentrations (0.5, 5, and 50mg/L). Gene expression of three classical TH-responsive targets (thra, thrb, and thibz) was measured in tadpole liver and tail fin tissue through reverse transcription quantitative polymerase chain reaction (RT-qPCR). DOSS disrupted gene expression in liver and tail fin tissue at all three concentrations tested but the patterns of expression differed by tissue, gene transcript, and TH treatment status. To our knowledge, this is the first demonstration that DOSS can alter TH signaling. Further exploration into DOSS disruption of TH signaling is warranted, because exposure may affect other TH-dependent processes, such as salmon smoltification and perinatal human development.

This study was conducted to understand the biological effects of microplastics (MPs), polystyrene microspheres (PSM), and polyethylene microparticles (PEM) in the juveniles of the giant river prawn, Macrobrachium rosenbergii. The PSM (0.5-1.0µm) and PEM (30.0-150.0µm) were separately incorporated into the artificial diets with concentrations of 1, 5, and 10mg per 100g. The prawns were fed with these diets for a period of 60days. Compared with control, the following dose-dependent changes have been recorded in PSM and PEM incorporated feeds fed prawns: declines in the survival rate, length and weight gains; increase in activities of antioxidant enzymes, such as superoxide dismutase, catalase, glutathione s-transferase, and glutathione peroxidase (GPx); elevated concentrations of reduced glutathione (GSH) and malondialdehyde; decreased activities of metabolic enzymes, such as glutamic oxaloacetic transaminase and glutamic pyruvic transaminase; higher total RNA in hepatopancreas (HP) of PSM fed prawns compared with that of PEM; higher total RNA in muscle (MU) of PEM-fed prawns compared with that of PSM; prominent cDNA bands in 150bp regions; up-regulated heat shock protein (HSP70) gene in HP; down-regulation of HSP70 gene in MU of PSM-fed prawns only; down-regulated myostatin (MSTN) gene. These results suggest that these MPs have affected the survival and growth, activated the antioxidant defense, inhibit the metabolic enzymes, positively regulated the HSP70 gene, and negatively regulated the MSTN gene in M. rosenbergii. Therefore, exposures to PSM and PEM caused biological effects in this species of prawn.