In vitro toxicity assessment of sediment samples from Huangpu River and Suzhou River, Shanghai, China

Long-term environmental surveillance of PM2.5-bound polycyclic aromatic hydrocarbons in Jinan, China (2014-2020): Health risk assessment

We established long-term surveillance sites in Jinan city to monitor PM_2.5 particles (PM2.5) and PM2.5-bound PAHs (2014-2020). The range of PM2.5 was 15-230 µg/m³. The average annual ƩPAH₁₆ were 433 ± 271 ng/m³ (industrial area) and 299 ± 171.8 ng/m³ (downtown). PAHs captured in winter accounted for 61.5% (industrial area) and 59.1% (downtown) of total PAHs. A hazardous seasonal benzo[a]pyrene level was detected in 2015-2016 winter as 14.03 ng/m³ (14 folds of EU standard). The dominant PM2.5-bound PAHs were benzo[b]fluoranthene (24-26%), chrysene (19-20%), benzo[g,h,i]perylene (15%), Indeno(1,2,3-cd)pyrene (12%) and Benzo[a]pyrene (10%). Toxic equivalent quotients of PAHs were 4.93 ng/m³ (industrial area) and 3.13 ng/m³ (downtown). Excess cancer risks (ECRs) were 4.3 × 10^-4 ng/m³ and 2.7 × 10^-4 ng/m³, respectively. The ECRs exceeded EPA regulatory limit of 1 × 10^-6 ng/m³ largely. Non-negligible excess lifetime cancer risks were found as 36 and 26 related cancer incidences per 1,000,000 people. Consistently, local prevalence of lung cancer raise from 56.97/100,000 to 72.38/100,000; the prevalence of thyroid cancer raise from 10.12/100,000 to 45.26/100,000 from 2014 to 2020. Our findings suggest an urgent need to investigate the adverse health effects of PAHs on local population and we call for more strictly restriction on coal consumption and traffic tail gas emission.

Oxidative stress and EROD activity in Caco-2 cells upon exposure to chlorinated hydrophobic organic compounds from drinking water reservoirs

Our previous studies showed hydrophobic organic compounds (HOCs) in the sediments of drinking water reservoirs caused DNA damage in human cells (Caco-2) after chlorination. However, the main mechanisms remained unclear. This study compared oxidative damage and EROD activity in Caco-2 cells upon exposure to chlorinated HOCs, and the role of antioxidants (catalase, vitamin C and epigallocatechin gallate (EGCG)) in reducing the toxicities was examined. The result showed that chlorinated HOCs induced a 4-fold increase in production of reactive oxygen species (ROS) compared with HOCs. Antioxidants supplement significantly reduced ROS yields and DNA peroxidation. HOCs with relatively higher TEQ_bio were greatly reduced (about 98%) after chlorination, indicating dioxin-like toxicity is not the main factor inducing oxidative damage by chlorinated HOCs. Yet, ROS and the associated oxidative damage seem to be more responsible for causing DNA damage in the cells. Antioxidants including catalase, Vitamin C and EGCG showed protective effect against chlorination.

Removal efficiencies and risk assessment of endocrine-disrupting chemicals at two wastewater treatment plants in South China

Endocrine-disrupting chemicals (EDCs) in the effluent from wastewater treatment plants (WWTPs) are an important pollutant sources of the aquatic system. In this study, the removal efficiencies of eight typical EDCs at two domestic WWTPs in Dongguan City, China, are reported based on instrumental analysis and bioassay results. Bioactivities, including steroidogenesis-disrupting effects, estrogen receptor (ER)-binding activity, and aryl hydrocarbon receptor (AhR)-binding activity were evaluated using the H295R, MVLN, and H4IIE cell bioassays, respectively. The potential environmental risks of these residual EDCs were also evaluated. The results of instrumental analysis showed that nonylphenol was the major chemical type present among the eight tested EDCs. Meanwhile, concentrations of estrogen compounds including estrone, 17β-estradiol (E2), estriol, 17α-ethinyl estradiol, and diethylstilbestrol were relatively low. The removal rates of all eight EDCs were relatively high. Although the chemical analysis indicated high removal efficiency, the bioassay results showed that steroidogenesis-disrupting effects as well as ER-binding and AhR-binding activities remained, with E2-equivalent values of effluent samples ranging from 0.16 to 0.9 ng·L^-1, and 2,3,7,8-tetrachlorodibenzo-p-dioxin-equivalent values ranging from 0.61 to 4.09 ng L^-1. Principal component analysis combined with regression analysis suggests that the chemicals analyzed in this study were partly responsible for these ER and AhR activities. Ecological risk assessment of the residual EDCs showed that estrone was the most hazardous chemical among the eight EDCs tested, with a risk quotient of 1.44-5.50. Overall, this study suggests that, despite high apparent removal efficiencies of typical EDCs, their bioactivities and potential ecological risks cannot be ignored.

Developmental instability is associated with estrogenic endocrine disruption in the Chilean native fish species, Trichomycterus areolatus

Endocrine disrupting compounds (EDCs) are widespread contaminants that alter the normal functioning of the endocrine system. While they cause dysfunctions in essential biological processes, it is unclear whether EDCs also impact developmental stability. In the present study, we investigated the occurrence of estrogenic endocrine disrupting compounds in a small watershed of south-central Chile impacted by anthropogenic activities. Then, we assessed their relationship with internal levels of estrogenic active compounds and fluctuating asymmetry (FA), a proxy of developmental stability in organisms with bilateral symmetry, in a native fish species (Trichomycterus areolatus). Yeast estrogenic screen assays were performed to measure estrogenic activity in river sediments and in male fish tissues collected from 17 sites along the Chillán watershed, and geometric morphometrics used to estimate fluctuating asymmetry based on the shapes of 248 fish skulls. Estrogenic activity was detected both in sediments and male fish tissues at concentrations of up to 1005 ng and 83 ng 17β-estradiol equivalent/kg dw, respectively. No significant correlation was found between the two. However, fish tissue estrogenicity, water temperature and dissolved oxygen explained >80% of the FA population variation. By showing a significant relationship between estrogenic activity and FA of T. areolatus, our results indicate that developmental stability can be altered by estrogenic endocrine disruption, and that FA can be a useful indicator of sub-lethal stress in T. areolatus populations.

Cyanobacterial blooms act as sink and source of endocrine disruptors in the third largest freshwater lake in China

Cyanobacterial blooms are of global concern due to the multiple harmful risks they pose towards aquatic ecosystem and human health. However, information on the fate of organic pollutants mediated by cyanobacterial blooms in eutrophic water remains elusive. In the present study, endocrine disruptive potentials of phytoplankton samples were evaluated throughout a year-long surveillance in a large and eutrophic freshwater lake. Severe cyanobacterial blooms persisted during our sampling campaigns. Estrogenic agonistic, anti-estrogenic, anti-androgenic, and anti-glucocorticogenic effects were observed in the phytoplankton samples using in vitro reporter gene bioassays. 27 endocrine disrupting chemicals (EDCs) of different modes of action were detected in the samples via UPLC-MS/MS system. Results from mass balance analysis indicated that the measured estrogenic activities were greater than the predicted estrogenic potencies from chemical analysis, demonstrating that chemical analysis of targeted EDCs is unable to fully explain the compounds responsible for the observed estrogenicities. Results from Spearman's correlation analysis concluded that the concentrations of ten EDCs in phytoplankton samples were negatively correlated with cyanobacterial biomass, suggesting the potential occurrence of biomass bio-dilution effects of EDCs due to the huge biomass of cyanobacteria during bloom seasons. The present study provided complementary information about the potential endocrine disruptive risks of cyanobacterial blooms, which is important for understanding and regulating EDCs in eutrophic lakes.

Occurrence, distribution and composition of aliphatic and polycyclic aromatic hydrocarbons in sediment cores from the Lower Fox River, Wisconsin, US

The Lower Fox River is a 39 mile section which supports approximately 270,000 rural inhabitants across 18 counties, 303,000 metropolitan residents in Green Bay and Appleton, Wisconsin, and several large industrial complexes such as paper mills and power plants. This paper presents the distribution and concentrations of aliphatic (n-alkanes) and aromatic hydrocarbons (polycyclic aromatic hydrocarbons [PAHs]) as well as total organic carbon (TOC) in the Lower Fox River to identify the sources of hydrocarbon contamination. Excluding one outlier, percent TOC values were between 0.73 and 19.9% with an average value of 6.74%. Total n-alkanes ranged from 3.51 μg/g to 117 μg/g and showed a strong presence of odd carbon-numbered n-alkane ratios (range of C25 to C35), suggesting source input from terrestrial biomass. The mean polycyclic aromatic hydrocarbon (PAH) concentration was 24,800 ng/g. High molecular weight PAH concentrations dominated the distribution of hydrocarbon contaminants. Cross-plots of PAHs were used to compare diagnostic source ratios of benz[a]anthracene (BaA), chrysene (Chr), fluoranthene (Flu), pyrene (Pyr), anthracene (Ant), phenanthrene (Phe), indeno[1,2,3-cd]pyrene (InP), and benzo[g,h,i]perylene (BghiP) by depth and area. PAH ratios varied slightly with the core depth. Deeper core sections indicated the presence of biomass combustion while the upper core sections indicated combustion of both petroleum and biomass. The PAH toxicity of one core was estimated using toxicity equivalency factors, and the benzo[a]pyrene toxic equivalence quotient totaled 2,293 ng/g-dry wt. Levels of PAHs in sediments are compared with established regulatory values and recommendations are made.