Distribution, Site-Specific Water Quality Criteria, and Ecological Risk Assessment of Heavy Metals in Surface Water in Fen River, China.

Due to a lack of toxicity reference values that match the regional environmental characteristics, the ecological risk of metals in water bodies cannot be accurately assessed. The Fen River is the second-largest tributary of the Yellow River in China, and the sustainability of this area is threatened by heavy metal pollution caused by intensive industrial and agricultural activities. In this study, site-specific water quality criteria (WQCs) for heavy metals in the Fen River were derived considering toxicity data from native aquatic organisms and regional water quality factors (e.g., water hardness). Short-term WQCs for Mn, Cu, Cd, Zn, Cr, Pb, and Ni were 2026.15, 98.62, 10.02, 63.07, 6.06, 166.74, and 132.73 µg/L, respectively, and long-term WQCs were 166.53, 29.71, 2.18, 19.29, 4.15, 6.38, and 14.76 µg/L, respectively. The distribution characteristics of these metals during the wet season in 2020 were explored, and their average concentrations in the river water did not exceed the environmental quality standards for surface water in China but were higher than the world average levels. Cr was the main pollutant in the sampling sites of Yaodu region, Hongdong Shitan, Xiao River, and Duanchun River, as was Pb in Duanchun River. Based on the site-specific WQCs, using hazardous quotient (HQ) and margin of safety (MOS10) approaches, a high risk of Pb was identified in the Duanchun River, and a medium risk of Cr might occur at midstream and downstream of Yaodu and Xiaodian. The results will provide a reference basis for heavy metal pollution control and water quality management in the Fen River.

Distribution, sources, and ecological risk assessment of polycyclic aromatic hydrocarbons in the sediments of Daihai Lake in Inner Mongolia, China.

Polycyclic aromatic hydrocarbons (PAHs) are typical toxic organic pollutants that can accumulate in sediments and may be toxic to aquatic organisms. In the present study, the contamination level, composition pattern, and sources of sixteen PAHs listed by the United States Environmental Protection Agency were investigated in surface sediments and a sediment core from Daihai Lake, which is located in a typical semiarid area of Inner Mongolia, China, and the ecological risk of these PAHs was assessed. The results show that the total concentration of PAHs in the surface sediments ranged from 204.6 to 344.5 ng/g with an average value of 287.2 ng/g and that compared with other aquatic systems, the level of PAHs in the sediments from Daihai Lake was low. However, a general upward trend was observed for the concentrations of PAHs in the sediment core, which might be related to the increase in human activities in the area. Moreover, the PAH concentrations were significantly positively correlated with the total organic carbon (TOC) content in the sediments, and it is thus inferred that TOC regulates the distribution of PAHs in Daihai Lake. Three-ring and four-ring PAHs were found to be predominant in all the sediment samples, and phenanthrene (Phe) was the most abundant compound. According to the composition of PAHs and the anthracene (Ant)/(Ant+Phe) or fluoranthene (Flt)/(Flt+pyrene (Pyr)) ratios, the PAHs in Daihai Lake mainly originated from the combustion of domestic coal, grass, and wood, and petroleum cannot be ignored as a source considering the growth of industry. Risk assessment based on a comparison of PAH concentrations and the effect range low (ERL) and effect range median (ERM) values demonstrated that acenaphthene (Ace) at 11 sites and fluorene (Flu) at 7 sites had occasional adverse biological effects.

Tissue-based assessment of hazard posed by mercury and selenium to wild fishes in two shallow Chinese lakes.

Total (all forms of inorganic and organic) concentrations of mercury (Hg) and selenium (Se) were measured in dorsal muscle and eggs of wild fishes from two shallow lakes in China: Tai Lake (Ch: Taihu; TL) and Baiyangdian Lake (BYDL). Hazard quotients (HQs) were calculated by dividing concentrations of Se or Hg in muscle or eggs of fishes by threshold concentrations for effects expressed as tissue residue toxicity reference values (TR-TRVs). Concentrations of Hg in whole bodies of fishes were estimated by concentrations in muscle. Based on concentrations of Hg in whole body, HQs for fishes in TL and BYDL were less than 1.0, which suggests little to moderate potential for effects on these fishes and unaccepted adverse effects of Hg are unexpected for adult fishes. HQs of Se in muscle of common carp from TL were closed to 1.0, and 27% of HQs based on concentrations of Hg in eggs of fishes from BYDL exceeded 1.0. Potential hazard due to Hg on common carp in TL and reproductive effects of Se on fishes from BYDL exhibited need for concern. Ratios of molar concentrations of Se to Hg were greater than 1.0. Thus, there might be some protective effects of Se on effects of Hg on fishes in TL and BYDL.

Toxicity reference values for polybrominated diphenyl ethers: risk assessment for predatory birds and mammals from two Chinese lakes.

PBDEs are persistent organic pollutants, and have the capability to produce adverse effects on organisms. Aquatic piscivorous species at higher trophic levels have the greatest exposure risk. Information on the toxic potency of a commercial PBDE mixture, DE-71, to mink and American kestrel was reviewed, and dietary- and tissue-based TRVs were derived and evaluated for ecological risk assessment of aquatic piscivorous species inhabiting wetland areas in China. The effect on mink thyroid function was identified as the most appropriate and protective endpoint for deriving the TRV s for mammals. The TRV was based on dietary exposure, and wa s0.1 mg DE-71/kg (wm) or 0.01 mg DE-71/kg (bm)/day (ADI); for liver of mammals,the TRV was 1.2 mg LPBDEslkg (lm). For birds, reproductive effects on American kestrels were used to derive the TRVs, in which an overall UF of 3.0 was used. The TRV was based on dietary exposure, and was 0.1 mg DE-71/kg (wm) or 0.018 mg DE-71/kg (bm)/day (ADI); for eggs of birds, the TRV was 2.35 jlgLPBDEs/g (lm). Reported concentrations of PBDEs in livers of aquatic mammals found dead, and in fish and bird eggs from Chinese wetland areas were compiled and compared to the corresponding criteria values. Results indicated that TRV values reported in this study can be used as indicators for screening-level risk assessment of piscivorous species in Chinese aquatic systems. Furthermore, based on monitoring concentrations of PBDEs in fishes from two lakes (DCL and TL) in China and the dietary-based TRV of 0.1 mg DE-71/kg (wm), a screening-level risk assessment of PBDEs was performed for predatory birds and mammals. The results suggest that concentrations of PBDEs in these two areas would not be expected to cause any adverse effects on the local fish-eating wild birds and mammals.

Predicted no-effect concentration and risk assessment for 17-[beta]-estradiol in waters of China.

Contamination of the aquatic environment by EDCs has received considerable attention from scientists, government officials, and the public. E2, one of the EDCs with high estrogenic effect, has the potential to cause multiple endocrine-disrupting effects, even at small concentrations. In the present review, the toxicity of E2 to aquatic organisms was reviewed. Results of published studies show that, for aquatic species, reproductive effects were the most sensitive endpoint for E2 exposure.Although the risks posed by EDCs have caused much attention, the research on the WQC 'for EDCs is still at the initial stage. It has been suggested in several reports that the PNEC can be regarded as the most appropriate reference value for developing WQC for the EDCs. The SSD method was applied to derive PNECs that were based on reproductive effects endpoints. In the present review, 31 NOECs, based on reproductive effect endpoints for different species, were selected to construct the curve. ThePNEC value was determined to be 0.73 ng E2/L, which could protect the biodiversity of aquatic ecosystems. Moreover, 6 NOECs for multigeneration species were also analyzed in anticipation of sensitivity comparison between the Fa and the F1 generations.When multiple generations of aquatic species were exposed to concentrations no greater than 100 ng E2/L, nearly 71.4% of the F 1 generation individuals were more sensitive to the effects of E2 than those of the Fa generation. This result indicated that different generations of the same species may respond differently to EDCs exposure.Individuals of the F 1 generation were slightly more sensitive than those of the Fa generation,in general. Therefore, protecting the F1 generation of aquatic organisms is particularly important when WQC values for the EDCs are established.Considering the toxic effects of EDCs on reproduction, long-term toxic effects(viz., full-life cycle study and the most sensitive life stage) should be used in settingWQC. Unfortunately, the NOECs of E2 for multigeneration species did not meet the requirement of PNEC derivation for protecting the Fl generation. Therefore, further research results are needed on the Fl generation of aquatic species to provide more insight into what constitutes adequate protection for aquatics lives. In the present review, the PNEC values derived in the study were compared to thePNEC values developed by others, and the results showed that they were highly consistent. In addition, we also compared the PNEC value for E2 to the PNEC value for EE2, a similar estrogen, and the result was also highly consistent when their EEFs were considered. These comparisons affirmed that the method we used for deriving the PNEC value of E2 was reasonable and the PNEC values we derived were acceptable for protecting aquatic organisms. By comparing the PNEC values we calculated to actual E2 concentrations in the natural water environment, we found that E2 in surface waters may pose high risks in many countries, especially China, Japan, the USA, Great Britain, and Italy.

[Ecological risk assessment of bisphenol A in Chinese freshwaters].

Bisphenol A (BPA) has many toxic effects on aquatic organisms, of which the most obvious effect is the estrogenic effect. The data collected in the study were divided into two parts, based on the response of the tested organisms to the estrogenic effects of BPA and their exposed time, and the risk of BPA to Chinese aquatic water was assessed by using quotient method, quotient exponent and probability method, safety threshold value method and joint probability risk assessment, respectively. Similar results were derived from the above four methods. Aquatic organisms were more sensitive to the estrogenic effects of BPA than other toxic effects. The results of risk assessment from safety threshold value method were more accurate and confident than the other three methods. Using the chronic data of BPA's estrogenic effect on tested organisms as the endpoint for risk assessment in safety threshold value method, it was found that in 64.70% of the Chinese freshwaters more than 5% of aquatic organisms were affected by the estrogenic toxicity of BPA, and the maximum allowable concentration of BPA was 15.72 ng x L(-1). Using the acute data of such effects as endpoint in safety threshold value method, in about 20.43% volume of the Chinese freshwaters more than 5% of aquatic organisms were affected by the estrogenic toxicity of BPA, and the maximum allowable concentration was 2.24 x 10(2) ng x L(-1).

Spatial distribution and pollution assessment of heavy metals in urban soils from southwest China.

To identify the concentrations and sources of heavy metals, and to assess soil environmental quality, 63 soil samples were collected in Yibin City, Sichuan Province, China. Mean concentrations of As, Pb, Zn, and Cu were 10.55, 61.23, 138.88 and 56.35 mg/kg, respectively. As concentrations were comparable to background values, while Pb, Zn, and Cu concentrations were higher than their corresponding background values. Industrial areas exhibited the highest concentrations of As, Pb, Zn, and Cu, while the lowest concentrations occurred in parks. Statistical analysis was performed and two cluster groups of metals were identified with Pb, Zn, and Cu in one group and As in the other. Spatial distribution maps indicated that Pb, Zn, and Cu were mainly controlled by anthropogenic activities, whereas As could be mainly accounted for by soil parent materials. Pollution index values of As, Pb, Zn, and Cu varied in the range of 0.24-1.93, 0.66-7.24, 0.42-4.19, and 0.62-5.25, with mean values of 0.86, 1.98, 1.61, and 1.78, respectively. The integrated pollution index (IPI) values of these metals varied from 0.82 to 3.54, with a mean of 1.6 and more than 90% of soil samples were moderately or highly contaminated with heavy metals. The spatial distribution of IPI showed that newer urban areas displayed relatively lower heavy metal contamination in comparison with older urban areas.

[Uncertainty characterization approaches for ecological risk assessment of polycyclic aromatic hydrocarbon in Taihu Lake].

Probabilistic approaches, such as Monte Carlo Sampling (MCS) and Latin Hypercube Sampling (LHS), and non-probabilistic approaches, such as interval analysis, fuzzy set theory and variance propagation, were used to characterize uncertainties associated with risk assessment of sigma PAH8 in surface water of Taihu Lake. The results from MCS and LHS were represented by probability distributions of hazard quotients of sigma PAH8 in surface waters of Taihu Lake. The probabilistic distribution of hazard quotient were obtained from the results of MCS and LHS based on probabilistic theory, which indicated that the confidence intervals of hazard quotient at 90% confidence level were in the range of 0.000 18-0.89 and 0.000 17-0.92, with the mean of 0.37 and 0.35, respectively. In addition, the probabilities that the hazard quotients from MCS and LHS exceed the threshold of 1 were 9.71% and 9.68%, respectively. The sensitivity analysis suggested the toxicity data contributed the most to the resulting distribution of quotients. The hazard quotient of sigma PAH8 to aquatic organisms ranged from 0.000 17 to 0.99 using interval analysis. The confidence interval was (0.001 5, 0.016 3) at the 90% confidence level calculated using fuzzy set theory, and the confidence interval was (0.000 16, 0.88) at the 90% confidence level based on the variance propagation. These results indicated that the ecological risk of sigma PAH8 to aquatic organisms were low. Each method has its own set of advantages and limitations, which was based on different theory; therefore, the appropriate method should be selected on a case-by-case to quantify the effects of uncertainties on the ecological risk assessment. Approach based on the probabilistic theory was selected as the most appropriate method to assess the risk of sigma PAH8 in surface water of Taihu Lake, which provided an important scientific foundation of risk management and control for organic pollutants in water.