Pollution characteristics and underlying ecological risks of primary semi-volatile organic compounds (SVOCs) in urban watersheds of Shanghai, China.

We investigated the pollution characteristics of ninety semi-volatile organic compounds (SVOCs) in the rivers and lakes of Shanghai. Total concentrations of Σ90SVOCs in water and sediment samples from 30 sites ranged from 1.47 to 19.5 µg/L and 2.38 to 9.48 mg/kg, respectively. PAEs and PAHs were the major contaminant compounds found in all samples. OCPs accounted for less than 3% of the total concentrations of Σ90SVOCs and other SVOCs were either not detected or only detected in trace amounts. Our results indicated that domestic swage, industrial wastewater, petroleum products, and other human activities were the pollutant sources to the water and sediment. It is noteworthy that products that contain the banned chemicals HCH and DDT are still under use within the studied areas. Ecological and health risk assessment results showed that dieldrin and BBP have the potential to cause adverse effects on the environment, while B(a)p and DBP have high carcinogenic risks to humans.

Electron beam irradiation induced degradation of antidepressant drug fluoxetine in water matrices.

With the development of psychiatric disorder in the current society, abuse of antidepressant drug fluoxetine (FLX) has made such compound an emerging contaminant in natural waters, and causes endocrine systems disturbance on some aquatic species. Herein, an efficient advanced oxidation process (AOP), electron beam irradiation was carried out to investigate the decomposition characteristics of such novel environmental pollutant, including the effects of initial concentration, pH, radical scavengers and anions. The results showed that FLX degradation followed pseudo-first-order kinetics. The degradation rate and dose constant decreased with increasing initial FLX concentration; and G-values elevated with the increase of initial concentration but reduced with increase of absorbed dose. Acidic condition was more conducive to FLX destruction than neutral and alkaline. The radical scavenger experiments indicated OH was the main reactive species for the decomposition of FLX, while the reductive species e-aq and H played an adjuvant role. The presence of anions slightly decreased or even no impact on FLX degradation rate. Various water matrices influenced degradation processes of FLX. Experimental results suggested radiolytic degradation showed the best performance in pure water rather than natural water no matter with filtration or not. Moreover, with the occurrence of defluorination and dealkylation during degradation process, some organic and inorganic intermediates were detected, and the possible degradation mechanisms and pathways of FLX were proposed.

Hexabromocyclododecane and tetrabromobisphenol A in tree bark from different functional areas of Shanghai, China: levels and spatial distributions.

The concentrations and spatial distributions of hexabromocyclododecane (HBCDD) and tetrabromobisphenol A (TBBPA) were measured in tree bark from different functional areas of Shanghai. ΣHBCDD (sum of α-, ß-, and γ-HBCDD) concentrations ranged from 1.2 × 102 to 6.6 × 103 ng g-1 lw (median 5.7 × 102 ng g-1 lw) and TBBPA concentrations ranged from 48 to 7.2 × 104 ng g-1 lw (median 2.8 × 102 ng g-1 lw). The concentrations of ΣHBCDD and TBBPA all followed the order of industrial areas > commercial areas > residential areas. The mean percentage of α-HBCDD in bark samples (44%) from Shanghai was higher than that in technical HBCDD products, but comparable with that in air. The concentrations of TBBPA and individual HBCDD diastereoisomers between industrial areas and commercial areas were correlated. Based on the concentrations of HBCDD in the bark, the corresponding atmospheric HBCDD concentrations were estimated. Compared with the published data for HBCDD in urban air, the estimated atmospheric HBCDD concentrations in Shanghai had a relatively high level, and more attention should be paid to the pollution status of HBCDD in Shanghai.

Hexabromocyclododecane diastereoisomers in surface sediments from river drainage basins of Shanghai, China: occurrence, distribution, and mass inventory.

Concentrations of hexabromocyclododecanes (HBCDs) were determined in surface sediments of Shanghai, China. The concentrations of total HBCD diastereoisomers (ΣHBCD) ranged from 0.01 to 13.70 ng g(-1) dry weight (dw) with a mean value of 3.41 ng g(-1) dw, which was up to several orders of magnitude lower than those reported for sediments from European countries. The ΣHBCD concentrations in sediments from chemical/textile industrial or densely populated areas were generally higher than those from rural or less chemical/textile industrialized areas in Shanghai. A high proportion of α-HBCD was observed in sediment samples and was significantly higher than that of commercial HBCD products. This might be due to thermal isomerization from γ-HBCD to α-HBCD and slower degradation rate of α-HBCD compared to γ-HBCD in anaerobic conditions. The mass inventory of ΣHBCD in surface sediments of Shanghai was estimated at 164.4 kg, representing a significant source of HBCDs to the Shanghai environment. This indicates that further study on potential transfer of HBCDs from sediments to aquatic organisms and ecological risk assessments is required.