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-, β-, 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.

Herein, we studied the occurrence and profiles of thirteen PBDE congeners in 30 river sediment samples from Shanghai, China. The concentrations of Σ13PBDEs ranged from 110 to 13,071 pg g−1 dw, with an average value of 2,841 pg g−1 dw. BDE-209 was the predominant congener accounting for more than 65 % of total PBDEs, demonstrating that the major source of PBDEs in sediment samples was associated with the prevalent use of technical deca-BDE products. Moreover, low brominated BDEs in sediments also came from the degradation of higher brominated BDEs. In addition, taking into consideration of dietary exposure, PBDEs in serum samples collected from the locals were also detected with range of 419–26,744 pg g−1 (average 5,561 pg g−1), which suggested a relatively low burden of PBDEs contamination to human body compared with the condition in other place. And in serum, low brominated compounds constituted the majority of total PBDE congeners.

Hydroxylated polyhalodiphenyl ethers (HO-PXDEs) have attracted considerable scientific interest as examples of emerging aquatic pollutants. However, a comprehensive assessment of disposal methods for this particular pollutant was seldom investigated. This study examined the UV light degradation of HO-PXDEs, using 2′-HO-2, 3′, 4, 5′-tetrabromodiphenyl ether (2′-HO-BDE-68) as a case study. The results showed that UV light was superior to visible light and electron beam irradiation for producing a high degradation rate of 2′-HO-BDE-68. At low concentrations of HO-BDE, the degradation rate was not obviously improved with decreasing initial concentration. The degradation efficiency was also found to be better in alkaline solutions. In a UV/H2O2 system, the hydroxyl radical provided by H2O2 was shown to enhance the degradation efficiency. The main photolysis products of 2′-HO-BDE-68 were identified, and the possible photodegradation pathways were proposed. 1, 3, 8-Tribromodibenzo-p-dioxin was one of the photoproducts, which indicates that secondary pollution must also be considered with the UV photolysis process.

Semivolatile organic compounds (SVOCs) in surface microlayer (SML) and subsurface water (SSW) from Dianshan Lake were studied to investigate their occurrence, distributions, as well as enrichment and potential sources. A sample was concentrated by solid-phase micro-extraction (SPME). Identification and quantification were carried out by gas chromatography coupled to mass spectrometry (GC–MS). Total SVOCs concentrations ranged from 25.93 to 47.49 μg/L in SSW and 38.19 to 77.23 μg/L in SML. The phthalic acid esters (PAE) concentrations in both SSW and SML are the highest of the total SVOC. The enrichment factors (EFs) of total SVOCs ranged from 0.80 to 2.98, while the highest EF was found in benzyl phthalate and dibutyl phthalate, compounds of PAEs (4.06). The EFs values calculated in this study were consistent with the EFs reported for other water ecosystems. Compared with other place, the EF of PAHs were in the normal level (0.88–2.37). The results of correlation analysis, principal component analysis (PCA) suggested that at least three sources, i.e., agricultural residual pesticides, industrial sewage and miscellaneous sources, were responsible for the presence of SVOCs in Dianshan Lake examined, accounting for 94.16% of the total variance in the dataset. Environmental risk assessment revealed that a majority of SVOCs posed relatively low risks (the values of risk quotient were less than 0.1), while naphthalene, acenaphthene, 2,4-dinitrotoluene, and dibutyl phthalat exhibited moderate risks (values of risk quotient were more than 0.1 but less than 1fore) to aquatic organisms.

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.

The electron beam (EB) radiolysis characteristics of carbamazepine (CBZ) in pure-water with different ions and that in surface water were studied in this paper. It suggested that the ·OH, ·H and eaq− all played roles on CBZ EB degradation, and the ·OH played the vital role. Acidic solution was favorable for CBZ degradation, while alkaline environment inhibited it. HSO4– and SO32− enhanced the CBZ degradation, but CO32−, NO2−, NO3− NH4+ and Cl− inhibited. In surface water, the EB-radiolysis was an effective way to degrade CBZ; and CBZ might evolve in three different ways during EB radiation: reduction by eaq− and ·H (intermediate 10,11-dihydrocarbamazepine (I)), oxidization by ·OH (intermediates 10,11-dihydro-10-11-expoxycarbamazepine (II) and 2(3)-hydroxycarbamazepine (III)) and hydration into 10,11-dihydro-10-hydroxycarbamazepine (IV) and finally the intermediates were all mineralized into CO2, H2O, N2 and NH4+. All the results contribute to study the EB-radiolysis of pharmaceuticals in surface water.

The photodegradation of clopyralid in pure and surface water under UV and simulated sunlight irradiation, were investigated to guide the treatment of clopyralid contaminated water in a natural environment. Under UV irradiation in pure water, the degradation rate of clopyralid was promoted with the decreasing of initial concentration and the degradation followed pseudo-first-order kinetics. Because of the competition between clopyralid and dissolved organic matters (DOM) for UV adsorption in surface water, the clopyralid degradation rate was lower in surface water than in pure water. The addition of H2O2 significantly enhanced the UV photodegradation of clopyralid; for example, after the addition of 0.2 mM H2O2 and 240 min irradiation nearly 100% degradation was achieved, compared with only 15% degradation without H2O2. To further understand the degradation process of clopyralid, the probable degradation pathway of clopyralid under UV/H2O2 was proposed. The removal of clopyralid was more effective under acidic condition than under neutral and alkaline conditions. Under simulated sunlight irradiation, there was no degradation of clopyralid in pure water, while it could be removed by adding hematoporphyrindihydrochloride (HPDHC) through indirect photodegradation, as HPDHC could generate single oxygen by absorbing the long wavelength sunlight and the single oxygen could facilitate clopyralid degradation. Similarly, a slight decomposition was observed in surface water, which was induced by DOM.

The degradation characteristics of clopyralid irradiated by electron beam (EB) was studied in aqueous solutions. The effects of factors, such as initial clopyralid concentrations, addition of radicals scavenger, initial solution pH and addition of H2O2, were investigated on clopyralid degradation efficiency and mechanism. It was found that the EB-radiolysis was an effective way to degrade clopyralid and its degradation rate decreased with the increasing of substrate concentration. In the investigated initial concentrations range of 100–400 mg L−1, the radiolytic degradation of clopyralid followed a pseudo-first kinetic order. The results from addition of radicals scavenger indicated that both •OH and eaq− played significant roles in the degradation of clopyralid. Furthermore, the alkaline condition and addition of H2O2 (<10 mM) in the solution also slightly enhanced the efficiency of clopyralid degradation. The ion chromatography analysis showed that some organic acids (formic acid, acetic acid and oxalic acid) were formed, while the completely dechlorination of the substrate was achieved and organic nitrogen was recovered in the form of ammonium and nitrate ions during the irradiation process.

•BP-UV filters from various point sources including river and water theme parks were investigated.•Population is a major factor that determines BP levels in water.•BP-3, and BP-4 may have a similar source with BP, BP-1 and 4-OH-BP.•Environmental risks posed by BP, BP-3 and BP-4 should not be neglected.Benzophenone-type UV filters (BP-UV filters) are frequently introduced into aquatic environment from several sources. The occurrence and fate of select BP-UV filters and their metabolites were investigated in this study. All target compounds were detected in water samples, except for 2, 3, 4-trihydroxybenzophenone (2, 3, 4-OH-BP). The concentration reached up 131 ng L−1 for 5-benzoyl-4-hydroxy-2-ethoxybenzenesulfonic acid (BP-4), 30.0 ng L−1 for 2-hydroxy-4-methoxybenzophenone (BP-3), and mean value of 158 ng L−1 for benzophenone (BP). Concentrations of BP-UV filters were not related to recreational waters but with high population frequencies. In addition, five BP-UV filters, namely 2,2′,4,4′-tetrahydroxybenzophenone (BP-2), 2,3,4-OH-BP, 2,4-dihydroxybenzophenone (BP-1), 4-hydroxybenzophenone (4-OH-BP) and BP were investigated for probable sources, and found that they originate from BP-3 metabolism. There is a similar source for BP-3, BP-4, BP-1, 4-OH-BP and BP. Environmental risk assessment (ERA) showed that risk quotients (RQs) of BP-4, BP-3 and BP were 2.7, 0.8 and 0.5, respectively.Download high-res image (359KB)Download full-size image