Uptake and translocation of polybrominated diphenyl ethers in the rhizosphere soil-crop-atmosphere system in e-waste dismantling areas in Taizhou, China.

Air, crop, and rhizosphere soil samples were collected from e-waste dismantling areas in Taizhou City (Zhejiang Province, China). The mean PBDEs (Polybrominated diphenyl ethers) concentrations in air in the Fengjiang and Binhai areas were 27.8 and 25.1 pg m-3, respectively (no significant difference, P > 0.05). The mean PBDE concentrations in rhizosphere soil from Fengjiang and Binhai were 9.19 × 104 and 1.34 × 103 pg g-1 dry weight, respectively (no significant difference, P > 0.05). The mean PBDE concentrations in the crop samples from Fengjiang and Binhai were 1.38 × 103 and 6.64 × 102 pg g-1 dry weight, respectively (no significant difference, P > 0.05). PBDEs with≥6 bromine atoms (BDEs-153, -154, -183, and -190) were not translocated from the crop roots to other tissues. PBDEs were taken up by crops selectively. The root epidermis effectively prevented PBDEs from entering edible crop parts and kept the PBDE concentrations in edible roots low. PBDEs with≤5 bromine atoms (BDEs-15, -28, -47, -66, -85, -99, and -100) were selectively enriched from the rhizosphere soil into crop roots, but PBDEs with more bromine substituents were not transferred from the rhizosphere soil to the crop roots. PBDEs with≥6 bromine atoms were selectively enriched from the atmosphere into crop leaves. Crop roots and leaves took up PBDEs with ortho bromine substituents more readily than PBDEs with meta bromine substituents because the octanol-water partition coefficients are lower for ortho-brominated than meta-brominated PBDEs.

Uptake and distributions of polycyclic aromatic hydrocarbons in cultivated plants around an E-waste disposal site in Southern China.

Polycyclic aromatic hydrocarbons (PAHs) in air, soil, and cultivated plants at e-waste disposal sites in Taizhou, Zhejiang Province, were determined to allow PAH uptake by and distributions in plants to be investigated. The PAH distributions in air, rhizosphere soil, and surface soil were markedly different. This indicated that root morphology variations and root exudates may affect PAH compositions in soil around plants. The PAH concentrations in the plant samples were 29.7-2170 ng/g. The lowest PAH concentration was found in a peeled taproot sample. The PAH concentration gradients from the plant shoots to roots suggested that PAHs entered the plants through various pathways. The three- and four-ring PAHs were found to be absorbed more readily than the higher-molecular-weight (five- and six-ring) PAHs. This indicated that high-molecular-weight PAHs in soil can be prevented from entering plants, particularly taproots, via root exudates and the root peel. For most plants, the highest PAH concentrations were found in leaves, indicating that atmospheric deposition may strongly affect PAH concentrations in aerial plant parts. High-molecular-weight PAHs are more readily absorbed from ambient air by leaves than other parts. Lower PAH concentrations were found in fruits than other plant parts. This and the differences in PAH distributions between fruits and other aerial parts indicated that PAHs may be selectively absorbed by fruits.

[Polybrominated Diphenyl Ether in E-waste Dismantling Sites in Taizhou City, Zhejiang Province: Concentration, Distribution, and Migration Trend].

The concentration of polybrominated biphenyl ethers (PBDEs) in surface soil and atmosphere of e-waste dismantling sites in Taizhou city, Zhejiang Province was determined. The concentration ranges of ∑12PBDEs in surface soil of e-waste dismantling site, farmland, and resident areas in Fengjiang Town (FJ) and Binhai Town (BH) were 21.8-1310 ng ·g-1 and 6.19-220 ng ·g-1, respectively. No significant difference was observed in the distribution of PBDEs between the FJ and BH soil. The concentration range of ∑12PBDEs in the atmosphere of FJ and BH were 262-3240 pg ·m-3 and 840-2990 pg ·m-3, respectively. The median levels of PBDEs in the atmosphere of FJ and BH were 1410 pg ·m-3 and 840 pg ·m-3 in winter and 1590 pg ·m-3 and 1960 pg ·m-3 in summer, respectively. However, a significant difference was observed in the distribution of 11 PBDE congeners, except BDE-209, during winter and summer seasons. The migration trend analysis showed the differences between the soil and air of FJ and BH. The main migration trend of 3-5-BDEs was the volatilization from soil to atmosphere, and the increase in temperature promoted the volatilization of these PBDEs from soil to atmosphere in FJ. This indicated that the PBDEs in soil had become a major source of pollution emission and suggested that soil remediation should be carried out at the e-waste dismantling site and parts of farmland in FJ. Contrary to FJ, atmospheric deposition was the major migration trend of PBDEs and the soil was the main sink of PBDEs in BH. This indicated that e-waste dismantling site in BH could be a new source of PBDEs emission in this area.

Concentrations and distributions of polybrominated diphenyl ethers (PBDEs) in surface soils and tree bark in Inner Mongolia, northern China, and the risks posed to humans.

Three functional zones, namely the industrial (IND), the agricultural (AGR), and the grassland (GRA) areas from Inner Mongolia (a remote province in northern China), were selected to evaluate the levels and distributions of PBDEs and the risks posed to local humans. PBDEs concentrations in surface soils and tree bark were detected and the air levels were estimated based on bark measurements. The total concentrations (∑8PBDEs) of BDE-28, -47, -100, -99, -154, -153, -183, and -209 in soils were 1.71-64.9 ng/g dry weight (d.w.), 0.720-4.08 ng/g d.w., and 0.604-3.76 ng/g d.w. in the IND, AGR and GRA areas respectively. The average total concentrations in bark and air were 0.792 ng/g d.w. and 0.125 ng/m³ in the AGR areas respectively, which were lower than those (1.69 ng/g d.w. in the bark and 0.476 ng/m³ in the air) in the IND areas. BDE-209 was the dominant congener, consistent with DeBDE being the dominant commercial products used in China. However, except for BDE-209, BDE-28 and BDE-47 in the AGR and GRA areas averagely contributed about half of the total PBDEs concentrations in soils. BDE-28 concentrations in the bark samples of the AGR areas were significantly higher (p < 0.05) than in the IND areas, and the average total hazard quotients (∑8PBDEs) were higher for humans in the AGR areas (0.12) than in the IND areas (0.08). Degradation of higher-brominated congeners (e.g., BDE-209) and migration of lower-brominated congeners (mainly BDE-28 and BDE-47) may increase the risks to humans in pristine areas.

Polychlorinated naphthalenes, polychlorinated dibenzo-p-dioxins and dibenzofurans, and polychlorinated biphenyls in soils in an industrial park in Northwestern China: Levels, source apportionment, and potential human health risks.

Seventeen soil samples collected in an industrial park located in Ningxia Province, Northwestern China were analyzed for polychlorinated naphthalenes (PCNs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs). The PCN, PCDD/F, and PCB concentration ranges were 183-3340, 7.00-215, and 45.1-355 pg/g, respectively. Positive matrix factorization showed that secondary ferrous metal smelters and cement kilns contributed more than 70% of the total PCN concentration. Historical use of Halowax 1051 also affected the PCN concentrations in soil. Principal component analysis indicated that the PCDD/F concentrations in soil in the study area were mainly affected by thermal processes in secondary ferrous metal smelters. CB-209 was an important contributor to total PCBs in the study area, and likely originated from the phthalocyanine-type pigments used in a local recycled paper mill. Samples S10, S1, S17, and S6 had high ∑TEQ (PCDD/Fs + PCNs + PCBs) concentrations, and the carcinogenic risks of PCDD/Fs, PCNs, and PCBs for workers from these samples were 0.487 × 10-6, 0.234 × 10-6, 0.230 × 10-6, and 0.210 × 10-6, respectively. According to our results, the health risks of PCDD/Fs, PCNs, and PCBs for workers in this area should be given more attention.

[Distribution of 16 Polycyclic Aromatic Hydrocarbons in Dianchi Lake Surface Sediments After the Integrated Water Environment Control Project].

The external pollution of Dianchi Lake has been effectively controlled with the implementation of the integrated water environment control project. However, further attention should be paid to endogenous pollutants, such as surface sediments. To investigate the distribution of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Dianchi Lake, PAH concentrations in 19 surface sediment samples (collected in December 2016) were quantitatively measured by gas chromatography-mass spectrometry (GC-MS). The spatial and temporal distribution, sources, and ecological risks were also analyzed. The concentration of total PAHs (TPAHs) in the Dianchi Lake surface sediments varied in the range of 92.31-1546.78 ng·g-1 with an average of 496.30 ng·g-1. The average concentration of TPAHs in the surface sediments from Caohai (932.37 ng·g-1) was much greater than that from Waihai (380.02 ng·g-1). With the implement of the integrated water environment control project, the concentration of TPAHs in the surface sediments from Dianchi Lake was significantly lower than those detected in 2012, and was already relatively low level among other key waterbodies in China. The PAH with the highest concentration was fluoranthene (80.65 ng·g-1) and the substance with the highest toxic equivalent quantity (TEQ) was dibenz[a, h] anthracene (42.97 ng·g-1). The PAHs were mainly composed of 4 ring and 5-6 ring compounds (with the concentration ratio of 40.38% and 40.22%, respectively), which indicated that the proportions of middle-ring and high-ring compounds were generally consistent. The results of the molecular diagnostic ratio analysis showed that the primary source of PAHs in Dianchi Lake surface sediments are biomass and coal combustion. Based on the potential ecological risk marker comparison method, the entire lake was classified as having a low ecological risk, while the ecological risk of Caohai was relatively higher, which should be concerned further. The results provide initial data and act as an important reference for the conservation and improvement of water quality in Dianchi Lake.