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Результаты 201-210 из 3,240
Exploring the bioaccessibility of polybrominated diphenyl ethers (PBDEs) in sewage sludge Полный текст
2015
Meng, Xiang-Zhou | Xiang, Nan | Yu, Lihong | Zhang, Jiying | Chen, Ling | Dai, Xiaohu
Environmental risks of polybrominated diphenyl ethers (PBDEs) in sewage sludge are assessed based on the concentration by exhaustive extraction, which is a likely overestimation of the pool available to exposed organisms. This study evaluated the bioaccessibility of PBDEs in sewage sludge from Shanghai using a 3-compartment model and a 6-d Tenax extraction. The very slowly fraction contributed 56–88% of total PBDEs in spiked sludge, whereas the rapidly desorbing fraction contributed only 1.1–10%. For the same PBDE congener, the rapidly desorbing fractions for sewage sludge measured in the present study were lower than those for sediment. The bioaccessible concentrations of PBDEs were 2.3–56 ng/g dry weight in sewage sludge from Shanghai, which represented 5.2% of the concentration determined by exhaustive (Soxhlet) extraction. BDE-209 was the predominant congener in sludge, contributing to 63% of the total. Moreover, the Ratio between 6-h Tenax and Soxhlet concentrations (T/S Ratio, indicating bioaccessibility) was lower in sludge generated from industrial wastewater treatment compared to sludge from facilities that treated mostly domestic wastewater. The T/S Ratio of PBDE congeners was related to KOW, specifically as KOW increases, the T/S Ratio decreased. These results will improve understanding of the fate and potential toxicity of PBDEs during land and/or landfill application of sewage sludge.
Показать больше [+] Меньше [-]Health impact of bioaccessible metal in lip cosmetics to female college students and career women, northeast of China Полный текст
2015
Gao, Peng | Liu, Sa | Zhang, Zhaohan | Meng, Ping | Lin, Nan | Lu, Binyu | Cui, Fuyi | Feng, Yujie | Xing, Baoshan
Actual measure-based studies have estimated ingestion rate of moderate and high daily use to female college students and career women in northeast of China. Sequential extraction analyses showed that total bioaccessible metals concentration in lipstick ranged from 2.103 to 31.103 μg/g and in lip balm ranged from 0.100 to 3.716 μg/g. The relationship between total bioaccessible metal concentrations and the cost of lip cosmetics showed a negative correlation. Lead was detected in all 30 products (100%), with an average concentration of 0.346 for lip balm and 0.407 μg/g for lipstick. With the exception of chromium content in three lipsticks, the estimated exposure in female college students and career women to target metals via lipstick and lip balm ingestion (calculated for moderate and high use) were much lower than the acceptable reference limits. The findings strongly emphasize the need to focus on the health risk of lip balm.
Показать больше [+] Меньше [-]Temporal trends of mercury, organochlorines and PCBs in northern gannet (Morus bassanus) eggs from Bonaventure Island, Gulf of St. Lawrence, 1969–2009 Полный текст
2015
Champoux, Louise | Rail, Jean-François | Lavoie, Raphael A. | Hobson, Keith A.
Since 1969, northern gannet (Morus bassanus) eggs from Bonaventure Island, Québec, have been collected to monitor concentrations of contaminants. Levels of p,p′-DDE, which caused low breeding success of Bonaventure gannets in the 1960s, decreased by 99.4% from 1969 to 2009 (17.1–0.1 mg/kg ww), with concomitant improvement of hatching success. PCBs, most organochlorines and mercury also showed decreasing trends. Stable isotopes of carbon (δ13C) and nitrogen (δ15N) were measured to track the possible influence of diet changes on concentrations of contaminants over time. The confounding effect of the combustion of fossil fuels on baseline values of δ13C (the Suess effect) was taken into account. No temporal trends were observed in δ13C and δ15N values in gannet eggs. Hence trophic level or foraging area had a negligible influence on temporal trends of contaminants.
Показать больше [+] Меньше [-]Influence of organic amendment on fate of acetaminophen and sulfamethoxazole in soil Полный текст
2015
Land application of biosolids or compost constitutes an important route of soil contamination by emerging contaminants such as acetaminophen and sulfamethoxazole. Using 14C labeling, we evaluated the influence of biosolids and compost on individual fate processes of acetaminophen and sulfamethoxazole in soil. The amendment of biosolids or compost consistently inhibited the mineralization of both compounds but simultaneously enhanced the dissipation of their extractable residues or parent form. Immediately after treatment, the majority of 14C-residue became non-extractable, reaching 80.3–92.3% of the applied amount at the end of 84-d incubation. Addition of biosolids or compost appreciably accelerated the formation of bound residue, likely due to the fact that the organic material provided additional sites for binding interactions or introduced exogenous microorganisms facilitating chemical transformations. This effect of biosolids or compost should be considered in risk assessment of these and other emerging contaminants.
Показать больше [+] Меньше [-]Investigation on the distribution and fate of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in a sewage-impacted bay Полный текст
2015
Wang, Shiliang | Wang, Hui | Zhao, Wei | Cao, Yuanxin | Wan, Yi
The distribution and fate of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) were investigated in the water and sediment of Bohai Bay, China, during 2011–2013. A total of 360 water samples and 60 sediment samples were collected from 20 locations. The median concentrations of PFOS and PFOA were 4.8 and 12.15 ng/L in the water, and 2.65 and 0.62 ng/g-dry in the sediment, respectively. Significant enrichment were observed for PFOS and PFOA in water of sea surface microlayer. The concentrations of these two compounds showed an apparent gradient from nearshore to offshore stations. The correlation analysis and the distribution tendencies indicated that freshwater inflowing to the bay was the main source of PFOS and PFOA. The salinity of seawater and the total organic carbon (TOC) content of sediment heavily affected the spatial distribution and the partitioning of PFOS and PFOA in the sediment-water system.
Показать больше [+] Меньше [-]Effects of oil pipeline explosion on ambient particulate matter and their associated polycyclic aromatic hydrocarbons Полный текст
2015
Zhao, Yue | Cao, Lixin | Zhou, Qing | Que, Qiming | Hong, Bo
Effects of the oil pipeline explosion on PM2.5-associated polycyclic aromatic hydrocarbons (PAHs) and their substituted (alkylated, nitrated, oxygenated, hydroxyl and chlorinated) derivatives are assessed near the accident scene of Qingdao, China. Compared with those in TSP-PM2.5, gaseous phase, burn residue and unburned crude oil, eighty-nine PAHs in PM2.5 are identified and quantified to investigate the composition, temporal and spatial distribution, and sources. The concentrations of PM2.5-associated parent PAHs increase approximately seven times from the non-explosion samples to the explosion samples (mean ± standard deviation: 112 ± 2 vs 764 ± 15 ng/m3), while some substituted products (nitro- and oxy-) increase by two orders of magnitude (3117 ± 156 pg/m3 vs 740 ± 37 ng/m3). The toxicity evaluation indicates the BaP equivalent concentrations (based on the US EPA's toxicity factors) in PM2.5 are much higher than those in the other phases, especially for a long duration after the tragic accident.
Показать больше [+] Меньше [-]Joint toxicity of sediment-associated permethrin and cadmium to Chironomus dilutus: The role of bioavailability and enzymatic activities Полный текст
2015
Chen, Xin | Li, Huizhen | Yau, Ching
Pyrethroid insecticides and metals commonly co-occurred in sediment and caused toxicity to benthic organisms jointly. To improve accuracy in assessing risk of the sediments contaminated by insecticides and metals, it is of great importance to understand interaction between the contaminants and reasons for the interaction. In the current study, permethrin and cadmium were chosen as representative contaminants to study joint toxicity of pyrethroids and metals to a benthic invertebrate Chironomus dilutus. A median effect/combination index-isobologram was applied to evaluate the interaction between sediment-bound permethrin and cadmium at three dose ratios. Antagonistic interaction was observed in the midges for all treatments. Comparatively, cadmium-dominated group (the ratio of toxicity contribution from permethrin and cadmium was 1:3) showed stronger antagonism than equitoxicity (1:1) and permethrin-dominated groups (3:1). The reasons for the observed antagonism were elucidated from two aspects, including bioavailability and enzymatic activity. The bioavailability of permethrin, expressed as the freely dissolved concentrations in sediment porewater and measured by solid phase microextraction, was not altered by the addition of cadmium, suggesting the change in permethrin bioavailability was not the reason for the antagonism. On the other hand, the activities of metabolic enzymes, glutathione S-transferase and carboxylesterase in the midges which were exposed to mixtures of permethrin and cadmium were significantly higher than those in the midges exposed to permethrin solely. Cadmium considerably enhanced the detoxifying processes of permethrin in the midges, which largely explained the observed antagonistic interaction between permethrin and cadmium.
Показать больше [+] Меньше [-]Chronic bisphenol A exposure alters behaviors of zebrafish (Danio rerio) Полный текст
2015
Wang, Ju | Wang, Xia | Xiong, Can | Liu, Jian | Hu, Bing | Zheng, Lei
The adult zebrafish (Danio rerio) were exposed to treated-effluent concentration of bisphenol A (BPA) or 17β-estradiol (E2) for 6 months to evaluate their effects on behavioral characteristics: motor behavior, aggression, group preference, novel tank test and light/dark preference. E2 exposure evidently dampened fish locomotor activity, while BPA exposure had no marked effect. Interestingly, BPA-exposed fish reduced their aggressive behavior compared with control or E2. Both BPA and E2 exposure induced a significant decrease in group preference, as well as a weaker adaptability to new environment, exhibiting lower latency to reach the top, more entries to the top, longer time spent in the top, fewer frequent freezing, and fewer erratic movements. Furthermore, the circadian rhythmicity of light/dark preference was altered by either BPA or E2 exposure. Our results suggest that chronic exposure of treated-effluent concentration BPA or E2 induced various behavioral anomalies in adult fish and enhanced ecological risk to wildlife.
Показать больше [+] Меньше [-]Potential environmental factors that influence the nitrogen concentration and δ15N values in the moss Hypnum cupressiforme collected inside and outside canopy drip lines Полный текст
2015
Skudnik, Mitja | Jeran, Z. (Zvonka) | Batič, Franc | Simoncic, Primoz | Kastelec, Damijana
Samples of the moss Hypnum cupressiforme were collected at 103 locations in forests of Slovenia. At each location, samples were taken at two types of sites: under tree canopies and in adjacent forest openings. The results show that the moss collected in the forest openings reflects the surrounding land-use characteristics and, consequently, the main N emission sources. For moss sampled under canopies, the characteristics of the forest at the moss-sampling locations are more important than the main emission sources outside the forest. A regression model was used to provide the nitrogen (N) concentration in moss from the forest openings in relation to the N concentration in moss under canopies and other environmental variables. The spatial distribution of the locations of the N concentrations and δ15N values in moss collected in the forest openings and under the canopies in relation to main N deposition sources is discussed.
Показать больше [+] Меньше [-]The effects of rice canopy on the air–soil exchange of polycyclic aromatic hydrocarbons and organochlorine pesticides using paired passive air samplers Полный текст
2015
Wang, Yan | Wang, Shaorui | Luo, Chunling | Li, Jun | Ming, Lili | Zhang, Gan | Li, Xiangdong
The rice canopy in paddy fields can influence the air–soil exchange of organic chemicals. We used paired passive air samplers to assess the exchange of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in a paddy field, South China. Levels of OCPs and light PAHs were generally higher under the canopy than above it. We found that the rice canopy can physically obstruct the evaporation of most OCPs and light PAHs, and can also act as a barrier to the gaseous deposition of p,p'-DDT and heavy PAHs. Paddy fields can behave as a secondary source of OCPs and light PAHs. The homolog patterns of these two types of chemical varied slightly between the air below and above the rice canopy, implying contributions of different sources. Paired passive air samplers can be used effectively to assess the in situ air–soil exchange of PAHs and OCPs in subtropical paddy fields.
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