细化搜索
结果 481-490 的 3,208
Influence of organic amendment on fate of acetaminophen and sulfamethoxazole in soil 全文
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.
显示更多 [+] 显示较少 [-]Investigation on the distribution and fate of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in a sewage-impacted bay 全文
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.
显示更多 [+] 显示较少 [-]Effects of oil pipeline explosion on ambient particulate matter and their associated polycyclic aromatic hydrocarbons 全文
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.
显示更多 [+] 显示较少 [-]Joint toxicity of sediment-associated permethrin and cadmium to Chironomus dilutus: The role of bioavailability and enzymatic activities 全文
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.
显示更多 [+] 显示较少 [-]Chronic bisphenol A exposure alters behaviors of zebrafish (Danio rerio) 全文
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.
显示更多 [+] 显示较少 [-]Potential environmental factors that influence the nitrogen concentration and δ15N values in the moss Hypnum cupressiforme collected inside and outside canopy drip lines 全文
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.
显示更多 [+] 显示较少 [-]The effects of rice canopy on the air–soil exchange of polycyclic aromatic hydrocarbons and organochlorine pesticides using paired passive air samplers 全文
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.
显示更多 [+] 显示较少 [-]Pharmaceuticals and personal care products alter the holobiome and development of a medically important mosquito 全文
2015
Pennington, Marcus J. | Rivas, Nicholas G. | Prager, Sean M. | Walton, William E. | Trumble, John T.
The increasing demand for fresh water has forced many countries to use reclaimed wastewater for agricultural purposes. This water contains pharmaceuticals and personal care products (PPCPs) that remain biologically active following passage through wastewater treatment plants. Run-off from farms and contaminated water from treatment facilities exposes aquatic ecosystems to PPCPs. This study examined the effects of PPCPs on a lower trophic organism. Culex quinquefasciatus larvae were reared in water contaminated with environmentally relevant concentrations of common PPCPs. Acetaminophen alone and a mixture of contaminants were found to increase developmental time of larvae. Susceptibility to Bti increased in larvae exposed to antibiotics, acetaminophen, or a mixture of PPCPs. Antibiotics, hormones, and the mixture altered the mosquito bacterial microbiome. Overall, the results indicate that at environmentally relevant concentrations, PPCPs in reclaimed water can have biologically important effects on an ecologically and medically important lower trophic level insect.
显示更多 [+] 显示较少 [-]Occurrence and sources of selected organochlorine pesticides in the soil of seven major Indian cities: Assessment of air–soil exchange 全文
2015
Chakraborty, Paromita | Zhang, Gan | Li, Jun | Sivakumar, A. | Jones, K. C. (Kevin C.)
India is an agricultural country and organochlorine pesticides (OCPs) accounts for nearly three fourth of the annual pesticide consumption. Selected OCPs were therefore quantified in 81 soil samples along urban–suburban–rural transect from New Delhi and Agra in the north, Kolkata in the east, Mumbai and Goa in the west and Chennai and Bangalore in the southern part of India. ΣOCPs ranges from 2 to 410 ng/g dry weight (Mean, 35) with dominance of endosulfan sulfate in the rural sites. Urban centers and suburbs reflects OCP usage for vector control. Lower winter temperature in New Delhi favored site-specific deposition of most OCPs in soil. Volatilization of OCPs from soil occurred in the Indian cities having higher ambient temperature. Due to the compounded impact of past and ongoing usage of selected OCPs like DDT, a sporadic cycle of emission and re-emission from Indian soil is expected to continue for many more years to come.
显示更多 [+] 显示较少 [-]Titanium dioxide nanoparticles enhance mortality of fish exposed to bacterial pathogens 全文
2015
Jovanović, Boris | Whitley, Elizabeth M. | Kimura, Kayoko | Crumpton, Adam | Palić, Dušan
Nano-TiO2 is immunotoxic to fish and reduces the bactericidal function of fish neutrophils. Here, fathead minnows (Pimephales promelas) were exposed to low and high environmentally relevant concentration of nano-TiO2 (2 ng g−1 and 10 μg g−1 body weight, respectively), and were challenged with common fish bacterial pathogens, Aeromonas hydrophila or Edwardsiella ictaluri. Pre-exposure to nano-TiO2 significantly increased fish mortality during bacterial challenge. Nano-TiO2 concentrated in the kidney and spleen. Phagocytosis assay demonstrated that nano-TiO2 has the ability to diminish neutrophil phagocytosis of A. hydrophila. Fish injected with TiO2 nanoparticles displayed significant histopathology when compared to control fish. The interplay between nanoparticle exposure, immune system, histopathology, and infectious disease pathogenesis in any animal model has not been described before. By modulating fish immune responses and interfering with resistance to bacterial pathogens, manufactured nano-TiO2 has the potential to affect fish survival in a disease outbreak.
显示更多 [+] 显示较少 [-]