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Результаты 2631-2640 из 4,043
Occurrence, fate, and risk assessment of selected endocrine disrupting chemicals in wastewater treatment plants and receiving river of Shanghai, China Полный текст
2016
Xu, Gang | Ma, Sihan | Tang, Liang | Sun, Rui | Xiang, Jiajia | Xu, Bentuo | Bao, Yangyang | Wu, Minghong
The occurrence and fate of five endocrine disrupting chemicals (EDCs), including nonylphenol (NP), 4-tert-octylphenol (4-t-OP), 4-tert-butylphenol (4-t-BP), bisphenol A (BPA) and norethindrone (NET) was investigated in four wastewater treatment plants (WWTPs) and receiving river (Suzhou River and Yangtze River) of Shanghai. Selected EDCs in WWTPs influents ranged from 1.02 to 3560 ng L⁻¹, which dominated by NP and BPA. Target compounds detected in effluents were from N.D. to 1136 ng L⁻¹, with NP as most prevalent. The removal rates of target compounds varied from negative of NET to 99 % of BPA. Except of NET, efficiently removal rates (>70 %) were observed in WWTPs. Biological treatment was the major removal stage of selected EDCs in WWTPs. Furthermore, the selected EDCs were detected from N.D. to 424 ng L⁻¹ in receiving river. The correlation analysis suggested EDCs pollution in receiving river might be mainly contributed by WWTPs effluents. The risk quotient of NP (RQ > 1) was higher than any other pollutants, indicating its relatively higher potential risk for the aquatic organism. These results will provide significant background data to future EDCs pollution control and management in Shanghai, China.
Показать больше [+] Меньше [-]Popular pharmaceutical residues in hospital wastewater: quantification and qualification of degradation products by mass spectroscopy after treatment with membrane bioreactor Полный текст
2016
Chiarello, M. | Minetto, L. | Giustina, S. V Della | Beal, L. L. | Moura, S.
The occurrence of drugs in wastewater has been considered an imminent risk to the population, for the treatments used are usually ineffective. The presence of four popular drug residues (metformin, paracetamol, tetracycline, and enalapril) in hospital effluents, by using ultra-fast liquid chromatography tandem mass spectrometry (UFLC-MS/MS) with electrospray (ESI) ionization, and removal/degradation by membrane bioreactor (MBR) system are investigated in this study. For analysis method, all standard calibration curves showed satisfactory linearity (R ² ≥ 0.993) within a relatively wide range. The recovery was between 70.4 and 105.0 %, and the relative standard deviation (RSD) values were within the ranges of 8.2 and 13.5 %. The effluent samples were collected at the end of the process treated in a bench-scale MBR treatment system and preconcentrated on solid-phase extraction (SPE) cartridges. Following that procedure, the chemical analysis demonstrated that the MBR system was effective in enalapril 94.3 ± 7.63 %, tetracycline 99.4 ± 0.02 %, and paracetamol 98.8 ± 0.86 % removal. However, the polar metformin was less effectively removed (35.4 ± 12.49 %). Moreover, the degradation products were investigated using high-resolution mass spectrometry (HRMS) by quadrupole–time of flight (Q-TOF), which has been indicated a tetracycline metabolite. In order to investigate the environmental impact, the wastewater potential risk was evaluated. The risk quotient (RQ) by measure environmental concentration (MEC) and its predicted no effect concentration (PNEC) ratio (RQ = MEC/PNEC) was between 0.003 (enalapril) to 0.815 (paracetamol). Finally, this work demonstrates that UFLC-MS/MS (ESI-Q) is a sensitive and selective method for drug analysis in wastewater and with ESI-Q-TOF has the accuracy required for determining the degradation products of these compounds. Also, it indicated that membrane bioreactor systems represent a new generation of processes that have proved to outperform conventional treatment showing better effluent quality. The removal capacity studied in this work demonstrates the efficiency of this process.
Показать больше [+] Меньше [-]Heavy metals in the surface sediments of the northern portion of the South China Sea shelf: distribution, contamination, and sources Полный текст
2016
Xu, Fangjian | Tian, Xu | Yin, Feng | Zhao, Yongfang | Yin, Xuebo
The concentrations of seven heavy metals (Cr, Ni, Cu, Zn, As, Cd, and Pb) in the surface sediments of the northern portion of the South China Sea (SCS) shelf collected between 2012 and 2014 were measured to assess the potential contamination levels and determine the environmental risks that are associated with heavy metals in the area. The measured concentrations in the sediments were 12.4–72.5 mg kg⁻¹ for Cr, 4.4–29.2 mg kg⁻¹ for Ni, 7.1–38.1 mg kg⁻¹ for Cu, 19.3–92.5 mg kg⁻¹ for Zn, 1.3–12.1 mg kg⁻¹ for As, 0.03–0.24 mg kg⁻¹ for Cd, and 8.5–24.4 mg kg⁻¹ for Pb. These results indicate that the heavy metal concentrations in the sediments generally meet the China Marine Sediment Quality criteria and suggest that the overall sediment quality of the northern portion of the SCS shelf has not been significantly impacted by heavy metal pollution. However, the enrichment factor (EF) and geoaccumulation index (I gₑₒ) clearly show that elevated concentrations of Cd occur in the region. A Pearson’s correlation analysis was performed, and the results suggest that Cr, Ni, Cu, and Zn have a natural origin; Cd is primarily sourced from anthropogenic activities, with partial lithogenic components, and As and Pb may be affected by factors such as varying input sources or pathways (i.e., coal burning activities and aerosol precipitation). Heavy metal contamination mostly occurred to the east of Hainan Island, mainly because of the rapid economic and social developments in the Hainan Island. The results of this study will be useful for marine environment managers for the remediation of pollution sources.
Показать больше [+] Меньше [-]Structural benefits of bisphenol S and its analogs resulting in their high sorption on carbon nanotubes and graphite Полный текст
2016
Guo, Huiying | Li, Hao | Liang, Ni | Chen, Fangyuan | Liao, Shaohua | Zhang, Di | Wu, Min | Pan, Bo
Bisphenol S (BPS), a new bisphenol analog, is considered to be a potential replacement for bisphenol A (BPA), which has gained concern because of its potentially adverse health impacts. Therefore, studies are needed to investigate the environmental fate and risks of this compound. In this study, the adsorption of BPS and four structural analogs on multi-walled carbon nanotubes (MWCNTs) and graphite (GP) were investigated. When solid-phase concentrations were normalized by the surface areas, oxygen-containing functional groups on the absorbents showed a positive impact on phenol sorption but inhibited the sorption of chemicals with two benzene rings. Among BPS analogs, diphenyl sulfone showed the lowest sorption when hydrophobic effects were ruled out. Chemicals with a butterfly structure, formed between the two benzene rings, showed consistently high sorption on MWCNTs, independent of the substituted electron-donating or accepting functional groups. This study emphasizes the importance of chemical conformation on organic, contaminant sorption on engineered, carbonaceous materials.
Показать больше [+] Меньше [-]Effects of sewage sludge fertilizer on heavy metal accumulation and consequent responses of sunflower (Helianthus annuus) Полный текст
2016
belhaj, Dalel | Elloumi, Nada | Jerbi, Bouthaina | Zouari, Mohamed | Abdallah, Ferjani Ben | Ayadi, Habib | Kallel, Monem
Use of sewage sludge, a biological residue produced from sewage treatment processes in agriculture, is an alternative disposal technique of waste. To study the usefulness of sewage sludge amendment for Helianthus annuus, a pot experiment was conducted by mixing sewage sludge at 2.5, 5, and 7.5 % (w/w) amendment ratios to the agricultural soil. Soil pH decreased whereas electrical conductivity, organic matter, total N, available P, and exchangeable Na, K, and Ca increased in soil amended with sewage sludge in comparison to unamended soil. Sewage sludge amendment led to significant increase in Pb, Ni, Cu, Cr, and Zn concentrations of soil. The increased concentration of heavy metals in soil due to sewage sludge amendment led to increases in shoot and root concentrations of Cr, Cu, Ni, and Zn in plant as compared to those grown on unamended soil. Accumulation was more in roots than shoots for most of the heavy metals. Moreover, high metal removal for the harvestable parts of the crops was recorded. Sewage sludge amendment increased root and shoot length, leaves number, biomass, and antioxidant activities of sunflower. Significant increases in the activities of antioxidant enzymes and in the glutathione, proline, and soluble sugar content in response to amendment with sewage sludge may be defense mechanisms induced in response to heavy metal stress. Graphical abstract Origin, fate and behavior of sewage sludge fertilizer
Показать больше [+] Меньше [-]The toxicity of arsenic(III), chromium(VI) and zinc to groundwater copepods Полный текст
2016
Hose, G. C. | Symington, K. | Lott, M. J. | Lategan, M. J.
Groundwater ecosystems globally are threatened by anthropogenic contamination, yet there are few ecotoxicological data using obligate groundwater biota on which to base risk assessments. Copepods are found inhabiting aquifers of different geologies around the world and so are a useful taxon for use in ecotoxicological studies of groundwater. The aim of this study was to test the sensitivity of obligate groundwater copepods to metal contaminants (arsenic(III), chromium(VI) and zinc) in groundwater in static 96 h, 14 days and 28 days exposure tests. The copepods were variably sensitive to As, Cr and Zn, with Cr being the most toxic across all taxa. No taxon was consistently most sensitive and there was no apparent relationship between the hardness, pH and organic carbon concentration of the diluent water and the sensitivity of biota. As expected, toxicity increased with exposure period and we encourage the use of longer exposure periods in future toxicity tests with groundwater organisms to reflect the greater exposure periods likely to be associated with groundwater contamination.
Показать больше [+] Меньше [-]Effects of chlorinated drinking water on the xenobiotic metabolism in Cyprinus carpio treated with samples from two Italian municipal networks Полный текст
2016
Cirillo, Silvia | Canistro, Donatella | Vivarelli, Fabio | Paolini, Moreno
Drinking water (DW) disinfection represents a milestone of the past century, thanks to its efficacy in the reduction of risks of epidemic forms by water micro-organisms. Nevertheless, such process generates disinfection by-products (DBPs), some of which are genotoxic both in animals and in humans and carcinogenic in animals. At present, chlorination is one of the most employed strategies but the toxicological effects of several classes of DBPs are unknown. In this investigation, a multidisciplinary approach foreseeing the chemical analysis of chlorinated DW samples and the study of its effects on mixed function oxidases (MFOs) belonging to the superfamily of cytochrome P450-linked monooxygenases of Cyprinus carpio hepatopancreas, was employed. The experimental samples derived from aquifers of two Italian towns (plant 1, river water and plant 2, spring water) were obtained immediately after the disinfection (A) and along the network (R1). Animals treated with plant 1 DW-processed fractions showed a general CYP-associated MFO induction. By contrast, in plant 2, a complex modulation pattern was achieved, with a general up-regulation for the point A and a marked MFO inactivation in the R1 group, particularly for the testosterone metabolism. Together, the toxicity and co-carcinogenicity (i.e. unremitting over-generation of free radicals and increased bioactivation capability) of DW linked to the recorded metabolic manipulation, suggests that a prolonged exposure to chlorine-derived disinfectants may produce adverse health effects.
Показать больше [+] Меньше [-]Distribution and estrogenic potential of endocrine disrupting chemicals (EDCs) in estuarine sediments from Mumbai, India Полный текст
2016
Tiwari, M. | Sahu, S. K. | Pandit, G. G.
Endocrine disrupting chemicals (EDCs) are responsible for inappropriate development and they alter the hormonal and homeostatic systems of organism. Phthalates (PAEs), bisphenol A (BPA) and other EDCs were monitored in surface sediments at different stations across Thane Creek, India. Analysis of PAEs was carried out using GC–MS technique, while BPA and other EDCs were analyzing on UPLC-PDA instrument. Di-n-butyl phthalate (DBP) had the highest concentration among all fourteen analyzed phthalates ranges between 0.13 and 0.4 mg kg⁻¹; and was detectable in all sediment samples. Strong correlation (r = 0.95, p < 0.01) was observed between total organic carbon (TOC, %) and total PAEs. BPA was also detected in all samples; average BPA concentration varies from 16.3 to 35.79 μg kg⁻¹ with mean value 25.15 μg kg⁻¹ dry weight of sediment. Synthetic EDCs such as 4-para-nonylphenol (NP) and 4-tert-octylphenol (OP) were also analyzed; and their average concentrations were founds to be 356.5 and 176 μg kg⁻¹, respectively. Estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) were the main contributors to the overall estradiol equivalent concentration (EEQs) in sediment, their average total percentage contributions is more than 90 %.
Показать больше [+] Меньше [-]Does anatoxin-a influence the physiology of Microcystis aeruginosa and Acutodesmus acuminatus under different light and nitrogen conditions? Полный текст
2016
Chia, Mathias Ahii | Cordeiro-Araújo, Micheline Kézia | Lorenzi, Adriana Sturion | Bittencourt-Oliveira, Maria do Carmo
Due to changing global climatic conditions, a lot of attention has been given to cyanobacteria and their bioactive secondary metabolites. These conditions are expected to increase the frequency of cyanobacterial blooms, and consequently, the concentrations of cyanotoxins in aquatic ecosystems. Unfortunately, there are very few studies that address the effects of cyanotoxins on the physiology of phytoplankton species under different environmental conditions. In the present study, we investigated the effect of the cyanotoxin anatoxin-a (ATX-A) on Microcystis aeruginosa (cyanobacteria) and Acutodesmus acuminatus (chlorophyta) under varying light and nitrogen conditions. Low light (LL) and nitrogen limitation (LN) resulted in significant cell density reduction of the two species, while the effect of ATX-A on M. aeruginosa was not significant. However, under normal (NN) and high nitrogen (HN) concentrations, exposure to ATX-A resulted in significantly (p < 0.05) lower cell density of A. acuminatus. Pigment content of M. aeruginosa significantly (p < 0.05) declined in the presence of ATX-A, regardless of the light condition. Under each light condition, exposure to ATX-A caused a reduction in total microcystin (MC) content of M. aeruginosa. The detected MC levels varied as a function of nitrogen and ATX-A concentrations. The production of reactive oxygen species (H₂O₂) and antioxidant enzyme activities of both species were significantly altered by ATX-A under different light and nitrogen conditions. Our results revealed that under different light and nitrogen conditions, the response of M. aeruginosa and A. acuminatus to ATX-A was variable, which demonstrated the need for different endpoints of environmental factors during ecotoxicological investigations.
Показать больше [+] Меньше [-]Influence of substrate water saturation on pesticide dissipation in constructed wetlands Полный текст
2016
Vallée, Romain | Dousset, Sylvie | Billet, David
Constructed wetlands are an effective and practical option for removing pesticide pollution from runoff or subsurface drainage water. The objective of this study was to assess the efficiencies of a ditch with a bundle of straw placed in its centre and a vegetated pond installed in grass cover bands at downstream of a drained plot. The dissipation rates of three herbicides and three fungicides were monitored on four substrates commonly found in constructed wetlands (two soils, sediment and straw). The influence of water content was determined in a sequence of three steps (flooded-unsaturated-flooded) over 120 days. The pesticide dissipation rates observed during the 120 days of incubation ranged from 1.4 to 100 %. Isoproturon and 2,4-MCPA (MCPA) showed the highest dissipation rates, which ranged from 61.0 to 100 % of the applied quantities during the 120 days of incubation. In contrast, boscalid and tebuconazole showed the lowest dissipation rates, which ranged from 1.4 to 43.9 % of the applied quantities during the 120 days of incubation. The estimated DT₅₀ values ranged from 20.5 days to more than 1 year and were influenced by the substrate water content. The soil and straw substrates had the lowest DT₅₀ values during the unsaturated conditions, whereas the sediments had the lowest DT₅₀ values during the flooded conditions. These results could be explained by an adaptation of microbial communities to their environmental conditions. Thus, the most favourable conditions of dissipation for soils and straw are observable when the drainage ceases (spring and summer). However, favourable conditions occur all year for the sediments, except when the constructed wetlands are dry. The results suggest that the dissipation of pesticides in constructed wetlands contributes to the long-term effectiveness of these buffer zones for reducing water pollution.
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