Mcgrawtravis5347

dification and metal contamination in Antarctic echinoderms.In this study, ultraviolet (UV)-activated persulfate under alkaline condition was developed as an alternative Total Oxidizable Precursor (TOP) assay to convert per- and polyfluoroalkyl substances (PFASs) precursors into detectable perfluoroalkyl acids (PFAAs). The conventional heat-based TOP assay takes 6 h at 85 °C, which is time consuming and may lose the volatile PFASs. Shorter time treatment would be beneficial to promote the analysis efficiency of the samples. We here report the UV-based TOP method as faster replacement of conventional heat-based TOP assay. The 62 fluorotelomer sulfonate (FTS), 82 FTS, and perfluorooctanesulfonamide (FOSA) achieved nearly complete conversion (with the molar yield of PFAAs of 97.2%-109.9%) at 60 min. This new UV-based TOP assay was then applied to 23 industry samples, and the results are comparable with the heat-based TOP assay. The perfluoroalkyl carboxylic acids (PFCAs) concentrations of 23 samples before and after normal TOP assay were 0-4290 mg L-1 and 438-77,420 mg L-1, respectively. The PFCAs after 60 min UV-based TOP assay was 310-81,881 mg L-1. The QuotientMol of 21 samples were 0.71-1.28, the QuotientMol of other two samples were 1.45 and 1.68, this probably due to the loss of volatile precursors during heat-based TOP assay. The UV-based TOP assay is an efficient, reliable and faster alternative to the conventional heat-based TOP assay.Urban industrial areas were being built globally, which decreased key geographical separation between agriculture and industrial areas, especially in developing countries. Now, limited studies concerned coordinated the vegetables and soil management for toxic elements (TEs) in this mixed land system. MK-2206 ic50 To fill this gap, an integrated environmental multi-media risk management method was explored based on laboratory analysis, health risk assessment, uncertainty control, and source apportionment. The Chinese Beihu area of Wuhan City was selected as a typical case and the measurements of Zn, Cr, Cu, Pb, As, and Cd in soil revealed that TEs pollution was slight and concentrations met the Chinese standards. Meanwhile, some vegetables exceeded corresponding standard limits. To further quantify negative health effects posed by the studied TEs both in soils and vegetables, an established fuzzy health risk assessment for farmers was employed and the results indicated that the soil exposure of As and the vegetable consumption needed the priority control. The carcinogenic risk (CR) of As in soil was [4.60E-6, 1.45E-5] and the cumulative CR (sum of CRAs, CRPb and CRCd) in leafy vegetables was [1.08E-4, 1.38E-4], which was higher than that of the other vegetables. Preventing soil oral exposure and reducing self-grown vegetable consumption (30%-50%) were proven as effective risk interventions via uncertainty control methods. Spatially, the risk grades under maximum membership principle decreased from south to north in the Beihu area, and the south area was identified as the priority control area. Source apportionment identified four source patterns (Zn-Cr-Cu, Pb, As, and Cd) for soil, and the probable bioaccumulation mechanisms for leafy vegetables by multivariate statistical analyses. Finally, the integrated management strategies were formulated from perspectives of the risk sources, exposure pathways and the scenario.Estrogenic hormones and organic ultraviolet-filters (UV-filters) have attracted increased attention as endocrine disrupting chemicals (EDCs) due to their potent estrogenicity and widespread occurrence in the environment. This study investigated the accumulation of three estrogenic hormones and five UV-filters in red swamp crayfish (Procambarus clarkii). Exposure experiments were conducted for 42 days with a mixture of EDCs at two environmentally-relevant design concentrations (i.e., 500 and 5000 ng L-1). The aqueous-phase EDC concentrations decreased over time and were re-established every two days. Within 14 days of exposure, the five UV-filters were measured at 2.2 to 265 ng g-1 (dry weight) in crayfish tail tissue. Only one estrogenic hormone, 17β-estradiol, was detected in the crayfish at 10.4-13.5 ng g-1. No apparent changes were observed for EDC concentrations in the tail tissue over the next four weeks of exposure. The apparent bioaccumulation factors for the EDCs ranged from 23 L (kg tail tissue, dry weight)-1 for 4-methylbenzylidene camphor to 1050 L (kg tail tissue, dry weight)-1 for 2-ethylhexyl-4-methoxycinnamate. EDC input was stopped after 42 days, and the more hydrophobic UV-filters (i.e., octocrylene, 2-ethylhexyl-4-methoxycinnamate, homosalate) were found to be persistent throughout a 14-d elimination period. A lyticase-assisted yeast estrogen screen demonstrated that the residual estrogenic activity of water samples aligned with (or was lower than) predictions from targeted chemical analysis. These results suggest that the transformation products did not contribute significant estrogenicity, although further analysis of endocrine disruption outcomes in crayfish is recommended.In this study, three different structures of MnO2 were synthesized and used to activate peroxymonosulfate (PMS) for the degradation of DDT in aqueous solutions. It was found that DDT was efficiently degraded in the MnO2/PMS system and the degradation rate was dependent on the properties of MnO2 including crystal structure (followed the order α-MnO2 > γ-MnO2 > β-MnO2), surface area and Mn(III) content. Sulfate radicals (SO4-) was primarily responsible for the degradation of DDT based on the results of electron paramagnetic resonance (EPR) and quenching experiments. The degradation of DDT was suppressed at alkaline pH because the formation of SO4- was inhibited. The results of GC-MS indicated that dichlorobenzophenone, 4-chlorobenzoic acid and benzylalcohol were the dominant intermediates for DDT degradation. The possible pathways of DDT degradation were proposed according to the identified products.The open burning of municipal solid waste (MSW) -frequently observed in developing countries- emits harmful pollutants, including fine particulate matter (PM2.5) and black carbon (BC), and deteriorates the air quality in urban areas. This work reports on PM2.5 and BC measurements (fixed and mobile) conducted in a residential neighborhood on the outskirts of a Brazilian city (Londrina), complemented by a public opinion survey to understand the open burning in the context of waste management. Mean (± standard deviation) BC concentration (1.48 ± 1.40 μg m-3) at the fixed sites of the neighborhood was lower than downtown, while PM2.5 (9.68 ± 8.40 μg m-3) concentration was higher. The mobile monitoring showed higher mean PM2.5 concentrations but lower BC/PM2.5 ratios than downtown, with sharp and fast spikes (up to 317.87 and 565.21 μg m-3 for BC and PM2.5, respectively). The large spatial heterogeneity of particulate concentrations was associated with the occurrence of MSW burning events. Our observations were verified by the survey respondents who identified poor waste management practices garbage in streets, waste burning, and illegal dump sites.