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Query: UMLS:C1835664 (TOC)
 2,763 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Groundwater samples contaminated by BTEX (benzene, toluene, ethylbenzene, xylene isomers and TPHs (total petroleum hydrocarbons) were treated with advanced oxidation processes (AOPs), such as TiO(2) photocatalysis and Fe(2+)/H(2)O(2) exposed to solar light (37 degrees N and 128 degrees E) with an average intensity of 1.7 mW/cm(2) at 365 nm. These AOP processes showed feasibility in the treatment of groundwater contaminated with BTEX, TPH and TOC (Total Organic Carbon). Outdoor field tests showed that the degradation efficiency of each contaminant was higher in the Fe(2+)/H(2)O(2) system without solar light compared to the TiO(2)/solar light and H(2)O(2)/solar light systems. However, the TiO(2)/solar light and the Fe(2+)/H(2)O(2)/solar light systems showed significantly enhanced efficiencies in the degradation of BTEX, TPH and TOC with the additional use of H(2)O(2). Near complete degradation of BTEX and TPH was observed within 2 and 4 hrs, respectively, however, that of TOC was slower. Without pretreatment of the groundwater, fouling of the TiO(2), due to the ionic species present, was observed within 1 hr of operation, which resulted in the inhibition of further BTEX, TPH and TOC destruction. The degradation rate of n-alkanes with carbon numbers ranging from C10 to C15 was relatively greater than that of n-alknaes with carbon numbers ranging from C16 to C20. From this work, the AOP process (Fe(2+)/H(2)O(2)/solar light and TiO(2)/H(2)O(2)/solar light) illuminated with solar light was identified as an effective ex situ technique in the remediation of groundwater contaminated with petroleum.
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PMID:Solar-chemical treatment of groundwater contaminated with petroleum at gas station sites: ex situ remediation using solar/TiO(2) photocatalysis and Solar Photo-Fenton. 1648 76

Possible alterations in the distribution and composition of total petroleum hydrocarbon (TPH), polycyclic aromatic hydrocarbons (PAHs), and benzene, toluene, ethyl benzene, and xylene isomers (BTEX) in the released oil at Idu-Ekpeye in Niger Delta (Nigeria) were studied within two seasonal variations of two months and six months, with a view to assessing the level of attenuation of these hydrocarbons in impacted soils. Although there were significant contaminations in the kerosene range (n-C10-n-C14) two months after, especially of the n-C12 and n-C13 fractions, the complete disappearance of the n-C8 to n-C23 hydrocarbons, including the acyclic isoprenoids (pristane and phytane), and the reduced amounts of PAHs, and BTEX, six months after, provided substantial evidence of attenuation as indicated in the reduction in total hydrocarbon content (THC) from 61.17 to 42.86%. Soil physicochemical properties such as pH, moisture content, heavy metal, TOC, and TOM, all provided corroborative evidence of hydrocarbon attenuation. The pristane/phytane ratio of the spill samples suggests that the spilled oil was genetically oxic.
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PMID:Attenuation of petroleum hydrocarbons by weathering: a case study. 1719 79

As the most complex halogenated contaminants, short chain chlorinated paraffins (SCCPs) are scarcely reported in marine environments. In this work, a total of 117 surficial sediment (0-3 cm) samples and two sediment cores were collected from the Chinese Bohai and Yellow Seas to systematically study the spatial and temporal trends of SCCPs at a large scale in the Chinese marine environment. Total SCCP concentrations in the surficial sediments were in the range of 14.5-85.2 ng g(-1) (dry weight, d.w.) with an average level of 38.4 ng g(-1) d.w. Spatial distribution showed a decreasing trend with the distance from the coast to the open waters. Compositional pattern analysis suggested that C10 was the most predominant homologue group, followed by C11, C12, and C13 homologue groups. The concentrations of total SCCPs in sediment cores ranged from 11.6 to 94.7 ng g(-1) d.w. for YS1 and from 14.7 to 195.6 ng g(-1) d.w. for YS2, with sharp rise from the early 1950s to present based on (210)Pb dating technique. The historical records in cores correspond well to the production and usage changes of CPs in China. Multivariate regression statistics indicate TOC, latitude and longitude are the major factors influencing surficial SCCP levels in the Chinese East Seas by combining analysis with the data from the East China Sea (R(2) = 0.332, p < 0.01). These findings indicated that the sources of SCCPs were mainly from river outflows via ocean current and partly from atmospheric depositions by East Asian monsoon in the sampling areas.
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PMID:Spatial distributions and deposition chronology of short chain chlorinated paraffins in marine sediments across the Chinese Bohai and Yellow Seas. 2402 49

Results of an extended survey on the production and quality of sewage sludge produced in Italy are herewith reported and discussed. Data are relevant to 2015. They were provided by 84 Italian water utilities responsible for municipal wastewater treatment serving approximately 35 million persons. Total production was estimated at about 395,000 t dry solids/year, of which 9.9% is used in agriculture without further treatments, 26.4% is sent to external plants for compost production, 5.6% is sent to external plant for production of a soil conditioner called 'chalk of defecation', 17.2% is disposed to landfill, and 5.9% is sent to incineration or co-incineration plants. The rest (35%) is sent to external sludge centres for further treatments (manly chemical and physical processes) before recovery/disposal. Regarding chemical characterization the following parameters were investigated: TOC, total nitrogen, total phosphorus, potassium, arsenic, cadmium, copper, nickel, lead, zinc, mercury, total chromium, chromium VI, selenium, hydrocarbons C10-C40, sum of polycyclic aromatic hydrocarbons, sum of polychlorinated biphenyls, sum of polychlorinated dibenzo-p-dioxins/dibenzo-p-furanes (toxic equivalent) salmonella, faecal coliforms, sulphur, sum of absorbable halogenated organic compounds, nonylphenol and nonylphenolethoxylates with one or two ethoxy groups, and di(2-ethylhexyl)phthalate. All the parameters showed that the quality of Italian sewage sludge is consistent with a typical sludge in Europe, Asia and America and the maximum concentrations of pollutants are well below the fixed standards of the European Directive 86/278 and the third draft of the European Commission's Working Document on Sludge.
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PMID:Production and characteristics of sewage sludge in Italy. 3097 28