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341.
342.
Gon Ok Sung-Hee Ji Sang-Jo Kim Young-Kyo Kim Ji-Hoon Park Young-Seup Kim Young-Ho Han 《Chemosphere》2002,46(9-10)
The atmospheric contamination levels of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were evaluated from the analysis of pine needles in South Korea. Pine needles were collected from 30 sampling points at five main cities in South Korea (Busan, Daegu, Gwangju, Changwon and Jeju island). The highest concentrations of PCDDs/DFs (2.19–26.88 pg I-TEQ/g of dry weight) were measured at Busan, where is the city of the highest population density and traffic volume among five cities. The lowest concentration was detected at Jeju with 0.62 pg I-TEQ/g dry weight, suggesting Jeju could be an environmental background area in Korea. The dominant homologues of PCDDs/DFs in pine needles were the lower chlorine-substituted compounds such as tetra CDDs and CDFs, and the distribution ratios of PCDDs/DFs decreased with increase of the number of chlorine substituents. Homologue profiles of pine needle samples were similar to PCDDs/DFs profiles of the vapor phase in the ambient air, and thus the pine needles absorbed the vapor phase of PCDDs/DFs from air. Results suggested that pine needles could be used as an indicator of the atmospheric contamination for PCDDs/DFs in Korea. 相似文献
343.
Protano G Riccobono F Sabatini G 《Environmental pollution (Barking, Essex : 1987)》2000,110(3):451-458
Four different sampling surveys were carried out in 1998 to evaluate the possible causes of severe mercury contamination involving many wells spread over a vast territory along the coast of southern Tuscany (Italy). Several samples of groundwater and coastal sea water were collected to determine the Hg, Cl, Ar, He and N contents. Anthropogenic or deep-seated sources of the Hg involved in the contamination event can be excluded. The observed coupling of Hg pollution with progressive salt water intrusion along the coastal aquifer indicates a close causal relation between these two phenomena. 相似文献
344.
底泥对河流的二次污染浅析 总被引:39,自引:1,他引:39
根据底冲中污染物质累积和释放过程和底泥对河流二次污染的机理,运用适用的模式和苏州河的实测资料,可得到二次污染BOD和COD的年释放量,以及增加上覆河上的BOD和COD浓度。由此认为,对于底泥污染严重的河流,疏浚是必不可少的,其目的在于清除或隔绝黑富集层上覆河上的二次污染。 相似文献
345.
The fate of organic chemicals in the soil-plant-atmosphere environment and the governing processes were studied with a coupled dynamic soil transport and plant compartment model. Scenarios with applications of pesticides on sand and loam soils with chemical uptake in barley and wheat were used in the model calculations. Root uptake and concentrations in the plant compartments stem, leave and fruit were calculated for the pesticides terbuthylazine, isoproturon and carbofuran.
The effectivity of uptake from soils with different soil sorption coefficients had been shown for sand and loam soils. The processes degradation in plant and volatilization from leaves to atmosphere are especially effective for carbofuran and terbuthylazine. Although the concentrations in corn at harvest are lower than the maximum allowed concentrations, the peak concentrations in the course of the vegetation period are significantly higher (factor ≤ 200). 相似文献
346.
研究了有机磷农药甲基对硫磷长期污染对土壤微生物的影响,结果表明:污染土壤中细菌、放线菌、真菌数量变化不大,自生固氮菌和反硝化细菌数量减少,氨化细菌、亚硝化细菌、硝化细菌数量有所增加;与对照土壤相比,污染土壤呼吸作用下降29.93%,而氨化作用和硝化作用则增强。1g对照土壤(以干土计)中微生物总DNA提取量为(13.01±1.91)μg,污染土壤中则为(12.23±1.36)μg。 相似文献
347.
Fluoride contamination in soil was studied in the vicinity of a hot spring in Nayagarh district of Orissa. Both bulk soil from 0 to 30 cm depth and profile soils from 0 to 90 cm depth were analyzed for total fluoride (Ft) and 0.01 M CaCl2 extractable fluoride (Fca), major elements, pH, EC and Organic Carbon (OC). High concentrations of both Ft and Fca were observed in the area surrounding the hot spring and the village of Singhpur. Principal factor analysis (PFA) on the parameters of the bulk soils suggests that two major chemical processes due to three factors, control the soil geochemistry of the area. Factor-1 contributes 37.11% of the total variance and is strongly loaded with Al, Si, Fe, Ftand Fca, and explains the fluoride enrichment of the soil, whereas the second and the third factors contribute 16.6 and 12.2%, respectively and explain the controlling process of carbonate precipitation and soil alkalinity. Multiple regression analysis of the scores of the factors was performed to derive a fluoride contamination index in soil. The magnitude of the factor effect on the contamination index follows the order of Factor-1 > Factor-2 > Factor-3. The spatial distribution of the contamination index is used to classify the area into highly contaminated, moderately contaminated and uncontaminated zones. 相似文献
348.
349.
Acid hydrolysis of estuarine water samples for the determination of amino acids (AAs) was tested and found to be effective
at high (250 μM) nitrate concentrations when the anti-oxidant, ascorbic acid, was added to the samples. Hydrolysable AA concentrations
were then determined in surface sediments collected from low and high salinity regions of the Tamar Estuary (UK) during winter
2003 and 2004, and in overlying water when simulated resuspension of sediment particles was performed. Concentrations of AAs
in sediment samples comprised <50% of particulate nitrogen, fitting the paradigm that most sedimentary nitrogen is preserved
within an organic matrix. When sediment samples were resuspended in overlying water (salinity 17.5), the rapid, measured increase
in dissolved AA concentrations almost equalled the reported nitrate concentration in the lower estuary, with the subsequent
decrease in the total dissolved AA levels suggested that bacterial uptake was occurring. Our data concur with previous studies
on nitrogen desorption from sediments and suggest that an understanding of organic nitrogen cycling will be an important aspect
of future effective estuarine management. 相似文献
350.
Sheehan P Dewhurst RE James S Callaghan A Connon R Crane M 《Environmental geochemistry and health》2003,25(1):9-16
Part IIA of the Environmental Protection Act 1990 requires environmental regulators to assess the risk of contaminants leaching from soils into groundwater (DETR, 1999). This newly introduced legislation assumes a link between soil and groundwater chemistry, in which rainwater leaches contaminants from soil into the saturated zone. As the toxicity of both groundwater and overlying soils is dependent upon the chemicals present, their partitioning and their bioavailability, similar patterns of soil, leachates and groundwater toxicity should be observed at contaminated sites. Soil and groundwater samples were collected from different contaminated land sites in an urban area, and used to determine relationships between soil chemistry and toxicity, mobility of contaminants, and groundwater chemistry and toxicity. Soils were leached using water to mimic rainfall, and both the soils and leachates tested using bioassays. Soil bioassays were carried out using Eisenia fetida, whilst groundwater and leachates were tested using the Microtox test system and Daphnia magna 48 h acute tests. Analysis of the bioassay responses demonstrated that a number of the samples were toxic to test organisms, however, there were no significant statistical relationships between soil, groundwater and leachate toxicity. Nor were there significant correlations between soil, leachates and groundwater chemistry. 相似文献