The Impact of Scrubber Sludge on Ground Water Quality at an Abandoned Mine Site

A sulfate-rich flue gas desulfurization scrubber sludge was used as a substitute backfill material in reclamation of an abandoned coal strip mine. The site was surrounded by monitor wells and the material was characterized for leaching behavior using open column experiments. A drain was placed directly beneath the 45 000 ton fill to enable sampling before dilution or attenuation. The column studies indicated that the scrubber sludge would adsorb manganese, iron, aluminium, cobalt, nickel, thallium and zinc contaminants from the water. Changes in pH appear inadequate to explain the removal by precipitation. The groundwater cleaning phenomenon has been confirmed on a field scale by the drain samples. Boron and molybdenum leach from the fly ash was used to fix the scrubber sludge and serve as marker elements enabling calibration of the dispersivity in computer models of the groundwater system at the site. The leachate front appears to be diluted by a factor of 8 : 1 within the first 15 meters. Since boron and molybdenum release are associated only with the first flush, environmental impacts will be minimal. Columns appear to create a time compression effect on the duration of leaching phenomenon. The effect for this site appears to be at least 5 : 1. The columns were effective in predicting which elements would leach or adsorb in the field and in predicting the actual source concentrations. Other shake tests such as the TCLP and the ASTM shake test were found to be less effective at predicting which elements would leach and were not helpful in predicting field concentrations.     

农药施用对兴凯湖水中农药残留的影响及其风险评价

主要研究了中国东北兴凯湖周围水稻种植区域农药残留以及对湖水水质的影响.分别于水稻抽穗期和水稻成熟期在兴凯湖地区对稻田、排干和大小兴凯湖地表水进行采集并对27种农药及其降解产物进行分析.结果表明,在水稻抽穗期所分析的27种农药及其降解产物全部检出,总浓度范围为247.97~6 094.49 ng·L^-1;水稻成熟期检出25种,总浓度范围为485.36~796.23 ng·L^-1,两时期对比,抽穗期的农药及其降解产物检出数量更多且总浓度更高;在水稻抽穗期阿特拉津、西草净和多效唑为主要检出农药,在水稻成熟期阿特拉津和稻瘟灵为主要检出农药;大小兴凯湖水中农药的分布特征与排干水相似,表明大小兴凯湖水中农药及其降解产物很可能来源于稻田排干的输入;在排干和大小兴凯湖水中,阿特拉津、西草净、扑草净、丁草胺、稻瘟灵和草酮RQ均值大于0.1,对水生生物存在潜在生态风险.     

Monitoring of Pesticide Residues in Fruits

Fruit samples of ber, grapes and guava analysed for pesticide residues employing multiresidue analysis by gas liquid chromatography equipped with ECD and NPD detectors and capillary columns showed contamination with organochlorine, synthetic pyrethroid and organophosphate insecticides. Among organochlorines, HCH, DDT and endosulfan were detected in almost all the samples. Residues of HCH and DDT were maximum in ber followed by grapes and guava where as of endosulfan were maximum in guava followed by grapes and ber. All the fruit samples showed the presence of residues with one or the other group of pesticides. Residues of none of the pesticides exceeded the MRL values in any sample. On the basis of these studies, it is suggested that monitoring studies should be extended to other fruits grown in different agro climatic regions which may serve as basis for future policy in chemical use.     

四溴双酚A在土壤中的降解转化及残留研究进展

四溴双酚A(tetrabromobisphenol A,TBBPA)是全球生产量最大的溴代阻燃剂,广泛应用于电子产品和塑料等高分子材料的生产中.由于高的亲脂性及环境稳定性,TBBPA在土壤中易于累积.土壤作为污染物主要的汇之一,污染物在土壤中的环境过程和归趋对正确评价污染物的环境风险至关重要.本文综述了土壤中TBBPA...     

多环芳烃在全土及其碱提残余物上的吸附行为

以菲和芘为代表性化合物,采用8种有机质含量不同的天然全土样品及其碱提残余物进行吸附实验,并利用不同吸附模型进行数据拟合,藉以探讨有机质含量对土壤吸附行为的影响.结果表明,Freundlich吸附模型的非线性指数n都小于1,显示全土和碱提残余物在多环芳烃的吸附过程中表现出非线性特征.菲和芘的吸附行为随土壤有机质含量不同而变化,碱提残余物的吸附能力强于全土,两者吸附行为的差异主要归因于土壤有机质含量和性状的区别.     

固相萃取小柱净化-气相色谱法测定土壤和沉积物中有机氯和拟除虫菊酯农药残留

建立了毛细管气相色谱法测定土壤和沉积物中α-六六六,β-六六六,γ-六六六,δ-六六六,硫丹,p,p'-DDE,p,p'-DDD,o,p'-DDT,p,p'-DDT,三氯杀螨醇,甲氰菊酯,氯氰菊酯,联苯菊酯,氟氯氰菊酯,氰戊菊酯,溴氰菊酯等16种农药残留量的方法.16种农药的残留组分在25min内能很好分离.标准加入回收率在81.2%-111.9%之间;方法变异系数2.9%-14.9%(0.01-0.1μg·ml-1,n= 6),检出下限在0.08-0.44μg·kg-1之间.     

Leaching behavior of Pb and Zn in air pollution control residues and their modeling prediction

Increasing attention has been paid to air pollution control （APC） residues in China recently due to the rising proportion of waste incineration and the hazardous characteristics of the residues, among which heavy metal leaching toxicity plays an important role. Leaching behavior and potential risk of Pb and Zn in the APC residues from a Shanghai municipal solid waste （MSW） incinerator was studied, based on the leaching tests under different conditions and theoretical calculation using a geochemical thermodynamic equilibrium model MINTEQA2. Results showed that, extractant species and liquid to solid （L/S） ratio predominantly controlled the leaching toxicity of Pb and Zn, while ionic strength, vibration method and leaching time had less effect on the metals release. Leachate/final pH determined the metal leaching behavior, which changed the speciation of heavy metals in the extraction system. The equilibrium aqueous speciation, precipitation-dissolution of Pb and Zn was investigated according to the model computation, which was well in agreement with the experimental results.     

Testing the efficiency of extraction of incurred residues from soil with optimized multi-residue method

The reproducibility of extraction of residues from spiked soil samples and from soils containing incurred residues was tested with ¹⁴C-labeled test compounds of different physical-chemical properties. Nearly 100% of the compounds added to the sample before extraction could be recovered with an average reproducibility relative standard deviation (CV) of 5.4%. The additional steps of the determination process (cleanup, evaporation, etc.) contributed to the major part of the variability of the results (CV = 10–20%). The incurred residues were most efficiently extracted with acetone for 30 min followed by the mixture of acetone/ethyl acetate 1:1 for additional 30 min. However, they could only be recovered at various extent (64–90% of total residues), underlying the importance of testing the efficiency of extraction. The residues were identified and quantified by gas chromatography applying thermionic detector. The performance parameters of the method complied with the international method validation guidelines, and they proved to be robust and suitable for determination of pesticide residues in soils of widely different physical–chemical properties.     

Fate of the 14C-labeled herbicide prosulfocarb in a soil and in a sediment-water system

The fate of ¹⁴C-labeled herbicide prosulfocarb was studied in an agricultural soil and in a sediment-water system, the sediment part of which was derived from Yangtze Three Gorges Reservoir, China. Time-course studies were performed for 28 d and 49 d, respectively. Main transformation routes of ¹⁴C-prosulfocarb were mineralization to ¹⁴CO₂ and formation of nonextractable residues amounting to 12.13% and 10.43%, respectively, after 28 days (soil), and 9.40% and 11.98%, respectively, after 49 d (sediment-water system). Traces of prosulfocarbsulfoxide were detected by means of TLC, HPLC, and LC-MS; other transformation products were not found. Initial extraction of soil assays using 0.01 M CaCl₂ solution showed that the bioavailability of the herbicide was considerably low; immediately after application (0.1 d of incubation), only 4.78% of applied radioactivity were detected in this aqueous fraction. DT₅₀ values of ¹⁴C-prosulfocarb estimated from radio-TLC and -HPLC analyses were above 28 d in soil and ranged between 29 d and 49 d in the sediment-water system. Partitioning of ¹⁴C from water to sediment phase occurred with DT₅₀ slightly above 2 d. With regard to the sediment-water system, adsorption occurred with log K_oc = 1.38 (calculated from 2 day assays) and 2.35 (49 d assays). As similarly estimated from portions of ¹⁴C found in CaCl₂ extracts of the 0.1 d assays, ¹⁴C-prosulfocarb's log K_oc in soil was 2.96. With both experiments, similar portions of nonextractable radioactivity were associated with all soil organic matter fractions, i.e. nonhumics, fulvic acids, humic acids, and humin/minerals. Throughout all sample preparation, the experiments were severely impaired by losses of radioactivity especially with concentration of samples containing water in vacuo. All findings pointed to volatility of parent prosulfocarb in presence of water rather than volatility of transformation products. According to literature data, this behavior of prosulfocarb was not expected, though volatility was demonstrated under field conditions.     

广西北部湾蔬菜种植基地土壤中代森锌类农药残留调查

采用顶空-气相色谱-质谱法,对南宁、北海、钦州和防城港等4个北部湾区域城市蔬菜种植基地60份土壤样品中的代森锌类农药残留进行检测。结果表明,南宁市的15份土壤样品均未检出代森锌类农药残留;北海市有5份土壤样品检出代森锌类农药残留,检出率为33.3%,其质量比范围为0.005 2 mg/kg~0.034 6 mg/kg;钦州和防城港2市30份土壤样品均检出代森锌类农药残留,检出率为100%,其质量比范围为0.004 9 mg/kg~0.674 mg/kg。