苯达嗪丙酯在土壤和小麦中的田间残留试验

建立了土壤和小麦种子、茎杆中苯达嗪丙酯的残留分析方法.研究了高剂量施药条件下土壤中的消解动态,并测定了土壤、小麦种子和茎杆中的最终残留.苯达嗪丙酯的最低检出限为10ng,在土壤和小麦中的最低检出浓度为0.05mg·kg-1.方法的平均添加回收率为88.7%—103.3%,变异系数为4.3%—16.4%.苯达嗪丙酯的消解动态试验表明:高剂量施药条件下苯达嗪丙酯在土壤中的半衰期分别为2.5d(北京)和3.1d(石家庄);当按推荐剂量施药时,小麦收获前10d,在土壤、小麦种子和茎杆中,北京和石家庄两地均未检出苯达嗪丙酯.     

臭氧-固定化生物活性炭滤池深度处理石化废水的试验研究

针对石化废水中不同特征污染物,采用人工分离筛选去除COD和油工程菌6株、硝化工程菌10株(亚硝化细菌5株、硝化细菌5株)构建高效混合菌群,通过臭氧固定化生物活性炭滤池除污染效能中试研究表明,该系统深度处理石化难降解有机废水是可行的,能同时实现去除COD、油类、NH3 N等污染物的功效,对COD、油类、NH3 N和色度的平均去除率分别为73 0%、90 5%、81 2%和90%,相应的出水分别为33 2mg/L、0 4mg/L、4 5mg/L和10倍,各项指标均达到了国家循环冷却水的用水要求,它的推广应用必将带来显著的环境效益、社会效益和经济效益。     

Microbial cycling of iron and sulfur in acidic coal mining lake sediments

Lakes caused by coal mining processes are characterized by low pH, low nutrient status, and high concentrations of Fe(II) and sulfate due to the oxidation of pyrite in the surrounding mine tailings. Fe(III) produced during Fe(II) oxidation precipitates to the anoxic acidic sediment, where the microbial reduction of Fe(III) is the dominant electron-accepting process for the oxidation of organic matter, apparently mediated by acidophilic Acidiphilium species. Those bacteria can reduce a great variety of Fe(III)-(hydr)oxides and reduce Fe(III) and oxygen simultaneously which might be due to the small differences in the redox potentials under low pH conditions. Due to the absence of sulfide, Fe(II) formed in the upper 6 cm of the sediment diffuses to oxic zones in the water layer where itcan be reoxidized by Acidithiobacillus species. Thus, acidic conditions are stabilized by the cycling of iron which inhibits fermentative and sulfate-reducing activities. With increasing sediment depth, the amount of reactive iron decrease, the pH increases above 5, and fermentative and as yet unknown Fe(III)-reducing bacteria are also involved in the reduction of Fe(III). Sulfate is reduced apparently by the activity of spore-forming sulfate reducers including new species of Desulfosporosinus that have their pH optimum similar to in situconditions and are not capable of growth at pH 7. However, generation of alkalinity via sulfate reduction is reduced by the anaerobic reoxidation of sulfide back to sulfate. Thus, the microbial cycling of iron at the oxic-anoxic interface and the anaerobic cycling of sulfur maintains environmental conditions appropriate for acidophilic Fe(III)-reducing and acid-tolerant sulfate-reducing microbial communities.     

新型固体进样汞镉测定仪测定固体样品中的镉

使用由北京吉天仪器有限公司开发的新型固体进样汞镉测定仪(DCMA-200),对采集的土壤、大气颗粒物和固体废物样品中镉的浓度进行分析。在测试过程中,选择9种标准土(GBW07407、GBW07402、GBW07410、GBW07425、GBW07426、GBW07428、GBW07419、GBW07309和GBW07418),研究了进样量对测定的影响,并分别在1.0~10.0 mg称量范围内建立了标准曲线(R ²> 0.93)。当固体样品进样量为10.0 mg时,镉的检出限为0.004 7 mg/kg,测定下限为0.016 mg/kg。利用7种标准土(GBW07418和GBW07419除外)绘制的标准曲线,测得的5种实际土壤中镉的浓度与利用电感耦合等离子体质谱仪(ICP-MS)测得的结果较一致。但与ICP-MS测得的结果相比,利用该固体进样汞镉测定仪测得的大气颗粒物中镉的浓度明显偏高,而危险废物中镉的浓度偏低。因此,建议在检测某地区的固体样品时,尽可能选择该区域和该类固体样品的标准品来设计标准曲线,从而提高测试结果的准确性。     

SATELLITE MICROWAVE OBSERVATIONS OF SOIL MOISTURE VARIATIONS1

ABSTRACT: Results from studies in the Illinois-Indiana and Texas-Oklahoma areas indicate that satellite microwave observations at the 1.55 cm wavelength are responsive to relative moisture variations in the near surface layer of the soil. Because significant vegetation cover absorbs the 1.55 cm microwave emission from the soil, the target area must be predominately bare soil or low density vegetation cover for meaningful measurements to result. The 25 km resolution of the satellite sensor limits application of the microwave techniques to large areas such as watersheds or agricultural districts rather than individual fields. In general, at 1.55 cm. there is an inverse relationship between microwave brightness temperature and changes in soil moisture levels (as indicated by antecedent rainfall) in agricultural regions before the planting of crops or during the early growing season when vegetation cover is sparse. Even early season observations should be of great value in deciding on the time and type of crop planting and for initial irrigation scheduling when the root zone is still in close proximity to the surface.     

砖红壤中Al和Pb的竞争吸附

从pH值和离子加入量两个角度研究了砖红壤中Al和Pb的竞争吸附 .结果表明 ,当低数量的Al和Pb共存时 ,离子的吸附量与其单独存在下的情形相比都有所下降 ,该现象在低pH值的条件下较为明显 ,而随着pH值升高则逐渐减弱 ;若Al和Pb共存时的初始浓度均为 1 0mmol·l- 1 ,两者之间的竞争吸附在pH 3 5至 5 5范围内都较为显著 ;此外 ,当0 1mmol·l- 1 的Pb与 1 0mmol·l- 1 的Al共存时 ,Al的吸附没有受到Pb的影响 ,此时尽管Al和Pb的浓度比为 1 0∶1 ,但土壤对Pb的吸附并没有被Al完全抑制 ,反映出土壤表面某些吸附位对Pb具有高度的选择性     

头屯河流域水土流失现状及治理对策

介绍头屯河流域气候、植被、水土资源状况,分析了流域水土流失的现状,提出了水土流失治理对策,总结了水土流失治理措施并提出一些建议。     

生物炭对Cd污染土壤的修复效果与机理

通过修复培养实验和BCR连续提取实验研究牛粪生物炭（DM）和水稻秸秆生物炭（RS）对2种镉污染土壤的修复效果、影响因素及修复后的Cd的形态分布,探讨可能存在的修复机理。经56 d修复后,与CK相比,5%添加量的牛粪生物炭（DM5%）和水稻秸秆生物炭（RS5%）使TCLP提取态Cd在S1土壤中分别降低了15%和18%,在S2土壤中分别降低了5%和6%。但生物炭添加量为1%时对S2土壤中Cd无显著修复效果。DM5%和RS5%处理使Cd的酸可溶态在S1土壤中降低8.66%和9.25%,在S2土壤中降低7.86%和13.4%,相应的残渣态在S1土壤中升高8.30%和10.54%,在S2土壤中升高8.67%和14.92%。同时,DM5%和RS5%处理使土壤pH提高了7.69%~13.13%,TCLP提取态P增高了0.046~0.39 mg·g-1。结果表明,添加量为5%的牛粪生物炭和秸秆生物炭可有效修复Cd污染土壤。     

新构造运动对安徽土壤分布的影响

安徽地跨亚热带与温带,过渡性特征明显,境内有山地,丘陵和平原,自然地理景观复杂多样,各区域由于所处大地构造单元不同,其新构造运动的表现形式也不同,它制约着区域地貌的发育,成土母质类型和地面气候状况,从而影响了该区域土壤的分布特征。     

酸沉降物对土壤化学性质的影响

本文综述了酸沉降物对土壤酸化、营养物质的淋溶、重金属的活化、矿物分解等化学性质的影响，以及阻止酸雨危害土壤的化学方法。