气相色谱法测定水和土壤中苯醚甲环唑的残留量

研究并建立了气相色谱法测定水和土壤中苯醚甲环唑残留量的分析方法。实验结果表明：水中添加苯醚甲环唑的含量为0．005～0．500mg／kg时，平均回收率为97．9％～100．5％，相对标准偏差小于6．7％；土壤中添加苯醚甲环唑的含量为0．005～0．500mg／kg时，平均回收率为95．7％～109．5％，相对标准偏差小于7．5％。将该法用于水和土壤残留实验，土壤试样在拖药后10～88d进行采样分析，其残留消解动态回归方程为y=0．8803e^-0.0122x，相关系数为-0．915，消解半衰期为56．8d；水试样在施药后0～21d进行采样分析，其残留消解动态回归方程为y=0．2624e^-0.2539x，相关系数为-0．899，消解半衰期为2．7d。     

气相色谱-质谱法测定水稻、土壤及稻田水中的恶庚草烷残留量

建立了一种用于测定糙米、稻壳、植珠（稻草和秧苗）、土壤及稻田水中恶庚草烷残留量的分析方法,样品中的恶庚草烷用乙腈或炳酮提取和微型柱固相萃取净化后,用ＧＣ／ＭＳ（ＳＩＭ）方法测定。仪器的灵敏度低于５０ｐｇ,样品中恶庚草烷的最低检出质量浓度为０．００５ｍｇ／ｋｇ,不同浓度下恶庚草烷的平均回收率为８０．０％－９６．４％,变异系数〈１３％,在恶庚草烷／水稻的残留试验中应用本方法测定恶 草烷残留量取得了满意     

流动注射-氢化物发生-原子吸收法测定土壤中微量砷

用混酸消解土壤试样，用体积分数为20％的盐酸作酸介质，质量分数为1．5％的硼氢化钾作还原剂，体积分数为1％的盐酸作载液，采用流动注射-氢化物发生三-原子吸收法定量测定土壤中的微劈砷。通过实验确定，在原子化温度为920℃、土壤中共存元素含量低于5mg／kg时对测定无干扰。该方法的榆出限为0．5μg/L，线性范嘲为5～100μg/L．相对标准偏差为0．89％，平均回收率达98．99％：     

盖草能在棉花上残留量的测定及消解动态研究

用碱性甲醇提取棉籽、棉叶及土壤中残留的盖草能,经溶剂萃取、微型Sea-Pak硅胶柱分离、甲基化反应和酸性氧化铝柱净化后,进行气相色谱(ECD)测定。方法回收率大于80％,最低检出限为0.002ppm。研究了盖草能在棉叶和棉田土壤中残留的消解动态,测定了消解半衰期及棉籽和土壤中的最终残留量。据此,制定了盖草能在棉花上的合理使用准则。     

流动注射在线富集分光光度法测定水样中痕量Cr(Ⅵ)

采用流动注射在线富集分光光度法测定水样中痕量Cr（Ⅵ），考察了流路条件、显色条件和共存离子的影响。在H：SO。浓度为1．2mol/L、2-（5-溴-2-吡啶偶氮）-5-二乙氨基酚溶液质量浓度为1．75g／L的条件下，试样富集4min，测定Cr（Ⅵ）的线性范围为0．01～0．60mg／L，检出限为3μg/L。连续10次测定质量浓度为0．20mg／L的Cr（Ⅵ）标准溶液相对标准偏差为0．4％。方法可应用于河水和工业废水中痕量Cr（Ⅵ）的测定，加标回收率为93．3％～106．4％。     

苹果中多种农药残留气相色谱分析方法的研究

进行了双气路、双检测器气相色谱法测定苹果中有机磷、有机氯及菊酯类１３种农药残留量的研究。该方法简便、快速、灵敏度高，重现性好，辛硫磷及水胺硫磷的最低检出浓度为０．０５ｍｇ／ｋｇ，其它１１种农药的最低检出浓度≤０．０１ｍｇ／ｋｇ，１３种农药的平均回收率均大于８０％，变异系数均小于１５％。该方法用于果园中不同品种苹果多种农药残留的实测时，取得了满意的结果。     

自动进样气相色谱法测定气体中的非甲烷烃

用泰德拉气体采样袋采样，自动进样气相色谱法测定气体中的非甲烷烃含量。甲烷、总烃的线性范围分别为0～2439，0—2066mg／m^3。进样量为1mL时，检出限为0．02mg／m^3（信噪比为3）。对3种不同浓度甲烷与丙烷混合标准气进行测定，重复性相对标准偏差为0．4％-1．0％。对4种不同性质的试样进行加标回收实验，加标回收率为96．7％-102．0％。5名实验人员分别用自动进样法及手动进样法分析4种不同性质的试样，自动进样法的重现性相对标准偏差为1．2％～1．8％，优于手动进样法的6．5％～8．3％。该法可一次连续测定21个试样，精密度高、重现性好、分析效率高。     

氢化物-原子吸收法测定土壤、水中微量锑

本文介绍了氢化物发生-原子吸收法测定土壤、水中微量锑的方法。研究了仪器最佳工作条件、样品处理及实验条件;考察了共存离子的干扰;介质的影响与消除。用本方法测定土壤样品的灵敏度为0.995纳克/1％吸收,变异系数为5.54％;测定水样的灵敏度为3.93钠克/1％吸收,变异系数为10.9％。 `     

一种适用于盐渍土的土壤固化剂

一种适用于盐渍土的土壤固化剂，可用于含盐量高的盐渍土的固化。各原料的质量组成：普通硅酸盐水泥1．0％，粉煤灰1．5％-2％，水淬高炉矿渣2％-3％，活性矿物掺和料（煅烧媒矸石粉、亚高岭土、磷渣或镁渣中的一种或几种）1．0％-1．5％，石灰（生石灰粉或消石灰）0．5％-1．5％，碱金属或碱土金属的氢氧化物0—0．3％，化学分散剂（萘璜酸盐缩合物或密胺类物质）0—0．1％。     

ICP-AES测定电镀污泥中的Ag,Cu,Ni

介绍了用王水消解-氨水浸取含银电镀污泥试样的预处理方法，并对试样预处理中的若干问题进行了讨论。研究了分别在碱性和酸性介质中用高频电感耦合等离子体-原子发射光谱（ICP-AES）仪直接测定污泥中Ag，Cu，Ni等金属元素的分析方法。实验结果表明：在选定的最佳仪器工作条件下，Ag，Cu，Ni，Al，Ca，Fe加标回收率为97％～105％，相对标准偏差小于1．5％。该方法简便、快速、准确，适用的试样测定含量范围为0．01％-12．5％（干基试样）。     

Distribution of Cd,Ck, Pb and Zn in Soil and Vegetation Compartments in Stands of Five Boreal Tree Species in N.E. Sweden

Concentrations and total quantity of cadmium (Cd), cupper (Cu),lead (Pb) and zink (Zn) were determined in biomass and soil compartments in a replicated tree species experiment with 27-yr-old stands growing on former farmland in N.E. Sweden. Sequentialextractions of soil samples were performed in order to estimate the exchangeable and an organically bound fraction of each element. The tree species included were Picea abies (L.)H. Karst., Pinus sylvestris L., Pinus contorta Dougl., Larix sibirica Ledeb., and Betula pendula Roth.Tree species influenced the rate of removal of Cu, Pb and Zn incase of stemwood harvesting, and of Cd, Cu and Zn in the case ofwhole-tree harvesting. B. pendula and P. abies had higher quantities and average concentrations of Zn in the biomass. For all species, >50% of the Zn in the stems was found in the bark. P. abies and L. sibirica had higher quantities of Cu in the biomass than the other species.P. abies and P. contorta had high quantities of Cd inthe biomass in relation to the other species. Branches and stembark contained high concentrations of Cd and Pb in relation to foliage and stemwood. Dead branches had especially high concentrations of Pb. The high accumulation rate of Zn in thebiomass of B. pendula was related to a low exchangeable amount of Zn in the A horizon. In the superficial centimeters ofthe A horizon, a depletion similar to that found for Zn was detected for Cu, whereas for Cd and Pb, no correlations were found between quantities of elements in the trees and element pools in the soil.     

Programs assessing implementation and effectiveness of state forest practice rules and BMPs in the West

The major forest nonpoint source control programs in the West are largely regulatory, either under forest practices acts (California, Idaho, New Mexico, Nevada, Oregon, and Washington) or a streamside management act (Montana). These programs and the specific rules they enforce continue to undergo intensive scrutiny. Still, the questions are the same for these regulatory programs as for states that base nonpoint source control on voluntary BMPs (Arizona, Colorado, Utah, Wyoming). Are the rules or BMPs being applied, and are they effective in reducing nonpoint source pollution to levels that protect beneficial uses of water? The level of debate about forestry in the West has resulted in detailed monitoring and research to answer these questions. In the past, state agencies have assumed levels of BMP compliance based on the percent of operations without enforcement actions. These estimates are being replaced by statistically valid and reproducible monitoring of forest practices rules and BMP compliance levels. BMP effectiveness is being assessed using both qualitative and quantitative methods. This can involve field assessments, process-based research, and control watershed studies. Some trend monitoring is also beginning. With the regional implementation rate for forestry BMPs at about 94% and rising, it is likely that effectiveness testing will continue to be a priority and consume the majority of assessment resources for this region.     

Hysteresis in Reversal of Central European Mountain Lakes from Atmospheric Acidification

Extremely high emissions of S and N compounds in Central Europe (both 280 mmol m^-2 yr^-1) declined by 70and 35%, respectively, during the last decade. Decreaseddeposition rates of SO₄ ^-2, NO₃ ^-, and NH₄ ⁺ in the region paralleled emission declines. The reduction in atmospheric inputs of S and N to mountain ecosystemshas resulted in a pronounced reversal of acidification in the Tatra Mountains and Bohemian Forest lakes. Between the 1987–1990and 1997–1999 periods, concentrations of SO₄ ^-2 and NO₃ ^- decreased (average ± standard deviation) by 22±7 and 12±7 mol L^-1, respectively, in theTatra Mountains, and by 19±7 and 15±10 mol L^-1, respectively, in the Bohemian Forest. Their decrease was compensated in part (1) by a decrease in Ca²⁺ + Mg²⁺ (17±7 mol L^-1) and H⁺ (4±6 mol L^-1), and an increase in HCO₃ ^-(10±10 mol L^-1) in the Tatra Mountains lakes, and (2) by a decrease in Al (7±4 mol L^-1), Ca²⁺ + Mg²⁺ (9±6 mol L^-1), and H⁺ (6±5 mol L^-1), in Bohemian Forest lakes. Despite the rapid decline in lake water concentrations of SO₄ ^-2 and NO₃ ^- in response to reduced S and N emissions, their present concentrations in some lakes are higher than predictionsbased on observed concentrations at comparable emission rates during development of acidification. This hysteresis in chemical reversal from acidification has delayed biological recovery of the lakes. The only unequivocal sign of biological recovery hasbeen observed in erné Lake (Bohemian Forest) where a cladoceran species Ceriodaphnia quadrangular has recentlyreached its pre-acidification abundance.     

Reconstruction of Long-Term Changes in Lake water Chemistry,Zooplankton and Benthos of a Small,Acidified High-Mountain Lake: Magic Modelling and Palaeolimnogical Analysis

Starolesnianske pleso is a small and shallow acid lake in the High Tatra Mountains, situated at 2000 m above sea level, on granitic bedrock, with sparse and thin soil cover. When detailed measurements began in the 1980s Starolesnianske pleso had pH below 5 and only one species of cladoceran zooplankton, the ubiquitous Chydorus sphaericusPalaeolimnological investigations show changes in cladoceran zooplankton and chironomid zoobenthic assemblages since about 1920 and a major change in 1970–1980. The dynamic acidification model MAGIC was used to reconstruct changes in water chemistry over the past 150 years. The results from MAGIC agree well with the sediment record; pH levels gradually decreased from 6.5 in the mid-1800s to about 5.6 in 1920 (first response in biota) to below 5.0 by 1970, and concentrations of inorganic aluminium rose dramatically beginning about 1960. In the 1990s the lake water chemistry showed clear signs of reversal in acidification brought about by a major decline in S deposition.     

Heavy Metals Removal by Biosorption and Flotation

The removal of a mixture of heavy (toxic) metal cations (copper, nickeland zinc) from liquid effluents was investigated in this study at pilotscale, using counter-current contact mode. The innovative processinvolved the abstraction of metal ions onto fungal biosorbents, followedby the application of flotation for the subsequent solid/liquid separationof biomass particles. The ability of microorganisms to remove metal ionsfrom aqueous solutions is a well-known phenomenon. Nevertheless,engineering considerations are very important in decisions, concerningthe commercial future of biosorption and practical solutions are neededfor certain problems, such as the efficient post-separation ofmetal-loaded biomass. The two processes (flotation and biosorption) caneffectively operate in combination, in what it was termed biosorptiveflotation process. The sorbents may be recycled, after appropriate elutionof metals, as well as the treated (clean) water.     

Starch-plastic materials—Preparation,physical properties,and biodegradability (a review of recent USDA research)

Recent starch-plastic research at the National Center for Agricultural Utilization Research is reviewed and related worldwide efforts are noted. Properties of starch that influence its formulation and performance in plastics are discussed. Methods are given for preparation of starch-poly(methyl acrylate) graft copolymer, starch-poly(ethylene-co-acrylic acid), and starch-poly(ethylene-co-acrylic acid)-polyethylene plastics. Their physical properties are discussed, as is degradability by enzymes or amylolytic organisms from soil, ponds, and streams.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Bioassessment of silvicultural impacts in streams and wetlands of the Eastern United States

Bioassessment is a useful tool to determine the impact of logging practices on the biological integrity of streams and wetlands. Measuring biota directly has an intuitive appeal for impact assessment, and biota can be superior indicators to physical or chemical characteristics because they can reflect cumulative impacts over time. Logging can affect stream and wetland biota by increasing sedimentation rates, altering hydrologic, thermal, and chemical regimes, and changing the base of food webs. Biotic impacts of logging on streams compared to wetlands probably differ, and in this paper we review some of those differences. In streams, invertebrates, fishes, amphibians, algae, and macrophytes have been used as indicators of logging impacts. In wetlands, bioassessment is just beginning to be used, and plants and birds are the most promising indicator taxa. Various best management practices (BMPs) have been developed to reduce the impacts of logging on stream and wetland biota, and we review quantitative studies that have evaluated the efficacy of some of these techniques in streams and wetlands in the eastern United States. Remarkably few studies that address the overall efficacy of BMPs in limiting biotic changes in streams and wetlands after BMP implementation have been published in scientific journals, although some work exists in reports or is unpublished. We review these works, and compile conclusions about BMP efficacy for biota from this body of research.     

Characterization of air emissions and residual ash from open burning of electronic wastes during simulated rudimentary recycling operations

Air emissions and residual ash samples were collected and analyzed during experiments of open, uncontrolled combustion of electronic waste (e-waste), simulating practices associated with rudimentary e-waste recycling operations. Circuit boards and insulated wires were handled separately to simulate processes associated with metal recovery. The average emissions of polychlorinated dibenzodioxins and dibenzofurans (PCDD/PCDFs) were 92 ng toxic equivalency (TEQ)/kg [n = 2, relative standard deviation (RSD) = 98%] and 11 900 ng TEQ/kg (n = 3, RSD = 50%) of the initial mass of the circuit boards and insulated wire, respectively. The value for the insulated wire is about 100 times higher than that for backyard barrel burning of domestic waste. The emission concentrations of polybrominated dibenzodioxins and dibenzofurans (PBDD/PBDFs) from the combustion of circuit boards were 100 times higher than for their polychlorinated counterparts. Particulate matter (PM) sampling of the fly ash emissions indicated PM emission factors of approximately 15 and 17 g/kg of the initial mass for the circuit boards and insulated wire, respectively. Fly ash samples from both types of e-waste contained considerable amounts of several metallic elements and halogens; lead concentrations were more than 200 times the United States regulatory limits for municipal waste combustors and 20 times those for secondary lead smelters. Leaching tests of the residual bottom ash showed that lead concentrations exceeded U.S. Environmental Protection Agency landfill limits, designating this ash as a hazardous waste.     

Selection of Autochthonous Plant Species from SE Spain for Soil Lead Phytoremediation Purposes

Mining activity in SE of Spain, in the west Mediterranean coast, originated more than two millenniums ago. It has generated huge areas affected by heavy metals contamination, especially of lead, which is possibly one of the most important. Investigations related to the selection of autochthonous plant taxa from a typical Spanish Mediterranean area, useful for phytoextraction and phytostabilization purposes in these polluted areas are shown. Under these edaphoclimatic conditions 12 interesting species were considered, from them six taxa were chosen for further studies. Some plant species have been proposed either for phytoextraction or phytostabilization purposes. Recommendations for further research have been discussed.     

Concentrations and Pools of Heavy Metals in Urban Soils in Stockholm,Sweden

The concentrations of heavy metals (Cd, Cr, Cu, Hg, Ni, Pb andZn) and arsenic (As) were surveyed and the metal pools estimatedin soils in Stockholm Municipality. The sampling sites were distributed all over the entire municipality with a higher sampling density in the city centre. Soils were sampled to a maximum depth of 25 to 60 cm. Soil texture, total-C content, electrical conductivity and pH were analysed. Heavy metal concentrations were determined after wet digestion with boiling7 M HNO₃.The results showed a wide range in heavy metal concentrations, as well as in other soil properties. The city centre soils constituted a rather homogeneous group whereas outside this areano geographical zones could be distinguished. These soils were grouped based on present land use, i.e. undisturbed soils, public parks, wasteland (mainly former industrial areas), and roadside soils. The city centre and wasteland soils generally hadenhanced heavy metal concentrations to at least 30 cm depth compared to park soils outside the city centre and rural (arable)soils in the region, which were used to estimate background levels. For example, the mean Hg concentration was 0.9 (max 3.3)mg kg^-1 soil at 0–5 cm and 1.0 (max 2.9) at 30 cm depth in the city centre soils, while the background level was 0,04 mg kg^-1. Corresponding values for Pb were 104 (max 444) and135 (max 339) mg kg^-1, at 0–5 and 30 cm, respectively, while the background level was 17 mg kg^-1.The average soil pools (0–30 cm depth) of Cu, Pb and Zn were 21,38 and 58 g m^-2 respectively, which for Pb was 3–4 timeshigher and for Cu and Zn 1.5–2 times higher than the backgroundlevel. The total amount of accumulated metals (down to 30 cm)in the city centre soils (4.5^*10 ⁶ m² public gardens and green areas) was estimated at 80, 1.1, 120 and 40 t for Cu, Hg, Pb and Zn, respectively. The study showed (1) thatfrom a metal contamination point of view, more homogeneous soilgroups were obtained based on present land use than on geographicdistance to the city centre, (2) the importance of establishing a background level in order to quantify the degree of contamination, and (3) soil samples has to be taken below the surface layer (and deeper than 30 cm) in order to quantify theaccumulated metal pools in urban soils.