微生物抗菌、降解有机磷农药研究进展

有机磷农药作为一种高效、广谱的内吸性杀虫剂,被广泛应用于防治粮食等经济作物害虫,以保护幼苗和作物生长。滥用农药造成的有机磷农药在环境中的残留量逐步上升,农药污染治理是当前环境科学研究的热点。微生物降解技术具有资源丰富、可原位修复污染场地、对环境污染小、成本低的优点,以生物修复作为理论基础的农药残留微生物降解技术是目前降低农产品和农业生产环境中农药残留的重要方法,在土壤和水体污染修复中应用前景广阔。首先对我国当前农药使用情况进行简单介绍,在此基础上概述了现今对于微生物抑制植物病害以及可降解有机磷农药微生物的研究成果,并对海洋微生物的生理特性、抗菌效能进行了论述。根据目前的研究进展,提出了今后重点研究内容,为筛选出高效的拮抗菌、降解菌提供理论基础。     

有机农药污染土壤的修复方法研究进展

农药的大量使用污染了环境,对土壤的危害最为严重。介绍有机农药污染的危害,论述近年来修复有机农药污染土壤的研究成果,农药污染土壤的化学、生物及联合修复方法,分析各种方法的优缺点,结合近年来研究热点,认为采用联合修复是今后农药污染土壤修复的主要方向。     

仪征市耕地土壤环境质量调查与分析

本文以仪征市现有耕地土壤为调查对象，通过布点、采样、检测、统计，结果表明，仪征市沿江圩区长江冲积母质发育的土壤比丘陵地区下蜀黄土重金属含量相对较高，土壤重金属含量多年来有升高现象，少数田块存在高残农药的残留，点源污染和农药污染对耕地环境质量的影响不容忽视，需要采取工程、生物和化学等技术对土壤进行修复。     

秦皇岛市蔬菜农药污染的主要原因及其防治对策

本文在对秦皇岛市蔬菜农药污染的情况调查研究的基础上，指出了蔬菜受农药污染的主要原因为农药种类多，使用量大，品种结构不合理；农药产品合格率低，高效低毒新农药少；农民缺乏农药科学知识。合理预防和控制农药污染的措施包括农业措施、生物防治、物理防治、化学防治、综合防治等。     

化学农药对环境的危害及其防止对策的探讨

农药主要表现在对土壤、水体和大气的污染，对鸟类、昆虫及农产品品质的影响。针对农药对现实生态环境的破坏，我国应从完善法规管理，加强执法力度，淘汰高毒农药，发展绿色化学农药，加强技术培训，科学施用农药，提高测报水平，合理选用农药，综合防治，修复和预防并用等方面采取措施，解决农药污染问题。     

农药清洁生产:从源头上治理土壤污染

农药污染是农村土地污染的重要来源,是我国环境治理的难题。长期不合理、过量使用农药,农药毒性高、残留多等问题,不仅严重损害了生态环境,也不利于现代农业发展和食品安全。清洁生产工艺应用不足是导致农药污染突出的重要原因,农药行业市场结构不合理、企业创新动力不足、新工艺推广应用支持政策不到位等是主要障碍。应从供给和需求两个方面综合治理农药污染,通过严格环境执法、加快淘汰落后工艺,设立农药技术创新基金,加快推进农药行业整合重组和市场结构优化,构建理性、和谐的社会舆论环境等方式,有效推动农药清洁生产、治理农药污染。     

农药水环境化学行为研究进展

农药在水中的环境化学行为包括农药的光化学降解、水化学降解和农药对水生生物的毒性。结合国内外在农药水环境化学行为的研究进展，讨论了农药在水中的直接光解和间接光解行为；农药水化学降解的机理以及pH、温度对农药水化学降解的影响，并以藻类、鱼类等为例阐述了农药对水生动植物及水生生物群落的毒性。     

农药对蔬菜质量安全影响研究

从农药污染蔬菜的方式途径、不同种类蔬菜对农药的吸收机理和影响蔬菜发生药害的因素等方面阐述了农药对蔬菜的危害,并对怎样防治蔬菜农药污染提出了对策和措施。     

油污土壤微生物生态研究

利用微生物降解土壤中的油等有机污染物的就地生物治理技术受土壤及环境的诸多条件影响,在使用该技术之前,首先要进行油污土壤微生物生态研究,弄清影响微生物处理效果的各种因素。通过对胜利油田油污土壤微生物研究得知：胜利油田油污土壤的ｐＨ值、含水量等指标利于微生物降解原油。土壤优势菌种多为原油降解菌,并且与含油量呈正相关。油污土壤中氮、磷等营养物质含量不足时,向其添加一定数量的营养物质和降解菌,能够提高微生物处理地面溢油的处理效率。     

菌剂及酶制剂在有机污染治理方面的研究进展

通过介绍菌剂及酶制剂的制备原理与作用原理,重点阐述了菌剂在净化水质与修复土壤方面的应用及发展前景,并阐明了非生物因素与生物因素对菌剂及酶制剂作用效果的影响,同时对两种制剂的安全性进行论证.突出利用两种制剂作用效果好、专一性好、能迅速将有毒有害有机物降解为无毒无害物质的特点,达到环境污染治理的目的,并提出未来微生物法降解...     

农用化学物资对土壤的污染状况与控制措施

随着现代化学农业的兴起与发展,不可避免地给环境造成污染。结合目前研究进展,主要从化肥、农药、地膜三方面入手,论述现代农业生产实践中,农用化学物资对重要的自然资源—土壤的污染状况及控制措施     

Pesticides,valuations and politics

In this paper, I will discuss some aspects of the Swedish policy to reduce pesticide use by 50%, a decision that has attracted great interest and may sometimes have been over-advertised. It has also been followed by similar programmes in other countries such as Denmark, Holland and Canada, What are the cultural and political backgrounds? What is general and what is specifically swedish? Why did the demand for this decision first occur in Sweden, where the problems concerning pesticide use are much less pronounced than in many other countries and agricultural areas? Does the Swedish policy imply a new approach with completely different conditions for pesticide use, or should it preferably be described as an adaptation to what modern pesticide and agricultural technology can achieve?     

Turfgrass thatch effects on pesticide leaching: a laboratory and modeling study

Process-based models are frequently used to assess the water quality impacts of turfgrass management emanating from proposed or existing golf courses. Thatch complicates the prediction of pesticide transport because surface-applied pesticides must pass through an organic-rich layer before entering the soil. This study was conducted to (i) compare the use of a linear equilibrium model (LEM) and two-site nonequilibrium (2SNE) model to predict pesticide transport through soil and thatch + soil columns, and (ii) evaluate thatch effects on pesticide transport through soil columns with a volume-averaging approach. Pesticide breakthrough curves were obtained for soil and thatch + soil columns from a 1 cm h(-1) flux applied one day after applying triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) and carbaryl (1-napthyl-methyl carbamate). Pesticide and bromide transport parameters indicated that nonequilibrium processes were affecting pesticide transport. Columns containing zoysiagrass (Zoysia japonica Steud.) thatch had lower triclopyr and carbaryl leaching losses than did soil-only columns, although total reductions attributable to thatch did not exceed 15% of the applied pesticide. When laboratory-based retardation factors were used, the 2SNE model explained 88 to 93% of the variability for triclopyr and 70 to 94% of the variability for carbaryl. Laboratory-based retardation factors performed well in a 2SNE model to predict the peak concentration and tailing behavior of triclopyr and carbaryl with a volume-averaging approach. These results suggest that separate representation of the thatch layer in process-based models is not a prerequisite to obtain reasonable estimates of pesticide transport under steady state flow conditions.     

Continuing Issues in the Limitations of Pesticide Use in Developing Countries

The rationale for pesticide use in agriculture is that costs associated with pesticide pollution are to be justified by its benefits, but this is not so obvious. Valuing the benefits by simple economic analysis has increased pesticide use in agriculture and consequently produced pesticide-induced “public ills.” This paper attempts to explore the research gaps of the economic and social consequences of pesticide use in developing countries, particularly with an example of Nepal. We argue that although the negative sides of agricultural development, for example- soil, water, and air pollution; pest resistance and resurgence; bioaccumulation, bio-magnification; and loss of biodiversity and ecosystem resilience caused by the use of pesticides in agriculture, are “developmental problems” and are “unintentional,” the magnitude may be increased by undervaluing the problems in the analysis of its economic returns. Despite continuous effort for holistic system analyses for studying complex phenomena like pesticides impacts, the development within the academic science has proceeded in the opposite direction that might have accelerated marginalization of the third world subsistence agricultural communities. We hypothesize that, if these adversities are realized and accounted for, the benefits from the current use of pesticides could be outweighed by the costs of pollution and ill human health. This paper also illustrates different pathways and mechanisms for marginalization. In view of potential and overall negative impacts of pesticide use, we recommend alternative ways of controlling pests such as community integrated pest management (IPM) along with education and training activities. Such measures are likely to reduce the health and environmental costs of pesticide pollution, and also enhance the capabilities of third world agricultural communities in terms of knowledge, decision making, innovation, and policy change.     

A GIS model-based screening of potential contamination of soil and water by pyrethroids in Europe

The paper presents a geographic information system (GIS) model-based approach for analysis of potential contamination of soil and water by pyrethroids for the European continent. Pyrethroids are widely used pesticides and their chemical and toxicological characteristics suggest there may be concerns about human health and ecosystems, although so far there is no strong evidence indicating actual risk. However, little monitoring has been conducted and limited experimental information is available. We perform an assessment exercise that demonstrates how accessible information and GIS-based modeling allow to estimate the spatial distribution of chemical concentrations and fluxes at a screening level. The assessment highlights potential hot spots and the main environmental transport pathways, in a quick and simple way. By combining information on pesticide use, crop distribution and landscape and climate parameters we identify potential problem areas to help focusing monitoring campaigns. The approach presented here is simple and fast, and can be applied to virtually all pesticide classes used over a large domain, and is therefore suitable for the screening of large quantities of chemicals, of which the majority has not undergone any systematic environmental monitoring program. The method has been tested through benchmarking with other well-established models. However, further research is needed to evaluate it against experimental observations.     

FACTORS AFFECTING PESTICIDE OCCURRENCE AND TRANSPORT IN A LARGE MIDWESTERN RIVER BASIN1

ABSTRACT: Several factors affect the occurrence and transport of pesticides in surface waters of the 29,400 km² White River Basin in Indiana. A relationship was found between pesticide use and the average annual concentration of that pesticide in the White River, although this relationship varies for different classes of pesticides. About one percent of the mass applied of each of the commonly used agricultural herbicides was transported from the basin via the White River. Peak pesticide concentrations were typically highest in late spring or early summer and were associated with periods of runoff following application. Concentrations of diazinon were higher in an urban basin than in two agricultural basins, corresponding to the common use of this insecticide on lawns and gardens in urban areas. Concentrations of atrazine, a corn herbicide widely used in the White River Basin, were higher in an agricultural basin with permeable, well‐drained soils, than in an agricultural basin with less permeable, more poorly drained soils. Although use of butylate and cyanazine was comparable in the White River Basin between 1992 and 1994, concentrations in the White River of butylate, which is incorporated into soil, were substantially less than for cyanazine, which is typically applied to the soil surface.     

A model for linking the effects of parathion in soil to its degradation and bioavailability kinetics

Parathion is an insecticide of a group of highly toxic organophosphorus compounds. To investigate the dissipation and toxicological impact of parathion [O,O-diethyl O-(4-nitrophenyl) phosphorothioate] and its highly toxic metabolite, paraoxon, soil laboratory experiments were conducted in columns during a 19-d experiment under variably saturated conditions. Water and pesticide transport, sorption, and biodegradation of parathion were measured in three soil pools (soluble phase, weakly and strongly sorbed phases) using C-labeled pesticide. The effects of parathion and its metabolite on the mobility of soil nematodes were observed and then modeled with an effective variable, which combined pesticide concentration and time of application. Results showed that parathion was highly sorbed and slowly degraded to a mixture of metabolites. The parent compound and its metabolites remained located in the top 0.06-m soil layer. A kinetic model describing the sorption, biodegradation, and allocation into different soil pools of parathion and its metabolites was coupled with heat and water transport equations to predict the fate of parathion in soil. Simulated results were in agreement with experimental data, showing that the products remained in the upper soil layers even in the case of long-term (11-mo) simulation. The strongly sorbed fraction may be regarded as a pesticide reservoir that regularly provides pesticide to the weakly sorbed phase, and then, liquid phase, respectively. From both modeling and observations, no major toxicological damage of parathion and paraoxon to soil nematodes was found, although some effects on nematodes were possible, but at the soil surface only (0.01- and 0.02-m depth).     

美国环保署农药地下水风险评估模型

在介绍美国农药环境风险评估的概念、分级、地下水农药监测情况及水资源的立法保护等基础上,重点阐述了美国环保署在农药登记管理过程中使用的2个地下水风险评估模型,即SCI-GROW和PRZM-GW模型。SCI-GROW是以好氧条件土壤半衰期和土壤有机碳分配系数为自变量的经验线性回归模型,而PRZM-GW则是描述农药在土壤中运动的一维、有限差分模型。本文通过对美国环保署这2个特点鲜明的模型的介绍,希望能为我国的农药地下水风险评估及模型的开发提供一个新视角。     

Propagation of uncertainties in soil and pesticide properties to pesticide leaching

In the new Dutch decision tree for the evaluation of pesticide leaching to groundwater, spatially distributed soil data are used by the GeoPEARL model to calculate the 90th percentile of the spatial cumulative distribution function of the leaching concentration in the area of potential usage (SP90). Until now it was not known to what extent uncertainties in soil and pesticide properties propagate to spatially aggregated parameters like the SP90. A study was performed to quantify the uncertainties in soil and pesticide properties and to analyze their contribution to the uncertainty in SP90. First, uncertainties in the soil and pesticide properties were quantified. Next, a regular grid sample of points covering the whole of the agricultural area in the Netherlands was randomly selected. At the grid nodes, realizations from the probability distributions of the uncertain inputs were generated and used as input to a Monte Carlo uncertainty propagation analysis. The analysis showed that the uncertainty concerning the SP90 is 10 times smaller than the uncertainty about the leaching concentration at individual point locations. The parameters that contribute most to the uncertainty about the SP90 are, however, the same as the parameters that contribute most to uncertainty about the leaching concentration at individual point locations (e.g., the transformation half-life in soil and the coefficient of sorption on organic matter). Taking uncertainties in soil and pesticide properties into account further leads to a systematic increase of the predicted SP90. The important implication for pesticide regulation is that the leaching concentration is systematically underestimated when these uncertainties are ignored.     

Impact of data quality and model complexity on prediction of pesticide leaching

Accurate input data for leaching models are expensive and difficult to obtain which may lead to the use of "general" non-site-specific input data. This study investigated the effect of using different quality data on model outputs. Three models of varying complexity, GLEAMS, LEACHM, and HYDRUS-2D, were used to simulate pesticide leaching at a field trial near Hamilton, New Zealand, on an allophanic silt loam using input data of varying quality. Each model was run for four different pesticides (hexazinone, procymidone, picloram and triclopyr); three different sets of pesticide sorption and degradation parameters (i.e., site optimized, laboratory derived, and sourced from the USDA Pesticide Properties Database); and three different sets of soil physical data of varying quality (i.e., site specific, regional database, and particle size distribution data). We found that the selection of site-optimized pesticide sorption (Koc) and degradation parameters (half-life), compared to the use of more general database derived values, had significantly more impact than the quality of the soil input data used, but interestingly also more impact than the choice of the models. Models run with pesticide sorption and degradation parameters derived from observed solute concentrations data provided simulation outputs with goodness-of-fit values closest to optimum, followed by laboratory-derived parameters, with the USDA parameters providing the least accurate simulations. In general, when using pesticide sorption and degradation parameters optimized from site solute concentrations, the more complex models (LEACHM and HYDRUS-2D) were more accurate. However, when using USDA database derived parameters, all models performed about equally.