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1.
This paper describes the effect of a herbicide applied at levels consistent with off target movement on hawthorn the year following exposure. In the experiment, metsulfuron-methyl was applied in five dosages to individual trees in seven different hawthorn hedgerows. Spraying was conducted both at the bud stage and at the early flowering. Five endpoints (i.e. leaves, buds, flowers, green berries and mature berries) were sampled and counted. All were significantly reduced with increasing exposure. Present day risk assessment of effects on non-target plants is therefore likely to overlook significant effects on perennial non-target plants in the spray drift zone due to the focus on results from short-term laboratory test studies. The significance of the present study is underlined by the fact that the effects observed were significant, even though other influential factors such as herbivory and differential pollination were not eliminated and that experiments were conducted in multiple locations.  相似文献   

2.
In the present study the primary drift of 10 herbicides was investigated in five field experiments, and the amount deposited per surface area was quantified outside the application area using simple passive dosimeters. In addition, samples for measuring a possible background value were taken upwind of the sprayed field. Deposits of spray drift were common to all spray equipment and spray was detected up to 150 m off-target. There were deposits of 0.1-9% of the applied amount close to the sprayed field (up to 2 m). But 3m from the spraying zone deposits were reduced to 0.02-4%. The amounts decreased exponentially when moving away from the field. The differences in drift could be described mainly by the different drop sizes, the wind velocity, the formulation and the filtering effect of vegetation on the sampling area. The tendency of the active ingredients to evaporate could also have an, although less important, influence on the drift. This is a factor, which ought to be exposed to a further study. The findings supported that it is the physical properties of the spray and the conditions of application (i.e. equipment and meteorology) that are the primary determinants of primary drift rather than the chemical property of the pure active ingredients.  相似文献   

3.
K M Erstfeld 《Chemosphere》1999,39(10):1737-1769
The aquatic fate and persistence of synthetic pyrethroids under spray drift and field runoff treatment regimens were determined in outdoor pond microcosms. In this paper, the experimental design and construction of outdoor microcosms is presented, as well as the aquatic fate of tralomethrin and deltamethrin. Tralomethrin is rapidly degraded to deltamethrin, with a half-life of 12.7 hours under spray drift conditions. Degradation profiles of tralomethrin in water indicated rapid conversion of deltamethrin and to less active isomers and then to decamethrinic acid (BR2CA). After 24 hours, the percent radioactivity of tralomethrin was 25% of the test material in the water column. In sediment, tralomethrin was immediately converted to deltamethrin. Deltamethrin is rapidly degraded with a half-life of 8 to 48 hours, depending on mechanisms of introduction into water. Degradation profiles of deltamethrin in water indicated rapid conversion of deltamethrin to decamethrinic acid (BR2CA), comprising approximately 90% of the radioactivity in the aqueous phase at 168 hours. Extraction and analysis of fathead minnows (Pimephales promelas) after 96 hours revealed that tissue residues contained parent compounds and metabolites alpha-R-deltamethrin, trans-deltamethrin and Br2CA. Fish residues are directly related to aqueous concentrations, thus bioavailability under field runoff regimes were an order of magnitude lower than tissue residues under spray drift conditions. Plant tissue was found to significantly accumulate pyrethroids.  相似文献   

4.
In the present study the evaporation of 10 herbicides was investigated during five field experiments, and the amount deposited per surface area was quantified inside the field using simple passive dosimeters consisting of microscope slides placed on plastic lids. On an average basis 90% of the applied amount reached the field. The accumulated evaporation from the microscope slides was largest during the first hours after application, and the losses in 24 h (from 0% for tribenuron-methyl, fluroxypyr-1-methylheptylester and phenmedipham to 80% for prosulfocarb) was similar to other studies of losses from plant surfaces. An indication of a diurnal difference in the evaporation was observed, probably caused by the differences in temperature or by global radiation. The evaporation did not generally correlate to the vapour pressure. The amounts collected at t=0 on the passive dosimeters were for all field experiments in the same range as the reported amounts applied to the field, and the passive-dosimeters method was found to be a good and reliable method for collection of sprayed pesticides. The advantage of this method was also that it was simple and cheap and easy to set up for screening of evaporation of pesticides from the field after spraying.  相似文献   

5.
There has been increasing awareness of the possible impact of herbicide drift on vegetation in nature reserves and field-margin habitats adjacent to treated areas. However, relatively little is known about the impact of such drift on species typical of these habitats. To investigate this problem a series of bioassay experiments simulating spray drift were carried out with five native plant species of different age placed at different distances up to 4 downwind from a sprayer under standardized conditions. These experiments used three herbicides--glyphosate, MCPA and mecoprop--in three types of surrounding vegetation structure--short, medium-height and tall grassland. Many plants showed symptoms of damage after spraying but showed no significant growth reduction at the end of the season even underneath the sprayer. Where a reduction in yield was found, it occurred close to the sprayer. In general, young plants were more often affected than old ones. Yield promotion occurred for some species between 2 and 4 m downwind of the sprayer (curvilinear response) with unknown ecological consequences. The structure of the surrounding vegetation influenced the response for some species, which indicates that deposition patterns can be complex, and thus there may be difficulty in predicting effects in semi-natural communities from simple deposition models.  相似文献   

6.
Environmental Science and Pollution Research - This paper reviews the current state-of-the-art, limitations, critical issues, and new directions in freshwater plant ecotoxicology. We selected...  相似文献   

7.
Abstract

An improved drift shield for attaching to the lance of conventional knapsack sprayer to reduce wind induced drift and operator exposure was designed and tested. The drift shield consists of a conical wire frame covered with polythene and has an annular opening at the point of attachment to the lance which allows air to be drawn into the shield while spraying. Tests conducted with winds in the range of 1.25–5.75 m/s show that wind can increase the width of spray swath from an unshielded lance, up to 4.3 times the normal swath in no‐wind condition. Use of a conventional shield contained the swath width within 3.5 times and the improved shield restricted the swath width to 3.1 times the normal swath. Spray deposit from an unshielded lance, within the normal swath decreased to as low as 45%, due to wind effects. However, use of the conventional, and the improved shields enhanced the spray deposit to 54.2% and 68%, respectively. The improved drift shield improved the spray pattern displacement (SPD) significantly (P<0.05) compared with the conventional shield and the unshielded lance when the wind speed exceeded 1.25 m/s. The improved shield decreased the off target drift by as much as 63% compared with the unshielded spray. It also decreased the quantity of pesticide deposit on the operator's body by 41–84% and thereby reduced exposure and improved safety.  相似文献   

8.
大气环境影响评价(简称环评)技术复核是指依据国家发布的标准与规范要求,针对重点项目环评报告书中有关环境影响预测与评价部分内容开展的技术复核工作,重点分析预测模型、基础数据与参数以及预测方法是否符合技术导则相关要求,并提出复核结论与建议。针对60多个重大环境敏感项目的技术复核报告进行统计分析,发现超过60%的被复核环评报告需返回修改或直接退回。复核案例及经验表明,污染源确定、模型应用规范化是大气环评中需要解决的关键技术。最后,结合典型案例说明大气环境影响预测技术复核的主要内容、过程和复核结论,提出了加强技术复核有效性、提高大气环境影响预测技术水平的结论与建议。  相似文献   

9.
We review the basic mathematical concepts of random walk particle tracking (RWPT) and its advantages and limitations. Three different numerical approaches to overcome the local mass conservation problem of the random walk methodology are examined: (i) the interpolation method, (ii) the reflection principle, and (iii) the generalized stochastic differential equations (GSDE). Analytical solutions of the spatial moments for a two-layer system are compared to model predictions using the different techniques and results demonstrate that the interpolation method reproduces correctly average velocity, but fails to reproduce macrodispersion at higher hydraulic conductivity contrasts between the two layers. On the contrary, the reflection principle and the GSDE approach underestimate average velocity, but reproduce macrodispersion better for high contrasts. The different behavior is based on an artificial shift of mass for increasing heterogeneities for the GSDE approach and the reflection principle, whereas the interpolation method suffers from the smoothing of the dispersion tensor. The behavior of these approaches was furthermore analyzed in two-dimensional heterogeneous hydraulic conductivity fields, which are characterized by different random function models. Solute transport was simulated correctly by all three approaches for the reference fields having Gaussian structures or non-Gaussian structures with an isotropic spatial correlation, even for a variance of the natural log of hydraulic conductivity of sigma(lnK)(2)=4. However, for the non-Gaussian model with a strong anisotropic spatial correlation and a variance of sigma(lnK)(2)=2 and higher, the interpolation method was the only technique modelling solute transport correctly. Furthermore, we discuss the general applicability of random walk particle tracking in comparison to the standard transport models and conclude that in advection-dominated problems using a high spatial discretization or requiring the performance of many model runs, RWPT represents a good alternative for modelling contaminant transport.  相似文献   

10.
Petit S  Firbank L  Wyatt B  Howard D 《Ambio》2001,30(2):81-88
In this paper, we present the methodology and some results from the application of an integrating conceptual framework, MIRABEL, to analyze the consequences of environmental change for biodiversity. For 28 European countries, MIRABEL tabulates changes in the status of threatened habitats predicted to result from 10 environmental pressures. Regional variations in the severity of the pressures and impacts are taken into account by compiling separate impact tables for each of 13 Ecological Regions. Results suggest that agricultural intensification is one of the main threats, however, differences recorded by MIRABEL in the intensity of the pressures, their rate of change and their past and expected impacts on biodiversity in the various Ecological Regions is telling evidence of Europe's biogeographical variety, and of the need to take this into consideration when assessing environmental change.  相似文献   

11.
Environmental Science and Pollution Research - Evaluation of water quality is a priority work nowadays. In order to monitor and map, the water quality for a wide range on different scales (spatial,...  相似文献   

12.
Environmental Science and Pollution Research - Life cycle assessment (LCA) is widely used to quantify the environmental performance of buildings. Recently, the potential temporal variations in the...  相似文献   

13.
This review summarizes the existing knowledge on the occurrence of tire wear particles in the environment, and their ecotoxicological effects. A meta-analysis on tire components in the environment revealed that tire wear particles are present in all environmental compartments, including air, water, soils/sediments, and biota. The maximum Predicted Environmental Concentrations (PECs) of tire wear particles in surface waters range from 0.03 to 56 mg l−1 and the maximum PECs in sediments range from 0.3 to 155 g kg−1 d.w. The results from our previous long-term studies with Ceriodaphnia dubia and Pseudokirchneriella subcapitata were used to derive Predicted No Effect Concentrations (PNECs). The upper ranges for PEC/PNEC ratios in water and sediment were >1, meaning that tire wear particles present potential risks for aquatic organisms. We suggest that management should be directed towards development and production of more environmentally friendly tires and improved road runoff treatment.  相似文献   

14.
Environmental Science and Pollution Research - A wide diversity of plant protection products (PPP) is used for crop protection leading to the contamination of soil, water, and air, which can have...  相似文献   

15.
生命周期评价理论与方法作为一种量化环境影响的工具,在诸多领域中得到了广泛的应用。在垃圾处理领域,生命周期评价最早在20世纪90年代得到应用。生命周期评价与城市生活垃圾处理的有效结合,将促进城市生活垃圾的减量化、资源化、无害化目标的实现。总结了生命周期评价理论与方法在城市生活垃圾处理中的应用现状。对国内不同城市生活垃圾处理方式环境影响因子进行比较分析,诸如全球变暖潜力、酸化潜力和富营养化潜力等因子。针对其目标范围定义、数据收集、评价方法的选择、结果解释及工艺改进等方面指出了目前研究的局限性和不足。并对未来城市生活垃圾处理生命周期评价的发展方向进行展望。  相似文献   

16.
The basic aim of this work is (1) to review and present practically operational requirements for a sustainability assessment of marine environment, such as describing the monitoring process, research approaches, objectives, guidelines, and indicators and (2) to illustrate how physico-chemical and biological indicators can be practically applied, to assess water and sediment quality in marine and coastal environment. These indicators should meet defined criteria for practical usefulness, e.g. they should be simple to understand and apply to managers and scientists with different educational backgrounds. This review aimed to encapsulate that variability, recognizing that meaningful guidance should be flexible enough to accommodate the widely differing characteristics of marine ecosystems.  相似文献   

17.
Sulfur is an extremely motile and vital element in the Earth's biogeochemical environment, one whose active redox chemistry maintains small reservoirs in the atmosphere and biosphere yet large fluxes through both. Essential for life, intimately linked to the climate state, and an important component of air quality, sulfur and its transport and processing in the atmosphere have been the subject of active research for several decades. This review article describes the current state of our understanding of the atmospheric sulfur cycle, focusing on the marine atmospheric boundary layer, with the aim of identifying the largest roots of uncertainty that most inhibit accurate simulation of sulfur cycling in the atmosphere. An overview of the emissions by phytoplankton and shipping, dispersion and entrainment in the marine boundary layer, and chemical processing by aerosols, clouds, and dry deposition is presented. Analysis of 20 contemporary modeling studies suggests that the greatest ambiguity in global sulfur cycling derives from (in descending order) wet deposition of aerosol sulfate, dry deposition of sulfur dioxide to the Earth's surface, and the heterogeneous oxidation of SO2 in aerosols and clouds.  相似文献   

18.
Sulfur dioxide (SO2) is considered as a main air pollutant in industrialized areas that can damage vegetation. In the present study, we investigated how exposure to SO2 and foliar application of iron (Fe) would affect certain physiological characteristics of Plantago major. The plant seedlings exposed or unexposed to SO2 (3900 μg m?3) were non-supplemented or supplemented with Fe (3 g L?1) as foliar spray. Plants were exposed to SO2 for 6 weeks in 100 × 70 × 70 cm chambers. Fumigation of plants with SO2 was performed for 3 h daily for 3 days per week (alternate day). Lower leaf Fe concentration in the plants exposed to SO2 at no added Fe treatment was accompanied with incidence of chlorosis symptoms and reduced chlorophyll concentration. No visible chlorotic symptoms were observed on the SO2-exposed plants supplied with Fe that accumulated higher Fe in their leaves. Both at with and without added Fe treatments, catalase (CAT) and peroxidase (POD) activity was higher in the plants fumigated with SO2 in comparison with those non-fumigated with SO2. Foliar application of Fe was also effective in increasing activity of antioxidant enzymes CAT and POD. Exposure to SO2 led to reduced cellulose but enhanced lignin content of plant leaf cell wall. The results obtained showed that foliar application of Fe was effective in reducing the effects of exposure to SO2 on cell wall composition. In contrast to SO2, application of Fe increased cellulose while decreased lignin content of the leaf cell wall. This might be due to reduced oxidative stress induced by SO2 in plants supplied with Fe compared with those unsupplied with Fe.  相似文献   

19.
The aim of the current research was to systematically review and summarize the studies that evaluated the concentration of lead (Pb) and cadmium (Cd) in cow milk in different regions of Iran and to perform a meta-analysis of the findings. Moreover, the non-carcinogenic and carcinogenic risks of Pb and Cd through milk consumption in adult and child consumers were assessed. As a result of a systematic search in the international and national databases between January 2008 and October 2018, 17 reports involving 1874 samples were incorporated in our study for meta-analysis. The pooled concentrations of Pb and Cd were estimated to be 13.95 μg mL−1 (95% CI 9.72–18.11 μg mL−1) and 3.55 μg mL−1 (95% CI − 2.38–9.48 μg mL−1), respectively, which were lower than the WHO/FAO and national standard limits. The estimated weekly intake (EWI) of Pb and Cd through consuming milk was 16.65 and 7 μg day−1 for adults of 70 kg and 45 and 34 μg day−1 for children of 26 kg, respectively, which was well below the risk values set by Joint FAO/WHO Expert Committee on Food Additives (JECFA). The maximum target hazard quotient values (THQs) of Pb and Cd were 5.55E−5 and 5.55E−5 for adults and 5.55E−5 and 5.55E−5 for children, respectively, which were lower than 1 value, suggesting that Iranian consumers are not exposed to non-carcinogenic risk through consuming milk. Moreover, the incremental lifetime cancer risk (ILCR) of Pb estimated to be 2.96E−04 in adults and 1.0E−03 in children, indicating that consumers in Iran are at threshold carcinogenic risk of Pb through consuming milk (ILCR > 10−4). Therefore, planning and policy making for the sustainable reduction of these toxic metals in milk, particularly in industrial regions of Iran, are crucial.  相似文献   

20.
Environmental Science and Pollution Research - Acrylamide is a water-soluble toxicant found in high-protein and carbohydrate-containing foods exposed to high temperature like bread as the staple...  相似文献   

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