文章来源:未知 文章作者:enread 发布时间:2011-06-16 05:50 字体: [ ]  进入论坛

Assessing the environmental risk of pesticide1 use is an important, complex task that requires knowledge of the equilibrium2(均衡,平静) sorption(吸附作用) parameter3. This helps researchers assess the risk of pesticides4 leaching5 into groundwater. For cost-effective assessments6, this is usually determined7 through batch8 experiments that find the amount of pesticide in test soils as a function of concentration at a constant temperature. These experimental conditions differ considerably9 from real-world conditions. Thus, the validity of the data collected using this method is widely debated. Recently, scientists from Germany and New Zealand evaluated parameters10 from different experiments that used the same pesticides and soils. Using this data, scientists analyzed11 the relationships between flow velocities12(流速) of soil water, the residence time of the pesticides in the soil and the sorption parameters. Results from the study were published in the May-June 2011 issue of the Journal of Environmental Quality.

Scientists found that the range of sorption constants increased with increasing water velocity13. Only for water velocity values lower than 35 mm/day, the range of sorption constants was between zero and one. Typically, these values have been obtained in field-scale experiments run under unsaturated flow conditions using undisturbed soil columns. The scientists showed that replacing equilibrium constants obtained from standard measurement protocols14(协议,条款) for pesticide registration15 purposes would lead to misinterpretation of the data. Experiment operation times greater than one day, with a typical duration of several days to weeks, yield the most realistic results.

According to the authors, it is also important to consider sorption and desorption(解吸,去吸附) kinetics. The movement of pesticides into a soil matrix was found to depend strongly on the amount of accessible sorption sites, which is determined by soil water content and soil structure. An understanding of this movement will require experimental protocols that take soil structure and soil moisture content into account when researching the impact of pesticides.


1 pesticide OMlxV     
  • The pesticide was spread over the vegetable plot.菜田里撒上了农药。
  • This pesticide is diluted with water and applied directly to the fields.这种杀虫剂用水稀释后直接施用在田里。
2 equilibrium jiazs     
  • Change in the world around us disturbs our inner equilibrium.我们周围世界的变化扰乱了我们内心的平静。
  • This is best expressed in the form of an equilibrium constant.这最好用平衡常数的形式来表示。
3 parameter eK4xZ     
  • It is the parameter of distribution.这就是分布参数。
  • One parameter which always comes into play is the national economy.国民经济是一个经常起作用的参量。
4 pesticides abb0488ed6905584ea91347395a890e8     
n.杀虫剂( pesticide的名词复数 );除害药物
  • vegetables grown without the use of pesticides 未用杀虫剂种植的蔬菜
  • There is a lot of concern over the amount of herbicides and pesticides used in farming. 人们对农业上灭草剂和杀虫剂的用量非常担忧。 来自《简明英汉词典》
5 leaching 1e372f36a995d8d1d41109f43f4cfdb5     
n.滤取,滤去v.(将化学品、矿物质等)过滤( leach的现在分词 );(液体)过滤,滤去
  • The lack of humus and the excessive leaching make this soil almost useless for agricultural purpose. 缺少腐殖质和过度淋滤使这种土壤对农业几乎无用。 来自辞典例句
  • The deep oxidation and groundwater leaching solubilizes much of the loosely bound uranium. 深部氧化和地下水淋蚀使大部分固定得比较松散的铀溶解。 来自辞典例句
6 assessments 7d0657785d6e5832f8576c61c78262ef     
n.评估( assessment的名词复数 );评价;(应偿付金额的)估定;(为征税对财产所作的)估价
  • He was shrewd in his personal assessments. 他总能对人作出精明的评价。 来自《简明英汉词典》
  • Surveys show about two-thirds use such assessments, while half employ personality tests. 调查表明,约有三分之二的公司采用了这种测评;而一半的公司则采用工作人员个人品质测试。 来自百科语句
7 determined duszmP     
  • I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
  • He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。
8 batch HQgyz     
  • The first batch of cakes was burnt.第一炉蛋糕烤焦了。
  • I have a batch of letters to answer.我有一批信要回复。
9 considerably 0YWyQ     
  • The economic situation has changed considerably.经济形势已发生了相当大的变化。
  • The gap has narrowed considerably.分歧大大缩小了。
10 parameters 166e64f6c3677d0c513901242a3e702d     
因素,特征; 界限; (限定性的)因素( parameter的名词复数 ); 参量; 参项; 决定因素
  • We have to work within the parameters of time. 我们的工作受时间所限。
  • See parameters.cpp for a compilable example. This is part of the Spirit distribution. 可编译例子见parameters.cpp.这是Spirit分发包的组成部分。
11 analyzed 483f1acae53789fbee273a644fdcda80     
v.分析( analyze的过去式和过去分词 );分解;解释;对…进行心理分析
  • The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。 来自《简明英汉词典》
  • The young man did not analyze the process of his captivation and enrapturement, for love to him was a mystery and could not be analyzed. 这年轻人没有分析自己蛊惑著迷的过程,因为对他来说,爱是个不可分析的迷。 来自《简明英汉词典》
12 velocities 64d80206fdcbbf917808c5b00e0a8ff5     
n.速度( velocity的名词复数 );高速,快速
  • In experimenting we find out that sound travels with different velocities through different substances. 在实验中,我们发现声音以不同的速度通过不同的物质而传播。 来自《现代汉英综合大词典》
  • A gas in thermal equilibrium has particles of all velocities. 处于热平衡的气体,其粒子有一切速度。 来自辞典例句
13 velocity rLYzx     
  • Einstein's theory links energy with mass and velocity of light.爱因斯坦的理论把能量同质量和光速联系起来。
  • The velocity of light is about 300000 kilometres per second.光速约为每秒300000公里。
14 protocols 66203c461b36a2af573149f0aa6164ff     
n.礼仪( protocol的名词复数 );(外交条约的)草案;(数据传递的)协议;科学实验报告(或计划)
  • There are also protocols on the testing of nuclear weapons. 也有关于核武器试验的协议。 来自辞典例句
  • Hardware components and software design of network transport protocols are separately introduced. 介绍系统硬件组成及网络传输协议的软件设计。 来自互联网
15 registration ASKzO     
  • Marriage without registration is not recognized by law.法律不承认未登记的婚姻。
  • What's your registration number?你挂的是几号?
TAG标签: water pesticide soils