摘要当今社会，人类活动对环境造成的污染越来越严重，工业生产产生的各种重金属离子对人类健康的危害途径也越来越多样化。由于重金属污染物的不可降解性等，在进入人体器官后就会大量富集，进而产生一系列损伤效应。重金属离子威胁人类健康最主要的途径就是通过饮水和食物链危害人类健康[12]。铅是水体中的一种典型的污染物，其具有来源广、蓄积性。残留时间长等特点。42691

本文以中华新米虾为研究对象，将通过铅离子对中华新米虾在24-96h内的急性毒性实验，进一步探究铅离子对中华新米虾的半数致死浓度以及随时间变化不同时间段内LC50的变化，主要过程和结果如下:

1.预实验阶段：先在一定范围内设置不同浓度梯度的硝酸铅溶液，做24小时急性毒性实验，以米虾的死亡率为标准，逐步缩小溶液浓度范围，直至找到24小时内的全活最高浓度3mg/L和全致死最低浓度14mg/L，并以此范围作为正式实验的基础。

2.正式实验阶段：根据预实验阶段的结果，在3-14mg/L范围内逐步缩小浓度梯度，设置一个实验组和两个平行组，在每个实验组中放入等数目的米虾，分别记录24h、48h、72h、96h后的死亡个数并计算出死亡率，并以死亡率和浓度梯度为XY轴绘制出统计图图和趋势线，并根据趋势线求得一元线性回归方程，计算出各个时间段所对应的LC50。

该毕业论文有图1幅，表7个，参考文献12篇。

关键词：中华新米虾  浓度梯度  死亡率  半数致死浓度

 Experimental study on acute toxicity of lead ion on Neocaridina denticulata sinensis

Abstract

The pollution caused by human activities to the environment is more and more serious, the industrial production of various heavy metal ions on human health hazards are increasingly perse ways. Due to the heavy metal pollutants can not be degradation, after enters the human body organs will accumulate and body other chemicals combined into more toxic metal organic compounds, resulting in dysfunction of the human body and a series of such as carcinogenic, teratogenic damage effect. The most important way to threaten human health by heavy metal ions is to endanger human health through drinking water and food chain. Lead is a kind of typical pollutants in water, which has a wide range of sources, accumulation. Characteristics of long residual time.

In this paper, Neocaridina denticulata sinensis as the research object, which expose to lead ion for 24-96 h, to further explore the lead ion to the Neocaridina denticulata sinensis's half lethal concentration and the change of LC50 with time in different time periods, the main process and results are as follows:

1. Pre experimental phase: first in a certain range set lead nitrate solution of different concentration gradient, 24 hours of acute toxicity test, to shrimp mortality as the standard, and gradually narrowing the range of solution concentration, until you find within 24 hours of life the highest concentration of 3mg / L and lethal minimum concentration of 14mg / L, and regard the scope for formal experiment foundation.

2. The formal experimental stage: according to the results of the pre experimental phase, within the scope of 3-14mg/L gradually narrow concentration gradient and set up a experimental group and two parallel group, in each experimental group into an equal number of shrimp were recorded 24h, 48h, 72h, 96h after death number and calculate the mortality and mortality, and concentration gradient for XY axis draw statistical Tutu and trend line, and according to the trend line obtained a linear regression equation, calculated for each time period corresponding LC50.

Key Words: Neocaridina denticulata sinensis  concentration gradient  mortality  median lethal concentration