土壤和植物中总砷、无机砷及有机砷的测定方法

METHOD FOR ANALYSIS OF TOTAL As, INORGANIC As AND ORGANIC As IN SOIL AND PLANT

各种价态与形态的砷的毒性差异较大,毒性顺序为砷化氢>三价砷>五价砷>有机砷。虽然有机砷的毒性最小,然而在农药施用区似乎土壤中残存有机制约占总砷量的1/2或1/3。为了确切评价砷对环境的污染,对环境样品中有机砷、无机砷和总砷分别测定是非常必要的。本文介绍的方法是利用差减法即总砷减去无机砷获得有机砷,方法简便易行,回收率为82—92％,最低检出限0.1vg砷。曾利用所拟定的方法在长期施用有机砷的果树地区采集了近60个样品进行实测,取得了良好的社会效益和经济效益,对正确评价有机砷农药的环境污染提供了一定依据。

The toxicity of As varies with its form and valeuce, its toxic order is A8H3> A. ( 111 )>A5 ( V )>organic As. Although the toxicity of organic As is less than that of inorganic As, half or 1/3 of total As in the soils applied with pesticide are organic As. In order to assess properly the environmental pollution caused by As, it is necessary to determine the amount of total As, inorganic As and organic As in the environment. Organic As was determined by the differences between total As and inorganic As in this study. This method is simple and feasible. The recovery rate of this method is 82-92%, and the detection limit is 0.1 ppm.This method was used to determine more than 60 samples in pesticide-applied fruit garden. Good social and economic benifits were achieved from the analysis. The method provides scientific bases for proper assessment of [organic As in environmental pollution.