Evaluation Of Main Farm Produce Safety And Its Management System In Zhejiang Province,China

Nowaday, farm produces safety issues are becoming more and more important to Chinese people and government. Contents of heavy metals in soil, contents of heavy metals in farm produces, residues of pesticide in farm produces and contents of nitrite are four key factors to farm produces safety. Estimation of these factors is a credible way to know whether farm produces are safety or polluted. In Furthermore, establishing a farm produce safety background database and developing farm produce safety management system in Zhejiang province using database technology and 3S technology (i.e. Remote Sensing, Global Positioning System and Geographic Information System), will help to store and utilizate these investigated data conveniently.At present thesis, farm produces, including tea, vegetable, fruit, rice and rape, and its soils were investigated in 44 counties of Zhejiang Province. 907 soil samples and 1021 farm produce samples were collected. Analysis items in laboratory include content of heavy metal and residues of pesticide in soil, contents of heavy metal and residues of pesticide and nitrite in farm produces. Size of samples accounts of 70,000 approximately. With these datas, integrating to estimat model, sampling points were analyzed and estimated in this theme. Then, the spatial analysis of GIS, integrating to 1:250,000 geographical data, investiged irea were estimated, map about evalauting result were designed. Finnally, farm produce safety management system in Zhejiang province was developed by combining Visual Basic 6.0 and GIS component ( ESRI — MapObjects 2.0).1. Evaluation of status of farm produces safety Contents of heavy metal in soil were evaluated synthetically by Nemerow integrated indexes method,content of heavy metal in soil,content of heavy metal and residues of pesticide in farm produce, nitrite in vegetable were assessed by monomial index method. There are 798 soil sample points that their integrated indexes are less than 1, which occupying 89 percent of all soil sample points, these points are safe. The order of over-standard value of Ni, Cd , Cu ,Zn,Cr , Hg , As and Pb in soil was Ni> Cd > Cu (Zn )> Cr > Hg > As >Pb. It is obvious that pollution of Ni is most seriously among heavy metals in soil. But these only occupy 2.03 percent of all soil sample. It could be coucluded that pollution of heavy metal in soil is not serious. The order of over-standard value of Se, Cd , Cu ,Zn,Cr, Hg , As and Pb in farm produces is Pb> Cr> Cd>As>Zn> Cu> Hg. Pollution of Pb is most seriously among heavy metals in farm produces, which reaches 27.7 percent of all soil sample. Pollution of Se wasn't discovered. Evaluation of residues of nitrite was proved that the order of over-standard...