Relationship Of Lead Contents Between Soils And Rice In Coastal Areas,Fujian Province

Rice as one of the staple food of Chinese people,its lead content that exeed national standerd become a hotspot these years.Soil is the main source for heavy metal contents in plants. The lead content in soil in coastal areas of Fujian Province is higher than background value of China. So there is potential risk for food safety and the environment.Based on 58 suites of soil and rice samples from classic plough from critical riceplanting area of Fujian province, we measure the contents of heavey metals in soil and rice,and divided 28 samples of selected soil into 5 grain gradations with the use of ultrasonic vibrating screen, with a view to further studying the distribution rule of soil lead grain gradation and the content of 4 extractions.The resrarch indicates that the average content of soil lead in this area is 2.6 times higher than the background value of soil lead in China. The grain gradations of soil lead are distributed unevenly, with a tendency of accumulation in the soil of fine gradations. The results of four extraction methods show that the quantity order of soil lead extracted from the soil is acid extraction>complexant extraction>salt extraction>water extraction. Through comparisons, extraction and complexant extraction can offer the best extraction effects of palnt. The relationship analysis indicated that lead contents in rice is significant positively related with lead contents in soil(correlation coefficient is 0.401), negative related with organic carbon contents(correlation coefficient is-0.320), and weakly negative related with pH of soil(correlation coefficient is-0.149). A multiple linear regression equation of the lead content in soil and rice physiochemical properties is set up.It shows that soil lead is the main source for rice lead. Abundant of organiccarbon and neutral-alkaline soil condition may reduce bioavailability of lead in soils and diminish its uptake by rice.This research result provides the sciencific foundation for setting up the methods of assessing the soil availability, and predicting the eco-risk of soil lead pollution upon the safety of rice, remediation of lead contaminated soils and guaranteeing the safety of rice.