Study On The Determination Of As、Cd、Pb、Cr、Zn In The Vegetables、Planted Soil By ICP-AES And Evaluation Of Pollution

In recent years, as people’s living standards constantly improved, the awareness of food safety is gradually strengthened. One of the important issues in food safety is the heavy metal pollution. Determining the heavy metal contents in vegetables and planted soil has great significance in controlling environmental pollution and protecting human heath. In this paper, the vegetables and soils from the representative locations were selected for study, heavy metals were determined by ICP-AES, and the data were evaluated in accordance with the standards. The main contents were as follows:(1) Firstly, the status of heavy metal pollution in soil and vegetables、the hazards of heavy metals、detection technology of heavy metals,as well as heavy metals evaluation are descripted briefly.(2) As、Cd、Pb、Cr and Zn were selected as the object for determination. Then Experimental program were designed to optimize instrument parameters after determining wave lengths, so the best work condition of the instrument to analyze the five metals simultaneously is obtained. A new method was used in this paper. This method has higher accuracy and precision, the results of determination of standard soil samples GBW07366(n=4) showed that the measured value were close to the standard value, except the recovery rate of vegetable samples, the reason may be the detection limit of the As is too high.(3) In this article, hydride generation and ICP-AES hyphenated techniques were selected to determine the trace amounts of arsenic in the vegetables. Firstly, instrument conditions were optimized. Secondly, digestion system, the amount of digestion solution, the concentration of acid medium and NaBH4, the dosage of pre-reluctant, the placed time after constant volume and the interference of coexistent elements of inspection were studied to decide the best experimental program. The method can be used to determined the content of As in vegetables which is accurate, rapid and sensitive, with the detection limit was0.0003mg/L, and the RSD was6.62%under determination of the blank solution10times, the recovery rate of vegetable Samples are between90%to106.4%, which can meet the requirements of the low content of As in vegetables.(4) When the experimental conditions were chosen, the heavy metals in soil and vegetables of along Xiangjiang River and Xiangtan were measured and analyzed, while the evaluation pollution of heavy metals carried through with the single pollutions and Nemerow index, according to national environmental quality standard and maximum levels of contaminants in foods. As、Cd、Pb in soil of along the Xiangjiang River and Xiangtan is seriously polluted, the results of vegetables determination indicated that vegetables like leaves are much easier to accumulate heavy metals than other types of vegetables. Cd is the easiest enriched in the most polluted, and also accompanied with different levels pollution of Pb、Cr、Zn, due to the different varieties of vegetables. Finally, the source of heavy metals was discussed and put forward recommendations to resolve heavy metal contamination.