厦门市售蔬菜重金属、硝酸盐和亚硝酸盐污染研究及评价

为了解厦门市蔬菜中有害重金属、硝酸盐和亚硝酸盐的污染情况,于2004年8月至2005年12月从厦门市各超市、农贸市场、蔬菜批发市场和蔬菜产地上采集46个品种532份蔬菜样品,用国标法(GB/T5009.11-17-1996、GB/T5009.33-2003)分别分析蔬菜中的重金属、硝酸盐和亚硝酸盐的含量。结果表明,检测样品中Pb、Cd、As、Hg、硝酸盐和亚硝酸盐的平均值分别为0.0099、0.083、0.056、0.003、1090.3、0.59mg/kg;根据国家标准1-2,仅部分品种如菠菜、甘蓝、花菜、萝卜的铅超标,有潜在污染风险;大部分蔬菜中砷、汞、镉三种重金属的含量都较低,潜在的污染风险不大。硝酸盐污染程度严重的占36.5%;中、重度污染的占20.2%;轻度的占43.3%,硝酸盐含量依次为嫩茎叶菜类>根茎类>花菜类>瓜菜类>鲜豆菜>茄果类>水生蔬菜类,各样品间含量差别较大;而蔬菜中亚硝酸盐含量相对较低。

Survey and Evaluation of Heavy Metals, Nitrate and Nitrite Contamination in Vegetables in Xiamen's Market

The contents of heavy metal (Pd, Cd, As, Hg), nitrate and nitrite in vegetables from the markets and plant fields were investigated in Xiamen. The vegetable samples supplied seasonally were collected during August 2004 and December 2005. 532 samples in 46 groups of vegetables were analyzed according to GB/T5009.11-17-1996 and GB/T 5009.33-2003 to evaluate the status of the contamination. The results showed that the average contents are 0.0099, 0.083, 0.056, 0.003, 1090.3, 0.59 mg/kg for Pb, Cd, As, Hg, NO3-, NO2-, respectively. According to national standards1-2], the samples of standard exceeding lead contents were found only in some limited vegetables. The potential trend of lead pollution was little. The contents of arsenic, mercury and cadmium in the most samples were very low, the pollution hazards of these three heavy metals were not serious. The prevalence of severe nitrate contamination was 36.5% in samples analyzed, the prevalence of heavy and medium nitrate contamination was 20.2%, the prevalence of mild contamination was 43.3%. The content of nitrate in vegetables was ranked in the following descent order, tender stem and leaf vegetables>root and stem vegetables>inflorescent vegetables>melon vegetables>beans>eggplant and fruit vegetables>water plant vegetables. However the contents in diferent species differed greatly. The nitrite in vegetables was comparably low.