Detection and Analysis of Lead, Cadmium and Arsenic Content in Common Vegetables

This study was carried out to detect content of heavy metals (Pb, Cd, and As) in vegetables, understand the current situation of heavy metal contamination in vegetables, and to provide scientific reference for further researches. It randomly selected 6 large vegetable markets and 6 supermarkets in Changsha City, selected 8 types of typical vegetables, and detected 96 samples. In accordance with maximum level of contaminants in foods in existing GB2762-2012 standard, Nemerow composite pollution index (Pt) and grading standards, it made evaluation: uncontaminated (Pt ≤ 1), mildly contaminated (1 ＜ Pt ≤2), moderately contaminated (2 ＜ Pt ≤3), and highly contaminated (Pt ＞ 3). Among 96 samples, range of content of Pb, Cd and As is (0.06-1.41), (0.06-1.26) and (0.00-0.91) mg /kg respectively; the over-limit rate of these metals exceeding the safety level is 78.13%, 45.83%, and 34.38% separately; the composite pollution index is in (0.90-6.05), the eggplant is 6.05 and hot pepper is 3.24; the content of Pb (F = 23.908, P = 0.001) and Cd ( F =64.908, P =0.000) are significantly different between 8 types of vegetables and there is no significant difference between the content of As ( F = 4. 634, P = 0.705 ＞ 0. 05) in 8 types of vegetables. Study shows that common vegetables in Changsha City has problem of excess Pb, Cd and As, and the Pb over-limit rate is the highest. The composite pollution index indicates that most heavy metal contamination of vegetables is mild and moderate contamination, melon, fruit and vegetable contamination is high contamination, and Cd is the major factor leading to contamination of melons, fruits and vegetables.