Lead and cadmium contents in organic, hygienic and conventional chinese kales

Abstract

This study is conducted to determine and compare lead and cadmium contents in Chinese kales grown under three cultivation practices. Chinese kales were collected from a number of farms in different locations and the same location from different seasons. Closed system digestion method and GFAAS, was used as lead and cadmium determination. The study found that the median lead and cadmium levels in the hygienic Chinese kales were significantly higher than in the organic and the conventional Chinese kales (p<0.05). However, there was no significant difference in the median lead and cadmium levels found in the organic and the conventional Chinese kales. According to the study, the usage of pesticides may not be critical factor leading to lead and cadmium accumulation in the vegetables. As a consequence, a number of possible factors that lead to lead and cadmium contamination in the Chinese kales were raised. This includes the history of the farms, the environment around farms, organic and bio-extract fertilizers. The study indicates that the environment around the farm has an important factor on lead and cadmium accumulation in vegetables. The Chinese kales from the farms in the industrial areas contained higher lead and cadmium levels than the Chinese kales from the farms in the agricultural areas. However, the usage of raw materials contaminated with high lead or cadmium in the fertilizers may also provide high lead and cadmium levels in crops from agricultural areas. The use of organic and bio-extract fertilizers also have an impact on cadmium accumulation in vegetables. This study found high cadmium levels occurred in the Chinese kales grown on farms located in the agricultural areas. In addition, the seasonal factors play a major role in lead accumulation in the Chinese kale samples, whereas there was insignificant impact in cadmium accumulation in the Chinese kale samples. That is, the highest lead level in Chinese kale was found in the rainy season, whereas the lowest level was found in winter. The study of le;"คะน้าเป็นผักใบชนิดหนึ่งที่คนไทยนิยมบริโภค การศึกษานี้เป็นการหาปริมาณตะกั่ว และแคดเมียมในผักคะน้าที่มีการเพาะปลูก 3 รูปแบบ ได้แก่ ผักคะน้าอินทรีย์