Relationship between Metals in Vegetables with Soils in Farmlands of Kuching, Sarawak

The accumulation of Fe, Zn, Cu, Mn, Co and Pb in vegetables was investigated in two farmlands, Siburan and Beratok at Kuching, Sarawak. Leafy and fruit vegetable samples were collected and analysed for metal content using the acid wet digestion method. Topsoil samples (0-30 cm) were characterised for pH, organic matter, particle size, nitrogen content, phosphorus content and heavy metals. Leafy vegetables accumulated higher amount of metals compared to fruit vegetables. Metals were determined at the highest concentrations in leaves of kale at Beratok compared to other plant parts. No clear pattern of metal uptake in different parts was observed for green mustard and white mustard. Essential metals, Fe, Zn and Cu, were generally high in the vegetables. Pb levels in the vegetables analysed (dry weight basis) exceeded slightly the level recommended by the Malaysian Food Act 1983. Atmospheric deposition and gas emissions from traffic were the contributing factors for Pb contamination since Pb displayed a tendency to accumulate in leaves compared to other parts of the vegetables. Element concentrations in the soils differed between sampling sites. Correlation analysis yielded a significant relationship between Zn concentrations in soils and vegetables (n = 15, r = 0.86, P = 0.001) and moderate correlation for Cu (r = 0.55, P<0.05) and Pb (r = 0.65, P<0.05).