PT08 Metals and Metalloids
Exhibit Hall
8:00 AM - Tuesday, 11 November 2003
(PT137) Determination of bioavailable lead concentration in vegetable plants grown in a farm allotment near a reclaimed industrial site.
Anyanwu, E1, Oyewole, A1, El Saeid, M1, Saleh, M1, 1 Biomonitors Laboratory, Environmental Chemistry and Toxicology, Texas Southern University, Houston, Texas, USA
ABSTRACT- Although, the total elemental contents of a given soil sample can be determined using modern analytical techniques such as AAS and ICP-AES, however there is no established quantitative method for determining directly the exact or fractional amount of metals that are available to plants. This is because of many factors such as variations in pH, temperature, chemical composition and redox conditions. In this research, the bioavailability of Pb concentration in a given soil sample is determined indirectly by using nitric acid (10 cm3, 25% v/v), disodium EDTA (0.05 M at pH 7.0) and water. The aim was to find out the effectiveness of EDTA in extracting 'bioavailable' Pb in the soil sample relative to other indirect methods. The results showed that the 'total' Pb concentration of the unknown soil sample concentration was 5593.4 mg/l, while the concentration of the reference soil sample was 274 mg/l. The Pb concentration of EDTA and Water extraction methods were 7103.05 mg/l and 135.5 mg/l respectively. Overall, the 'bioavailable' Pb concentration was 1509.65 mg/l while the % of extractable Pb concentration was 27% by calculation. These results showed that EDTA is more effective in extracting 'bioavailable' Pb concentration in the soil, and could be used in an indirect determination of other bioavailable metals to crops and vegetables.
Key words: AAS and ICP-AES