Field tests for the detection of lead in soil are not frequently accepted, since the tests are rather cumbersome or not reliable for screening determinations. Recently, we developed the LEADQuick field test kit for the detection of lead in water with 3 g/L sensitivity. This test is further modified to detect lead in soil with a sensitivity 0.03 g. We developed an extraction protocol using nitric acid and potassium nitrate for the extraction of lead from soil. Most of the organic and inorganic compounds of lead are readily extracted as Pb2+ using the developed extraction procedure and are detected using the LEADQuick field test kit. The solubility of the lead salts in the soil is adequate for a quick extraction procedure without any heating. The experimental details, results of the soil testing and interferences are presented. This will demonstrate the potential application of our extraction procedure along with LEADQuick field test kit for soil lead monitoring.
KEYWORDS: Soil Reference Materials, Extraction, LEADQuick field test kit, Interference study, Standard addition method
Lead is a most troublesome toxic metal. Government agencies have taken many preventive steps to control lead in the environment, but still large-scale incidents of metal poisoning have occurred (Lau, 1994). The principal target organ systems of lead poisoning are the blood, brain, nervous system, kidney and reproductive system. Acute exposure to lead leads to shock, severe anemia, acute nervousness and irreversible brain damage. Lead poisoning also causes a range of health effects such as behavioral problems,learning disabilities, seizures and death. Lead is transferred to animals and human beings through the food chain system of soil-plant-animal-human (Melaku et al., 2005; Prasad et al., 2006).
Many consumers felt that lead was the first toxic metal when metal poisoning was mentioned. The government and industry organizations reluctantly accepted the dangers of lead in the 1900’s and new laws and regulations were enacted to safeguard the
consumer. In view of this, the extraction and detection of Pb2+ at very low concentrations in the soil was very critical for environmental monitoring.