. Typical fresh-water concentrations are between 1 and 10 μg/1 while natural lead concentrations in soil range from 2 to 200 ppm and average 10 to 15 ppm. Deep ocean waters, below 1,000 m, contain lead at 0.02 to 0.04 μg/kg concentrations; in contrast, surface waters contain from 0.2 to 0.35 μg/kg (National Academy of Science, 1972). Besides, drinking water concentrations of lead may be greatly increased in solf-water area through corrosion of lead-lined piping and connections.