Fish uptake of inorganic and mucus complexes of lead

Carassius auratus were exposed to lead in synthetic water. Mucus secreted from the fish was measured and characterized for its lead binding capacity. The increase in mucus concentration in the water depended on secretion and degradation rates and the former was speeded up by lead. The complexation between mucus and lead can be described based on a single-site interaction model. Lead speciation in the system with or without mucus was calculated using chemical equilibrium modeling. The dominant species of lead was PbCO(3)(0). Other major species included Pb(OH)(+), Pb(OH)(2)(0), Pb(CO(3))(2)(2-), Pb-mucus, and Pb(2+), among which free lead and lead hydroxo complexes were available to fish uptake.