UPTAKE OF AQUEOUS METHYLMERCURY BY LARVAL CHAOBORUS-AMERICANUS

The uptake of monomethylmercury (mmHg) from water by larval Chaoborus americanus was studied: When exposed to aqueous mmHg for 6 days, the p attern of uptake was sigmoidal. The concentration of mmHg in the expos ure water, however, was subject to demethylation and volatilization an d therefore decreased over time. A model of passive diffusive uptake u nderestimated the uptake constant while a bioenergetics-based uptake m odel provided a reasonable estimate. The data suggest that uptake is n ot merely a passive diffusive process but may be coupled with oxygen u ptake.