The Uptake of Mercury from Water by the Grass Shrimp, Palaemonetes vulgaris (Say)

In order to assess the toxicity of mercury to the grass shrimp (Palaemonetes vulgaris [Say]), the lethal concentration for 50% (LC50) of the tested population in a 24‐hour period for HgCl2 and MeHgCl were determined. The LC50 values were approximately 400 parts per billion (ppb) Hg for HgCl2 and 125 ppb Hg for MeHgCl. When shrimp were held in mercury solutions at sublethal concentrations (1.5 ppb Hg as HgCl2) for 15 days, a maximum of 500 ppb Hg was accumulated in the animal's tissues after 3 days. The average tissue concentration of mercury for the remaining 12 days was 450 ppb Hg. The actual tissue distribution of mercury was determined by exposure of shrimp to radioactively labeled HgCl2 and MeHgCl. No difference could be found in the tissue distribution of the two compounds. A significant difference is tissue mercury distribution occurred between the 24‐hour and 72‐hour exposures.