Toxicity of metal mixtures to the Pacific white shrimp Litopenaeus vannamei postlarvae
Frías-Espericueta, M.G.; Voltolina, D.; Osuna-López, I.; Izaguirre-Fierro, G.
Marine Environmental Research 68(5): 223-226
ISSN/ISBN: 1879-0291 PMID: 19604575 DOI: 10.1016/j.marenvres.2009.06.011
According to the literature, the safe level of a toxic substance for any given organism may be calculated from its median lethal concentration multiplied by a suitable application factor (AF: usually 0.1 and 0.01). The medial lethal concentrations for Litopenaeus vannamei postlarvae exposed to the mixtures in equitoxic proportions of Cd-Hg, Hg-Zn and Hg-Pb were close to one order of magnitude lower than the values calculated from individual toxicity tests, indicating a synergistic effect, while the mixture Cd-Zn showed an antagonistic effect. Exposure to the mixture of Cu, Fe, Mn, Zn, Cd, Hg and Pb caused 63.3% and 100% mortality after 21 and 13 days for 0.05 and 0.1 AF, showing that environmental safe concentrations of toxicants should not be calculated from individual toxicity tests.