Effects of chromium and cadmium upon respiration and survival of Callinectes similis.

Abstract

Studies using toxicity tests for determining the effects of heavy metals on aquatic organisms have traditionally been carried out under controlled laboratory conditions. However, the results thus obtained are of limited value in establishing criteria for limiting the discharge of these contaminants. One method which produces more realistic results in the performance of tests under similar conditions to those existing in the organism's original habitat. Although the mortality of organisms has never been associated with heavy metal pollution in Tamiahua Lagoon, the actual concentrations are above the established limits by Mexican legislation. In the southern zone of this coastal lagoon, one may find large populations of crabs Callinectes similis, in which levels of certain heavy metal accumulation have been detected. These crabs are currently fished commercially for human consumption under conditions lacking adequate sanitary control. For the above reasons, the authors chose to orient this study on determination of the effects of lethal concentrations of Cd and Cr{sup +6} on survival, and more specifically on the effects on oxygen consumption and oxygen extraction mechanisms of crabs.