Development of the Sea Urchin Arbacia Punctulata in the Presence of the Environmental Toxin Sodium Hypochlorite

Abstract

Sodium hypochlorite (NaOCl) or bleach, found in effluent from wastewater treatment plants, can act as an environ-mental toxin. The sea urchin Arbacia punctulata is a common subject of embryological toxicity tests due to its sensitiv-ity to environmental pollutants. Using concentrations of NaOCl that mimic those found in treated wastewater (0.11 ppm, 0.06 ppm, and 0.03 ppm) we observed minimal affects on early larval development, though most larvae took longer to develop at higher NaOCl concentration. There was a significant difference in the percentage of non-normal plutei based on concentration (P = 0.038) and significant interaction between the percent of each morphology and NaOCl concentration (P = 0.0027). The most significant change in non-normal plutei was in the retarded (shortened skeletal rods) malformation which increased in frequency with NaOCl concentration (P = 0.001). There was a significant re-duction in skeletal length in both normal and retarded plutei (P < 0.05) as NaOCl increased.