The utility of chemical toxicity testing as an environmental protection strategy has been an
accepted practice since the mid 1900s. Extensive aquatic toxicity testing began in the 1960s and
tests were categorized into three different formats according to duration and measured parameters.
The acute toxicity test generally ran 48-96 hr and was a measurement of survival. The subchronic
test lasted 30-60 days and measured organism hatchability, larval/juvenile survival, and growth
parameters of surviving test organisms. Full life cycle tests required six months to two years for
completion and measured reproductive effects of toxicants in addition to the aforenamed parameters