A biological index to predict pulp mill pollution levels

Abstract

The species diversity of mid to low rocky intertidal beaches along the protected coast of British Columbia, Canada, increases significantly as exposure to pulp mill effluent decreases. Species were categorized according to hardiness and ranked as either pollution tolerant, sensitive, or intolerant. Indicator species whose presence or abundance is highly correlated to exposure to mill effluent were discovered. A biological index (Bioindex) was developed to predict a rocky shore's exposure to mill effluent by analyzing the hardiness of the resident biota. The Bioindex is useful to evaluate the environmental stress from pulp mills, to pinpoint depleted beaches for cleanup, and to evaluate pristine areas to be protected. The Howe Sound mills were found to have the most detrimental and widespread effect on rocky shore beaches of all regions surveyed, followed, in order of decreasing severity, by the Crofton mill, the Prince Rupert mill, and the Powell River mill.