Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2006
Publication Date: 5/24/2006
Citation: Greenway, S.L., Guerra, B., Farris, J.L., Moore, M.T. Assessing caffeine as an emerging environmental concern using conventional approaches. Abstracts of the Mid-South Regional Society of Environmental Toxicology and Chemistry Annual Meeting. p.19, 2006. Interpretive Summary: Interpretative summary not required. Abstract only.
Technical Abstract: Treated effluents from wastewater treatment plants are regulated by the US EPA as point-source discharges. There is recent evidence for the contribution of additional contaminants from these discharges in the form of pharmaceuticals and organic compounds. At some point, many of these emerging contaminants are included in investigations for their individual contribution to impact of aquatic communities. Caffeine is an organic compound that can be detected in most streams receiving wastewater discharge. Despite recent measurement in US streams, caffeine=s toxic effects to freshwater organisms are not well documented. The present study measured lethal and sublethal toxicity endpoints to caffeine for the freshwater species, Ceriodaphnia dubia, Pimephales promelas, and Chironomus dilutus. These standard test organisms used for effluent monitoring were exposed to aqueous caffeine solutions under static exposure for 48 hours and under static renewal exposure for seven days. Endpoints were measured following range finding exposures. Acute endpoint calculations (48 h) indicated C. dubia was more sensitive to caffeine exposures than either P. promelas or C. dilutus. Comparative seven-day chronic responses between C. dubia and P. promelas did not represent as broad a range measured with acute responses. Sublethal effects measured for caffeine exposure included impaired C. dubia reproduction and inhibited P. promelas growth. These test results will be used to establish suitable endpoints with standard test species exposed to caffeine and be available for further species comparisons. The question of caffeine=s impact on aquatic communities below municipal discharges remains unanswered without additional measured environmental concentrations tied to instream assessments.