Eutrophication and Harmful Algal Blooms: A Scientific Consensus

In January 2003, the US Environmental Protection Agency sponsored a "roundtable discussion" to develop a consensus on the relationship between eutrophication and harmful algal blooms (HABs), specifically targeting those relationships for which management actions may be appropriate. Academic, federal, and state agency representatives were in attendance. The following seven statements were unanimously adopted by attendees based on review and analysis of current as well as pertinent previous data: 1) Degraded water quality from increased nutrient pollution promotes the development and persistence of many HABs and is one of the reasons for their expansion in the U.S. and the world; 2) The composition - not just the total quantity - of the nutrient pool impacts HABs; 3) High biomass blooms must have exogenous nutrients to be sustained; 4) Both chronic and episodic nutrient delivery promote HAB development; 5) Recently developed tools and techniques are already improving the detection of some HABs, and emerging technologies are rapidly advancing toward operational status for the prediction of HABs and their toxins; 6) Experimental studies are critical to further the understanding of the role of nutrients in HAB expression, and will strengthen prediction and mitigation of HABs; and 7) Management of nutrient inputs to the watershed can lead to significant reduction in HABs. Supporting evidence and pertinent examples for each consensus statement is provided herein.

Gastrointestinal and respiratory tract symptoms following brief environmental exposure to aerosols during a pfiesteria-related fish kill

An outbreak of illness with flulike symptoms among state workers responding to a Pfiesteria bloom that resulted in fish death and distress on the Chicamacomico River on Maryland's Eastern Shore was investigated. Using case-control methodology, seven workers present at the Chicamacomico were compared to seven occupationally matched controls not present. Participants completed questionnaires assessing their exposures to water and their symptom histories and were assessed with a standard neuropsychological test battery. Three months later, the same questionnaires and neuropsychological tests were repeated. Three of the seven exposed workers cited minimal direct contact with water and four cited none. During the event, four developed burning eyes or nares and six developed a headache or sore throat. Six developed crampy abdominal pain, nausea, or diarrhea within 4 h of their exposure. In contrast, the only aforementioned symptom reported by controls was headache in two individuals. Acute and follow-up neuropsychological tests showed no consistent pattern of deficiency among the exposed. In conclusion, a flulike clinical illness was observed following exposure to a Pfiesteria-related fish kill, possibly as a result of inhalation of toxic aerosols.