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CYANOBACTERIA AND THEIR TOXINS.
Citation:
HUDNELL, H. K. CYANOBACTERIA AND THEIR TOXINS. Presented at BOSC Review, Cincinnati, OH, March 29 - 31, 2005.
Description:
Science Questions
Harmful algal blooms (HAB) of cyanobacteria, also known as blue-green algae, have recently become more spatially and temporally prevalent in the US and worldwide. Cyanobacteria and their highly potent toxins are a significant hazard for human health and the ecosystem in drinking water, recreational water, and aquaculture. Currently, the US has no guidelines or regulations on cyanobacteria or cyanotoxins. Bloom incidence, toxin occurrence, bloom prevention and mitigation, toxin stability, toxin removal from drinking water, routes of exposure, health and ecosystem effects, and estimates of risk are key issues for the Office of Water (OW). Cyanobacteria and their toxins are on the Agencys Unregulated Contaminant Monitoring Regulation List 3 (UCMR), and the Contaminant Candidate List. The OW is unable to promulgate regulations or produce guidelines at this time due to the lack of sensitive, specific, and field-ready analytical methods; data on the occurrence of cyanobacterial HABs; proven prevention and mitigation technologies; and human-health risk estimates.
The Research
The ORD and OW are organizing an international symposium on cyanobacteria and their toxins to identify and prioritize research needed to support risk assessments and regulatory determinations on cyanobacteria and cyanotoxins. To date, the OW has assembled an interactive database of over 3,000 scientific articles on cyanobacteria, produced a document on the state of science on cyanobacteria and their toxins, and prepared a summary document for cyanotoxins in drinking water. The OW will initiate a study under the UCMR to monitor cyanotoxins when appropriate analytical methods are available.
ORD scientists are reviewing the literature on cyanobacterial toxicology, identifying data needed to assess the risk of exposure to four cyanotoxins, and assessing the plausibility of modeling quantitative structural-activity relationships (QSAR) for cyanotoxins. A number of scientists are refining analytical methods to detect selected cyanotoxins in water to support the UCMR monitoring study. Several investigators have assessed the efficacy of cyanobacteria removal and cyanotoxin destruction by conventional water treatment processes and are currently exploring advanced oxidation technologies and sonolysis to inactivate and/or destroy cyanotoxins in water. The behavioral and developmental effects of cyanotoxins are being studied. The feasibility of an epidemiologic study on the health effects of repeated, low-level exposure to cyanotoxins in drinking water is being assessed. These tasks are being carried out through collaborations within the Agency, and with academia and stakeholders.
NCER is supporting cyanobacterial research by funding five research grants, two student fellowships, and two small business initiatives. Research topics include the development of microarrays to detect toxic cyanobacteria and cyanotoxins (STAR Grant #R831627), as well investigating functional relationships between nutrient loading and cyanobacterial dominance.
Impact and Outcomes
The ORD sponsored international symposium on cyanobacteria will be held in September, 2005. Invited speakers and workgroup members will respond to specific charges to identify and prioritize cyanobacteria research needs. The products of this symposium will enable ORD management to assess the need for an integrated research program on cyanobacteria to support risk assessment, regulatory determination, and guideline development. This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.