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M the reef is designed to attract and shelter. In the case of reefs made from oil -ash blocks, a matter of particular concern is the potential effect of toxic constituents of the oil -ash and/or other constituents of the blocks that could leach from intact or broken blocks and contaminate the surrounding and interstitial water, that might be ingested as particles from broken or crumbling block material, or that might affect organisms settling upon, burrowing into or otherwise colonizing the reef structure. Florida Power & Light Company, through its consulting agents, Harbor Branch Foundation and Florida Institute of Technology, have conducted a series of laboratory and field tests to investigate these effects. Test organisms selected for the experimental studies included bacteria, algae, crustacea, an echinoderm, a mollusc, and two species of fin fishes so as to represent the different components of the food chain and the different feeding and habitat types that inhabit such reefs. Field studies consisted of exposing test blocks of standard oil -ash mixture together with control blocks of inert material to two different marine environments. Organisms colonizing the test and control surfaces were monitored with respect to total biomass, species identification and numbers, and species diversity indices. Finally, selected organisms from both the laboratory experi- ments and the field tests were analyzed for six trace metals that might have been taken up from the oil -ash blocks and concentrated by the organisms through processes of bioaccumulation. In summary, the laboratory and field tests revealed that oil-ash/fly ash test blocks contain ingredients or create conditions that may be toxic to a limited extent to some but not all species of marine organisms. The evidence demonstrat- ed, however, that such toxicity is limited to a brief period of time (i.e., one or a very few days) immediately following the first exposure of the block material to seawater. There is no indication from the studies that intact blocks previously exposed to seawater have any residual toxic effects upon any kind of marine life. There is some indication that metals in blocks made from oil ash may be accumulating in the tissues of organisms that live attached to their surface. However, rigorous field studies need to be conducted before conclusions about hazards of bloaccumulation can be made. The proposed project will provide the long-term research monitoring and data needed to evaluate the feasibility of using oil -ash blocks in the construction of artificial reefs. RECOMMENDATION: It is recommended that the Board of County Commissioners authorize staff to forward the following comment regarding this project to the Florida Department of Environmental Regulation: 1) The D.E.R, in permitting this project, should recognize that the primary purpose of the project is for research and development and should not be construed as a general permitting activity. If, after a sufficient monitoring period, the toxic effects of the blocks pose a threat to marine life or water quality, the D.E.R. should require that the reef be dismantled and the blocks removed from the ocean floor; 2) Indian River County requests that monitoring data be forwarded to the County for review during the study period. 43 JUN 18 1986 BOOK 64 Fm) -L 737