28th ANNUAL EASTERN FISH HEALTH WORKSHOP April 21-25, 2003 Human Health Risks Associated With Formaldehyde Treatments Used In Aquaculture: Pilot Study Greg A. Wooster1, Casandra M. Martinez1, Dustin S. Ohara2 and Paul R. Bowser1 1Aquatic Animal Health Program, Department of Microbiology and Immunology Veterinary College, Cornell University, Ithaca, New York, USA 14853; 2Occupational Safety, Department of Environmental Health and Safety, 125 Humphreys Service Building, Cornell University, Ithaca, New York 14853 In the field of aquatic animal health, formalin/ formaldehyde is commonly used to treat fish parasites and fungal diseases.  In order to treat such diseases fish are commonly immersed in a formaldehyde bath.  Concentrations frequently used are 25 ppm as an indefinite bath treatment or 250 ppm for a one-hour bath. Human health risks caused by formalin/formaldehyde are well documented. Studies have shown that formalin/formaldehyde may be carcinogenic, antigenic and toxic or fatal to humans at elevated concentrations.  The United States Department of Labor, Occupational Safety and Health Administration (OSHA) has set exposure concentration limits for humans at 2.0 ppm for an exposure of fifteen minutes (Short Term Exposure Limit or STEL) and  0.75 ppm for an exposure over an eight hour time period (Permissible Exposure Limit or PEL). No studies exist that address the health risks to humans when using formalin/formaldehyde to treat fish diseases. This study monitored two treatment scenarios to better ascertain the health risk. When a single 110 L tank with under-gravel filtration using air diffusers was treated as an indefinite bath treatment at 250 ppm formalin/formaldehyde (10X the typical dose), STEL averaged  0.76 ± 0.73 ppm and PEL averaged 0.152 ± 0.10 ppm at 10 cm from the source. One meter from the source, STEL and PEL averaged 0.45 ± 0.35 ppm and 0.061 ppm ± 0.029 ppm, respectively.  The second scenario used a 530 L flow through tank (mean flow 265 L/h) treated at 250 ppm for a one-hour flow through bath.  Here, STEL averaged 1.73 ± 0.14 ppm and PEL averaged 0.143 ± 0.005 ppm at 10 cm from the source. One meter from the source STEL and PEL averaged 1.23 ± 0.66 ppm and 0.144 ± 0.065 ppm, respectively.  For both scenarios both STEL and PEL were below the recommended exposure limits set by OSHA. However, water temperature, room air exchange rates, and number of tanks treated must be considered when evaluating human health risk. Further investigations using additional scenarios are suggested to better understand that risk. Return to 28th Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page