COMPLIANCE INFO_2020 - Laserfiche WebLink

Home Browse Search

California Fish and Game 99(2):110-112;2013 Treatment of laboratory waste formalin solutions with Neutralex® KATHRYN A. HIEB* AND LINDA WARKENTIN California Department of Fish and Wildlife,2109 Arch-Airport Road,Suite 100, Stockton, CA 95206, USA *Correspondent:Kathy.Hieb@wildlife.ca.gov Key words: formaldehyde,formalin,laboratory,Neutralex,neutralization,treatment The California Department of Fish and Wildlife (CDFW) Stockton office has collected several thousand zooplankton,larval fish,fish diets,and other biological samples annually from the San Francisco Estuary that were processed in their laboratories. Most of those samples were fixed and preserved in a 10%formalin(3.7% formaldehyde with 1.0 to 1.5%methanol)solution and many were archived in 5 or 10%formalin solutions. The formalin solutions were often amended with sodium borate to increase the pH or buffered with sodium phosphate monobasic and sodium phosphate dibasic. The process of rinsing,sorting,processing,and archiving those samples resulted in waste formalin solutions that were successfully treated with Neutralex®(Scigen Scientific, Gardena, CA, USA). An aldehyde neutralization agent,Neutralex® is a noncombustible and stable powder; however, contact with an acid solution of a pH of 4 or less releases sulfur dioxide gas (Scigen 2009). This note documents the procedures used to treat 5 to 10%waste formalin solutions with Neutralex®in the CDFW Stockton laboratories,and the results thereof. Our Neutralex®treatment procedures generally followed the manufacturer's procedures (Sakura 2003, Scigen 2010), adapted for our laboratories and waste formalin solutions. Each chemical transfer and treatment was conducted in a fume hood. The waste formalin was decanted from the sample through a sieve (43 to 300 microns) to remove debris and organisms,and the waste formalin transferred to a—10-liter treatment container (American MasterTech,item number FRC-03K). Because the reaction between Neutralex® and formalin was exothermic,treatment containers were frequently inspected and replaced if any evidence of cracking,thinning,or failure was detected. Treatment containers were labeled "Hazardous Waste, Formaldehyde" and stored under the fume hoods located in each of five laboratories until—7.6 liters of waste formalin had accumulated. There were two treatment containers per laboratory,with one container used for treatment and the other for accumulation. After —7.6 liters of waste formalin accumulated in a treatment container, the container was moved to the sink in a fume hood. Using a pH meter(model 85005, Sper