Fate,behavior, and aquatic toxicity of the fungicide IPBC in the Canadian environment

Canadian water quality guidelines (CWQG) for 3‐iodo‐2‐propynyl butyl carbamate (IPBC) were developed based on a review of environmental chemistry, fate, and toxicology of IPBC. IPBC is used in Canada in antisapstain formulations for treatment of freshly sawn lumber, as an industrial mildewcide, and as an antimicrobial. In British Columbia, IPBC is an active ingredient in the most widely used antisapstain formulation (Kop‐Coat NP‐1); 36,020 kg of IPBC were used by lumber mills for antisapstain purposes in 1996. IPBC is moderately soluble in water, and is not likely to adsorb to suspended solids or sediments. It is not persistent in the water column; hydrolysis is expected to be the main route of dissipation. IPBC was reported to affect fathead minnows at levels as low as 0.019 mg L⁻ and Daphnia magna at levels as low as 0.07 mg L⁻¹. It is not expected to bioaccumulate. An interim water quality guideline for the protection of freshwater aquatic life of 1.9 μg L⁻¹ is recommended. This guideline was derived according to the Canadian Council of Ministers of the Environment's (CCME) Protocol for the Derivation of Water Quality Guidelines for the Protection of Aquatic Life, and is intended to be protective of all forms of freshwater aquatic life at all aquatic life stages. © 2000 John Wiley & Sons, Inc. Environ Toxicol 15: 201–213, 2000