IVL Swedish Environmental Research Institute

IVL Swedish Environmental Research Institute has performed a 'Screening Study' of difenacoum and related compounds as an assignment from the Swedish Environmental Protection Agency. Difenacoum is used as a second generation anticoagulant rodenticides (SGAR). It is mainly used to control rodents around buildings and inside transport vehicles. Difenacoum is uptaken via ingestion and acts by disrupting the blood clotting process. In addition to difenacoum, the current study also includes another six substances with similar functions. The overall objectives of the study were to determine the concentrations of the selected substances in the Swedish environment. A sampling programme was developed and 60 samples were included in the study, representing surface water, sediment, fish, soil, in- and effluent water from sewage treatment plants, sludge, storm water, storm water and sludge, and eagle-owl tissues. All of the seven anticoagulant rodenticides were below detection limit in all abiotic samples and in fish. This shows that these substances are not widely distributed in the Swedish environment. However, difenacoum and three of the related compounds (coumatetralyl, bromadiolone and bromadifacoum) were found in three of the eagle-owl individuals. Coumatetralyl and bromadiolone were found in highest levels followed by difenacoum and the liver sampled contained higher concentrations compared to muscle samples. This shows that secondary poisoning of animals feeding on rodents not can be excluded. Additional studies focusing on areas with known usage could reveal if other non-target organisms other than eagle-owls are likely to be exposed to rodenticides. The study also confirms that the liver is the main target for retention of these rodenticdes.Version 2 april 2012

IVL Swedish Environmental Research Institute has performed a 'Screening Study' of difenacoum and related compounds as an assignment from the Swedish Environmental Protection Agency. Difenacoum is used as a second generation anticoagulant rodenticides (SGAR). It is mainly used to control rodents around buildings and inside transport vehicles. Difenacoum is uptaken via ingestion and acts by disrupting the blood clotting process. In addition to difenacoum, the current study also includes another six substances with similar functions. The overall objectives of the study were to determine the concentrations of the selected substances in the Swedish environment. A sampling programme was developed and 60 samples were included in the study, representing surface water, sediment, fish, soil, in- and effluent water from sewage treatment plants, sludge, storm water, storm water and sludge, and eagle-owl tissues. All of the seven anticoagulant rodenticides were below detection limit in all abiotic samples and in fish. This shows that these substances are not widely distributed in the Swedish environment. However, difenacoum and three of the related compounds (coumatetralyl, bromadiolone and bromadifacoum) were found in three of the eagle-owl individuals. Coumatetralyl and bromadiolone were found in highest levels followed by difenacoum and the liver sampled contained higher concentrations compared to muscle samples. This shows that secondary poisoning of animals feeding on rodents not can be excluded. Additional studies focusing on areas with known usage could reveal if other non-target organisms other than eagle-owls are likely to be exposed to rodenticides. The study also confirms that the liver is the main target for retention of these rodenticdes.Version 2 april 2012