Landfill sites, botulism and gulls.

Botulism due to Clostridium botulinum type C causes considerable mortality in gulls in the UK, and refuse disposal sites are suspected as a major source of toxin. C. botulinum types B, C and D were each found in 12 (63.2%) of 19 landfill sites examined. Type E was detected in only one (5.2%) and types A, F and G were not found. The prevalence of type C spores was much higher than that demonstrated in the UK environment by earlier surveys. The presence of these spores, together with the rotting organic matter and generated heat associated with landfill sites, undoubtedly leads to bacterial proliferation and toxigenesis. This is likely to result in botulism in scavenging gulls unless skilled landfill management prevents the ingestion of toxic material. Type D spores were previously shown to be rare in the UK environment and their high prevalence on landfill sites was therefore surprising. Four composite samples of refuse collected before distribution on a landfill gave negative results for C. botulinum and it seems likely that the gulls themselves play a major role in introducing contamination.