New research indicates that hormone disrupting pollutants are affecting the health and development of wild birds nesting along the urban rivers of South Wales.
Findings published today in the Environmental Toxicology and Chemistry journal reveal that chicks of the Eurasian Dipper a river bird that feeds exclusively on insects and fish in upland streams are underweight compared to their rural counterparts. Also of concern is that birds nesting in urban rivers have altered hormone levels, and are hatching fewer female chicks than those nesting along rural rivers, which could have negative implications for the population's breeding and survival.
Data obtained by a team of scientists from Cardiff University, working in collaboration with the Universities of Saskatchewan and Exeter, and the Natural Environment Research Council, suggest that urban contaminants such as PCBs (polychlorinated biphenyls) and PBDE flame-retardant chemicals (polybrominated diphenyl ethers) acquired through their food are to blame. Results showed a strong correlation between contamination by PBDEs and PCBs with depressed thyroid hormone levels in chicks one thyroid hormone was 43% lower in chicks from urban rivers than those rural rivers.
Professor Steve Ormerod from Cardiff University School of Biosciences, who has spent 35 years investigating rivers, commented:
"Our findings are important in showing that pollutants are still a source of concern for the wildlife along Britain's urban rivers despite very major recovery from the gross pollution problems of the past. Wild birds, such as dippers, are very important indicators of environmental well-being and food-web contamination, and we need to know if populations, other species or even people - are also at risk."
Dr Christy Morrissey from the School of Environment and Sustainability at the University of Saskatchewan said:
"We've known for some time that endocrine disrupting
|Contact: Steve Ormerod|