WWF: Tradiční moudrost i věda odhalily toxické látky z jihu v druzích, žijících na severu

A new report released by WWF-Canada reveals that subtle changes in the health of Arctic wildlife is occurring as a result of chemical build-ups.

The study, conducted by researchers at Trent University in Canada, investigated the health of Arctic species through a variety of assessment techniques, including contaminant analysis, a histological survey (the microscopic structure of animal tissues), and the documentation of observations by Inuit hunters.

Inuit Elders and hunters living in three eastern Arctic communities participated in the Nunavut Wildlife Health Assessment Project (NWHP) out of concern for the increased rate of physical changes they are seeing in species they rely on to maintain their way of life.

The primary goal of the three-phase project is to assess the impact of contaminants on the health of wildlife such as caribou, Arctic char, ringed seal, beluga whale, and polar bear.

According to Trent University's Dr Gordon Balch, greater attention needs to be directed towards wildlife health issues to determine the magnitude and significance of these changes to the long-term sustainability of Arctic wildlife.

"This is particularly important in the context of climate change, which has a strong potential to influence the toxicological effects of persistent organic pollutants," added Dr Susan Sang, a Senior Manager with WWF-Canada who headed up the study.

The histological survey found conditions in some tissues of seals and beluga which appeared unusual. These anomalies included reactive and/or draining lymph nodes (suggestive of infection in surrounding tissues), evidence of bacterial infection in liver tissue, and inactive spermatogenesis.

Polychlorinated biphenyls (PCBs) and DDT, banned for more than twenty years, were also found to be present in the tissue of Arctic wildlife.

"Even less is known about what cumulative impacts could occur when animals are exposed to both contaminants, plus the stress of climate related alterations to habitat, such as loss of food, competition from southern species, migration of pathogens, and diseases," Dr Sang said.

Mercury, a potent toxic metal that targets the nervous system and brain development, was detected in various tissues and organs of Arctic char, ringed seals, and beluga whales. The concentrations of total mercury increased from char to ringed seal to beluga, demonstrating greater accumulation in those species closest to the top of the food chain.

Mercury levels in the kidney and the liver of ringed seals, as well as muscle, kidney, and liver in beluga are much higher than the 0.5 ppm level recommended for human consumption by Canadian health officials.

The NWHP results also showed that new contaminants such as polybrominated diphenyl ether (PBDE), used in fire retardants, and the organochlorine insecticide endosulfan, were detected in species submitted for chemical analysis.

"Although the environmental levels of these emerging contaminants are generally one to two orders of magnitude below the levels associated with the more notable legacy of persistent organic pollutants, these compounds possess many of the same toxicological qualities of legacy contaminants," said Dr Sang.

"Based on other studies, these levels are rapidly increasing in Arctic wildlife tissues."

These results are of concern given the reliance of Inuit communities on "country food" obtained through hunting and fishing – a main source of the Inuit diet.

"I believe that more research needs to be done on animals’ (health) to keep track of how things are going because country food is what we depend on to live," said Moe Keenainiak, Acting Executive Director of Qikiqtaaluk Wildlife Board.

Inuit hunters and Elders believe that pollutants from afar, as well as those used locally, like oil and gas, spill from boats and land vehicles, and are contaminating the Arctic environment and wildlife.

Sixty per cent of those interviewed in a survey believe that any pollutants in the Arctic's environment would have a negative impact on the health of wildlife.

The contamination of Arctic wildlife with chemicals, including some no longer used in most industrialized countries and many still used in industrial and consumer applications, demonstrates the ineffectiveness of health and environmental protection laws in Canada and elsewhere.

European countries have taken a first step towards pollution prevention by requiring scientific data as a precondition for producing and marketing chemicals or products containing chemicals. The proposed Registration, Evaluation and Authorisation of Chemicals (REACH) system should lead to the identification and phasing out of the most harmful chemicals.

WWF-Canada has urged the Canadian government, in the context of the current review of the Canadian Environmental Protection Act (CEPA), to pursue a similar approach to protect the environment, wildlife, and humans from toxic chemicals.


NOTES:

• The Nunavut Wildlife Health Assessment Project (NWHP) is a joint initiative with the Hunters’ and Trappers’ Organizations/Associations (HTOs/HTAs) within the Nunavut communities of Arviat, Coral Harbour and Pangnirtung, WWF-Canada and researchers from Trent University.

• The Nunavut Wildlife Health Assesment executive summary and IQ report are available on WWF-Canada’s website and final results report will be available in June.