A comprehensive study on the risks of a group of pollutants called EDCs has found the chemicals have "extensive" effects on wildlife and calls for further research on the effects on humans.

The World Health Organization's International Programme on Chemical Safety report, released Monday, examined the effects of endocrine disrupting chemicals (EDCs) on people and animals.

EDCs are a group of synthetic and natural chemicals that been used for decades. They're sprayed on crops as pesticides, formed into soft plastics, or created as waste in industrial production. EDCs inadvertently mimic hormones that the body's endocrine system secretes to control a wide variety of functions, including reproduction.

They've been blamed for a slew of health problems including infertility, some cancers and early onset puberty. A number of studies have also indicated a possible link to a decline in human sperm quality.

"It is becoming clearer that many of the major health issues that face humans in Western developed countries are associated with hormonal problems," said Dr. Richard Sharpe of the UK Society for Endocrinology.

Scientists have identified dozens of these compounds that people are exposed to through pesticide residues on food, plastics, household products and industrial chemicals.

The World Health Organization says their research showed only a tenuous link between high EDC exposure and health problems and calls for further testing on the dangers of EDCs.

"The state-of-the-science assessment has revealed that our current understanding of the effects posed by EDCs to wildlife and humans is incomplete," it says.

"The evidence that high-level exposure may impact both humans and wildlife indicates that this potential mechanism of toxicity warrants our attention."

Animals greatly affected

But the researchers found that EDC's have "extensive effects" on animal populations.

Examples include population decline among Baltic seals due to exposure to certain pesticides, and eggshell thinning and altered gonadal development in birds of prey exposed to DDT. A pesticide spill in a Florida lake caused a sharp population decline among alligators.

Some groups say that anecdotal evidence should be enough to prompt policy makers to adopt new laws closely regulating the use of the compounds.

Canada has been resistant to making such changes. The Pest Control Products Act has gone essentially unchanged since it was passed in 1969, and permits chemicals that have since been banned by many other countries. Environmentalists say this latest report should prompt Ottawa to reassess the chemicals it approved decades ago.

"We owe it to our children and to wildlife to act now to eliminate exposure to man-made hormone disrupting chemicals," says Gwynne Lyons of the World Wildlife Fund. "We cannot wait decades for precise causal mechanisms to be established."

The WHO study says there is an "urgent need" for more testing in so-called vulnerable populations, such as infants and children. But it doesn't advocate implementing interim laws until the studies can be conducted. Still, experts feel it's a positive first step.

"When an organization such as the World Health Organization says that there needs to be more work on endocrine disruptors, we're working in the right direction for sure," Lori Stahlbrand of the World Wildlife Fund told CTV News.

"I hope that it's going to encourage governments all over the world ... to put more money into research in endocrine disruption. And to start looking very seriously at policies and at practical decisions that will stop our reliance on endocrine disrupting chemicals," Stahlbrand says.