Chemicals Survive Waste Treatment to be Released into Environment: Study

Bob Weber, The Canadian Press
October 14, 2010

Chemicals in household drugs and cleaning products routinely survive waste treatment and are released into the environment, where little is known about their effects on land, water and human health, according to a government-funded study.

“What are really needed are risk assessments,” said Hugh Monteith, a research consultant who conducted the recently released study for the Canadian Council of Ministers of the Environment. “The whole ecosystem needs to be assessed for the effects of the materials that are present in here.”

Monteith looked at treatment in 11 Canadian communities from coast to coast. He analyzed sludge entering the system and the so-called “biosolids” at the end that are often spread on fields or used in land reclamation. His study looked for 82 different chemicals, including bisphenol A, which was declared a toxic substance on Wednesday. Two dozen of those compounds were still present in more than half the treated samples. Bisphenol A remained in 86 per cent of the treated samples at an average concentration of 325 parts per billion. Triclocarban, an antibacterial agent found in soap and disinfectant and known to cause hormone disruption in rats, was found in all the treated samples. The mood-stabilizing drug Carbamazepine was also found in all the samples, although at low levels. Antibiotics, fragrance compounds, anti-fungal agents and painkillers all survived treatment in more than two-thirds of the samples. As well, Monteith found that the type of treatment used in most Canadian municipalities seem to be less effective at breaking down compounds than other methods.

Aerobic systems, which use oxygen to help break down waste, seem to outperform more common systems that don’t. But Monteith said neither system is really designed to address the type of compounds he was looking at. “The processes we looked at were not designed to reduce (these substances) in the feed sludge,” he said. “They’re there to either de-water the sludge or to reduce the pathogens and to make them safer microbiologically.”

Monteith said it’s hard to say to if any of the chemicals have reached dangerous levels. Safe levels haven’t even been set for most of them, he said. Consequences are most likely to be felt by ecosystems that absorb the treated biosolids, said Monteith. The impact on crucial soil bacteria, plants or worms and insects is largely unknown.

A literature review conducted last spring found that while much is known about the presence of chemicals going into waste treatment, much less is known about what happens to them after they enter the environment. “Our awareness of them is emerging,” Monteith said. “It’s only because our analytical abilities are starting to improve that we’ve been starting to see them. “We don’t know whether we should be concerned or afraid of them or not.”

Liz Dykman of the council that sponsored the research said the findings will be used in a cross-country effort to establish some sort of consistent national approach to such compounds. “We’re in the process of determining what it’s going to look like,” Dykman said. “There’s a lot of work going on.”

Environment Canada is currently working on a plan to classify and assess thousands of chemicals in wide use. Some chemicals will be phased out; others will come under management plans developed by industry and government. Ottawa will is also developing best practices for the disposal of products such as pharmaceuticals and personal-care products to reduce the environmental burden.