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Cutting toxic chemicals in sewers
July 21, 2006
 Changes to the city's sewer-use bylaw will now restrict the dumping of PCBs, PAHs, Volatile Organic Compounds and about twenty other persistent organic compounds. Limits on what can be discharged to the sewer system are also being placed on a range of popular pesticides, including Mirex, Chlordane and Aldrin/Dieldrin, but won't affect the city's own use of these toxic compounds on parkland.
Jim Harnum, the city's manager of water and wastewater, reported on studies done for the city and outlined the changes to councillors last week. They include some tightening of the bylaw with respect to mercury, cadmium, copper and several other metals, but Harnum emphasized that the chemicals were "the real issues that we wanted to get at", following the example of Kingston and Toronto who have recently upgraded their bylaws.
"What we're doing is we are looking at making our by-law one of the strongest because we are an area of concern in the Hamilton Harbour and we do have, at times, the perception of allowing pollution," noted Harnum, "and we're battling that perception by reviewing our by-laws and ensuring that we are not inadvertently allowing polluters to pollute our harbour and our watershed."
Hamilton's sewage treatment plant can't deal with these toxic chemicals. Some are known to cause cancer and many bio-accumulate in living organisms - increasing in concentration as they move up the food chain toward humans and other top predators such as bald eagles.
The changes to the bylaw will allow the city to force industries and other polluters to eliminate the dumping of these chemicals into sewers. "There is a compliance agreement which we will give you time to change your process and try and stop discharging this," Harnum said. "But there comes a point in time where we would disallow the discharge into our system."
The city's consultant noted that concerns about pesticides "really relate to stability of several compounds, the bio-accumulation effects, the toxicity, and in some cases the carcinogen issues." That led mountain councillor Tom Jackson to ask why this information hasn't been brought to council's pesticide sub-committee that is debating whether to restrict the cosmetic use of these chemicals. He also pointed out that the city itself is still using pesticides on parkland.
"I don't recall any information being referenced or referred by your department or through your department to our pesticide sub-committee", Jackson noted. Harnum responded that the bylaw changes are "not about land application of pesticides" but are focused on "the disposal of pesticides into the sewer system and the impacts to the infrastructure and the treatment and bio-solids."
"So you're not worried about run-offs after an application on a garden, in a park, on a private lawn?" Jackson asked. "It's not that we're not worried about it," replied Harnum. "That is an issue that is not a mandate of our section. We're dealing with the issues of the sewer use by-law and the sewers themselves."
Jackson extracted a promise that Harnum, "in concurrence with the public health department and with parks" will make a presentation to the pesticide sub-committee.
The consultant study also raised concerns about the effects of prescription drugs and endocrine disrupting chemicals and their presence in the sewer system, but concluded most can't be regulated because accepted testing procedures are not yet available.
The bylaw will, however, places limits on the dumping of phthalates which have been shown to cause liver damage, reproductive and birth defects, and interference with human hormonal systems. Phthalates are used to make plastic more pliable and are also found in flame retardants.
The staff report on changes to the sewer use bylaw can be viewed at http://www.myhamilton.ca/NR/rdonlyres/678432AE-CCBB-42AB-96E0-
96B1CD7CA211/0/Jul12PW04050b.pdf.
More information on the health effects of pesticides and endocrine disrupting chemicals can be found at
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