A bylaw banning pesticide use in the Waterloo region went into effect Sunday and will remain until the end of August.

This is the first time the area's been under the regulation, approved earlier this year.

Residents found violating the bylaw will have to pay $150, unless they're treating lawns infected by fungus or bacteria.

The region's bylaw is lax compared to other municipalities in the GTA - - most have banned or committed to ban the cosmetic use of pesticides on residential lawns year-round.

Several Ontario municipalities, such as London, Oakville and Peterborough, are among 125 cites and towns across Canada that have passed regulations.

Toronto's pesticide bylaw, which came into effect in 2004, restricts the outdoor use of pesticides in public and private land.

The regulation applies to all pesticides used on lawns and gardens, including herbicides, insecticides, and fungicides, with the exception of ragweed.

Residents caught applying pesticides can be fined anywhere from $225 to $5,000, and can also be held liable if a lawn care company they hire uses them.

Some cities, like Halifax and Montreal, have pesticide bylaws, but others, like Ottawa, don't.

Gideon Forman, the Executive Director for the Canadian Association of Physicians for the Environment, thinks the provincial or federal government should step in and ban residential pesticide use on a wider scale.

"There are 60 pesticides in Canada that have been banned in other Western countries because they're dangerous to the environment and to human health," he said.

A specific product 2,4-D, the most widely used herbicide in Canada, has been banned in Denmark, Norway and Sweden.

A study last year by the Canadian Pediatric Society concluded that 2,4-D, an active ingredient in products like Kilex and Turfbuilder Pro with Weed Control is linked to cancer, neurological impairment and reproductive problems.

The Ontario College of Family Physicians also found children exposed to lawn and garden pesticides have a higher risk of developing leukemia than those who aren't.

Health Canada has even found 2,4-D in the semen of Ontario farmers.

Forman said regulations need to stretch beyond municipalities, because chemicals in pesticides do -- and choosing not to use them on your lawn doesn't mean you're immune to the health risks.

"Even if you're not using pesticides, and your neighbour is, you're being exposed. The chemicals go into the air, and they migrate to rivers and lakes, into our drinking water," Forman explained.

"In Ottawa, where it's still permitted, every location sampled on the Rideau river contained traces of 2,4-D," Forman said.