ELMVALE, Ont. - Keith and Ina Wood don't look like your average criminals.

Most criminals don't shuffle from place to place with the aid of a cane, like 82-year-old Keith does.

Nor do they often knit hats for their newborn grandchildren, like Ina, 76.

But that's how the Woods, retired dairy farmers married for 57 years, now describe themselves. Last week, they and a handful of others were arrested for protesting the construction of a 20-hectare landfill about 40 kilometres northwest of Barrie, Ont., known locally as Site 41.

The landfill is being built on central Ontario's Alliston Aquifer, which the site's vocal opponents claim is one of the most pristine sources of groundwater in the world. Its construction has been a contentious issue for decades, but opposition has swelled over the summer, after the Ministry of the Environment allowed excavation work to begin in earnest.

Premier Dalton McGuinty has stood by the site's construction, saying he believes the scientific experts who feel the aquifer won't be contaminated. Simcoe County says the site meets standards set out by the ministry, and argues it needs to be built since the area has been without local trash disposal options since the 1980s.

But the protesters -- who include farmers, Simcoe County residents, and members of the nearby Beausoleil First Nation -- say they don't buy the science the government is relying on.

In July, a blockade went up outside the landfill. The Woods admit they took part, taking shifts sitting in front of one of the site's main gates.

On Aug. 4, Ina Wood was at home when she got a call from the local provincial police detachment. An officer asked the couple to come down to the station, to be charged with mischief.

If they didn't, the officer said, the charges would become more serious.

Ina laughs when she recalls how she felt.

"I'm a 76-year-old grandmother. What would they do with me anyway? So I wasn't going to get too upset about it."

Her husband, however, takes a more cynical view.

"I felt I was targeted," he says. "I was one of the oldest protesters. And I figure they just picked me out. I wouldn't fight. They were just going to pick out a few of us old guys, scare the heck out of us, and get the road cleared out."

The Woods acknowledge they sat in front of the gates, but say they never prevented anyone from entering.

They turned themselves in two days after the call from police. But they didn't show up at the detachment alone. They were flanked by a convoy of at least 100 supporters, who stuck around waving flags while the couple was processed.

Ten people have been arrested so far, including Vicki Monague, a member of the Beausoleil First Nation.

Monague, 28, was charged with mischief and intimidation for taking part in the blockade, which was dismantled after the police moved in. She has a court date in October, and is unable to come within a kilometre of the site.

Sitting in a Tim Hortons in Elmvale, Ont., about ten minutes away from the landfill, Monague -- one of the most outspoken critics of Site 41 -- suspects Simcoe County and the police acted together to make the arrests happen.

"I kind of knew it (the arrests) would have to come," she says. "Because I did sit in blockades. I mean, you don't just do that and think you're not going to have any repercussions."

Monague says that if the leachate -- water that's come into contact with waste stored in the landfill -- seeps out, it would have disastrous effects for the Beausoleil First Nation, which occupies three islands in Georgian Bay and relies heavily on clean waters for fishing.

The protest has attracted the support of a number of high-profile politicians, with both Green party Leader Elizabeth May and former U.S. presidential candidate Ralph Nader showing up at the site. Andrea Horwath, the leader of Ontario's New Democrats, has also spoken out against the landfill.

Site 41 has also exposed fracture lines at the local political level. In 2007, Simcoe County voted to proceed with construction by the slimmest of margins, 16-15, and a vote on a one-year moratorium is scheduled for later this month.

"It's an issue for everybody," says Monague. "At a time when we're running out of fresh water sources, and we have countries that don't have water, this has to be internationally protected."

For any contaminants to reach the Alliston Aquifer's water, they would have to first pass through three to 12 metres of what Simcoe County Warden Tony Guergis calls "the most dense clay you will ever see."

The county says the groundwater is under constant upward pressure. So if leachate does breach the landfill's thick plastic liner, the theory is that it shouldn't be able to seep downwards into the aquifer's lower level.

When it comes online, Site 41 will store garbage generated by four of the county's 16 municipalities. Currently, those four municipalities are shipping their trash to other landfill sites in Simcoe County -- all of which sit on the Alliston Aquifer, says Guergis.

"It's always just been about (putting the landfill) in someone else's backyards, not ours," says Guergis of the protesters' motives.

Even if the landfill's liner were to fail, the county vows the site still meets provincial guidelines for safeguarding water resources.

Guergis denies Simcoe County had anything to do with the arrests. And he has what he calls a "simple solution" to the fury over Site 41: since the only trash that will enter the landfill will come from those four municipalities, rather than protesting, residents should cut down on the amount of garbage they put at the end of their driveways.

"It's in their hands," he says. "They're responsible. They create the waste."

Monague says she also has doubts the upward pressure of the groundwater is as strong as the county says it is, and whether the lower level of the Alliston aquifer is truly confined by the clay.

If it's not confined, and the landfill's walls breach, contaminated water could end up in Georgian Bay "within 24 hours," says Monague.

The Beausoleil First Nation has erected a camp across the road from one of the site's gates, on the field of a farmer who supports their cause. It's replete with tents, a communal kitchen, even a trailer with a computer and Internet access.

Sunday marks the camp's 100th day. The only protesters still guarding the landfill's entrances are a couple of mannequins in lawn chairs. But while the blockade is over, Monague says, the camp isn't going anywhere.

"We have committed to staying there until Site 41 is stopped," she says. "And we are going to stop it. We have to win."