The Vancouver Coastal Health (VCH) Authority hosted a forum on arsenic in drinking water last weekend where experts passed on their scientific knowledge to the community.
VCH Coast Garibaldi drinking water officer Tim Adams organized the meeting at the Pender Harbour Legion last Saturday afternoon, where approximately 40 people attended. The speakers were chief environmental health officer Bob Weston, medical health officer Dr. Paul Martiquet, B.C. Ministry of Environment hydrologist Gwyn Graham and Dr. Steve Reiber from the University of Washington.
The discussion centred around preventing and treating arsenic in both private wells and community drinking water systems. Studies have shown arsenic levels in well water throughout the Sunshine Coast, with the most concentrated area being Pender Harbour as discovered in a 1994 well water survey. Arsenic and non-arsenic wells can be right beside each other because of the irregularity of bedrocks, Graham noted.
"Arsenic is very hard to predict in terms of where it is going to occur," Graham said. He explained that arsenic is similar to metals and can be found in low concentrations of rock.
Martiquet's handout further explained that arsenic is a natural element. "It can enter drinking water quite naturally when mineral deposits or rocks containing arsenic dissolve. It can work its way through fissures, ending up in wells and other sources of drinking water." Arsenic can also come from industrial wastes through fossil fuel burning, metal production, agricultural use or waste burning, Martiquet explained. "In our region, elevated levels of arsenic occur naturally in groundwater throughout the area."
Martiquet said arsenic intake can cause bladder cancer and he discussed prevention measures.
"Be aware of the arsenic in your water and take precautions to decrease your exposure," Martiquet said. He advised using common sense.
Weston urged people to test and re-test their wells because arsenic concentration levels can vary over time. "Even lot to lot, the concentrations can vary dramatically," Weston noted. "Don't assume anywhere is going to be a problem or not a problem."
Reiber said the most effective way to remove arsenic from water is coagulation and filtration, and that the most effective oxidant is chlorine.
Throughout the meeting, the audience asked the experts their opinions on whether Pan Pacific Aggregates' proposed mining operation in the Caren Range could result in arsenic in the water.
Graham said if the source rock has arsenic minerals, then if they are exposed to oxygen or if there are changes to the water table, then "there is a chance." When asked specifically about limestone - one of the minerals Pan Pacific would mine - Graham said, "I haven't seen arsenic associated with limestone." He also said contamination would depend on the quality of the groundwater entering the mine pit and flowing through it and that it is hard to know without having studies of the water quality around the proposed mine pit.
Reiber essentially said the mine would not affect surface water.
After the meeting, Adams noted that two qualified hydrologists and scientists were saying the evidence is unclear.
"It's a very complex issue, so to answer it in a forum like this is difficult to do," Adams said. "It's something that needs to be looked at."
Adams mentioned Graham has already been notified that he would be involved as a referral in the B.C. Environmental Assessment Office process for Pan Pacific's proposed operations.
