Post on 22-Dec-2015
Environment Ministry evidence for elevated fluoride levels
Malaspina well-water sampling program was initiated in 2000
Focused on Yellow Point and Gabriola Island areas because they showed some particularly high levels, and are close to
Nanaimo.
~ 100 wells at Yellow Point (2000)
~ 75 wells on Gabriola (2001)
Proportion of water samples with fluoride levels above the MAC (maximum acceptable
concentration)
Yellow Point ~13%Gabriola ~8%
representative n.g. g-waters
"Representative" Nanaimo Gp. water data from M. Env. website*
Location type Depth pH Ca Mg Na HCO3 Cl Cond.
m mg/L mg/L mg/L mg/L mg/L uS/cm
Denman recharge 3 6.3 16 2.9 7.9 71 4.1 150
Gabriola recharge 11 6.8 7 1.0 32 80 5.4 183
Hornby recharge 6 7.3 29 6.7 40 171 20 368
Mayne recharge 24 7.3 24 6.7 12 110 6.9 229
N. Pender recharge 55 6.8 55 14.0 33 244 25 523
Saltspring recharge 30 7.8 25 2.6 37 156 11 315
Denman discharge 18 8.5 11 0.2 313 189 390 1500
Gabriola discharge 27 8.7 21 0.0 170 109 223 911
Hornby discharge 24 8.0 30 4.9 1270 238 1890 6100
Mayne discharge 23 8.7 21 5.3 854 287 960 4900
N. Pender discharge 50 8.0 58 4.6 815 287 1130 4260
Saltspring discharge 62 9.0 2 0.2 354 510 220 1600
*Kohut, A, Foweraker, J and Hodge, W, Groundwater Resources of British Columbia, 9.13 Gulf Islands,
• According to the Le Chatelier principal, a decrease in the Ca content (because Ca is being removed from the water and adsorbed onto clays) will drive this reaction to the right, increasing the bicarbonate level, and resulting in a higher pH. This is base-exchange softening.
CaCO3 + CO2(g) + H2O = Ca2+ + 2HCO3-