Towards a Baltic Sea Region Strategy in Critical ... - Helsinki.fi

CRITICAL INFRASTRUCTURE PROTECTION IN THE BALTIC SEA REGION
for water works (Sosiaali- ja terveysministeriö 2000). The water levels in the
vicinity of the groundwater works are also regularly monitored.
In general, the water quality at the Hanko water works is good. In
Hopearanta the chloride content occasionally increased, but the values were,
however, less than the limit value. The reasons for the chlorine-increased values
may be seawater intrusion, relic salt water, de-icing of the road or the landfill.
Also, the iron and manganese contents increased in some samples. Ampumarata
water works has had problems with high iron and manganese concentrations, and
there was an observed increase in volatile organic compounds (VOC) and small
amounts of pesticides. The fluoride content has also increased occasionally at the
Ampumarata and Mannerheimintie water works.
Table VI—1 Comparison of groundwater quality parameters in the Hanko penisula to Finnish
average.
Parameter
Shallow groundwater in Hanko
peninsula *
Shallow groundwater in
Finland**
Median Mean Median Mean
pH 6.7 6.7 6.4 6.5
El. conductivity, mS/m, 25 o C 13.4 18.48 12.5 16.4
Chloride, Cl - , mg/L 10.5 19.08 4.46 8.6
Sulphate, SO 2- 4 , mg/L 15.0 16.79 10.4 14.6
HCO - 3 , mg/L 41.5 44.69 32.9 51.9
NO - 3 , mg/L 0.6 1.58 3.19 8.43
Ca, mg/L 11.9 17.2 11.4 15.2
Mg, mg/L 1.68 2.68 2.38 3.83
Na, mg/L 6.71 12.75 4.18 7.02
K, mg/L 2.02 2.33 2.78 4.97
KMnO 4 -number, mg/L 3.4 15.43 4.5 8.48
Fe, mg/L 0.03 0.17