4.6. Chemical Analyses of Water
On arrival at the laboratory, the samples were pooled into four composite samples and kept cool (+4˚C). Ana-lyses were carried out within one month as follows:
pH was determined with a pH-meter, type Beckman N-2 (accuracy ±0.02). In calculating average pH, the pH
values were first transformed to concentration of hydrogen ions and the average was converted back to pH (cf.
Barrett & Brodin 1955)