Påverkan av torvbrytning på fem vattendrag i Gävleborgs län

During the past 20 years, data from five peat mines in north-central Sweden were collected. The analytical results have been compiled into a database. This project aimed at analyzing the data and assessing the environmental impact of peat mining on the recipient waters. Specifically, focus was put on the chemical and physical parameters such as nitrogen, phosphorus, ammonium, organic carbon, pH, alkalinity, conductivity, colour, and suspended material. The collected water samples were obtained from reference streams unaffected by the peat mine, drainage water from the peat mine just prior to and after the sedimentation dams as well as from the recipient streams further downstream. Tukey HSD test was used for analyzing statistical differences (p<0.05) in the water quality between sampling sites at each peat mine. The recipients were characterized according to the Swedish Environmental Protection Agency classification system. Downstream the peat mines, the recipients had a greater buffering capacity (alkalinity), a higher pH and higher levels of nutrients (phosphorus and nitrogen). Total organic carbon (TOC), conductivity and suspended material varied between mines whereby no conclusions can be drawn on the effects of peat excavation. Analyses made with the Swedish Environmental Protection Agency classifications system also indicated higher nitrogen classes downstream of the peat mines. An assessment of the monitoring program methods indicated non-optimal localization of some of the sample stations and too few sampling occasions for describing the annual water quality variations. In general, runoff measurements were lacking.