page_title: Bällstaån
section_title: Environmental influence
hierarchical_section_title: Bällstaån / Catchment area / Environmental influence
caption_attribution_description: Bällstaviken, the mouth of w:Bällstaån. Stockholm / Sundbyberg, Sweden
context_page_description: Bällstaån or Spångaån is a small stream in northern Stockholm. Flowing through the municipalities of Järfälla, Stockholm, Sundbyberg, and Solna, it empties in the bay Bällstaviken, the innermost part of Ulvsundasjön.
  Some 1,4 km of the stream is passing through culverts and long stretches of it have been straitened out to form part of the local stormwater system. Notwithstanding, other sections are furnished with promenades and ponds and therefore considered as of local recreational interest. The municipalities sharing the catchment area, together with the county administrative board, are collaborating to improve water quality and the areas surrounding the stream.
context_section_description: As most of the inflow comes from settled grounds, including industrial areas and streets, the stream contains high levels of nutrients, metals and bacteria, with sediments contaminated with oil.  The river receives 1400 kg/year of phosphorus and 16000 kg/year of nitrogen.  Increased levels of pollutants and bacteria downstream Spånga is believed to stem from stormwater pipes but no source have been identified.  Increased levels of metals, particularly copper, has been reported, and minor oil discharges are rather common with negative impact on local bird life.
caption: Bällstaviken.
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