Overvåking av vannmasser, blåskjell og o-skjell i Høyangsfjorden i 2012

It has previously been found high levels of metals, especially lead (Pb) and cadmium (Cd) in addition to elevated PAH levels in the Høyangsfjord. On the basis of these findings NIVA is carrying out a three year surveillance of the inner parts of the fjord on contract by Eras Metal a.s (now Nystar) and Hydro Høyanger metallverk. The main focus of the investigations are: • To characterise the present environmental status of the Høyangsfjord • To establish a surveillance program in order to detect possible changes in the environmental status of the fjord • To give the public environmental authorities a decision basis in order to revalue the food restrictions related to blue mussels (Mytilus edulis) In 2012 the investigations have included metal analyses of ordinary water samples, blue mussels and horse mussels (Modiolus modiolus). The mussels was in addition analyzed for PAH compounds. The results showed that the Høyangsfjord is affected by metal pollution. However, the environmental situation has improved over time. In the watermass there are some stations showing elevated levels of lead (Pb), copper (Cu) and zink (Zn). In blue mussels there are elevated levels of lead and cadmium (Cd) and in horse mussels there are elevated levels of lead, cadmium, mercury (Hg) and also arsen (As) in 2012. The results from the PAH analyses in mussels showed low conentrations of PAH16. All stations could be classified as unpolluted or moderately polluted. The concentration of the PAH-congener benzo(a)pyren was classified to markedly polluted for the blue mussel at stations located in the harbour area. Different from the metals, the lowest PAH concentrations were observed at the stations farthest off known sources had.