Results of Monitoring at Olkiluoto in 2006 - Environment (pdf) - Posiva

45In winter (February) the averages P concentrations of water columns were between 23-25 µg/l (Table J-4). The concentrations were slightly higher than the average for 1996-2005 and higher than the background concentration in coastal waters of the BothnianSea measured at Pyhäranta (19 µg/l in 2004-2006). The wintertime P concentrationshave increased significantly between 1979 and 2002. In 2003-2004 the P concentrationswere lower, but grew again in 2005-2006. The average P concentrations of the nearbywaters during the open water season (13-26 µg/l) were higher than in 2005, and theaverage for SEA09 was exceptionally high (Fig. 33). This was caused by the nutrientscarried by River Eurajoki in October.4035Total P, mg/m33025201510SEA05SEA06SEA03SEA09SEA10SEA08SEA07Reference site501979-841985-891990-941995-992000 2001 2002 2003 2004 2005 2006Figure 33. The concentrations of total P (µg/l) during open water seasons 1979-2006.Water columns 0-10 m in locations SEA03, 06 and 10, and 0-6, 7.5, 8.5, and 8 m for therest, respectively. The reference site is in Pyhäranta. (Turkki 2007).The wintertime concentrations of substance matter were clearly lower than the averagefor 2001-2005 (Table J-5). Also during the open water season the values of substancematter was low (Fig. 34). The cloudiness values of water were unusually low in thewinter (February, 0.7-1.7 FNU). In May the values were 0.7-2.3 FNU, in August 0.7-2.8 FNU and in November 2.3-4.5 FNU. The average open water season values weresmall, 26-51% lower than in 1996-2005 on average.