Tiltaksrettet overvåking i Håøyfjorden i 2017 for Chemring Nobel AS

The Norwegian Environmental Agency has instructed Chemring Nobel AS to carry out studies in 2017 on phytoplankton (chlorophyll-a with supporting parameters) and maximum depth for growth of macroalgae. The studies are to be performed in the water body 0101020601-C Oslofjord, where the company have their discharges. Modelling of where in the water column the discharges will end should also be done. The results of these investigation are presented in this report. The company has annual permission to release 135 tons Tot-N (total nitrogen) and 260 tons KOF (chemical oxygen-consuming organic material). After the survey in 2015 and 2016 was reported, the company discovered that they had a breakage of the discharge pipe at about 20 m deep (normal discharge depth was 38 m). This breakdown has probably occurred before the monitoring was carried out in 2015 and 2016. A new discharge pipe was launched in the autumn of 2017 with a planned discharge depth of 54 m, approx. 125 m from land. The new pipe was not operational at de end of 2017 implementing that during the monitoring in 2017, discharges have mainly been at 20 m deep. The monitoring carried out in 2017 is aimed at throwing light on possible eutrophication related effects. The following quality elements were measured: Phytoplankton (Chlorophyll A) (1 Station), maximum depth for growth of macroalgae (5 stations in 2017) and physiochemical quality elements (supporting parameters) as nutrient (ammonium, nitrate / nitrite, total nitrogen) (1 station in 4 deep), and Secchi depth (1 station). (...)