Waitangi Soda Springs alum dosing – bioavailability of aluminium 2015

Abstract

Continuous alum dosing of the Waitangi Soda Springs at Lake Rotoehu commenced in 2010 to reduce inflows of dissolved reactive phosphorus to Lake Rotoehu. Analyses of bioaccumulation in the tissues of kōura and goldfish from Lake Rotoehu were undertaken on animals collected in November 2015 to determine the bioavailability and bioaccumulation of aluminium to satisfy annual resource consent conditions 11.7 and 11.8 of resource consent 65966. Comparative analyses were undertaken on goldfish collected from Lake Rotorua and compared to values obtained from goldfish and kōura collected from Lakes Rotoehu, Rotorua and Rotoiti in 2013. Lake Rotoehu kōura and goldfish showed slightly elevated aluminium concentrations in the gills indicating enhanced exposure to aluminium as a result of alum discharge from the Waitangi Soda Springs but little evidence for significant bioaccumulation in tissues.