Accumulation of metal contaminants in rural roof-harvested drinking water tanks in the vicinity of a metal mine and coal mines

The central objective of this study was to investigate metals accumulating in water at the bottom of roof-harvested drinking water tanks in rural inland NSW, located from 220 km west to 420 km northwest of Sydney. Two of three study areas contained mining operations. The Narrabri study area contained five coal mines, the Cadia study area a large gold and copper mine. A third region (Mendooran) had no mines. In this study, turbidity, pH, salinity and the total concentration of 15 metals were measured in water tank samples. Four metals (cadmium, lead, nickel and manganese) and arsenic from the bottom of tanks often exceeded Australian Drinking Water Guidelines. Of drinking water samples, 90% exceeded lead guidelines (<10 µg L⁻¹), with 54% exceeding by 100 times and 3.6% of samples exceeding lead guidelines by 1000 times. Contamination was generally greater in Cadia area tanks. It is likely that metal-enriched mine particulate emissions contribute through fallout onto roofs used to harvest drinking water. Improved environmental monitoring and governance to address metal-contaminated dust emissions from mines and improved information on fallout plumes are needed. Action is also needed to encourage regular cleaning of drinking water tanks.