Merimbula (New South Wales) – Copper
From a total of 246 samples, 2 exceedances occurred from 1 Jan 2004 to 31 Mar 2014. The
highest copper exceedance was 2.59 mg/L at sample site 312 in Merimbula on 1 Aug 2011. The
ADWG guideline limit for copper is 2 mg/L for health considerations and 1 mg/L for aesthetic
considerations. The taste threshold for copper is in the range of 1‐5 mg/L and at concentrations
above 1 mg/L copper can cause staining on sanitary ware. Evidence of this has been recorded for the system, particularly in Merimbula and Tura Beach.
Based on health considerations, the concentration of copper in drinking water should not
exceed 2 mg/L.
Based on aesthetic considerations, the concentration of copper in drinking water should
not exceed 1 mg/L.
Copper is widely distributed in rocks and soils as carbonate and sulfide minerals.
Copper is relatively resistant to corrosion and is used in domestic water supply pipes and fittings. It is also used in the electroplating and chemical industries, and in many household goods. Copper sulfate is used extensively to control the growth of algae in water storages.
Copper is present in uncontaminated surface waters at very low concentrations, usually less than 0.01 mg/L. The concentration can rise substantially when water with a low pH and hardness remains in stagnant contact with copper pipes and fittings. Under these conditions, the concentration of copper can reach 5 mg/L or higher. In one extreme case overseas, a concentration of 22 mg/L was reported.