Zinc And Storm Water Run-Off.

Article supplied courtesy of Jenny Bain, Rooflink.

The Auckland Regional Council (ARC) has done an about turn on its earlier claim that zinc-based roofs were responsible for increased levels of zinc in harbour sediments.
The ARC now acknowledges that the use of COLORSTEEL® prepainted steel and ZINCALUME® steel roofing products have contributed to falling zinc levels noted in the harbours and that this trend will be likely to continue.
The council has added that run off from unpainted ZINCALUME®roofs should also be treated no differently to painted ones – marking a major turning point in the debate over zinc run-off.