Posted on September 6, 2016
The Thames-Coromandel District Council is looking to allay fears over dredged material from Furey’s Creek dumped at an authorised cleanfill site recently.
The district council carried out soil sediment test on the material after it was contacted by Forest and Bird which expressed concerns over the dumped soil.
Thames and Coromandel Area Manager Greg Hampton says test results show there is no risk to either the Coromandel town water supply, to the public, or the surrounding environment.
“The results have come back showing all contaminants are within the cleanfill waste acceptance criteria, except a slightly elevated arsenic level,” he says.
The tests came back showing the average arsenic concentration was 26 mg/kg with a maximum concentration of 29 mg/kg. The cleanfill waste acceptance criteria for arsenic is 20 mg/kg.
The magnitude of this exceedance is not significant and is being managed on site through mixing with clean soil on site, which will dilute the levels. The material is also well contained within clay bunds with negligible risk of escape, says Greg.
Arsenic is a naturally occurring element in soil, bedrock and water on the Coromandel, says the council.
The natural background concentration in soils within the Waikato region is 6.8 mg/kg but can be higher in pastoral soils where concentrations can range up to 18.8 mg/kg. Coromandel backgrounds are likely to be naturally higher again than the Waikato due to its geology.
“We have been working closely with the Waikato Regional Council to allay the concerns of Forest and Bird and have also provided all information to the Medical Officer of Health.
“We also don’t want to alarm residents of Coromandel Town and surrounds as there is and has never been any risk to the drinking water supply and public health,” says Greg.
In June the Thames-Coromandel council spent several weeks removing mud and silt from Furey’s Creek, as well as dredging the outlying channel to improve tidal access to the Jack’s Point boat ramp.