Local Govt | National News Video | Parliament Headlines | Politics Headlines | Search

 


Stormwater continues to affect harbour sediment

Survey reveals stormwater continues to affect harbour sediment quality


The results of a 2011 Wellington Harbour sediment survey show Wellington’s stormwater continues to be an ongoing source of heavy metal contamination for the harbour.

The survey which was carried out by Greater Wellington Regional Council and part funded by Wellington City Council, was the second of its kind. It investigated sediment quality and the health of the sediment-dwelling animals, at 16 subtidal sites in the Wellington Harbour.

Results show that concentrations of copper, lead, zinc and mercury exceeded nationally recognised guidelines at several sites with the highest concentrations found at sites closer to the city. Sources of these contaminants include vehicle brake and tyre wear, galvanised roofs, road dust and soil that has in the past been contaminated with leaded petrol and lead based paints.

Hydrocarbon concentrations (such as from vehicle exhausts and tyre wear) also exceeded guidelines at inner harbour and Evans bay sites but it is thought that much of this contamination is historic from industries such as the gasworks at Miramar. Despite being banned in the late 1980s, the pesticide DDT is also apparent throughout the harbour with higher concentrations closer to the city.

Examination of creatures living on the harbour floor identified 124 species, among them tiny crustaceans, worms, urchins, bivalves and brittle stars. These invertebrate communities have shown little change in the last five years and remain reasonably diverse. However, invasive species and those with a high degree of pollution tolerance appear to dominate at sites with higher amounts of mud and contaminants.

Regional Council coastal scientist, Dr Megan Oliver says that while there were some statistically significant changes in contamination levels between this survey and the 2006 study, it is still too early to determine if the changes are environmentally meaningful. “The accumulation of contaminants is a relatively slow process and at least another three surveys will be needed before we can say if the situation is improving or worsening.” Dr Oliver says. “Overall there are contamination hotspots but the animal communities living there appear reasonably healthy and diverse and are similar to harbour communities found elsewhere in New Zealand”.

The contaminated sediment poses little risk to people but could, if the accumulation of contaminant continues, have an adverse effect on marine life as sediment-dwelling organisms provide vital habitat and food for numerous fish and other species.

To confirm assumptions about contamination source, tests were also carried out on sediment collected from roadside stormwater catchpits. These also contained substantial amounts of copper, lead and zinc indicating that urban stormwater run-off is an ongoing source of heavy metal contamination for the harbour.

Wellington Regional Council’s Environmental Management spokesperson, Councillor Chris Laidlaw says the study reinforced the need for us to increase our awareness of how our actions on land impact on the quality of water.

“Wellington Harbour is one of our most important coastal environments. We have built our communities around it and because of this everything we do has an impact on it. The study is a timely reminder that we need to reduce the amount of contaminants we allow to flow into the stormwater system and ultimately the harbour. It is up to us to protect the marine ecosystem and we do that by caring for our waterways both, natural and manmade,” the councillor says.

Councillor Laidlaw points out that a catchment committee is soon to be established in the Hutt/ Wellington area and this committee will focus on land and water management ultimately influencing the rules and policies in the Regional Plan.

Ends

© Scoop Media

 
 
 
 
 
Parliament Headlines | Politics Headlines | Regional Headlines

 

PARLIAMENT TODAY:

Discussion Document: Fresh Look At Family Violence Laws

A discussion document launched today takes a hard look at the way the law prevents and responds to family violence, and proposes a comprehensive rethink to strengthen New Zealand’s legislative response. More>>

ALSO:

PM's Presser: ‘Precarious’ Solid Energy In Banks’ Hands

Liquidation of state-owned coal company Solid Energy “cannot be ruled out” but is “not the number one preferred option of the government,” says Prime Minister John Key, who confirmed the beleaguered company was discussed today at Cabinet as its banking syndicate grapples with its commercially dire prospects. More>>

ALSO:

Missed Opportunities: Amnesty International Report Card On NZ's UN Role

As New Zealand steps down from its month as President of the Council, Amnesty International has taken the opportunity to review New Zealand’s role on the Council so far and assess their performance and contribution to protecting human rights worldwide. More>>

ALSO:

Prince Charles Get More Jobs: PM Announces Honorary Military Appointments

PM John Key has announced that Her Majesty The Queen has approved the appointment of HRH The Prince of Wales to three honorary positions: Admiral of the Fleet of the Royal New Zealand Navy; Field Marshal, New Zealand Army; Marshal of the Royal New Zealand Air Force. More>>

ALSO:

No TPP Deal: Gordon Campbell On Why We Should Still Oppose Investor-State Dispute Measures

Even in this dark hour for the TPP, the secrecy farce continues... What is left to hide? Every single negotiator went into those talks in Maui knowing exactly where everyone else stood. More>>

REACTION:

Salvation Army On Homelessness: Hard Times In West Auckland

The report details an uncomfortable story of people whose only option is to live an unhealthy, dangerous and damaging street life... The social housing needed by these people is not currently available in sufficient quantity. More social housing is required in the West. More>>

ALSO:

Message For PM: NZ Supports Te Reo Māori – You Should Too

As Māori Language Week celebrations and commemoration of 40 years draws to an end, the Māori Language Commission, Te Taura Whiri i te Reo Māori, is once again hugely encouraged by the widespread support for Māori language from throughout the country ... More>>

ALSO:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news