Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 

Research Underway To Remediate Sheep Dip Sites

6 August 2002

Research Underway To Remediate Sheep Dip Sites

Landowners concerned about contamination from old sheep dip sites may soon learn more about a solution to their problem from HortResearch.

In the first step to address remediation, HortResearch is carrying out a trial using plants to degrade dieldrin, a persistent pollutant, still found on many sheep dip sites. The work is being carried out in the Waikato region and Environment Waikato's Environmental Initiatives Fund has contributed $10,000 towards it.

The trial began in September 2001 on a disused sheep dip site where willows were planted to restrict leachate. Willows remove water from the site and also help degrade contaminants in the soil. In late June this year, the site was interplanted with poplars to enhance further site remediation. The HortResearch-bred willow and poplar clones used in the trial have been shown to dry out soils more than pasture species.

As part of the trial, trees are also being grown at HortResearch, in soil collected from the sheep dip site, in an experiment to determine the tree rootzone degradation of dieldrin.

Results so far indicate that willows greatly enhance the microbiological activity in the soil, and thereby enhance the degradation of dieldrin in the rootzone. Over a five-month period, the dieldrin concentration in the root-zone of the willows was 20 percent lower than before the treatment.

Over the next four months the full impact of phytoremediation on the site will be assessed, and a 'whole system' model developed that details contaminant immobilisation and degradation over time under various scenarios.

Until the early 1990s all sheep farmers in New Zealand were required by legislation to dip sheep. As a consequence, sheep dips were often emptied into nearby creeks and directly on to soil. During the dipping process residue may have contaminated the surrounding area and wet sheep standing in a holding paddock have also contaminated the soil.

The half-life of dieldrin is about three years, meaning its concentration degrades by half only every three years. At many sites, therefore, the dieldrin is still present, and a threat to the environment and public health. It may also leach into groundwater.

Dieldrin is on the "dirty dozen" list of the Stockholm Accord.

Ends


© Scoop Media

 
 
 
Business Headlines | Sci-Tech Headlines

 

First Union On Mill Plans: Bitter Blow For Gisborne Workers

Up to 100 Gisborne jobs could go as JNL, the wood processing company, begins consulting on a proposal to nearly halve its workforce at its Gisborne mill. More>>

ALSO:

Employment:Slow Track For Most Contentious Labour Law

The government will announce a timetable for legislating a range of long-signalled labour law changes but is placing its intention to introduce new Fair Pay Agreement legislation on a slower track to allow consultation with both employers and trade unions. More>>

ALSO:

NZ's Space Programme: Rocket Lab's Successful Launch

Science Media Centre: Rocket Lab successfully launched its Electron rocket and deployed satellites into orbit Sunday afternoon, a milestone for the company and New Zealand's fledgling private space industry. More>>

ALSO:

BusinessDesk: Body massages and Uber are in, DVDs are out, says Stats NZ

Statistics New Zealand has rejigged the consumers price index basket in its latest three-year review, adding body massages, Airbnb and Uber and removing DVD and Blu-Ray players…More>>

ALSO:

StuffMe: Commerce Commission Welcomes Dismissal Of Merger Appeal

In a summary of their judgment released today, Justice Dobson and lay member Professor Martin Richardson dismissed the appellants’ process criticisms and found the Commission was entitled to place significant weight on the prospect of reduced quality of the products produced by the merged entity. More>>

ALSO:

Digital Futures: New Chief Technology Officer Role Created

Communications Minister Clare Curran has called for expressions of interest for the new role of Chief Technology Officer position to help drive a forward-looking digital agenda for New Zealand. More>>