An informal Tauranga City Council environmental think-tank is challenging the new council to take them and their advice on agri-chemical usage in the city seriously.

Since 2009, the Toxic Agrichemical Advisory Forum has been advising council on spray issues, but the group is frustrated council is ignoring advice, particularly on glyphosate, says forum co-chair Ian McLean.

Toxic Agrichemical Advisory Forum co-chair Ian McLean wants councillors to listen to advice on spray usage. Photo: Bruce Barnard

They have had one member quit and others are questioning their relevance, says Ian. They want a better way of working with TCC.

TAAF was formed after the public reaction and opposition to a proposal to spray Blake Park to remove worm casts by killing the earthworms.

There were six on the panel with a range of experience and knowledge of agri-chemicals and their use. The intention is for TAAF to be a source of independent advice, responding to issues raised by the community.

In 2012, TAAF delivered a report to council on glyphosate, or Roundup as it is commonly known, warning the adjuvants or additives added to different glyphosate brands have been scientifically proven to be more toxic to humans than the weed killer itself.

'We believe the glyphosate report had no impact on council operations,” says Ian.

TAAF was consulted twice in 2013, once over spraying the 4-wicket at Blake Park and again later in the year over spay mixtures in use in the dune restoration programme.

'We feel our advice is having little impact, and we believe more action is needed,” says Ian.

TAAF has good relations with city council staff, but is unable to connect with council officers and councillors. They need a closer connection with the committee that has the overview, says Ian.

The council has received two recent warnings on Roundup use. In 2011, TAAF advised the city council to research the additives used in glyphosate weed killers.

After the patents on Monsanto's Roundup, and its active ingredient glyphosate, expired in 2000, about 90 competing weed killers appeared, all containing gylphosate as the active ingredient, but with different chemicals in the mix.

Research finds some of the additional chemicals are more toxic than the weed killer itself. Council policy approves glyphosate for use on city reserves, but doesn't differentiate between brands.

The law doesn't require the additives to be disclosed.

TAAF asked council staff in 2011 to independently research the additives, so the council will only buy the ‘safest' brands for use on the city's parks reserves and playing fields.

In May 2013, naturopath and spray sensitive Robin Grierson warned TCC that published research now makes the council liable to being sued by people affected by Roundup in council weed spraying programmes.

A research paper head-lined, Ethoxylated adjuvants of glyphosate-based herbicides are active principles of human cell toxicity, authored by Robin Mesnage, Benoit Bernay and Professor Gilles-Eric Seralini, from the University of Caen, finds a Roundup ajuvant polyethoxylated tallowamine POE-15 is the most poisonous part of Roundup, toxic on human cells at 1-3 parts per million.

The danger is overlooked because the active ingredient glyphosate, and Roundup style herbicides with additives, are treated as the same by industry and regulators on long-term studies.

The French research challenges existing guidance values, such as the acceptable daily intake of glyphosate, when these are mostly based on a long term in-vivo test of glyphosate alone.

Chairman Kelvin Clout says Ian's concerns are in the minutes and he will make sure they are answered.