Call for a moratorium on market gardens in the eastern plains of Waimea


The nitrate level in parts of the Waimea Plains has long been a concern.

MARTIN DE RUYTER / STUFF

The nitrate level in parts of the Waimea Plains has long been a concern.

A call has been made for a moratorium on market gardening in the eastern Waimea Plains, near Nelson.

This appeal to the Tasman District Council is one of six from Water Information Network Inc secretary Lewis Solomon in response to concerns about nitrate levels in parts of the plains.

It comes after the council released a report last week on nitrate levels in groundwater. The report, covering the results of groundwater monitoring and the results of a soil survey on the eastern plains, states that market gardening is a “higher risk land use for nitrate leaching” compared to others. main land uses in the study area. – pastures, pome fruits and viticulture.

Groundwater monitoring shows that nitrate levels continued to exceed drinking water standards in parts of the plains while soil study reveals that in basement samples the average nitrate levels were three. four times higher in market gardens than in other land uses.

In addition to contemporary land uses, the council report pointed to an old pigsty that closed in the 1980s as a possible contributor to the high nitrate levels.

Solomon called the council’s report a “comprehensive analysis of the pollution of aquifers” under the eastern plains.

READ MORE:
* Market gardening “higher risk” of nitrate leaching in the eastern plains of Waimea
* Concern on the plains of Waimea because nitrates in some boreholes exceed water standards
* Call on DHB to consider nitrate levels in drinking water
* Rethinking nitrates as government orders examine link to cancer

Water Information Network Inc secretary Lewis Solomon says the concentration of nitrate in Richmond's water supply is

FASTER BRADEN / STUFF

Water Information Network Inc secretary Lewis Solomon said the nitrate concentration in Richmond’s water supply is “possibly the highest of all major urban areas in New Zealand.”

However, this did not address the “most important” issue for residents of the city of Richmond, he said.

“Namely, the high concentration of nitrate in the crosslinked water supply.”

Solomon said that while the concentration of about 5 mg / L of nitric nitrogen in the Richmond supply was below the maximum acceptable value of 11.3 in drinking water standards, it was “probably the highest. of all major urban areas of New Zealand “.

“Definitely, I couldn’t find any higher,” he said.

It was also above a level of risk found in a Danish study of 2.7 million people over 33 years. This study, published in February 2019, found that nitrates in drinking water may increase the risk of colorectal cancer. He found statistically significant increased risks at levels greater than about 1 mg / L of nitric nitrogen.

Solomon expressed his concerns at a meeting of the Nelson Marlborough District Health Board in July 2019 regarding the level of nitrates in Richmond drinking water in light of the results of the Danish study.

“The concern of healthcare professionals in New Zealand has been such that the Department of Health has assembled a team of scientists under the leadership of Professor Michael Baker to investigate the relevance of Danish research to New Zealand.” , Solomon said this week. “We look forward to the report.”

A graph showing the concentration of nitrate in city water supplies, based on information provided in 2019 to resident Lew Solomon.

A graph showing the concentration of nitrate in city water supplies, based on information provided in 2019 to resident Lew Solomon.

Data from the New Zealand Health Safety and Quality Commission website showed that for the period 2008-2012, the incidence of colorectal cancer in women in the Nelson region Marlborough District Health Board (NMDHB) was 24% higher than women in Canterbury DHB. while the incidence was the same for the other cancers combined.

At that time, the concentration of nitrate in drinking water in the NMDHB zone varied, but reached 10 mg / L nitrate nitrogen in Richmond and was “negligible” for the majority of the Canterbury DHB zone population.

“This result is completely consistent with the findings of Danish research,” Solomon said.

Councilor Dana Wensley said there could be “many reasons” for the higher incidence of colorectal cancer in the NMDHB data, such as an aging population and other environmental factors.

“But don’t we have a duty to look at this and say, ‘Maybe, when there are a lot of question marks, we need a moratorium on further intensification of market gardening‘” , Wensley said.

“I think this is about the perfect storm – there are poor soils, high nitrate levels when we know there is going to be a build-up in the plains after the Waimea dam [commissioning] and we also have potentially new information from the Ministry of Health, once it reports on its findings on the Danish study. “

The Tasman District Council has been called on to institute a moratorium on any new market gardening in the eastern Waimea Plains.

ROBERT CUISINE / STUFF

The Tasman District Council has been called on to institute a moratorium on any new vegetable growing in the eastern Waimea Plains.

The council was to “consider the impact this could have on us (…)

The council’s director of the environment and planning, Dennis Bush-King, said that as an urban supply authority, the council has taken steps to ensure that the water meets the standards of drinking water “to guarantee the safety of people”.

“As for the standards that we have to work with, there is a debate with the Department of Health on changing those standards.”

Natural resources policy planner Lisa McGlinchey said work has started to activate an existing schedule in Tasman’s resource management plan “which will require nutrient management plan information” from holders of water permits in the plains of Waimea.

This work would result in a targeted plan change.

“Ideally, we would like to see this notified by the end of the year,” McGlinchey said.

CANTERBURY / SUPPLIED ENVIRONMENT

A denitrification wall at Silverstream Reserve, North Canterbury, has already dramatically reduced nitrate levels in less than two months. (Video first published in January 2019)


Terri S. Tomasini