WHO adds popular weedkiller to list of potential carcinogens

The World Health Organisation has released a study saying the 2,4-D herbicide "possibly" causes cancer.

Dandelion. Image: MorgueFile
Dandelion. Image: MorgueFile

The WHO's International Agency for Research on Cancer reviewed the latest scientific literature on the insecticides DDT and lindane along with 2,4-dichlorophenoxyacetic acid (2,4-D), a herbicide included in many lawn-weed killers. The herbicide was introduced in 1945 and is widely used in weed control across forestry, agriculture and urban settings.

IARC's experts classified 2,4-D as "possibly" carcinogenic to humans, a step down from the "probably carcinogenic" classification given to glyphosate earlier this year. The lower carcinogenity rating was based on "inadequate evidence in humans and limited evidence in experimental animals".

The group's monograph did say there is "strong evidence that 2,4-D induces oxidative stress, a mechanism that can operate in humans, and moderate evidence that 2,4-D causes immunosuppression, based on in vivo and in vitro studies.

"However, epidemiological studies did not find strong or consistent increases in risk of NHL or other cancers in relation to 2,4-D exposure."

The reviewers also agreed there was sufficient evidence that the insecticide lindane was carcinogenic (causing non-Hodgkin lymphoma) and DDT was probably carcinogenic. Neither have been used in the UK for decades, however DDT exposure still occurs through diet as it is slow to break down in the environment.

IARC classifications indicate the strength of the evidence that a substance causes cancer, rather than the probability or risk of cancer occurring. Cancer risk can vary drastically between chemicals that have a similar classification due to the different ways a chemical is used, which result in different levels of exposure.

Before commenting please read our rules for commenting on articles.

If you see a comment you find offensive, you can flag it as inappropriate. In the top right-hand corner of an individual comment, you will see 'flag as inappropriate'. Clicking this prompts us to review the comment. For further information see our rules for commenting on articles.

comments powered by Disqus

Read These Next

IoG Saltex 2016 - show preview

IoG Saltex 2016 - show preview

This year's Saltex will be looking to build on the success of last year by packing in a multitude of exhibitors and sessions over the two days, Sally Drury reports.

According To Dunnett ... Horticulture needed to 'colour in' green infrastructure

According To Dunnett ... Horticulture needed to 'colour in' green infrastructure

It's now around one year since work started on Sheffield's groundbreaking "Grey to Green" scheme, one of the largest urban green infrastructure projects in the UK.

Tree lifting, moving  and planting

Tree lifting, moving and planting

Successful relocations can see even big trees flourish while costing less than buying new stock, says Sally Drury.

Follow us on:
  • Facebook
  • LinkedIn
  • Twitter
  • Google +
Horticulture Jobs
More Horticulture Jobs

Contracts & Tenders

Sally Drury on professional gardening

Sally Drury

A monthly checklist of things to do and watch out for to keep your garden looking its best.