Scientists call for new review of cancer causing herbicide

US regulators have relied on flawed and outdated research to allow expanded use of an herbicide linked to cancer, and new assessments should be urgently conducted, according to a column published in the New England Journal of Medicine.

There are two key factors that necessitate regulatory action to protect human health, according to the column: a sharp increase in herbicide applied to widely planted genetically modified (GMO) crops used in food, and a recent World Health Organisation (WHO) determination that the most commonly used herbicide, known as glyphosate, is probably a human carcinogen.

The opinion piece was written by Dr Philip Landrigan, a Harvard-educated pediatrician and epidemiologist who is Dean for Global Health at the Mount Sinai Medical Centre in New York, and Chuck Benbrook, an adjunct professor at Washington State University’s crops and soil science department.

“There is growing evidence that glyphosate is geno-toxic and has adverse effects on cells in a number of different ways,” Benbrook said. “It’s time to pull back ... on uses of glyphosate that we know are leading to significant human exposures while the science gets sorted out.”

The column argues that GMO foods and herbicides applied to them “may pose hazards to human health” not previously assessed.

“We believe that the time has therefore come to thoroughly reconsider all aspects of the safety of plant biotechnology,” the column states.

The authors also argue that the US Environmental Protection Agency has erred in recently approving a new herbicide that uses glyphosate because it relied on outdated studies commissioned by the manufacturers and gave little consideration to potential health effects in children.

Glyphosate is best known as the key ingredient in Roundup developed by Monsanto Co, one of the world’s most widely used herbicides, but it is used in more than 700 products.

It is sprayed directly over crops like corn genetically engineered to tolerate it and is sometimes used on non-GMO crops, like wheat before harvest. Residues of glyphosate have been detected in food and water.

The WHO’s cancer research unit after reviewing years of scientific research from different countries on March 20 classified glyphosate as “probably carcinogenic to humans.”

But regulators and agrichemical companies in the United States and other countries still consider glyphosate among the safest herbicides in use.

In July, Monsanto said it had arranged for an outside scientific review of the WHO finding.

Meanwhile, many of the world’s plants are turning “alien”, spread by people into new areas where they choke out native vegetation in a worsening trend that causes billions of dollars in damage, scientists said on Wednesday.

The invaders include water hyacinth from the Amazon, which has spread to about 50 nations where it crowds out local plants, while Japanese knotweed has fast-growing roots that have destabilised buildings in North America and Europe.

Citing a new global database, an international team of scientists wrote in the journal Nature that 13,168 plant species — 3.9 per cent of the global total — “have become naturalised somewhere on the globe as a result of human activity”.

The spread of alien plants was likely to increase with rising trade and travel by emerging nations led by China, it said.

“North America has had most — many came from Europe after Columbus because colonists brought plants with them,” lead author Mark van Kleunen of the University of Konstanz in Germany told Reuters.

The global numbers were higher than most earlier estimates of just one or two percent, he said. Plants can be introduced deliberately as crops, for instance, or can get accidentally carried as seeds.

“With continuing globalisation and increasing international traffic and trade, it is very likely that more species will be introduced outside their natural ranges and naturalise,” the authors wrote.

Scientists have previously estimated that all invasive species — including microbes, animals and plants - cause damage of more than $1.4 trillion a year to the world economy. One 2012 report estimated that water hyacinth cost China alone about $1.1 billion a year.

Piero Genovesi, who chairs a group of invasive species experts at the International Union for Conservation of Nature, welcomed the study as a step to control the spread of new plants.

The European Union was drawing up a “black list” of the worst species in which all trade would be banned from January 2016, he said.

Other European rules call for action to eradicate newly identified alien plants within three months.

“I don’t think it’s possible to stop (the spread of invasive plants) but we can indeed significantly reduce the impacts,” he told Reuters.