DisastersPakistan floods released tons of toxic chemicals
The floods in Pakistan earlier this year, in addition to forcing about 20 million people out of their homes, also released long-lived chemicals, known collectively as persistent organic pollutants (POPs); these include several banned pesticides and the insect repellent DDT; they are dispersed around the planet by atmospheric patterns, do not degrade naturally, and are linked to hormonal, developmental, and reproductive disorders, and increased risk of diabetes, cancer, and dementia
Floodwaters released a host of pollutants // Source: pops.int
The floods that tore through Pakistan earlier this year, affecting twenty million people, released some 3,000 tons of dangerous chemicals into the environment. A report due to be published next year will warn that the event was not a one-off.
Its findings were presented at the climate negotiations in Cancún, Mexico, earlier this week.
The long-lived chemicals, known collectively as persistent organic pollutants (POPs), include several banned pesticides and the insect repellent DDT.
They are dispersed around the planet by atmospheric patterns, do not degrade naturally, and are linked to hormonal, developmental, and reproductive disorders, and increased risk of diabetes, cancer, and dementia.
Catherine Brahic reports that “Climate Change and POPs Inter-Linkages,” published by the UN Environment Program, is the first study to look at how climate change will affect POPs, which are regulated under the UN Stockholm convention.
It found that climate change increases the risks posed in several ways. Both measurements and models show that as evaporation increases with warmer temperatures, more of the chemicals are released from the land masses, rivers and lakes where they are stored. Once in the atmosphere, they can travel great distances.
Likewise, glaciers lock away POPs, preventing them from causing more harm. Data shows, however, that as they are melting with global warming, their toxic load is being re-mobilized.
Storms and extreme weather events like this year’s floods in Pakistan are another factor in the release of POPs into the environment, when disasters release stockpiles stored in drums. Pakistan is a recent signatory or the Stockholm Convention and in 2009 it filed a preliminary audit of its POP stockpiles, stating that there were at least 6,000 tons of the chemicals locked up in stores around the country.
According to Pakistan’s audit, about half of the stores were in low-lying areas near bodies of water, including the areas that were flooded this year.
Michael Stanley-Jones of UNEP yesterday told New Scientist that aerial surveys after the floods found that the facilities had been destroyed by the force of the water crashing through the flooded plains.
Similar events took place after the Indian Ocean tsunami in 2004, said Donald Cooper, executive secretary of the Stockholm Convention, adding that more and more intense extreme weather events like this year’s floods and fires put the hundreds of thousands of tons of stockpiled chemicals around the world at risk.
“Throughout Asia and Africa there has been a large accumulation of old pesticides, many of which are POPs,” says Cooper. In a bitter twist or irony, the pesticides were often sent by rich nations as aid, in response to a past food crisis. Excess pesticide could not be sent back and so was simply stored for an indefinite period.
