A dangerous pesticide isn’t being monitored in key bird of prey populations — we’re shedding light on that gap

Subject: Environment

Context-

DDT is known for its devastating effects on the environment, as well as animal and human health.

About DDT-

It was first used in the second world war to protect Allied soldiers against malaria and typhus, which are spread by mosquitoes and body lice. Thus considered as miracle chemical.
Its insecticidal properties were discovered in 1939 by a Swiss chemist, Paul Hermann Müller and he won a Nobel Prize for medicine for discovering the usees of DDT.
It became a widely available pesticide to kill insect crops pests and insects causing disease in humans.
Continued exposure to the chemical can cause neurological damage, endocrine disorders and reproductive failure in both humans and animals.

Awareness about the harmful effect of DDT-

Rachel Carson’s book Silent Spring, published in 1962.
Silent Spring brought global attention to DDT’s environmental impacts and sparked a public outcry that forced much of the developed world – the “global north” – to ban the use of DDT in the 1970s and 1980s.
In 2004 the Stockholm Convention on Persistent Organic Pollutants – those that stay in the environment for a long time after use – was adopted by over 90 nations.
DDT was among the most dangerous pesticides, industrial chemicals and by-products placed on the convention’s “dirty dozen” list, and was banned in most parts of the world.
Two years later the World Health Organization recommended the restricted use of DDT to control malaria.
It remains in use for this purpose in various tropical countries in Asia, Africa, and South and Central America.
Its use here put the human as well as raptors health at risk.

Birds of prey as sentinels-

Being at top of the food chain they can act as an “ecological baraometer”, helping us gauge the health of the environment.
In addition to their value as indicator species, they provide valuable ecosystem services, controlling pest animals such as rodents and removing carrion from the environment, potentially reducing the spread of disease.
Because DDT accumulates in wildlife and magnifies up the food chain, many raptor populations were nearly wiped out by its use.
However, this bio-accumulation also means they have the potential to serve as a useful indicator to monitor levels of DDT in the environment.
Thus, raptors can be regarded as sentinels for DDT.

A global north bias

DDT monitoring in raptors is heavily biased toward the global north. Europe and North America account for 95% of samples.
This is a concern because most DDT use is currently in the global south, as are most raptor species.
Just three species account for half of all raptor samples collected: bald eagle, Eurasian sparrowhawk and peregrine falcon.
Only the peregrine falcon occurs on all continents, but have been sampled far less in Africa, Asia, Central and South America than Europe and North America.
The Eurasian sparrowhawk is also found in Asia but similar to the peregrine has been sampled far less frequently there than in Europe.

And it’s worrying for three reasons-

Most current DDT use is in the global south because of the chemical’s role in malaria control.
The region is home to most of the world’s raptors. There are also many declines of species in these regions.
Many countries in the global south are notoriously poor enforcers of environmental legislation.