About the doctoral thesis
On Thursday 5 December, Putheary Ngin, Department of Chemistry, defended her thesis entitled Pesticides in Cambodia: usage, fate, and health risk at Umeå University.
NEWS Researchers at Umeå University have investigated a group of substances used to combat weeds and insects suspected of carrying risks to human health and inducing cancer.
Putheary Ngin, PhD student at the Department of Chemistry.
ImagePrivateThey chose to study pollution loads and associated risks of such polar pesticides in the Southeast Asian country of Cambodia, and four provinces that share the Mekong River, important to biodiversity and livelihoods.
Putheary Ngin, Department of Chemistry, outlines their findings in a PhD dissertation that gives the concentrations of these modern pesticides, primarily in soils and water.
In 2022 the European Union banned one of the most common types and recommended in a regulation that polar pesticides be analysed both in plant and animal matrices. However, no comparable analyses had been performed in Cambodia since, according to the researchers.
There many farmers prefer to use imported products because of their relatively low price, but may not be able to understand the instructions on the package.
"It was discovered ten years ago, around 2011, that pesticides were very common in all food in Cambodia. We selected these novel pesticides to see if there was a risk to human health and which matrix was most exposed", Ngin said.
The researchers started from the assumption that the use of polar pesticides could carry a risk of toxic pollution of crops and the environment. They performed an encompassing study entailing field sampling and laboratory testing.
This marks a previously undocumented environmental presence of these chemicals.
Ngin also interviewed a number of farmers who had used modern pesticides to spray crops.
"There is a tendency for overuse. Spread today, sell tomorrow. This is one of our main conclusions", according to Ngin.
Fifty-six new polar pesticides were found in surface water and 43 in soil samples.
"This marks a previously undocumented environmental presence of these chemicals… Ten per cent of these pesticides present a high or very high risks to aquatic life, particularly in the Mekong River, a vital ecosystem supporting biodiversity and livelihoods in the region".
It is well known to the scientific community studying these matters, that analysis of polar pesticides does not come easy, however.
The research team including PhD student Ngin and her academic supervisor Jerker Fick, associate professor, circumvented the issue by combining a range of sophisticated techniques for analysis, available to them at Umeå University in northern Sweden and in the academic cluster to which it is attached.
"Results indicate that vegetables are the primary source of pesticide exposure, followed by rice and fish, with water identified as the least risky matrix", Ngin said.
The research results are aimed at policymakers, other scientists and public health campaigners.
"They also underscore the importance of targeted farmer education to prevent overuse and encourage sustainable agricultural practices".
On Thursday 5 December, Putheary Ngin, Department of Chemistry, defended her thesis entitled Pesticides in Cambodia: usage, fate, and health risk at Umeå University.