At the National University of Lesotho (NUL), Professor Mosotho George decided to get his hands dirty. Literally. He dug soil from the Tsosane Dumpsite in Maseru, one of those places where plastics, bottles, and broken household stuff are piled high. But instead of just looking at the trash with his eyes, he looked at it with scienc⁷e. What he discovered is something every Mosotho should know: the soil hides phthalates; chemicals from plastics that may harm people and nature.
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And yes, this story was important enough to be published in the International Journal of Environmental Analytical Chemistry published Taylor and Francis [https://www.tandfonline.com/doi/pdf/10.1080/03067319.2019.1618458?download=true]. This is just one of the four papers he wrote about the chemicals in the soil and air at the dumpsite.

Now, let’s slow down.

What on earth are phthalates? They are chemicals put into plastics to make them soft and bendy. Without them, your plastic water bottle would crack too easily, your school ruler might snap, and even some hospital equipment wouldn’t be flexible enough.

They’re everywhere! But the problem is: these same chemicals don’t just stay inside the plastic. Over time, they can “escape” into soil, water, or even food.

That’s where Professor George comes in.

He wanted to know: by how much are these invisible plastic chemicals hiding in Tšosane Dumpsite soil? To find out, he and his team at NUL built a smart detective method that sounds like something out of a science magic show: Bubble-In-Drop Microextraction.

Here’s how it works.

Imagine you have a droplet of cooking oil, but this one is teeny-tiny, just one millionth of a litre. Inside that droplet, you carefully trap a bubble of air, like making a little balloon inside a water droplet. This droplet-bubble combo is then dipped into water that has been in contact with the dumpsite soil. What happens? The chemicals in the water (if any are there) jump into the droplet because they like oil more than water. After some waiting, the droplet is pulled back into a syringe and—voilà—it carries all the “evidence” inside it. Think of it like fishing: the droplet is your bait, and the chemical pollutants are the fish.

But that’s not all.

To get the chemicals moving, the team added sonication, basically blasting the soil-in-water mixture with sound waves.

No, not the kind of sound you hear on the radio, but powerful vibrations that shake the water and soil so hard that any hidden chemicals are nudged out into the water. This step is clever because heating the soil would destroy the delicate phthalates.

So, sonication at room temperature was the safe way to coax them out without breaking them apart.

Once the droplet had sucked up whatever was in the water, the scientists put it into a fancy machine called a Gas Chromatograph–Mass Spectrometer (GC-MS). If that sounds complicated, just think of it like this: the GC sorts out all the different chemicals in a sample, while the MS tells you exactly what each one is, almost like a fingerprint scanner.

And what did Professor George’s fingerprint scanner find?

Out of all the possible suspects, one chemical stood out: bis-(2-ethylhexyl) phthalate (don’t worry, even scientists call it “DEHP” for short). This guy is one of the most common plastic softeners in the world, used in things like wires, vinyl flooring, plastic bags, and even medical tubing. At Tšosane, DEHP showed up at 0.62 nanograms per gram of soil.

That’s a super tiny number, you could compare it to a pinch of salt in an Olympic-sized swimming pool; but it’s still worrying because phthalates build up over time and don’t go away easily. Besides, chemicals like DEHP behave like hormones – those chemical messengers in our bodies, they are very effective even at very low concentrations. So their detection, no matter how low, keeps us awake at night.

Why does this matter?

Because dumpsites in Lesotho, including Tšosane, aren’t built like modern landfills in rich countries. There are no liners or protective barriers to stop chemicals from leaching into the soil. So, if phthalates are already showing up, it means they could eventually creep into water sources or farmland, affecting people and animals (if they haven’t already).

The study also revealed how tricky these chemicals are to work with. Many phthalates break down when exposed to too much heat or acidic conditions. That’s why the scientists couldn’t just boil the soil to get the chemicals out. They had to be patient, using gentle sound waves and clever chemistry tricks.

Still, this was a big win for NUL and Lesotho’s science community. For the first time, advanced methods like Bubble-In-Drop Microextraction were used to investigate local soil pollution.

“We’ve shown that harmful chemicals from plastics are not just a global story,” Professor George explained. “They are already here, right under our feet in Maseru.”

Image Credit: Molise Molise, The Post Newspaper.

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Brought to you by NUL Innovation Hub [Where Academia Meets Industry] & MILCO [a store that sells only Lesotho products at Sefika Complex]. MILCO was founded by NUL Innovation Hub!