Scientists uncover alarming contamination in water sources — here's why experts are worried

Scientists in Latin America are sounding the alarm over the presence of microplastics in freshwater sources — and the understudied human health impacts of the plastic pollution.

What's happening?

A new report by SciDev.net highlights two recent studies linking microplastic pollution to freshwater sources in Latin America. 

A Cuban study found microplastics, or plastic particles less than five millimeters long, in two freshwater rivers — the Almendares, which runs through Havana, and the Baños del San Juan River, located in a rural area near the capital. The study found higher concentrations of microplastics in the urban river versus the rural river, though levels were concerning to researchers in both.

The study identified common sources of plastic pollution in the region as plastic bags, personal care and cleaning product packaging, food containers, and rope. The researchers reported microplastics from these sources often accumulate in river sediment and likely disrupt the natural functions of microorganisms, including the vital decomposition of organic matter.

A similar Venezuelan study focused on a river and connected bay in the small fishing village of Chichiriviche de la Costa, about 40 miles from the Venezuelan capital of Caracas. This study found microplastic pollution was almost four times more downstream than upstream, identifying the village — and activities of the humans who live there — as a major source of plastic pollution.

According to the SciDev.net analysis, both studies highlighted clothing and textile fibers as the most common type of microplastic pollution. Synthetic fabrics like polyester release microplastics into water during washing. In areas with poor wastewater treatment, these microplastics enter rivers — and eventually end up in the ocean. 

Both studies also found that microplastic levels increased during the rainy season, indicating microplastics are being washed into rivers by storm drainage, according to SciDev.net. 

Why are microplastics concerning?

Research on microplastics and their impact is relatively new. But what little we know is quite alarming. 

Plastic also never truly biodegrades in the environment, turning into microscopic pieces that contaminate waterways, soil, air — everything. Microplastics are incredibly prevalent in global waterways and, therefore, the global drinking supply. Once in water, microplastics can enter the food supply via seafood and livestock, which — like us — depend on water for hydration. A recent study of protein-rich foods, including beef and tofu, found microplastics in nearly 90% of samples.

Microplastics can even travel through the air and enter our bodies — and the bodies of animals — simply through breathing. One Australian study estimated humans inhale approximately 16.2 bits of microplastics each hour, or the equivalent of a credit card per week.

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Recent research has connected microplastics to reproductive issues and cancers. In models, microplastics have also been found to cause "inflammation, cell death, lung and liver effects, changes in the gut microbiome, and altered lipid and hormone metabolism," according to Harvard Medicine.

As SciDev.net reports, studies estimate up to 40 million tons of microplastics are released into the environment each year. And scientists project this number could double by 2040 if the problem isn't addressed. 

What's being done to prevent microplastic exposure?

Researchers in the two highlighted studies called for more scientific attention to microplastics and their impact. Scientists recognize there's a long way to go before we fully understand how microplastics affect human health and the environment.

While it's impossible to avoid microplastics, we can all take action to limit our exposure. Buying clothing with natural fibers, avoiding plastic food and product packaging, and using reusable shopping bags to avoid single-use plastics can help. Since microplastics can be inhaled, regular vacuuming or the use of air purifiers — especially with HEPA-grade filters — can help protect from airborne microplastics. 

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