The pollution causing harmful algal blooms

Rising temperatures and pollution have led to an explosive growth of harmful algal blooms, contaminating rivers, lakes, drinking water and harming human health”. This natural disaster has been slowly increasing in many countries around the world, and has become an ongoing environmental issue in the USA.

“The explosive growth of algal blooms is linked to rising temperatures and rising pollution. These green waves are both a warning sign and a symptom of a changing climate. As farming fertilizer and a tsunami of human sewage hit our warming waterways, we are in danger of turning our very drinking water toxic”.

In the past, Belize has been known for its crystal-clear rivers, for its unpolluted waterways and abundant aquatic wildlife. However, the toll of agricultural and industrial pollutants and the impacts of limited sewage treatment and grey water management in river-side towns and villages is finally catching up. In the north of Belize, the New River winds from the low hills in the west across a flat limestone plain to empty into coastal waters. The slow flow of the river, combined with the increasing agricultural and urban footprints, and the changing weather of drought conditions and higher-than-normal temperatures, has provided the perfect conditions for eutrophication. The result? A toxic brew that results in fish-kills and sulphurous fumes that close schools, restaurants and hotels in close proximity to the river.

Rural communities that use the river for fishing and bathing are impacted by the changes in the river. Children develop skin rashes and the fish are inedible. People with houses near the river live and breathe in the sulphurous environment for the weeks or months that the river is eutrophicated, and the tour guides using the river are forced to look elsewhere for work, impacting their houseold incomes.

Is this the ‘new norm’? Can the eutrophication be reversed? Studies are being conducted in the New River area. Water quality testing is being conducted on an ongoing basis, and a New River watershed Management Plan is being developed. 2022 was a reprieve - a wetter year that flushed the contaminants out of the river fast enough for there to be only a few days where the river turned green and the air sulphurous. However, with increasing droughts, the future looks less certain.

"There will always be some of these blooms," says Stumpf. "The world is getting warmer which means that blooms may last longer." But, he says, it ultimately comes down to the pollution and nutrients we release into the water. It's the choices we make as to "how we use the land", he says. And we do have control over them.

The pollution causing harmful algal blooms