How Safe is Your Local Pond? - Chromatography Investigates

Sitting in the park watching the ducks play on the pond, a dog jumping in and out of the water chasing a ball thrown by a laughing child is an image that would make many people feel just a little bit better about the world; especially with the year of lockdowns just gone.

However, something sinister might be lurking in the water and air around your local pond. Pond scum, also known as algal bloom, is an unsightly matt that can form across the surface of still water around the world and it can be harmful to both humans and animals. A recent study on a pond in Massachusetts –reported in the journal Lake and Reservoir Management - has found that algal blooms could give rise to an airborne toxin. And chromatography was there to record the event.

Algal bloom on the water

Algae are vital to life on Earth with an estimated 50% of our oxygen being produced by these creatures. Algae are their own group of creatures that don’t fit neatly into a group like plants or animals do. The name is applied to creatures that live in marine or fresh water and depend on photosynthesis. They range in size from micro-algae or microscopic diatoms to large algae like seaweed.

An algae bloom happens when one type of algae gets out of control and becomes dominant. We don’t understand the exact mechanism behind this, but it has been linked to climate change and nutrients in agricultural run-off. Harmful algae blooms form a scum on the water’s surface and can red, blue, or green depending on the species behind the bloom.

Algae blooms can be deadly. Some blooms can make shellfish lethal to eat causing whole fisheries to shut down until the bloom has gone. They can also have a devastating effect in fresh water, with dead cyanobacteria sinking to the bottom of lakes and depleting the oxygen levels. This can lead to lakes ‘dying’ and losing much of their life.

Chromatography and ATX

In the study referenced above - The detection of airborne anatoxin-a (ATX) on glass fiber filters during a harmful algal bloom - scientists detected the presence of algal toxin anatoxin-a (ATX) for the first time in the air near a pond with a large algal bloom. ATX can cause a range of symptoms like respiratory paralysis and muscular twitching at acute doses and has been linked to the deaths of waterfowl and dogs.

The team analysed the air and water using liquid chromatography. The power of chromatography is discussed in the article, The Evolution of Data Independent Analysis: Complex Sample Analysis Using UPLC Ion Mobility Mass Spectrometry. It is the first time ATX has been detected in the air. Lead author Dr James Sutherland said: “ATX is one of the more dangerous cyanotoxins produced by harmful algal blooms, which are becoming more predominant in lakes and ponds worldwide due to global warming and climate change.”