Are you feeling a little more forgetful lately? It could be in your imagination or the sign of something serious (such as Alzheimer’s disease, a tumor or any number of causes). Yet you’d probably never suspect that the reason you can’t remember where your keys are is related to the water you drink. In the wake of the Flint Michigan water crisis, there has been a renewed interest in the importance of clean water. Unlike some countries where limited or poor infrastructure renders the public water supply undrinkable (Mexico is one such example), the United States boasts some of the cleanest & finest water in the world. That was, until recently. The discovery of toxic lead in Flint Michigan’s water supply shook the nation and harmed public trust. It also focused attention on a resource we previously took for granted; most people assume the water flowing from their faucets is safe. But is it? This isn’t the first time the US has faced a water crisis. Love Canal made international news following the discovery that buried toxic chemicals had contaminated the soil and ground water. The effects were devastating – increased rates of miscarriages, birth defects and cancers. In fact, a recent article in the highly respected journal Nature stated that the majority of cancers are related to the environment & exposure to carcinogens. But it’s not just carcinogens that can cause serious health problems. Contamination from biological sources can be devastating also. One such incident was the Pfisteria outbreak in Maryland in the 1990s due to Pfiesteria piscicida, a dinoflagellate phytoplankton (similar to algae). Pfiesteria is a very interesting organism; it produces a powerful neurotoxin but only makes large amounts of the toxin under specific circumstances. In other words, it requires an environmental stimulus. Pfiesteria lives by feeding off of the skin and flesh of fish; the toxin it produces is a type of neurotoxin, a chemical that inhibits or damages the brain and/or nervous system. Fish exposed to Pfiesteria’s neurotoxin become disoriented and unable to defend themselves. A true predator, Pfiesteria takes full advantage of the situation and literally eats the ambushed fish alive. As horrible as it sounds, fortunately this scenario is relatively uncommon. Normally, Pfiesteria is an organism found in small amounts as a dormant harmless form. The harmless form of Pfiesteria is relatively benign; it utilizes photosynthesis or feeding on small bacteria to sustain itself. But when it’s triggered by a nutrient rich environment, it transforms into a toxin-producing killer. It is this highly toxic form of Pfiesteria that’s so dangerous to fish and humans. So what happened?
In the late 1990s fishermen in Maryland’s Chesapeake Bay began to suspect something was wrong when they noticed fish with sores coming up in their nets. Little did they realize the seriousness behind the illness affecting the fish. The visual appearance of the fish was so shocking the term “Fish AIDS” was coined. Before long, thousands of dead fish literally covered the entire surface of the Pocomoke River, a tributary of the Chesapeake Bay. Scientists soon determined the cause — a massive increase in the local pfeisteria population. Also referred to as a “bloom,” this particular type of pfeisteria outbreak is one of the fish industry’s worst nightmares. And it has happened more than once. In October 1995, 14 million fish died during a pfiesteria outbreak in North Carolina. In response to the crisis, Maryland issued a total ban on fishing, boating and swimming in the affected areas and enforced it with armed patrols. But the story doesn’t end there. Fishermen and workers exposed to the pfiesteria began to notice they had trouble remembering things. Some developed headaches and rashes. Others developed visual impairments that made them accident-prone. Individuals suffering from suspected pfiesteria toxicity were referred for brain scans to assess for brain damage. Brain scans showed abnormal findings in the hippocampus, an area of the brain associated with short-term memory function. Fortunately, the effects of the toxin weren’t permanent and eventually subsided. Officials were left with the task of cleaning up the river and determining what caused the outbreak. Pollution & climate were ultimately deemed the most likely causes. As it turns out, Pfiesteria thrives in stagnant nutrient rich waters. The outbreak occurred following a wet winter when nitrogen and phosphorous (from fertilizers utilized in farming) entered the river in greater amounts. The agricultural run-off contaminated the river, triggering an explosion in the pfiesteria population. While considered an unusual event, the resulting environmental disaster (thousands of dead fish, loss of revenue from fishing and tourism and its toxic effects in humans) served as a precautionary ecological lesson. Whether we realize it or not, all living organisms are interrelated. Additionally, we have to be vigilant when it comes to the environment & our water supply. Close monitoring & safety precautions are essential.