Summer sunshine often calls us to the water’s edge. Lakes, ponds, and rivers become popular spots for swimming, boating, fishing, and simply cooling off. While these activities bring joy and relief from the heat, it’s important to be aware of a potential hazard lurking in some waterways: toxic algae blooms. Knowing how to spot them and what precautions to take can help ensure your summer fun stays safe and healthy.
What Exactly Are Algae Blooms?
Algae are simple, plant-like organisms naturally found in water bodies. They form the base of the aquatic food web. An algae bloom occurs when conditions – typically warm temperatures, stagnant water, and an abundance of nutrients like nitrogen and phosphorus (often from runoff containing fertilizers or wastewater) – allow certain types of algae to grow rapidly and uncontrollably. Think of it like weeds taking over a garden, but in the water. These blooms can involve various types of algae, including cyanobacteria (often called blue-green algae), which are particularly concerning.
Not every mass of algae you see is harmful. Many blooms are just unsightly accumulations of harmless species. However, certain types, especially cyanobacteria, can produce potent toxins. These are known as Harmful Algal Blooms, or HABs. Unfortunately, you can’t tell just by looking whether a bloom is toxic or not, which is why caution is always the best approach.
Spotting Potential Trouble: Visual Clues
While only lab testing can confirm toxicity, there are several visual signs that should make you wary of entering or letting pets near the water. Learning to recognize these can be your first line of defense.
Color Clues
HABs don’t always look the same, but common appearances include water that looks like:
- Pea soup or spilled green paint: This is a classic sign, often associated with cyanobacteria blooms. The water might appear thick and bright green.
- Blue-green, turquoise, or sometimes reddish-brown: The color can vary depending on the specific type of algae and environmental conditions. Don’t assume only bright green blooms are risky.
- White or brownish foam or scum: Sometimes blooms create thick mats or surface scum that can accumulate along shorelines or in calm areas. This scum can be particularly concentrated with toxins.
Texture and Appearance
Beyond color, look for changes in the water’s texture:
- Surface Scum or Mats: Thick layers floating on the surface are a major red flag. These can look like paint slicks, foam, or clumps of organic material.
- Streaks or Filaments: Sometimes the algae forms visible streaks or dots suspended in the water column.
- Cloudy or Murky Water: A sudden decrease in water clarity, especially with an unusual color tint, can indicate a bloom.
Unpleasant Odors
While not always present, some HABs produce a distinct smell. If the water emits a strong, unpleasant odor – often described as grassy, fishy, septic, or like gasoline – it’s best to steer clear. Trust your nose; a foul smell is often nature’s warning sign.
Important Safety Notice: Never assume an algae bloom is safe. Visual identification alone cannot determine if toxins are present or at what concentration. Always err on the side of caution when encountering suspicious-looking water.
Contact with water contaminated by harmful algal blooms can lead to unpleasant symptoms for both people and animals. The severity can depend on the type and concentration of toxins, and the duration of exposure.
Risks to Humans
Exposure can happen through skin contact, accidentally swallowing water, or inhaling water droplets or spray (aerosols) during activities like boating or water skiing.
- Skin Irritation: Rashes, hives, or itchy skin can occur after swimming or wading.
- Gastrointestinal Issues: Swallowing contaminated water might lead to stomach cramps, nausea, vomiting, or diarrhea.
- Respiratory Problems: Inhaling aerosols from affected water can sometimes cause coughing, wheezing, or shortness of breath, especially in sensitive individuals.
- Eye and Nose Irritation: Contact can cause redness, itching, or irritation.
Symptoms usually appear within hours or a couple of days after exposure. While most effects are temporary, repeated or high-level exposure can be more serious. If you believe you’ve been exposed and develop symptoms, rinse off thoroughly with fresh water and consider consulting a healthcare provider if symptoms persist or are severe, letting them know about the potential exposure.
Risks to Pets and Livestock
Animals, especially dogs, are often more vulnerable to HABs. They are more likely to drink contaminated water, even if it looks or smells bad. They may also lick algae off their fur after swimming. Even small amounts of toxins can be dangerous, potentially leading to severe illness or even proving fatal very quickly.
Signs of poisoning in pets can include vomiting, diarrhea, lethargy, weakness, staggering, drooling, difficulty breathing, or seizures. If you suspect your pet has been exposed to a HAB, rinse them immediately with fresh water (preventing them from licking their fur) and seek veterinary care without delay. Time is critical.
Staying Safe: Practical Prevention Tips
Enjoying summer water activities safely involves being observant and proactive.
Check Before You Go
Many local health departments, environmental agencies, or park services monitor water bodies for HABs, especially during warmer months. Check their websites or look for posted advisories at beaches and boat launches before heading out. These advisories provide the most reliable information about current conditions.
When in Doubt, Stay Out
This is the golden rule. If the water looks suspicious – if it resembles pea soup, has surface scum, looks discolored, or smells bad – do not swim, wade, or engage in activities that involve significant water spray. Find a different spot or choose a different activity for the day.
Keep Pets on Leashes Near Water
Prevent dogs from drinking stagnant, scummy water or swimming in areas where blooms are visible. Always provide fresh drinking water for your pets so they aren’t tempted to drink from the lake or pond. Rinse your dog thoroughly with fresh water after any swimming, even in seemingly clear water, just in case.
Avoid Water Skiing or Tubing in Blooms
Activities that create water spray increase the risk of inhaling toxins. Avoid high-speed water sports in areas where blooms are suspected.
If you do come into contact with potentially affected water, rinse yourself and your clothing thoroughly with clean, fresh water as soon as possible.
Be Careful with Fish
Toxins can accumulate in fish, especially in their organs. If you catch fish from water experiencing a bloom, rinse the fish well with fresh water and consider discarding the guts and liver before cooking and eating the fillet. Check local fish consumption advisories if available.
Reporting Suspected Blooms
If you encounter water conditions that suggest a harmful algal bloom, especially if no warnings are posted, consider reporting it. Contact your local health department, environmental agency, or park authority. Providing information about the location and appearance of the bloom can help officials investigate and issue advisories if needed, protecting others from potential exposure.
Summer and water go hand-in-hand, offering countless opportunities for recreation and relaxation. By staying informed about harmful algal blooms, knowing how to recognize the warning signs, and taking simple precautions, you can significantly reduce the risk and ensure your aquatic adventures remain safe and enjoyable for everyone, including your furry companions. Be aware, be cautious, and have a wonderful summer!
