What’s Safe To Put in a Lake? - from IISD Experimental Lakes Area

By Matthew Klachefsky, Manager of Education and Indigenous Relations, IISD Experimental Lakes Area

(AKA, If a Moose Can Pee in the Lake, Why Can’t I?)

Matthew Klachefsky - King of Compost

In my years as a camp director, I have heard many stories about what isn’t good to put in a lake. I’ve told kids to not bathe with soap in a lake, I’ve told them to walk thirty yards into the woods before they relieve themselves, which means absolutely no going off the side of the canoe -  paddle to the nearest island and do your business there, please.

I’ve enforced all of these rules but I’ve never really been able to answer the question of why these actions are harmful. Luckily, I now work with a bunch of incredibly smart scientists who have dedicated their lives to understanding lakes and how human activity affects lakes, and I recently got the chance to sit down with Dr. Scott Higgins, Senior Research Scientist for IISD-ELA, and ask him some questions that would help me understand how human activity at camps can affect a lake.

Urine: Lake Danger Rating of 4/10

Starting off with the ultimate question: Fish pee in the lake. Beavers pee in the lake. Deer pee in the lake, one assumes. What’s the big deal if people do it?

Let’s backup first. There will be a common thread in all of these categories, which is if one person was to do any of these things just one time, it probably won’t make a big difference. But remember: your behaviour creates a ripple effect over the people around you, so if you don’t explicitly have messaging that says it is not good to pee in a lake, and you aren’t specifically avoiding doing it yourself, you can pretty much assume a lot of people are peeing in a lake. That is when it becomes a problem. If you’re someone who tells themselves “it’s OK if I do it, I’m only one person,” you can assume that everyone else you see is thinking the same thing.

Here’s the other interesting thing I learned from my chat with Dr. Higgins: when we think about what make a lake suffer, we usually think about pollution like chemicals or poisons or refuse from factories; killing all the creatures they touch. But the thing that often causes the most chaos is actually naturally occurring nutrients like nitrogen, potassium, calcium, and phosphorus. A healthy lake is one that has a balance of these nutrients, but when that balance is thrown off you’ll have one organism multiplying at a higher rate and dominating over the others, that is when the problem occurs. 

One of the nutrients that causes the biggest problems is phosphorus, which is a mineral that can be found in urine. When a lake has too much phosphorus, algal blooms can occur, and the lake suddenly becomes a giant bowl of green pea soup. While Algal blooms are pretty nasty and unhealthy to swim in, but they also cause real damage to the rest of the lake by creating toxins, blocking sunlight, and depleting oxygen. This makes it difficult for other organisms to live in the lake, including fish.

Find out more about the Experimental Lakes Area’s research on phosphorus and algal blooms here! 

Soap: Lake Danger Rating 6/10

Soap is one that I have always found myself making rules for but never really understanding why. “Because soap is bad for lakes!” But why is soap bad for lakes? I just want the campers to not stink, is that such a problem?

The answer is surfactants. Soap is a surfactant, and while it helps us keep our bodies clean, it causes a lot of problems for the creatures in a lake.

For one, surfactants alter the surface tension of the water. This is a problem for Gerridae (AKA Water Striders), you see scooting across the surface of the water. If they don’t have that surface tension they sink and drown. Water striders are an important part of the food chain, so if there’s less water striders, there’s less food for fish, which means those fish will starve or die out, which means less fishing for us humans. 

Gasoline: Lake Danger Rating 8/10

We’ve all seen the pretty rainbows that spread out when you accidentally get a drop of gas into the lake. We know it’s bad, but why is it bad?

This one is your classic case of straight-up pollution. While a drop of gasoline won’t affect a fish on it’s own too terribly, it can absolutely decimate any insect population that comes near it. It would be as if all the air around you was suddenly replaced with a poisonous gas, the insects would be pretty dead pretty quickly. And once again, disruptions at the bottom of the food chain will affect those at the top so if there’s no bugs for fish to eat, there’s no fish! Don’t spill gas in a lake! Refuel on land!

During my chat with Dr. Higgins he pointed out a very important point: while gasoline is obviously very unhealthy for a lake, the boats that they power aren’t exactly beneficial either. Motorboats cause wakes that lead to soil erosion and their propellers can kick up the sediment under the lake causing an increase in turbidity (murkier water). Something to consider next time you plan on taking out a motorboat.

Food: Lake Danger Rating: 5/10

Let’s say you’ve just finished a long exhausting paddle and you raft up to plunder a bag of trail mix. You pass the bag from person to person and oops! A handful of nuts and raisins falls into the lake, never to be seen again. Does this mean there’s more food for the fish to eat? Surely that’s not a big deal… right?

Well you haven’t killed the lake, but it’s not great. The food that doesn’t float will sink to the bottom and it will take a long time to biodegrade. It will slowly decompose and as it does, bacteria will form on it. Sometimes that bacteria can be good, and be the building blocks for the food chain but often that bacteria can lead to diseases in the local organisms. 

Sunscreen: Lake Danger Rating 5/10

This one hurts! But it’s true, with all the effort we’re putting in to be sun safe and constantly getting campers to slather themselves with sunscreen every 20 minutes, sunscreen is not healthy for lakes. Unfortunately, most sunscreens are toxic to smaller organisms. 

While we aren’t suggesting campers shouldn’t wear sunscreen, there are steps you can take to mitigate the damage that they will cause to fresh water sources. Encourage your campers to apply sunscreen well before going for a swim so that it has had a chance to absorb into their skin, and don’t apply right before jumping in. Also encourage the use of hats and long sleeve swim shirts that will cover their skin to keep them safe from sunburns. You can be lake safe and sun safe at the same time, but it takes a little planning.

Cleaning Products: Lake Danger Rating 6/10

This one is kind of a trick question, because I would like to assume that no one reading this is intentionally adding cleaning solutions to a lake, and if you are, stop doing that. But I used the word intentionally, and that carries a lot of weight because the bad news is if you are using cleaning solutions like Lysol, Mr. Clean, or anything that contains something called quaternary ammonium compounds (QAC or Quats), some of it is being added to lakes, and it is causing some problems.

When you pour a cleaning solution down a drain, it will end up at a water treatment plant, either one you have on site like a septic field, or a municipal treatment plant somewhere further down the line. And while those plants are good for treating sewage, they cannot rid the water completely of QACs. That means those chemicals will be released out to lakes and rivers.

“OK” you say, “then I won’t pour any chemicals down the drain.” That’s great, but any chemicals that go onto the ground or anywhere else, will eventually get back to freshwater sources. The best way to avoid this is to minimize use of these types of products. Some alternatives are vinegar, which is a natural cleaner that can disinfect surfaces, or using a bleach and water mix as bleach will biodegrade over time.

The Experimental Lakes Area (ELA) is doing a study on this very topic as we speak, and you can read about it here.

Rocks: Lake Danger Rating: 0/10

Take a rock. Throw it as high up in the air as you can over a lake. Take another smaller rock. Throw that second rock and try to hit the first rock as it descends. Do this for the next three hours. Congratulations, you now know how to play Rock Rock, the game that is sweeping the nation, and it is 100% lake safe. Have fun!

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Matthew Klachefsky is the Manager of Education and Indigenous Relations at IISD Experimental Lakes Area. He has also worked 18 summers at summer camp all over the world including nine years as director of YMCA-YWCA Camp Stephens in Kenora, Ontario. 

He can be reached at mklachefsky@iisd-ela.org.