The following is an excerpt from Science Friday:


A recent study  indicates that the nation’s waterways are contaminated with human-made chemicals that water treatment facilities often don’t remove. Researchers took water samples from 35 different rivers and streams and tested for the presence of 719 different chemical compounds—and found over 400 of the materials they tested for, including pesticides and pharmaceuticals. Another study found that runoff from roadway ice treatment is increasing the salt level in lakes.

IRA FLATOW: You have two stories about freshwater in the US lakes and rivers and such, and one looked at human-made chemicals in water. It was astounding.

SOPHIE BUSHWICK: Yeah, it was really upsetting. They tested for over 700 different human-made chemicals. And they found more than half of the chemicals they tested for were present in the water, and we’re able to have an effect on cells, which is really disturbing news. When you consider that 85,000 different chemical compounds are actually manufactured in the US, and so the number that they tested for was a fraction of what could be out there.

IRA FLATOW: What kinds of things did they test for– are we talking about here?

SOPHIE BUSHWICK: Well, the top 10 items that they would find were– eight of them were pesticides, and then two of them were pharmaceutical compounds, one of them was everybody’s favorite, caffeine, and the other was a compound that’s used to treat Type 2 Diabetes.

IRA FLATOW: So if, you know, I’m just thinking out loud now, so if you think you’re getting organic food and it has no pesticides or whatever, if it’s in the water that they’re using to process the food, then maybe you’re getting the stuff in there anyhow.

SOPHIE BUSHWICK: That’s a really interesting point. And then another thing is that water treatment plants don’t filter out every single one of those chemicals. So some of them could be getting through in the drinking water, as well.

IRA FLATOW: And so this is– in how many places did they say– 35 bodies of water?


IRA FLATOW: And so it’s all over the place.

SOPHIE BUSHWICK: Yeah, Yeah. They were testing a bunch of different bodies of water, and some of them in rural areas, some of them in urban areas, and then some of them farther away from human habitation. And they found–

IRA FLATOW: And there must be stuff they didn’t test for that’s out there?

SOPHIE BUSHWICK: Absolutely. There’s thousands of chemicals that they didn’t test for that could be present.

IRA FLATOW: Wow. You also have a related story that’s quite interesting about road salt.

SOPHIE BUSHWICK: Mm-hmm. So this was another study where they tested the water in lakes. And in this case, they were looking at lakes to see if they were getting saltier over time. And they found that if the lake– if 1% of the area around that lake had been paved, it was very likely that it was getting saltier. And the problem is, when it’s winter, people put salt on the roads to prevent ice from forming, and that’s getting washed into these lakes, and it could be causing problems because at a certain level of saltiness, plants and animals– native plants and animals to those lakes might not be able to survive.

IRA FLATOW: Not to mention what the salt is doing to your lawn, but that’s a different–


To listen to the entire episode Click Here (the water segment starts when the clock counts down to -5:35 minutes)


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