Re: Lake/Freshwater Pollution
I am not too sure about chemical pollution in present times. I know it was a problem years ago and it still is, but I am not too sure exactly what chemicals are the problem now.
Yes I am obsessed with this topic...almost freakishly obsessed.
I don't know for sure, but I would think that it comes from both industrial and residential. One of the things I know for sure is that many fertilizers and things get into the water when it rains.
A big problem I know of is invasive species. One that is common where I live is Eurasian Watermilfoil. http://www.ecy.wa.gov/Programs/wq/plant ... lfoil.html
We have laws against invasive plants here. (But unfortunately, they are difficult to inforce). At every boat dock/landing there are signs telling you to inspect and clean your boat and trailer before entering a new lake.
The invasive plants tend to grow very well and they take over the native vegetation. Eurasian milfoil is thick so it prevents fish from breeding properly. It can reproduce sexually and asexually. When boats chop it up, each fragment can make a new plant. Then those fertilizers don't help any!
There are many ways to control it, including herbicides. But I don't like herbicides. They'll kill any vegetation. People claim that they will "minimize" the effects on the native plants, but now you're just putting more chemicals in the water. Really, just hand-pulling it is extremely effective.
But yeah, that's one major problem, at least in lakes around here.