>Okay, let me see if I can explain the leaf thing to you.
Back in the 1800’s, leaves remained where they fell and became part of the soil (or they were burned). Nowadays, we put them out at the street and collect them. The reason that you want to keep them out of the storm drains and the connected rivers and streams is primarily twofold.
1. Degradation of leaves in a aquatic system requires oxygen. If an ecosystem is using all of its oxygen to break down organics (such as leaves), there’s none left for organisms that live there and they die which then reduces oxygen further.
2. Chemicals must be bound to organic particles to enter into the food chain. Once they are bond, they are now “bioavailable” meaning that they are available to certain little critters that live there. These are mostly bottom feeders, filter feeders, deposit feeders. The little worm ingests retains the organic portion including the chemical (bioaccumulation and, perhaps, biomagnification). A bigger worm the little worm, a fish east the big worm and you eat the fish.
Water bodies with high organic contents and high levels of fine grained materials have high contamination levels. You don’t see any contamination associated with sand because organics (and therefore chemicals) cannot bond to it.
The progress that’s been made since the Clean Water Act was enacted in 1972 is astounding. The reason that you might not hear about it is that the state of the science is so much more precise. We used to know that dioxin in the parts per million range was bad because that was the level we could test to. Now we can measure to parts per trillion and find that dioxin at 1 part per trillion causing a significant cancer risk. This is one example but it’s really the same with most other chemicals. You hear things are bad not because they haven’t gotten better but because we simply know more than we used to.
So you see that there really is a reason for attempting to schedule leaf pick-up.
And, by the way, I’ve heard contractor excuses for 25 years. When they wanted to retrofit diesels and wante them to use Ultra Low Sulfer Diesel all we heard was how everyone was going to go out to business. Guess what, after a few months, the cost of ultra low sulfer diesel dropped to within a few pennies of regular diesel. And those new engines, they’re more efficient so the contractors are SAVING money.
