Summary for Monday February 15th

Today we began with a look at some of the resources that we can use to learn/study water quality both locally and nationally:

1. EPA Superfund sites where you live
2. USGS WaterQualityWatch
3. EPA TRI
4. Maury Service Authority Water Quality Report

We then looked at the results of the survey that you took a few weeks ago regarding the source of your water at home and how these results compare to national averages for the US. Before moving in to a discussion of the contaminants in drinking water that are tested/regulated by the EPA, we looked at a recent study by the USGS that looks at the quality of water from a sampling of private domestic wells that provide water to 15% of Americans (and 22% of the class). You should be familiar with the key findings of this study.
We then moved on to a discussion of the 89 contaminants that the EPA regulates in public drinking water. You should know how the list is broken down (7 microorganisms, 7 disinfectants & disinfection biproducts, 16 inorganic chemicals (mostly toxic 'heavy' metals, and 55 organic chemicals). We then looked briefly at the Contaminant Candidate List 3, "a list of contaminants that are currently not subject to any proposed or promulgated national primary drinking water regulations, that are known or anticipated to occur in public water systems, and which may require regulation under the Safe Drinking Water Act” the CCL 3 contains 116 candidates contaminants including 104 chemicals or chemical groups (mostly organic compounds) and 12 microbiological contaminants. We finished with a look at the "toxic iceberg" which suggests that the number of proven toxic substances in our environment is small relative to the number of substances that have been partially proven to be toxic or whose toxicity has not yet been or will never be recognized. From this discussion, you should be able to define and discuss: TRI, MCL, MCLG, and human health benchmark.

The end of today's lecture marks the end of the material that will be on the midterm. Material covered in class on Wednesday and Friday (and readings for both days) will not be on the midterm.

For lecture on Wednesday, please read:

That Tap Water Is Legal but May Be Unhealthy by Charles Duhigg (free registration possibly required)

Reactive Nitrogen: The Next Big Pollution Problem by Brandon Keim

The my maps page has been updated with the locations mentioned in today's lecture.

Slides shown in lecture today have been posted as a .pdf to Sakai.

There will be a review session for the midterm at 8:00pm Tuesday night in AG14 (our class room).