Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: Geezer on 10/06/2011 05:05:30

Title: What does MCL stand for?
Post by: Geezer on 10/06/2011 05:05:30

For some unknown reason I was elected to "Senior Executive Vice President in Charge of Water Sampling" for our community well.

Once a year, for equally unknown reasons, we have a water sample tested for the presence of nitrate. I did this quite recently, and the report came back indicating the sample contained 0.13 mg/L of the evil stuff. On the form there is a column adjacent to the result titled "MCL". Apparently this is the acceptable limit, and the MCL for nitrate seems to be 10 mg/L, so we seem to have squeaked past for another year.

At no place on the stinking form does it actually say what MCL stands for. It's obviously a TLA* known only to those skilled in the art.

I even looked here

http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=bf36597e4e385db2d9765f011e7fb73f&rgn=div8&view=text&node=40:22.0.1.1.3.3.16.3&idno=40

to no avail. Anybody know?


*Three letter acronymn

Title: What does MCL stand for?
Post by: CliffordK on 10/06/2011 06:04:08

My guess is that you would not be talking about a minimum.

So...  a quick internet search suggested....

Maximum Concentration Level (or Limit)
Maximum Contaminant Level/Limit

Title: What does MCL stand for?
Post by: Geezer on 11/06/2011 05:14:34

Yippee! "Maximum Contaminant Level" is correct.

http://water.epa.gov/drink/contaminants/#List

I will encourage the testing lab to add the definition to their @#$%^&* form.

Title: What does MCL stand for?
Post by: CliffordK on 11/06/2011 05:22:24

I hadn't thought much about nitrate in the well water.

Are you in an area exposed to significant amounts of agricultural runoff?

I suppose most other contaminants such as heavy metals don't change very much over the lifetime of the well.

The primary risk of NO₃ is apparently with infants.

Title: What does MCL stand for?
Post by: Geezer on 11/06/2011 05:39:15

Quote from: CliffordK on 11/06/2011 05:22:24

I hadn't thought much about nitrate in the well water.

Are you in an area exposed to significant amounts of agricultural runoff?

I suppose most other contaminants such as heavy metals don't change very much over the lifetime of the well.

The primary risk of NO₃ is apparently with infants.

There is some agriculture in the area, but none within a one mile radius of our well. The only required tests for our little system are quarterly coliform, annual nitrate, and a nitrite test every nine years.

We are fortunate to have a plentiful supply of really excellent water, and because it's a small system, we don't have to alter it in any way.