Quarry Lake Environment Report

Quarry Lake Environmental Report

The Shakopee-Prior Lake Waterski Association and the City of Shakopee have undertaken separate water quality and environmental studies of the site. Analysis of the studies showed that there are small amounts of Diesel Range Organics contaminants in the lake water. Here is more information about this finding.
Diesel Range Organics (DRO) could include, for example, fuel oil or diesel fuel. A finding of small amounts of DRO in Quarry Lake is not particularly surprising, because site was formerly an industrial quarry. The environmental study measured 640 ug/L DRO concentrations in the northwest corner of the land, and 130 - 150 ug/L in two specific locations in the water. We believe that these measurements may be from one or both of two spills in the area that were reported to the Minnesota Pollution Control Agency (MPCA) over the past 20 years or so. The MPCA supervised clean-up and closed both cases because all of the clean-up requirements were met.

The big question of course, is what these measurements mean. We sent a letter to the Minnesota Department of Health to get a handle on the meaning of these measurements. Here's what we have learned from their response:

The Department of Health for the State of Minnesota has set a "Health Based Value" (HBV) of 200 ug/L for DROs. The 200 ug/L HBV is set as a guideline. The highest Quarry Lake DRO water measurement is 150 ug/L, below the HBV guideline. We've learned further, however, that the Minnesota Department of Health's HBV of 200 ug/L for DROs assumes daily consumption of two liters of drinking water containing DRO over a long period of time – from several years to a lifetime. Generally, higher exposures can be tolerated over the short-term. Only in an extremely unusual circumstance would recreational use of water result in even a one-time consumption of two liters in a single day.

Further still, recreational use of the Quarry Lake water allows the possibility of dermal (skin) and inhalation (breathing) exposure. The HBV, however, is derived to allow for routes of exposure in addition to oral ingestion. The Minnesota Department of Health (MDH) tells us that in deriving an HBV, only twenty percent of the total allowable exposure is allocated to drinking water, thus leaving eighty percent for exposure through other routes.

No activity on our good green earth is without risk, and using the water at Quarry Lake is no different. By becoming a Shakopee-Prior Lake Shockwaves member, you are agreeing to use Quarry Lake at your own risk. While the DRO measurements in Quarry Lake are likely higher than what would be found in a public lake, however, the MDH tells us that the Quarry lake DRO measured amounts are small, and it is highly unlikely that those levels would pose additional risk to water-skiers.

If you have concerns or questions about these DRO measurements, please contact anyone of us by phone or e-mail. We would be happy to share the environmental report with any member who wants to see it.

For your information, we are including in an attachment text from response letter we received from the MDH. Please read the letter below.

Please let us know if you have questions, comments, or concerns.

Thank you.

Sincerely,
Your PLWSA 2005 Board of Directors

Here is text from a February 23, 2005 letter from the MDH regarding this issue:

---- Original Message -----

From: Anne Kukowski
To: John Davis
Sent: Wednesday, February 23, 2005 2:00 PM
Subject: Re: Fwd: DRO Specialist Advice

Dear Mr. Davis.

The Minnesota Department of Health's (MDH) Health Based Value (HBV) of 200 ug/L for diesel range organics (DRO) assumes daily consumption of two liters of drinking water containing DRO over a long period of time - from several years to a lifetime. Generally, higher exposures can be tolerated
over the short-term. Only in an unusual circumstance would recreational use of water result in even a one-time consumption of two liters in a single day.

Water skiing allows the possibility of dermal and inhalation exposure. Although I am not aware of any specific values setting health based limits for inhalation and dermal exposure to DRO, the HBV is derived to allow for routes of exposure in addition to oral ingestion. In deriving an HBV, only twenty percent of the total allowable exposure is allocated to drinking water, thus leaving eighty percent for exposure through other routes. It is therefore highly unlikely that DRO at the levels you cite would pose any risk to water skiers.

Sincerely,

Anne Kukowski

Anne Kukowski, M.S., J.D.
Minnesota Department of Health
Division of Environmental Health
121 East Seventh Place, Suite 220
St. Paul, Minnesota 55164-0975

Questions or Comments? Contact: waterskier@priorlakewaterski.org