A Deeper Look at Lake Whetstone's Dredging

On Dec. 13, county officials held a public meeting to address the proposed dredging of Lake Whetstone and the depositing of the dredge material (spoil) on a Northgate recreational field. The meeting was chaired by Montgomery County's Director of Environmental Protection, Bob Hoyt. The speakers included his staff and representatives from the Whitney Bailey Cox & Magnani LLC consulting firm.

The meeting was the County's account of the facts and disposition regarding the planned dredging and handling of the dredged material (spoil). Mr. Hoyt quickly got to the point: the dredging will occur -- however, testing of the sediment to be dredged indicates that it exceeds state law limits for a set of contaminants. The spoil material will not be deposited on recreational fields or anywhere else in a residential area.

The contractor hosted the rest of the discussion. Whenever any subject bordered on health and safety, the contractor's "scientist" spoke. The individual was very articulate. His performance reminded me of a professional witness, a trial specialist who is knowledgeable and skilled enough in a subject to raise doubt with a jury. He did not explain the only detailed Powerpoint slide shown and led a discussion that would indicate that all is well, there is no reason for concern - without addressing the obvious question, "if it is so safe, why is it illegal to place it in a residential area?"

We were provided facts that often had little to do with the issue at hand. For example, when speaking to the hazard of the level of polycyclic aromatic hydrocarbons (PAHs) found in the sediment at Lake Whetstone, the scientist indicated that they were within range of similar areas. One may be led to think that this means it is safe level. It is not.

Lake Whetstone is a stormwater retention basin designed to reduce downstream erosion by controlling flow rates and to capture pollutants picked up from nearby impermeable surfaces (roofs, sidewalks, roads and parking lots). These surfaces pick up and concentrate many dangerous chemicals, mostly from vehicles including petroleum products (gas, diesel and oil), coolant, solvents and pollutants that wash out of the air such as PAHs. A retention basin provides a large enough area for these contaminants to settle out of the water where they aggregate on the bottom. These contaminants can reach dangerous levels when aggregated in one area. So, saying that Lake Whetstone's levels were midrange to similar areas is like saying that the "asbestos level found was similar to other areas having asbestos" while deflecting any discussion to the fact that the PAH levels found exceed legal limits for fill material allowed in a residential area.

When speaking to the levels of sediment fecal coliforms, which also exceed health standards, the specialist turned our attention to the goose population. However, he did not indicate that the geese caused the fecal coliform levels. Any fecal material that the inflowing water came into contact including pet feces may have caused it. Fecal Coliform levels may also indicate a sewage leak from the nearby sewer systems. While the source of the fecal coliform levels is important, the discussion we wanted to hear about was the threat to our health and safety. We got nothing.

A good question was asked about the safety of eating fish caught in Lake Whetstone. The answer we got was that could not be determined without doing studies of the fish but there was no indication that such tests would occur. (A good project for the high school biology department.)

When the discussion of the heavy metal levels found came up, the specialist pointed out that these chemicals are found naturally in our environment. This is true; however, it is the aggregation of these heavy metals that make them a threat to health and safety. In areas of the country where arsenic levels are high, we do not drill wells -- we avoid the arsenic. We do not spread it out on recreational fields so that our children can come into regular contact with it.

What the consultants didn't say, even though they were prompted by a question asked by a Lake Whetstone community member, is that the contaminants likely pose little to no health risk to the community around Lake Whetstone. The contaminant levels only exceed health standards where they aggregate at the bottom and in the sediment below the "lake." The same material that was to be spread on our recreational fields.

The bottom line for the Village: A small portion of Lake Whetstone will be dredged and the dredged material will not be placed in any area within the Village. Because the level of contaminants found surprised our public officials, they established a new policy requiring testing of all future dredging sites before determining what's to be done with it.

So, "thank you" to the neighbors who objected to spreading the spoil on our recreational fields and demanding additional study.