Approaching some water quality problems with modest tools


This time of year, and with the weather as scorching as it has been, swimming is the most refreshing antidote to overheating and hot tempers. For several years, Islanders and their guests have been bewildered and harried mercilessly by intermittent beach closings of Martha’s Vineyard beaches and ponds. No one believes that ocean beaches and fresh water ponds on the Vineyard are generally unhealthy loci for disease and pestilence, but the Whack-a-Mole craziness of it has taken the carefree out of summer for many of us.

Consequently, it is welcome news that, as Times writer Steve Myrick has reported, “water quality data collected over the past five years shows that Sengekontacket Pond is improving since two major dredging projects changed the circulation flow inside the popular salt pond, according to local shellfish wardens.” Those projects, the first in 2008, cost hundreds of thousands of dollars, and water quality changes for the better take time.

We know the culprit in some of the contamination that the state’s regimen of testing is designed to detect results from foul surface runoff from roads, beaches, and surrounding property. The contamination follows significant rain and lasts for brief periods. This seems to account for the recent closings at Uncle Seth’s Pond, an intimate, friendly, prized, and generally safe setting for families with small children.

While the road along Sengekontacket is long, so that the opportunity for surface runoff into that pond is great, at Seth’s the pond’s exposure to the nearby road is limited. It may be possible, with some drainage and road construction work to overcome the runoff contamination problem, to limit these timeouts for families and kids. It’s worth considering.

But, the problem is complicated and although not dire health-wise, it may seem so. Apart from sea and pond water, beach sand harbors “a rich bacterial community,” in the words of Elizabeth Halliday, a biological oceanographer associated with the Woods Hole Oceanographic Institute and the Massachusetts Institute of Technology. Ms. Halliday describes these communities as “generally harmless.”

A review of some of the literature related to enterococci and e-coli contamination finds that, while the state’s acceptable levels of contamination and consequent actions may be sensible in a macro sense, they are hardly based upon a conclusive understanding of how the bacteria can exist in unacceptable concentrations in an ocean beach one day and be safely absent the next. Plus, the actual existence of dangerous pathogens in the ocean water where the bacteria are detected is not generally measured.

As we have reported, Ms. Halliday, speaking about the work that’s been done to measure concentrations of bacteria in beach sand, the more one messes with the sand, the greater the risk of illness. “…in total,” she added in an earlier interview, “the incidence of these (generally minor) illnesses is very low…one or two extra illnesses per thousand above the baseline ‘normal’ rate.

“The good news is that we don’t tell people to stay off the beach, but by understanding this slight increase in risk, we can take steps to reduce our exposure — like taking time to wash our hands before eating or showering off after being buried in the sand.”

Understanding such sensible risk assessments and aware of appropriate prophylactic strategies, beachgoers will on their own be able to guide their reasonable use of Island beaches.

That may be so, but tests that show high levels of enterococci bacteria, above the state standard for safe swimming, do nothing to inspire confidence in swimmers or their parents.

According to the Massachusetts Department of Environmental Protection (DEP), such bacteria are indicator organisms that may signal fecal coliform bacteria contamination. High levels of enterococcus can cause skin irritation, vomiting, or diarrhea. Nothing inviting about that.

Of course, the post-dredging water quality results from Sengekontacket signal better circulation in the pond and consequently a better environment for shellfish. Sengekontacket Pond is not a popular swimming venue. And the dredging work did not affect nitrogen levels in the pond, which is a problem that is plaguing surface water bodies across the Island, whether they are flushed by tidal action or not.

The threats to water quality — for drinking, swimming, fishing and shellfishing — will require increasing levels of public attention. And, they will demand a variety of strategies, some but not all very expensive to address. Where significant improvement can be made in the near term at modest cost — dredging, for instance, as at Sengekontacket, or perhaps road reconstruction adjacent to Seth’s Pond — we ought to get on it.