For the second straight year, the acreage of local waters condemned for shellfish harvesting has shown a sharp decline.

The red areas on this map show the bodies of water in Gloucester and Mathews where fecal coliform concentrations exceed limits for safe harvesting of shellfish. Graphic by Daniel Powell / Virginia Dept. of Health.

In turn that 2009 figure was a sharp drop from the acreage of 12 months prior to that, July 1, 2008, which totaled 7,224 acres, according to figures prepared by the Virginia Department of Health, Division of Shellfish Sanitation.

However, a number of perennially dirty waters are always on the list, including Put-In Creek in Mathews, which was condemned in 1927—and has never been considered clean since. This closure occurred during one of Virginia’s first inspections of public waters, according to the Mathews Journal of Dec. 8, 1927.

Other bodies of water that usually appear on the list include Sarah’s Creek at Gloucester Point, large parts of the upper East River and Ware, North and Severn rivers, and many of the inlets off the rivers that form the Middle Peninsula. A map prepared by Daniel Powell, GIS analyst with the Division of Shellfish Sanitation, shows bodies of water in which shellfish harvest is condemned due to high concentrations of bacteria or due to the presence of marinas and wastewater treatment plants.

Cleaner this year, by not making the list after having been condemned in 2009, are Elmington Creek, Ferry Creek and Purtan Creek in Gloucester County, and Blackwater Creek, Dyers Creek and White’s Creek in Mathews.

One explanation for this year’s drop, according to Powell, could be accounted for by the dry spring and summer. Scientists note that reduced runoff means less pollution entering the tidal waters. Powell also said VDH changed its lab procedures in 2007 from a method that counted the most probable number of fecal coliform in a test tube, to a method that counts "the actual number of fecal colonies in a sample."

Condemnation is based upon a level of fecal coliform in the water considered unsafe, according to the Division of Shellfish Sanitation’s website. The state notes that while crabs and fish caught in condemned bodies of water are safe to eat, the harvesting of molluscan shellfish such as oysters and clams is prohibited from these waterways, as the mollusks "can concentrate bacteria and viruses" to a level that may pose hazards to persons eating them.

Most of these waters are also safe for swimming, the state said.

Monthly water samplings are taken to keep tabs on the cleanliness of local waterways, and those condemned for shellfish harvest are marked.

Complete details on condemnation areas can be found on the shellfish office’s website, www.vdh.virginia.gov, following links to Environmental Health and Shellfish Sanitation.

The table printed with this article shows comparative acreages of condemned areas in bodies of water listed in 2010 and/or 2009.

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