The Virginia Department of Environmental Quality (DEQ) is holding meetings to formulate a “Total Maximum Daily Load (TMDL) Implementation Plan” to reduce bacterial concentrations in the Yeocomico River. A decade ago DEQ submitted bacterial (not nutrient!) TMDLs to EPA for all coastal plain creeks and rivers. DCR (VA Dept. Conservation and Recreation) was supposed to be responsible for the subsequent “Implementation Plan.” That seems to have changed.
Bacterial concentrations in excess of 14 MPN per 100 milliliter of water (think of that as 14 colonies of bacteria per half cup) restrict the harvesting of shellfish. 14 MPN is far below bacterial concentrations that are dangerous for swimming. Areas restricted for the harvesting of shellfish are always, without exception, present only at the headwaters of creeks.
What is the source of the bacteria? When a pollutant exists, most sensible people trace it back to its origin by following increases in concentration. In this case that leads to the headwaters of the creeks where there is forested or farmed land and few houses. Most houses are nearer the mouths of the creeks where the water (with few bacteria) is deeper, more saline, and there is easier access to the Bay. Irrespective of location, almost all human waste enters septic systems, so few bacteria could be sourced from human residents. Livestock are uncommon, and are certainly not uniformly distributed as are the areas restricted for shellfish harvesting which, literally, include the headwaters of every creek in the coastal plain (maps are available at www.vdh.virginia.gov/environmental-health/shellfish-sanitation/). There are a few free-roaming dogs, but it is obvious that the major source of bacteria must be wildlife like deer, raccoons, possums, foxes, squirrels, geese, herons and other birds, etc.
How do the bacteria get into the water? Runoff. I have a complete rainfall record for the Little Wicomico River, where I live. I compared rainfall to bacterial concentrations measured by VDH Shellfish Sanitation and found that heavy rainfall, accounts for most of the “spikes” in bacterial concentrations. The data are presented in the file <L_wic_bacteria.pdf> on the “Bacterial Pollution” page at my web site, www.VaBayBlues.org along with the voluminous previous correspondence with DEQ.
Why is the bacterial TMDL needed? It is not. Nobody in their right mind would try to grow oysters commercially in restricted water in the headwaters of the creeks because salinity fluctuations and sluggish currents result in slow growth. Additionally, to sell the oysters they must be “relayed” to uncontaminated water according to the Virginia Administrative Code (4VAC20-310-20), which significantly decreases profitability (I know because I’ve done it).
To make matters even more ridiculous, there is a huge source of human bacteria that DEQ refuses to acknowledge. Class B municipal sewage sludge spread on fields as “free” fertilizer can legally contain up to 2 million MPN per dry gram, or up to about 10 trillion bacteria in each 20 ton truckload, about the amount disposed on each acre. Poultry litter disposed by land application also contains fecal coliform bacteria. Thus there is absolute certainty that bacteria in sludge and litter are being imported into watersheds where restrictions for the harvesting of shellfish exist because of elevated bacterial concentrations. Do the bacteria get into the water? Certainly. There exists a huge literature on the role of seagulls as vectors of pathogen transport from wastewater treatment plants and landfills to water. No competent scientist could doubt that gulls foraging on fields where sewage sludge and poultry litter have been disposed transport pathogens to water. To make matters still worse, sewage sludge and poultry litter are extremely inefficient “fertilizers” compared to chemical fertilizers. In the case of sludge only 30% of the nitrogen is deemed “crop available” so that if the crop needs 150 pounds of nitrogen per acre, 500 pounds of nitrogen is legally applied using sludge. What do you suppose happens to the 350 pounds of nitrogen per acre that is not sequestered in the harvested grain?
DEQ should be concerned with the nutrient pollution of rivers and the Bay and not waste tax dollars on bacterial concentrations that can’t be eliminated and don’t matter. Most of the nitrogen and phosphorus pollution of Chesapeake Bay is of agricultural origin. Why is nutrient pollution from the cheap disposal of sludge and litter by land application being ignored? The answer is very simple, in my opinion. Politicians dictate what government agencies do, and the Chesapeake Bay does not make campaign contributions.