In his excellent commentary, "When it comes to animal waste disposal, cheap is costly," (October 2009), Lynton Land alluded in passing to the land application of sewage sludge (The reference to sewage sludge as biosolids is used by the multimillion-dollar sludge industry and their advocates, including regulatory agencies, to put the best possible face on this pollutant.)

As an adjunct to his presentation, an analysis of sewage sludge and its impacts on the Bay needs to be examined.

The "Harper Collins Dictionary of Environmental Studies" defines sludge as "A viscous, semi-solid mixture of bacteria and virus-laden matter, toxic metals, synthetic organic chemicals and settled solids removed from domestic and industrial waste at sewage treatment plants."

Seven million dry tons of sludge are produced annually in the United States by the thousands of treatment plants operating around the clock. An undetermined number of the estimated 100,000 biological and chemical elements or compounds that exist or are produced in the nation can reasonably be expected to end up in the waste stream flowing into sewage treatment plants.

Sewage sludge is currently disposed of by incinerating it, using it in landfills or spreading it on land, mostly farmland. The latter is the most prevalent means of disposal because it is the least expensive or the most expedient mode of disposal. But of the three alternatives, it presents, by far, the greatest health and environmental risk.

Sludge is an equal opportunity pollutant-it impacts or degrades the air, water and land.

Most classes of sludge represent such a threat to human health that in Pennsylvania, public access to a sludged site must have a warning sign. Some sites are restricted for up to a year.

A significant and growing number of respected scientists and agencies/organizations have raised serious concerns regarding the spread of sludge on farmland.

For example, the "Cornell University Guide for Integrated Field Crop Management" states that the heavy metals, toxic organic chemicals (PCBs, for example) and the pathogens contained in sludge are "particularly toxic to both animals and humans."

U.S. Geological Survey scientists found that "a variety of pharmaceuticals and household chemicals are contained in sewage sludge." The same agency recently found 25 chemicals in earthworms collected from sludged fields. Caroline Snyder, Ph.D., a professor emeritus at the Rochester Institute of Technology, has concluded, as a result of her studies, that "serious illnesses, including deaths, and adverse environmental impacts have been linked to land application of sewage sludge."

The Pennsylvania Department of the Environmental Protection has claimed sole permitting and management authority in regard to the land application of sludge. This agency has refused to permit local governments any authority to enact even complementary or supplementary regulations to govern sludge application to protect their residents or the sustainability of farmland.

The stringent standards enacted by the Board of Supervisors in Shrewsbury Township, PA, will likely be expunged under threat of a suit by the state's attorney general.

Both the EPA and the DEP claim that sewage sludge is a "fertilizer" primarily because in addition to the organic material, it also contains nitrogen and phosphorus.

Tons of sludge is applied per acre, depending on the nitrogen needs of the crop. Frequently, this is field corn, which requires approximately 200 pounds of actual nitrogen/acre. This usually results in excessive amounts of phosphorus being applied.

In Shrewsbury Township, recent sludge applications on farmland were not incorporated into the soil profile, but remained on the surface and were subject to accelerated runoff into local streams and ultimately, the Bay.

In addition, a percentage of the nitrogen being applied was lost to volatilization caused by being exposed to open air.

If any lingering doubt exists as to whether sewage sludge is a bona fide, safe fertilizer-why do sewage treatment plants have to pay about $50 a ton to entice sludge disposal brokers to haul it away from the treatment plants? Why do these brokers have to pay unsuspecting farmers to accept it?

The DEP's regulation and overall management of sludge on land is woefully inadequate to protect the watersheds of the Bay.

For example, sewage treatment plants are required to test for only 11 of the many thousands of pollutants contained in sludge.

And then, to make matters worse, the testing schedule at the facilities-which in some cases is only once a year-is flawed as each load delivered to the spreading site needs to be tested, because the constituents or components of raw sewage flowing to treatment plants varies appreciably from hour to hour, day to day.

In the past, a primary means of sewage sludge disposal along the northeastern coast of the United States consisted of ocean dumping.

This impacted the marine environment and beaches. Environmental groups were outraged and Congress was forced to prohibit ocean dumping.

The stakeholders, which is all of us, with an interest in a healthy Bay should be equally outraged with the practice of dumping sludge on farmland.