WASHINGTON, DC, July 15, 2014 -- According to new reports published by the Environmental Integrity Project (EIP), phosphorus and algae concentrations remain high in rivers on Maryland's Eastern Shore and have shown little improvement in the last decade.
The two new reports, titled "Poultry's Phosphorus Problem and Murky Waters: More Accountability Needed for Farm Pollution in the Chesapeake Bay," provide an analysis of trends in phosphorus pollution levels from 2003 to 2013 in the eight major waterways on Maryland's Eastern Shore. According to state monitoring data, phosphorus pollution levels have worsened at monitoring stations in three rivers -- the Nanticoke, the Sassafras and the Transquaking.
Between 2011 and 2013, average spring and summer concentrations of total phosphorus exceeded University of Maryland Center for Environmental Science benchmarks for healthy waterways at 16 out of 18 monitoring stations in the eight Eastern Shore rivers. The phosphorous levels surpassed these benchmarks by 338 percent in the Manokin River, 160 percent in the Transquaking, 69 percent in the Chester, 64 percent in the Sassafras, 50 percent in the Wicomico, 47 percent in the Upper Choptank, 21 percent in the lower Pocomoke, and 15 percent in the Nanticoke.
Phosphorus pollution spurs excessive growth of algae, which then dies and creates low oxygen "dead zones." Concentrations of spring and summer chlorophyll-a (an indicator of algae) were much higher in the Eastern Shore rivers than thresholds for healthy waterways. In 2011 to 2013, average spring concentrations of chlorophyll-a exceeded these thresholds by 1,152 percent in the Transquaking River, 368 percent in the Manokin and 51 percent in the Upper Choptank, according to the EIP analysis of Maryland data.
These high pollution levels are in rivers surrounded by 1,339 chicken farms that generate over 500 million broilers and at least 1 billion pounds of manure per year, according to the U.S. Department of Agriculture and state data. The waste contains an estimated 30 million pounds of phosphate. The agriculture industry is the largest single source of pollution in the Chesapeake Bay, contributing 57 percent of the phosphorus pollution, 42 percent of the nitrogen and 59 percent of the sediment in the estuary in 2013, according to the EPA Chesapeake Bay Program.