CHAPTER 2 - CCAMP STUDY AREA: TOWNS OF BARNSTABLE AND EASTHAM 



Cape Cod Aquifer Management Project Page 14 



characterized by their high biological- and chemical -oxygen demand, high 

 concentration of pathogens and chemical contaminants such as metals, nitro- 

 gen, phosphorus, sodium and volatile organic hydrocarbons. They therefore 

 have the potential to degrade groundwater quality to both private- and 

 public-supply wells. 



2.5.5 On-Site Wastewater Disposal 



Over 90 percent of the homes on Cape Cod use on-site subsurface sys- 

 tems for disposal of wastewater (CCPEDC, 1978; Gallagher and Nickerson, 

 1986). Until 1977 when Massachusetts adopted its minimum requirements for 

 the installation of on-site-disposal systems (Title 5), homes on Cape Cod 

 were equipped only with cesspools. These systems provide no separation or 

 treatment of effluent. While septic systems are a technological 

 improvement, in terms of siting and design, the only significant 

 improvement with respect to groundwater quality are bacterial and viral 

 filtration. Additional pollutants of concern that are not removed are 

 nitrogen species and synthetic organic hydrocarbons. Numerous public 

 water-supply test results show a distinct correlation between housing 

 density and nitrogen (nitrate) concentration in the well water. 



2.5.6 Fertilizer Use 



Nitrogen loading to groundwater from fertilizer application is an 

 additional significant source of groundwater contamination. While leach- 

 ing rates vary depending on a host of site-specific environmental factors 

 and on nitrogen application rates to crops and turf, the average has been 

 estimated at 1 . 8 pounds /year/1000 square feet of fertilized area (CCPEDC, 

 1978). Depending on lawn size, leaching from fertilizer application can 

 be a significant factor in contributing nitrogen to groundwater. The 

 recent increase in commercial lawn care services indicates that a 

 substantial number of Cape Cod residents actively maintain their lawns 

 with fertilizer. 



2.5.7 Pesticides 



Pesticide contamination of groundwater resources remains largely un- 

 characterized on Cape Cod. While limited testing of some public- and 

 private -supply wells, as well as an EPA/CCPEDC study of groundwater 

 quality beneath Cape Cod golf courses, have not identified significant 

 concentrations of pesticides, a data gap exists with respect to this 

 potential source of groundwater-quality degradation. Geologic and 

 environmental conditions on Cape Cod indicate the area is conducive to 

 pesticide leaching. A relatively high rate of recharge, combined with 

 sandy soils, shallow depths to water table and localized spots of elevated 

 nitrate -nitrogen in groundwater put the peninsula in a vulnerable 

 category. 



Fortunately, intensive agricultural practices with liberal pesticide 

 applications do not predominate on Cape Cod. A large number of commercial 

 applications are prevalent, however, including lawn care, 

 small -scale -agricultural operations and utility right-of-way maintenance. 



