large number of farms >500 AU are located along the Penobscot River and its 

 tributaries . 



The transport of agricultural fertilizer takes place by means of surface 

 runoff, spraying, soil erosion, and leaching. Most chemical fertilizers are 

 soluble and large quantities may be carried away by surface runoff. Since the 

 scarcity of phosphorus may limit plant growth in freshwater systems, additions 

 of phosphorus may accelerate growth. The scarcity of nitrogen limits plant 

 growth in estuarine systems. 



Excessive nutrient runoff degrades water quality in the lacustrine, 

 palustrine, riverine and terrestrial systems, and in poorly-flushed portions 

 of estuaries and embayments. In most estuaries flushing is adequate to 

 disperse and dilute agricultural runoff. 



The concentrations of animal-related nutrients actually reaching ground and 

 surface waters are difficult to determine. A study in Kennebec County 

 (immediately north of the characterization area) indicated that about 10% of 

 the animal-related phosphorus there reached lakes in that watershed, 

 approximately 1.4 lb (0.6 kg)/acre/year . 



Fertilizer runoff into lakes, ponds, and even wells can cause public health 

 problems. Livestock and aquatic life also can be affected when large amounts 

 of fresh manure accumulate in water. Bacteria, viruses, protozoans, and fungi 

 are among the pathogens found in manure. Enrichment of lakes and ponds can 

 result in excessive growth of algae, which may cause taste, odor, and 

 discoloration in water and its recreational value (e.g., Pleasant Pond, region 

 2). Excessive algal growth accelerates the eutrophication process. The decay 

 of the excess plant material by microbes depletes dissolved oxygen supplies to 

 levels that are lethal to fish. In addition, oxygen-depleted water may cause 

 mortality of some aquatic insects. High levels of nitrate in groundwater used 

 for water supply can cause methemoglobinemia, a rare blood disorder in infants 

 (U.S. Soil Conservation Service 1979). 



Pesticides 



A wide variety of agricultural chemicals are now used within the 

 characterization area (table 3-2). Although little field research has been 

 conducted on the toxicity of agricultural pesticides in Maine, isolated 

 instances of pesticide damage to the environment have been observed. The 

 amounts of agricultural chemicals used within certain coastal watersheds are 

 shown in table 3-3. In comparison to other parts of the country, pesticide 

 use in Maine could be considered moderate to low (personal communication from 

 A. Julin, U.S. Fish and Wildlife Service, Newton Corner, MA; February, 1980). 



Agricultural pesticides are used mostly on corn and other vegetables, fruit, 

 hay and other forage crops in all regions except 5 and 6, where most spraying 

 is on blueberries. Approximately one-half of the 15,000 acres (6073 ha) of 

 blueberry barrens in regions 5 and 6 have been sprayed with Guthion . This 

 insecticide caused a fish kill at a fish hatchery in Deblois (Washington 

 County) in 1972; 10,000 brook trout and 11,000 eggs were destroyed through 

 careless aerial spraying. Fish kills have occurred in the past due to DDT in 

 the Pleasant (regions 5 and 6) and Narraguagus (region 5) Rivers. 



3-9 



10-80 



