suspected industrial input, and Pease AFB, because of unknown influences of 

 operations there. Results of these analyses are tabluated in Table 2. 



From the information presented in Table 2, it may be concluded that, 

 despite the industrial component within the town, the Plymouth and Ports- 

 mouth treatment plants are not handling any significant amounts of industrial 

 wastes. In terms of sludge usage, these towns could be included with those in 

 Group 1. Apparently, the university contributes negligible amounts of poten- 

 tially toxic elements, so Durham sludge, along with that of Plymouth and 

 Portsmouth, can probably be considered typical of domestic sludges. The Pease 

 AFB sludge is moderately high in tin (500 ppm) and very high in silver (210 

 ppm) compared to other towns of New Hampshire. Levels of these two elements 

 are not normally reported, so it is unknown how these values compare to other 

 sludges throughout the United States. Berrow and Webber (1972) have, however, 

 reported the presence of these two elements in 42 sewage sludges from locations 

 in England and Wales. They found silver to range between 5 and 150 ppm, with 

 a median value of 20 ppm. Tin ranged from 40 to 700 ppm, with a median of 

 120 ppm. Based on these data, the Pease AFB sludge should probably be classed 

 as high in both silver and tin, and be included with the group 2 towns. The 720 

 ppm lead and 450 ppm tin in the Goffstown sludge is of moderate concern, but 

 the, 1,000 ppm antimony is sufficient to tentatively place Goffstown in group 

 three. (Again, there is little information on nation-wide sludges with which this 

 can be compared.) 



Based on data for content of sludges nationwide (Page, 1974), only Dover 

 and Newport sludges might be considered to have high chromium concen- 

 trations, with Dover sludge having chromium levels in excess of any values cited 

 in the literature. Newport sludge is also moderately high in nickel. Lead appears 

 to be the most prevalent metal in New Hampshire sludges. Lead concentration of 

 greater than about 1,000 ppm in sludge would normally indicate a substantial 

 industrial waste input (Page, 1975). The cadmium concentrations of the Keene, 

 Laconia, Meredith and Claremont sludges are of considerable concern since this 

 element is highly toxic to both plants and animals, (Allaway, 1968). Although 

 the cadmium concentrations are much lower than those reported for many 

 industrial sludges (Page, 1974), they are above that which might be considered 

 "common" for sludges. On the basis of the EngUsh and Wales data (Berrow & 

 Webber, 1972), high concentrations of tin are present in several New Hampshire 

 sludges. The other elements listed in Table 2 are not present in sufficient 

 concentrations to cause undue alarm. 



To provide a criterion for determining whether and how much sludge can be 

 safely disposed on land. Table 3 lists the soil concentrations of several toxic 

 elements. It is assumed that the common soil concentration can be equaled by 

 sludge input, but that it would be unwise to exceed this level of addition until 

 further information on the fate of toxic elements in soil is obtained. Thus, 

 Tables 2 and 3 can be used in conjunction to determine safe addition levels. For 

 example, the toxic element concentrations of Merrimack sludge are. not high 

 enough to limit the application of this material to land, whereas, only one ton of 

 dry Dover sludge would increase the common chromium concentration by 99 

 percent. Although the silver content of most sludges would limit application, on 

 this basis, the common soil concentration is so low that the soil concentration of 

 this element could probably be increased to 1 ppm with no adverse effects. 



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