Table 3: Amount of toxic elements, as listed by Allaway (1968), in soil and 

 amount of sludge of given concentrations needed to increase the 

 common concentration by 100%. 



Zinc 



50 



10-300 



200 



250 



Iprom Page (1974) and Allaway (1968) 



2The assumed sludge concentrations were chosen as being representative of 

 the majority of New Hampshire sludges. 



^This assumes that the sludge is well mixed with the upper six inches of 

 soil, a.s would occur in most tilled fields. Where the sludge is not 

 incorporated, as might occur in the forest, the accumulation in the surface 

 soil would be far more rapid. 



4-No information on the toxicity or non-toxicity of silver and tin was 

 found. Therefore, these two elements were included in this listing. 



13 



