2. Primary ecological alterations 



Alterations will vary according to the community type affected, 

 cleanup method, toxicity of the chemical substance that is re- 

 leased, and spill size. 



2.1 Partial or complete removal of vegetation within the spill and 

 cleanup site; magnitude varies according to spill size 



2.2 Loss of consumers from the affected area 



2.3 Increase in soil toxicants from petrochemicals 



2.4 Increase in soil salinity from brine spill or leakage 



2.5 Loss of soil structure due to excavation and other earth-moving 

 activities or because of petrochemical cohesion of soil 

 particles 



2.6 Possible loss of soil nutrients due to soil extraction and 

 replacement by soil materials of unknown fertility 



2.7 Possible increase in available nutrients due to burning of 

 contaminated vegetation 



3. Attribute alterations 



Plant assemblages are removed or altered by: (1) the toxic effects 

 of brine or hydrocarbons; (2) the cleanup procedures; or (3) modifi- 

 cations of the soil's microenvironmental regime. Areal extent is a 

 function of the spill size. If large quantities of the material 

 are not dispersed rapidly over wide areas, mobile terrestrial con- 

 sumers capable of avoiding contaminating substances leave the area. 

 Less mobile consumers may be coated with oil or other noxious effluents 

 and lost; food and shelter become so degraded as to provide minor 

 benefits to all consuiriers which previously utilized the site. 

 Discharge of brine effluent alters or removes plants because of 

 physiological stresses produced by osmotic water losses. Hydrocar- 

 bon fractions or derivates nay have similar effects, but act instead 

 upon other physiological mechanisms. Loss of plant cover, either 

 through immediate, direct means such as cutting and burning or 

 through slower acting mechanisms such as brine increasing soil salin- 

 ity, means locally increased soil heat, soil moisture evaporation, 

 and surface-water runoff. The magnitude and subsequent implications 

 upon the biotic systems depend upon too many unknown variables (spill 



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