CHAPTER 5. POLLUTION IN THE ESTUARINE ZONE 



Man has always used the biophysical environment as he needed it for 

 survival and thrown back into it his waste products and anything else 

 he did not need. As long as civilization was limited to small towns 

 and villages the impact of such treatment on tihe en\dronment was not 

 noticeable and apparently insignificant. With the development of a 

 civilization based on a complex socioeconomic environment, however, 

 his impact on the estuarine environment has increased until now the 

 most accurate term to express the relationship of man to the biophysi- 

 cal environment is "pollution." 



Pollution is the degradation of the biophysical environment by 

 man's activities; it is no longer limited to the discharge of sewage and 

 industrial wastes, but now includes direct or indirect damage to the 

 environment by physical, chemical, or biological modification. 



This chapter shows the relationship between man's presence in, and 

 use of, the estuarine environment and its degradation. The kinds of 

 materials and types of changes that tend to degrade the environment 

 are the first topics of discussion, then the relationship of pollutional 

 conditions to the various socioeconomic activities are described. The 

 chapter concludes with a description of the impact of the socioeco- 

 nomic environment on the biophysical environment and specific ex- 

 amples of pollutional effects. 



Section 1. Materials and Conditions That Degrade the 

 Environment 



Environmental degradation is the result of often-minute changes 

 in water quality, water circulation, or other conditions which are part 

 of the biophysical estuarine environment. Brightly colored or other- 

 wise visible waste materials (fig. IV.5.1) have obvious pollutional im- 

 plications, but by far the deadliest pollutants are those that are 

 invisible and often unsuspected until the damage is done. These pollut- 

 ants can be found only by the most delicate and sensitive tests ; even 

 then, the presence of some highly dangerous materials or conditions 

 can only be inferred from indirect evidence. 



decomposable organic materials 



One major constituent of municipal and many industrial wastes is 

 decomposable organic material. Such materials consist primarily of 

 carbohydrates from plants and paper, proteins from animal matter, 

 and miscellaneous fats and oils (fig. IV.5.2). The decomposable or- 

 ganics are not necessarily detrimental by themselves, but they exert 

 a secondary effect by reducing dissolved oxygen in the water. This 

 oxygen resource depletion results from the biochemical reactions in- 

 volved in microbial utilization of organics for food. 



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