IV-351 



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 otherwise visible waste materials (Figure IV. 5.1) have obvious 

 pollutlonal Implications, but by far the deadliest pollutants are 

 those that are invisible and often unsuspected until the damage 1s 

 done. These pollutants 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 1s 

 decomposable organic material. Suchmaterials consist primarily of 

 carbohydrates from plants and paper, proteins from animal matter, 

 and miscellaneous fats and oils (Figure IV. 5. 2). The decomposable 

 organics are not necessarily detrimental by themselves, but they 

 exert a secondary effect by reducing dissolved oxygen 1n the water. 

 This oxygen resource depletion results from the biochemical reactions 

 involved in microbial utilization of organics for food. 



The biochemical oxygen demand (BOD) is the standard test for this 

 component. It is an Index of the availability of organic matter for 

 biological food and the amount of oxygen utilized by organisms 1n 



