IV-365 



Toxic materials directly kill the biota, interact in the food chain, 

 or deleteriously affect the reproduction or growth processes. The 

 ultimate damage is to stress or eliminate parts of the energy- 

 conversion chain in the estuarine environment (Figure IV. 5. 6). 



HEAT 



The preceding discussion emphasized the many environmental factors 

 affecting the impact of various types of wastes on the estuarine 

 environment. Water temperature was mentioned in almost every 

 instance. Thus the addition of large quantities of heat from 

 industrial cooling water constitutes a form of pollution which must 

 be considered (Figure IV. 5. 7). 



The impact of heat pollution on the environment appears in several 

 different ways: 



(1) Heat affects the physical properties of water such as 

 density, viscosity, vapor pressure and solubility of 

 dissolved gases. Consequently, such processes as the 

 settling of particulate matter, stratification, circulation, 

 and evaporation can be influenced by changes in temperature. 

 Since the solubility of oxygen in water decreases as 

 temperature increases, thermal pollution reduces the oxygen 

 resources. Most aquatic organisms depend on dissolved 

 oxygen to maintain growth and reproduction. 



