ABSTRACT
The transformation from energy to mass or from mass to energy, however, does not take place in the environment but only by nuclear processes, which are very minor in nature. According to the law of mass conservation, mass can neither be created nor destroyed but only transformed from one form to another. When the mass conservation principles are applied to find unknown concentrations or amounts in various environmental compartments, it is convenient to distinguish between and steady state. Some toxic substances reach considerably faster an equilibrium concentration in various organisms, that is, the concentration that corresponds to an equilibrium between the environment and the organism. Water is the most abundant chemical compound on earth, and has some unique properties. Some of the water falls on the land sinks or percolates into the soil and ground to form ground water.
