Chemistry in natural water systems: A general discussion

Abstract

A general discussionConcern about the "diminished quality of life" which has accompanied rapid population growth and industrialization has become cliche. The natural framework within which air, water, soil, and noise pollution by industrial and agricultural contaminants must be limited is less easily described by most of us. Our hopes of setting meaningful standards for tolerable limits of contamination, however, rest on just this capacity for description of natural systems. Thence, defining whether or not our description is adequate, in turn, rests on several common sense principles 1) We must have a highly detailed concept of what constitutes normal composition and behavior for a living system, including its natural imperfections and redundancies, if we are to characterize conditions pathological to normal life processes. 2) We must have a regional, as opposed to a bulk, grasp of how a given mineralogical, atmospheric, or water system behaves if we are to predict accurately the concentration or dissipation of contaminants and nutrients at any particular location. We may choose to limit our region according to a variety of different properties, depending on the problem we are trying to solve. Perhaps our region was the scene of some special geological event, which exposed a vein of unusual ore to the action of the sea, perhaps an isothermal or isobaric contour in a large lake, which then (because of the nature of the equilibrium with dissolved CO2) supports the growth of particular algae; perhaps shrimp like to bed in this area, but not 50 ft outside it. This is to say, it would be fair to speak of the Atlantic Ocean as a homogeneous solution of 10" ionic species only if we are speaking in terms of systems of molecules with the following properties a) whose reaction kinetics are suited to bringing about equilibration of products in times short with respect to the residence time of the molecules in the region of interest.b) whose rate of introduction is homogeneous, or is in equilibrium with mixing times of the order of days to several thousand years.c) whose equilibrium thermodynamics are independent of temperature, pressure, proximity to sedimentary deposits and living matter.(For reference, the temperature extremes