Soil Processes As Solutions and Threats to Sustaining Groundwater Quality.

Water resources needed to meet domestic, agricultural, and industrial uses will be increasingly be stressed in the coming decades. Society’s ability increase use of surface water is limited, and thus an increasing demand on groundwater will necessarily transpire. Managing water storage in the subsurface is presently a new focus for water managers, ranging from rural to urban water districts. Missed within management plans, however, is an account of water contaminants that may threaten the viability of the precious groundwater resource. Owing to the high particle surface area to water volume ratio, which generally runs in near opposition to surface water reservoirs, native contaminant can be particularly problematic. Within the Indo-Gangetic Plain, for example, groundwater levels are largely being maintained, but more than 55% of the shallow (less than 200 m) aquifer is contaminated with salt (25%) or arsenic (28%). In nearly every subsurface environment, a naturally occurring metal residing within the soil/sediment may jeopardize water quality if a dissolution/desorption process is stimulated. Recognizing the ability of soil to remove organic, inorganic, and pathogenic contaminants is essential for groundwater management. Equally important is recognizing the processes by which native contaminants may be released to groundwater and avoiding such reaction conditions. Here, the common metals and partitioning processes are examined to establish a sustainable groundwater management scenario.