Water Quality

Abstract

It is a given that the availability of water, in terms of volume, is crucially important for management of the resource, as well as a determining factor in the development of society. However, there is another element that is just as important, and as such, should be given the same attention: water quality. A significant number of factors determine water quality, both natural and anthropogenic. For the purposes of this study we will only refer to the anthropogenic factors, specifically wastewater and residual solids. According to CNA data (1999a; 2001), municipal discharges, which include water of both domestic and industrial origin, total about 7.54 km³/year. Of this volume, 5.90 km³/year is collected through the sewage system, and only 1.46 km³/year receives any kind of treatment. These discharges contain organic material, toxic compounds, and even pathogens. Industries that do not discharge materials into the drainage system generate 5.36 km³/year, containing mainly toxic elements. There is installed capacity to treat just 16 percent of these discharges (INEGI 2000a). Another sector that is a heavy polluter and that is given little attention is agriculture, whose discharges contain agrochemicals and suspended particles. There are no studies on the quantities of water returned in this way on a nation-wide scale, but some studies (INEGI 1998a) estimate up to 21.20 km³/year.