ABSTRACT
Wherever people work and live there will be an increase in toxic substances, nontoxic salts and pathogens entering the water cycle. Industrial contamination, although more localized, is often more serious. The extensive nature of agriculture makes it the most serious threat to drinking water quality, mainly due to the diffuse nature of such pollution, making it diffi cult to control. Any material or chemicals that fi nd their way into the resource may need to be removed before supply, their removal generally being technically diffi cult and expensive. The main contaminants in water prior to treatment are listed in Table 11.3 . At the resource level there is increasing concern over contamination of both surface and groundwaters by pharmaceutical and personal care products and endocrine disrupting compounds, both of which are discussed in Section 13.1. As a general rule the cleaner the raw water, the cheaper the fi nished water is to produce, and the safer it is to drink. So where the concentration of these compounds is excessively high, the resource may be rejected due to the cost of adequate treatment.
