**Abstract**

One of the most important challenges facing humanity today is to conserve and sustain water resources (either surface water or groundwater). This challenge became more pronounced with the increase of urban, agricultural, and industrial activities that discharge a considerable amount of wastewater. Therefore, the preservation of water sources from pollutants is a major concern, shared by all, public, industrial, scientific, researchers, and decision-makers. This chapter analyzes in more detail the pollution and pollutants caused by agricultural and industrial activities. Particular attention is given to pollution via nitrogen and heavy metals (NO3 <sup>−</sup>, Cr(VI), and Cu(II)) in either international or national level. The effect of these pollutants on human health and environment, their standards/regulations, and the different current methods used for their detection and treatment are all discussed in the chapter.

**Keywords:** water chemistry, pollution, pollutants, nitrate, copper, chromium, detection methods, treatment methods

## **1. Introduction**

One of the most important challenges facing humanity today is to conserve and sustain natural resources, including water, in order to increase economic and social development along with environment protection. However, urban and industrial sectors not only use the available water but also discharge a considerable amount of wastewater. The impact of these effluents on living organisms may be harmful due to the direct or chronic toxicity of these substances or the products of their degradation. Significant efforts are being made to control the use and spread of these substances. These topics are addressed more thoroughly in this chapter. Particular attention is given to pollution via NO3 <sup>−</sup> and heavy metals. Besides the various activities that lead to the pollution of our freshwater bodies and the effect of these pollutants on human health and environment, the chapter also discusses the different methods used for water pollutant detection, standards/regulations, and some of the used treatment methods to protect water bodies.
