Physico-chemical characteristics of water in water sources undergo changes due to

Effluents (industrial, municipal and agricultural discharges) are the primary drivers of changes in the physico‑chemical characteristics of water because they directly introduce nutrients, salts, organic matter and synthetic chemicals that alter parameters such as pH, dissolved oxygen, conductivity, turbidity and toxicant concentrations. Water pollution is defined as alteration of physical, chemical and biological characteristics of water, which fits the effect of effluent inputs [1]. Agricultural fertilizers and industrial wastes that flow into water bodies change chemical composition and promote eutrophication and other water‑quality deterioration [2]. Empirical studies link wastewater treatment plant effluents to measurable downstream changes in physico‑chemistry and ecological stressors, confirming effluents as the key cause named here [4].

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > 2. Water (aquatic) Pollution > p. 35
2. [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > 2. Water (aquatic) Pollution > p. 36
3. [3] https://www.sciencedirect.com/science/article/pii/S0043135424008157
4. [4] https://ebooks.inflibnet.ac.in/esp05/chapter/physical-chemical-and-biological-characteristics-of-water/