What Does River Water Contain?

River water is a complex solution whose composition reflects geology, climate, and human activity. Major constituents include:

Dissolved Minerals

• Major ions: Calcium, magnesium, sodium, potassium, bicarbonate, sulfate, chloride – determine hardness, alkalinity, salinity.
• Trace elements: Iron, manganese, strontium, silica – from rock weathering.

Organic Matter

• Dissolved organic carbon (DOC): Humic/fulvic acids from decaying vegetation – color, reactivity, disinfection byproduct precursors.
• Particulate organic matter: Leaves, wood, algae, microbial detritus – food web base.

Biological Components

• Microorganisms: Bacteria, archaea, viruses, protozoa, algae – some pathogenic (E. coli, Giardia, Cryptosporidium).
• Indicator organisms: Coliforms signal fecal contamination.

Anthropogenic Contaminants

• Nutrients: Nitrate, phosphate – from agriculture, sewage; cause eutrophication.
• Chemicals: Pesticides, pharmaceuticals, PFAS, heavy metals, industrial organics.
• Microplastics: Ubiquitous in modern rivers.

Physical Parameters

Temperature, turbidity, dissolved oxygen, pH, conductivity – all vary diurnally and seasonally.

River water is rarely safe to drink untreated. Treatment (filtration, disinfection, advanced processes) is essential for potable use. Monitoring programs track water quality against regulatory standards (e.g., EPA Clean Water Act, EU Water Framework Directive).