Water pollution

One would is toxic substances such as oil, metals, plastics, pesticides, persistent organic pollutants, and industrial waste products.

The cause for this can be lack of sanitation procedures or poorly functioning on-site sanitation systems (septic tanks, pit latrines), sewage treatment plants without disinfection steps, sanitary sewer overflows and combined sewer overflows (CSOs)[14] during storm events and intensive agriculture (poorly managed livestock operations).

[17][18] Inorganic water pollutants include: The environmental effect of pharmaceuticals and personal care products (PPCPs) is being investigated since at least the 1990s.

[23] The European Union has declared pharmaceutical residues with the potential of contamination of water and soil to be "priority substances".

Microplastics persist in the environment at high levels, particularly in aquatic and marine ecosystems, where they cause water pollution.

[33] 35% of all ocean microplastics come from textiles/clothing, primarily due to the erosion of polyester, acrylic, or nylon-based clothing, often during the washing process.

[39] Even if sea plastic pollution were to stop entirely, microplastic contamination of the surface ocean would be projected to continue to increase.

[39] Elevated water temperatures decrease oxygen levels (due to lower levels of dissolved oxygen, as gases are less soluble in warmer liquids), which can kill fish (which may then rot) and alter food chain composition, reduce species biodiversity, and foster invasion by new thermophilic species.

One-quarter of the world's population depends on groundwater for drinking, yet concentrated recharging is known to carry short-lived contaminants into carbonate aquifers and jeopardize the purity of those waters.

Examples of sources in this category include discharges from a sewage treatment plant, a factory, or a city storm drain.

[2] Some industries discharge chemical wastes, including solvents and heavy metals (which are toxic) and other harmful pollutants.

The use of fertilizers as well as surface runoff from farm fields, pastures and feedlots leads to nutrient pollution.

[67][68] Carbon dioxide concentrations in the atmosphere have increased since the 1850s due anthropogenic influences (emissions of greenhouse gases).

Frequently used parameters that are quantified are pH, BOD,[72]: 102  chemical oxygen demand (COD),[72]: 104  dissolved oxygen (DO), total hardness, nutrients (nitrogen and phosphorus compounds, e.g. nitrate and orthophosphates), metals (including copper, zinc, cadmium, lead and mercury), oil and grease, total petroleum hydrocarbons (TPH), surfactants and pesticides.

This refers to the measurement of specific properties of an organism to obtain information on the surrounding physical and chemical environment.

[75] The specific contaminants leading to pollution in water include a wide spectrum of chemicals, pathogens, and physical changes such as elevated temperature.

Other natural and anthropogenic substances may cause turbidity (cloudiness) which blocks light and disrupts plant growth, and clogs the gills of some fish species.

[77] Persistent exposure to pollutants through water are environmental health hazards, which can increase the likelihood for one to develop cancer or other diseases.

Subsequent negative environmental effects such as anoxia (oxygen depletion) and severe reductions in water quality may occur.

Other important tools in pollution control include environmental education, economic instruments, market forces, and stricter enforcement.

Standards can be "precise" (for a defined quantifiable minimum or maximum value for a pollutant), or "imprecise" which would require the use of Best available technology (BAT) or Best practicable environmental option (BPEO).

Agricultural wastewater treatment for farms, and erosion control at construction sites can also help prevent water pollution.

While such advanced treatment techniques will undoubtedly reduce the discharges of micropollutants, they can also result in large financial costs, as well as environmentally undesirable increases in energy consumption and greenhouse gas emissions.

It states that it is the country's policy to protect, preserve and revive the quality of its fresh, brackish and marine waters, for which wastewater management plays a particular role.

[107] The study gained media attention, with comments from the UKs leading health professionals, including Sir Chris Whitty.

Outlining 15 recommendations for various UK bodies to dramatically reduce public health risks by increasing the water quality in its waterways, such as rivers and lakes.

After the release of the report, The Guardian newspaper interviewed Whitty, who stated that improving water quality and sewage treatment should be a high level of importance and a "public health priority".

[108] The study also identified that low water flows in rivers saw high concentration levels of sewage, as well as times of flooding or heavy rainfall.

[109] Whitty's comments came after the study revealed that the UK was experiencing a growth in the number of people that were using coastal and inland waters recreationally.

[111] Most notably, the 2024 Paris Olympics had to delay numerous swimming-focused events like the triathlon due to high levels of sewage in the River Seine.