“Industrial activities, urban runoff, and textile effluents release suspended solids, dyes, and toxic substances into rivers and other natural water bodies.”

Municipal separate storm sewer systems (MS4s) collect stormwater runoff from impervious surfaces such as roofs, roads, and parking lots, and convey it through pipes, ditches, or open channels to local waterbodies. This runoff picks up pollutants like trash, chemicals, oils, and sediments that can harm rivers, streams, lakes and bays.

The waste effluent from the textile industry is often highly polluted and contains various kinds of hazardous and refractory contaminants, mainly composed of acids, alkalis, dyes, toxic elements, and diversiform organic compounds. Early studies have reported that multiple potential toxic elements (PTEs) either in free ionic metals or complex metals were detected in the river near textile factories and effluent of the textile industry worldwide, such as chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), lead (Pb), cobalt (Co), antimony (Sb), arsenic (As), among others.

The denim textile industry generates wastewater with low biodegradability due to the presence of persistent pollutants, which can produce toxic and carcinogenic compounds. Synthetic indigo contains toxic chemicals such as aniline and N-methylaniline residues. Additionally, denim is often dyed with sulfur, reactive pigments, and direct dyes that are non-biodegradable and toxic to aquatic organisms; most of these dyes contain heavy metals, such as chromium, copper, zinc, and manganese. Dye effluents mixed with natural source water produce an unpleasant odor due to low light penetration, and effluent turbidity tends to form a visible layer on the water surface.

A multiagency study of organic and inorganic chemicals in urban stormwater from 50 runoff events at 21 sites across the United States demonstrated that stormwater transports substantial mixtures of polycyclic aromatic hydrocarbons, bioactive contaminants (pesticides and pharmaceuticals), and other organic chemicals known or suspected to pose environmental health concern. Numerous organic-chemical detections per site (median number of chemicals detected = 73), individual concentrations exceeding 10 000 ng/L, and cumulative concentrations up to 263 000 ng/L suggested concern for potential environmental effects during runoff events. Organic concentrations, loads, and yields were positively correlated with impervious surfaces and highly developed urban catchments.

Textile wastewater (TWW) contains toxic metals that are inimical to microbiome, aesthetic quality, and the health of the receiving freshwater. TWW-impacted freshwater (L2) was assessed for metals eco-toxicity and the consequent impact on microbiome taxonomic profile (MTP) compared to a pristine environment (L1). The biodegradables contained in TWW are residues of reactive dyes and chemicals that enrich the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of the hydrosphere, leading to eutrophication.

Wastewater from textile bleaching and dyeing (TDW) is consistently discharged into the environment, modifying the biological, chemical, and physical properties of natural resources and endangering global sustainable biodiversity. Wastewater and untreated sewage contain elements such as cadmium, chromium, nickel, arsenic, and lead, which ultimately permeate soil, agricultural goods, and subsequently enter human bodies via the food chain. Significant quantities of untreated effluent from these sectors are discharged into the environment.

Heavy rains in urban areas bring together a toxic mixture of man-made chemicals which make their way to waterbodies at levels that can harm aquatic life, according to new research published by a team of scientists from the U.S. Geological Survey (USGS) and the Environmental Protection Agency (EPA). Researchers aimed to provide a national snapshot of the contents of urban stormwater discharge by sampling 21 sites in 17 states over the course of 50 rainfall events. The team tested for 438 different compounds, including pesticides, pharmaceuticals, hormones, and other industrial chemicals.

To develop urban stormwater management effectively, characterization of urban runoff pollution between dissolved and particulate phases was studied by 12 rainfall events. The proportions of total dissolved solids, total dissolved nitrogen, and total dissolved phosphorus in total ones for all the catchments were 26.19%–30.91%, 83.29%–90.51%, and 61.54–68.09%, respectively. It could be observed that solids exist as particulate phase in urban runoff.

This study found that the land-use index can affect runoff water quality. Pollutant sediments are eventually discharged into the water body, and when harmful substances to the human body exceed the range within which tap water can purify itself, the properties of water will be adversely altered. In addition, some researchers point out that other factors relating to urban land can affect water quality, such as erosive rainfall events, heavy metals in surface sediments, natural biological filtration devices, and the landscape pattern of the surrounding zones in the urban area.

In the United States, dye pollution is a major source of industrial water contamination, accounting for approximately 20% industrial water contamination. Textile dyes and their fixation salts are released into rivers and other water bodies through industrial effluents, containing suspended solids, dyes, and toxic substances that harm aquatic ecosystems.

Dyes widely used in the textile industries pose a pressing threat to plant, animal and human health, as well as natural environments. Up to 80% of dye-containing industrial wastewaters created in low- and middle-income countries are released untreated into waterways. China, India and Bangladesh combined discharge around 3.5 billion tons of textile wastewater each year. Untreated dyes cause colouration of water bodies, reducing the degree of visible light that passes through the surface layer – hindering photosynthesis for aquatic plants.

The dyes have carcinogenic, mutagenic, allergic, and toxic nature on one hand, and on the other hand, they cause environmental pollution. As a result of insufficient bounding of dye molecules to the textile, unbounded dye molecules are released as the waste product. This causes 10% of dyes to be produced yearly out of the total usage as waste.

The textile industry is a significant contributor to water pollution, with wastewater containing high levels of pH, temperature, toxic chemicals, COD, BOD, and suspended solids.

Textile Industry Discharge – Dyes, bleaching agents, and detergents from textile factories release harmful chemicals into rivers, altering pH levels and rendering water unsafe. Industrial wastewater can infiltrate clean water sources through direct discharge into waterways, seepage into groundwater, surface runoff, and accidental spills, releasing suspended solids, dyes, and toxic substances.

Industrial effluents contaminate urban water sources, including rivers and lakes, with pollutants such as heavy metals (lead, mercury, arsenic, cadmium), dyes, and toxic chemicals from textile, pharmaceutical, and chemical industries. These untreated or partially treated effluents contribute to surface runoff, directly disposing into water bodies and infiltrating groundwater.

Industrial waste contributes to river pollution through the discharge of harmful chemicals, toxins, heavy metals like lead, mercury, and cadmium, as well as organic chemicals such as solvents and dyes into water bodies. Urban development introduces pollutants via stormwater runoff and sewage discharge, including heavy metals and bacteria, while surface runoff carries these contaminants into rivers.

Scientific consensus from environmental studies confirms that industrial activities, particularly textiles, release dyes, suspended solids, and toxic heavy metals into rivers; urban runoff carries these and additional pollutants like sediments into natural water bodies. This is documented in peer-reviewed literature and EPA reports, though mitigation via treatment reduces but does not eliminate impacts.

Traditional textile dyeing is one of the most polluting processes in the textile industry. It relies heavily on water, energy, and chemicals to fix colour onto the fabric, often coming with environmental consequences. Wastewater from dyehouses is frequently discharged untreated into rivers and streams, carrying toxic dyes and heavy metals that harm the environment and potentially contaminate drinking water.

Textile dyeing is the second-largest contributor to water pollution worldwide, with the fashion industry responsible for approximately 20% of water pollution. One of the lesser-discussed aspects of this impact is the discharge of clothing dye runoff into water systems, which occurs during the dyeing process when excess dye and chemicals are expelled into water streams untreated. This pollution has far-reaching consequences for both aquatic ecosystems and the communities that depend on them, as the toxins and chemicals present in these dyes can harm aquatic life.

The current textile dyeing systems are guilty of water pollution on a global scale. Post-production water containing residual dye, mordants, chemicals, and micro-fibres is expelled into water streams untreated. In China, over 70% of the rivers are polluted, meaning many of their 1.4 billion population cannot access uncontaminated water. Billions of tonnes of wastewater are expelled from factories untreated, lowering dissolved oxygen within waterways to levels unable to sustain life.

Water pollution has many sources. The most polluting of them are city sewage and industrial waste discharged into rivers, which release suspended solids, chemicals, dyes, and toxic substances from activities including textile effluents.

The most common culprit for water pollution is chemical pollution from industrial activities, including heavy metals and solvents used in manufacturing, dyes from textiles, and suspended solids released into rivers and natural water bodies via effluents and urban runoff.