The main sources of water contamination are industrial discharge from chemical industries, sewage from surrounding areas, pesticides from farming areas, petroleum products, detergents and fertilizers, storage leakage and also soil contamination.
Water contamination can be categorized in the following ways:
- Water pollution
- Surface water contamination
- Groundwater contamination
- Water turbidity
- Waste water contamination
- N on-biodegradable water contamination
- Bacterial water contamination >Biological Contamination (bacteria and virus)
- Mineral water impurities[i]
Humans require water that does not contain too many impurities which include metal salts and oxides (including copper, iron, calcium and lead) and/or harmful bacteria. Bottled water, city tap water, well water, rain water… people are trying to find the cleanest source of drinking water. By what are the possible contaminants and what are the health effects of drinking them? The EPA has set standards for more than 80 contaminants that may occur in drinking water and pose a risk to human health. The EPA sets these standards to protect the health of everybody, including vulnerable groups like children. The contaminants fall into two groups according to the health effects that they cause. Your local tap water supplier must alert you through the media, mail, or other means if there is a potential acute or chronic health effect from compounds in the drinking water. You may want to contact the supplier for additional information specific to your area.
EPA has established National Secondary Drinking Water Regulations that set non-mandatory water quality standards for 15 contaminants. EPA does not enforce these “secondary maximum contaminant levels” or “SMCLs.” They are established only as guidelines to assist public water systems in managing their drinking water for aesthetic considerations, such as taste, color and odor. These contaminants are not considered to present a risk to human health at the SMCL.
There are a wide variety of problems related to secondary contaminants. These problems can be grouped into three categories: Aesthetic effects – undesirable tastes or odors; Cosmetic effects — effects which do not damage the body but are still undesirable; and Technical effects — damage to water equipment or reduced effectiveness of treatment for other contaminants.
- Standards related to odor and taste:Chloride, Copper, Foaming Agents, Iron, Manganese pH, Sulfate, Threshold Odor Number (TON), Total Dissolved Solids, Zinc.
- Standards related to color:Aluminum, Color, Copper, Foaming Agents, Iron, Manganese, and Total Dissolved Solids.
- Standards related to foaming: Foaming Agents.
- Skin discolorationis a cosmetic effect related to silver ingestion.
- Tooth discolorationand/or pitting are caused by excess fluoride exposures during the formative period prior to eruption of the teeth in children.
- Corrosivity,and staining related to corrosion, not only affect the aesthetic quality of water, but may also have significant economic implications. Other effects of corrosive water, such as the corrosion of iron and copper, may stain household fixtures, and impart objectionable metallic taste and red or blue-green color to the water supply as well. Corrosion of distribution system pipes can reduce water flow.
- Scalingand sedimentation are other processes which have economic impacts. Scale is a mineral deposit which builds up on the insides of hot water pipes, boilers, and heat exchangers, restricting or even blocking water flow. Sediments are loose deposits in the distribution system or home plumbing.