Industrial, agricultural, and domestic wastes can contribute to the pollution of twater, and water pollutants can damage human and animal health. One of the most important categories of water pollutants is inorganic chemical. These inorganic chemicals are usually substances of mineral origin. Metals, salt, and minerals are examples of inorganic chemicals.
The chemicals are discussed below, which are the most common inorganic pollutants of of water pollution.
Alkalinity is a measure of the ability of water to neutralize acids. It is a commonly measured water characteristic that has little meaning or importance to the typical homeowner. Calcium (Ca) is a major component of alkalinity, as it is with hardness. High alkalinity of water, that means it is probably hard, too. There is no drinking water standard for alkalinity.
Arsenic occurs in groundwater from both natural sources and human activities. It is odorless and tasteless in drinking water. Arsenic has a primary drinking water standard because it can cause skin lesions, circulatory problems, and nervous system disorders. Prolonged exposure also can cause various forms of cancer. The present arsenic drinking water standard (0.05 mg/L) is being studied and will likely be lowered to 0.005 mg/L in the near future.
Like arsenic (As), barium occurs naturally in small concentrations in many groundwater supplies. Barium has a primary drinking water standard of 2.0 mg/L because it causes nervous and circulatory system problems, especially high blood pressure. Standard water softeners are effective in removing barium.
It is a general term used to refer to the calcium carbonate (CaCO3) content of water. Hardness does not pose a health threat, but it does cause aesthetic problems. you can ruin hot water heater elements, reduce soap lathering, and make laundry difficult to clean. Moderate levels of hardness are beneficial because they inhibit plumbing system corrosion. Removal of hardness using a water softener is necessary only if the water is causing aesthetic problems. Use of water softeners may result in undesirable levels of sodium in drinking water and may increase plumbing system corrosion.
Chloride occurs naturally in most groundwater but may become elevated due to leaching from salt storage areas around highways or from brines produced during gas well drilling. Other possible sources of chloride are sewage effluent, animal manure, and industrial waste. Chloride has a secondary drinking water standard of 250 mg/L because it may cause a salty taste in the water. Groundwater in Pennsylvania usually contains less than 25 mg/L of chloride.
Copper usually originates from corrosion of copper plumbing in the home. Copper has a secondary drinking water standard of 1.0 mg/L because it causes a bitter, metallic taste in water and a blue-green stain in sinks and bathtubs. Copper levels above 1.3 mg/L are a health concern because they may cause severe stomach cramps and intestinal illnesses.
Iron is a common natural problem in groundwater that may be worsened by mining activities. Iron does not occur in drinking water in concentrations of health concern to humans. The secondary drinking water standard for iron is 0.3 mg/L because it causes a metallic taste and orange-brown stains that make water unsuitable for drinking and clothes washing.
If lead is detected in drinking water, it probably originated from corrosion of the plumbing system. If your water supply is corrosive, then any lead present in the plumbing system may be dissolved into the drinking water. Lead concentrations are usually highest in the first water out of the tap (known as "first-draw" water), since this water has been in contact with the plumbing for a longer time. Lead concentrations typically decrease as water is flushed through the plumbing system. Lead poses a serious health threat to the safety of drinking water. Long-term exposure to lead concentrations in excess of the drinking water standard has been linked to many health effects in adults including cancer, stroke, and high blood pressure. At even greater risk are the fetus and infants up to four years of age, whose rapidly growing bodies absorb lead more quickly and efficiently. Lead can cause premature birth, reduced birth weight, seizures, behavioral disorders, brain damage, and lowered IQ in children.
In rare cases, the source of lead in drinking water might be from groundwater pollution rather than corrosion of the plumbing system. Such pollution may be the result of industrial or landfill contamination of an aquifer. The source of the lead usually can be determined by comparing water test results from a first-draw sample versus a sample collected after the water runs for several minutes. If the lead concentration is high in both samples, then the source of the lead is likely from groundwater contamination.
Hydrogen Sulfide (H2S)
It is a naturally occurring gas that is common in groundwater. Very small concentrations of hydrogen sulfide in water are offensive to most individuals. Although hydrogen sulfide is a highly toxic gas, only under the most unusual conditions would it reach levels toxic to humans as a result of its occurrence in drinking water. More often, it is simply an aesthetic odor problem that can be removed using several treatment processes.
As like iron, manganese is a naturally occurring metal that can be worsened by mining activities. Manganese at concentrations normally found in drinking water does not constitute a health hazard; however, even small amounts of manganese may impart objectionable tastes or blackish stains to water. For this reason, manganese has a recommended drinking water standard of 0.02 mg/L.
Nitrate or Nitrate Nitrogen
Nitrate in drinking water usually originates from fertilizers or from animal or human wastes. Nitrate concentrations in water tend to be highest in areas of intensive agriculture or where there is a high density of septic systems. Nitrate has a secondary drinking water standard that was established to protect the most sensitive individuals in the population (infants under 6 months of age and a small component of the adult population with abnormal stomach enzymes). These segments of the population are prone to methomoglobinemia (blue baby disease) when consuming water with high nitrates. Nitrate may be reported on the water test report as either nitrate or nitrate-nitrogen. Look carefully at your report to determine which form of nitrate is being reported. The primary drinking water standard or MCL is 10 mg/L as nitrate-nitrogen (NO3-N) but it is 45 mg/L as nitrate ((NO3).
Sulfates normally are present at some level in all private water systems. Sulfates occur naturally as a result of leaching from sulfur deposits in the earth. It has a secondary drinking water standard of 250 mg/L because it may impart a bitter taste to the water at this level. A proposal also exists to make sulfate a primary contaminant with an MCL of 500 mg/L, because it may have a laxative effect and cause other gastrointestinal upset above this concentration.