Water Quality Parameters: Metals

There are two types of metals: They are 1) Toxic metals 2) Nontoxic metals

Sources:

→) Metals in natural waters include dissolution from natural deposits.

→) Discharges of domestic, industrial or agricultural wastewaters.

Toxic Metals:

→) Harmful to humans and other organisms in small quantities.

→) Toxic metals that may be dissolved in water include arsenic. barium, cadmium, lead, mercury and silver.

→) Cumulative toxins such as arsenic, cadmium, lead and mercury are particularly hazardous.

→) Toxic metals are present in only minute quantities in most natural water systems.

Nontoxic Metals:

→) Common metals are sodium, iron, manganese, aluminum, copper and zinc.

Sodium:

→) Most common nontoxic metal found in natural waters and is highly reactive with other elements.

→) The salts of sodium are very soluble in water. 

→) Excessive concentration cause a bitter taste in water and are health hazard to cardiac and kidney patients.

→) Sodium is also corrosive to metal surfaces and also toxic to plants.

Iron and Manganese:

→) Quite frequently occur together and present no health hazards at concentrations normally found in natural waters.

→) Iron and manganese in very small quantities may cause color problems.

→) Iron concentration of 0.3 mg/L and manganese concentration as low as 0.05 mg/L can cause color problems.

Other Metals:

→) The other nontoxic metals are generally found in very small quantities in natural water systems, and most would cause taste problems long before toxic levels are reached.

→) Copper and zinc are synergetic and when both are present, even in small quantities, may be toxic to many biological species.