**4.2 Chemicals**

*Environmental Issues and Sustainable Development*

**3. Characteristics of hazardous waste**

contributes to corrosive hazardous waste.

containing cyanides or sulphides.

and toxic characteristics can be determined.

**4. Categories of hazardous wastes**

**4.1 Radioactive substance**

materials, or explodes when exposed to heat or a flame.

product.

**3.1 Ignitability**

**3.2 Corrosivity**

**3.3 Reactivity**

**3.4 Toxicity**

and oil based paints etc.

• The chemical in the waste must be unused

• The waste must contain one of the chemicals listed on the P or U list

• The chemical in the waste must be in the form of a commercial chemical

A waste is considered to be an ignitable hazardous waste if its flash point is less than 60**°**C, readily catches fire and burns vigorously as a hazard; or is an ignitable compressed gas or an oxidizer. Ex: Naphtha, lacquer thinner, epoxy resins, adhesives,

Any type of liquid waste whose pH is less than or equal to 2 or greater than or equal to 12.5 is considered to be corrosive hazardous waste. Sodium hydroxide (High pH) and hydrochloric acid (Low pH) is often used in many industries to clean or degrease metal parts. Prior to painting disposed solvents without any treatment

A material is considered as reactive hazardous waste, if it is unstable, reacts violently with water, and generates toxic gases when exposed to water or corrosive

Toxicity of a hazardous waste can be determined by taking a representative sample of the material and subjected to a test conducted in a certified laboratory

Radioactive waste is the type of hazardous waste that contains radioactive material. Radioactive waste is a by-product of various nuclear technology processes, industries based on nuclear medicine, nuclear research, nuclear power, manufacturing, construction, coal and rare-earth mining and nuclear weapons reprocessing. Any substances capable of emitting ionizing radiation are said to be radioactive and are hazardous because prolonged exposure often results in damage to living organisms. Radioactive substances attract special concern because they persist for a long period and disposal depends upon half-life period of the radioactive substance.

Examples of reactive wastes would be waste gunpowder, sodium metal or wastes

**170**

The hazardous chemical wastes can be categorized into five group's namely synthetic organics, inorganic metals, salts, acids and bases, and flammables and explosives. Some of the chemicals are hazardous because they threaten human lives.
