Priority Waste Streams

Priority waste streams (PWS) are some categories of wastes which are central to achieving the principle of Environmetally Sound Management (ESM) of hazardous wastes due to the danger their represent to the human health and the environment. They have been identified as priorities on account of their volume of generation, volume of traffic, hazardous nature or disposal characteristics. The Basel Convention has identified the following PWS:

• Electrical and electronic wastes.
• Used lead-acid batteries.
• Used oils.
• Persistent organic pollutant wastes including obsolete stocks of pesticides, PCBs, and dioxins and furans.
• Biomedical and health-care wastes.
• Household wastes mixed with hazardous wastes.
• By-products from the dismantling of ships.

Several projects has been carried out or are currently going on, specially in developing countries or regions with economies in transicion, addressing issues related to the generation, transport or disposal of PWS.

Some key hazardous waste

• Arsenic: Used as an alloy in lead shot and electrical circuits, as a pesticide, and as a preservative for wood. Highly toxic and carcinogenic.
• Asbestos: Once widely employed in construction primarily for insulation. Still used in gaskets, brakes, roofing and other materials. When inhaled can cause lung cancer and mesothelioma.

• Cadmium: Used in batteries, pigments, metal coatings, and plastics. Exposure risks include workplace activities, cigarette smoke and contaminated foods. Damages the lungs, causes kidney disease, and irritates the digestive tract.
• Chromium: Combines easily with other metals to form alloys such as stainless steel. Used as a rust-resistant coating on other metals, a pigment in paint, and in wood preservatives and liquids for tanning hides.
• Clinical wastes: Hospitals must dispose of large quantities of syringes, medication bottles and other materials that can be infectious and spread pathogens and harmful micro-organisms.
• Cyanide: A poison that in large doses can cause paralysis, convulsions and respiratory arrest. Chronic exposure to low doses can cause fatigue and weakness. Compressed hydrogen cyanide gas is used to exterminate rodents and insects on ships and to kill insects on trees.
• Lead: Used in the production of batteries, ammunition, paints, metal products such as solder and pipes, and devices to shield X-rays. If ingested or inhaled can harm the nervous system, kidneys, and reproductive system.
• Mercury: Used to produce chlorine gas, caustic soda, thermometers, dental fi llings, and batteries. Exposure occurs through contaminated air, water and food and through dental and medical treatments. High levels may damage the brain, kidneys, and developing foetuses.
• PCBs: Compounds used in industry as heat exchange fl uids, in electric transformers and capacitors, and as additives in paint, carbonless copy paper, sealants and plastics. Pose risks to nervous systems, reproductive systems, immune systems, and livers.
• POPS: Persistent organic pollutants are a class of chemicals and pesticides that persist for many years in the environment, are transported great distances from their point of release, bio-accumulate (thus threatening humans and animals at the top of the food chain), and cause a range of health effects.
• Strong acids & alkalis: Highly corrosive liquids used in industry that can corrode metals and destroy tissues of living organisms.