Written by eWASA
The DFFE identified various types of lighting equipment in the National Environmental Management: Waste Act of 2008, some of which may contain hazardous substances.
1. Fluorescent lights and CFLs
Fluorescent lamps are a type of gas discharge lighting. Fluorescent tubes and compact fluorescent lamps (CFL) are lined with phosphorous and contain an inert gas, typically argon, and about 4mg[ ] of mercury. Phosphorous is one the greatest contributors to unhealthy algal bloom when it contaminates water sources, while mercury is a neurotoxin that poses serious health risks for humans and animals. New regulations could soon ban the sale of CFLs in South Africa in favour of more energy-efficient LEDs.
2. Light-emitting diodes (LEDs)
LEDs use electroluminescence to produce light. The most common semiconductors in LEDs are gallium arsenide and aluminium gallium indium phosphide. LED technology is relatively new, and while the long-term environmental effects of indium and gallium are largely unknown, mounting evidence suggests they may have substantial toxicity. LED wiring and other electrical components also contain lead, nickel, and copper[ ] – all leachable metals unsuitable for landfill.
3.High-intensity discharge lamps (HIDs)
HIDs are arc lights that send an electrical discharge between two electrodes and through an ionised gas to produce extremely bright light. These lamps typically contain metal halides, mercury, or sodium vapour. Some HIDs, namely automotive headlamps, use xenon gas, which, while considered inert and relatively stable, may form toxic xenon-oxygen compounds in specific conditions.
4. Lasers
Lasers emit powerful, directional beams of monochromatic light and are prominent in the precision manufacturing, healthcare, optical communication, and display lighting industries. They contain solid-state, gas, semiconductor, or liquid-lasing mediums, which may have harmful environmental effects when sent to a landfill. Metal vapours, such as helium-mercury, neon-copper, and helium-cadmium, found in some gas lasers, may leach heavy metals into the soil and groundwater.
5.Neon signage lighting
Neon lamps are gas-discharge lights that pass electricity through neon gas to produce red light. Many neon signs also contain mercury vapour, xenon, krypton, argon, helium, and phosphorous to produce different colours. The most significant environmental risk of neon lighting waste lies in its lead glass tubing. Lead glass contains up to 40%[ ] lead oxide by weight. Lead is a toxic heavy metal that may leach into the soil, contaminate groundwater, and lead to lead poisoning with improper disposal.
6. Incandescent and halogen light bulbs
While incandescent lamps may not contain mercury, they do comprise various other metals, such as aluminium and copper, that may leach into the soil and groundwater over time. The tungsten filaments that give these bulbs their glow eventually degrade and acidify the soil. While research into tungsten’s effects on human health is ongoing, various studies have concluded that some plants and soil microbes can absorb it from the environment.
7. Ultraviolet lights (UVGI)
UV lamps used for germicidal irradiation (UVGI) emit short-wavelength UV-C rays to kill viruses, bacteria, and other pathogens. These disinfectant lamps contain 5 – 400 mg of mercury,[ ] depending on the light output. Some UV-C lamps use LED technology with various metal components that may pose environmental risks when disposed of in a mixed-waste landfill.