According to a study conducted by US, Light Emitting Diodes (LEDs) can be classified as hazardous waste due to the presence of rare earth metals like lead, copper, nickel and silver in their composition. The research confirmed that, despite LED being energy efficient and mercury-free its use of metals could have an impact on the environment and also contribute to the depletion of natural resources.
The study examined nine different LEDs available in the US market and ran a standard toxicity leaching test to determine whether they are hazardous as per the US federal and California regulations. The results confirmed the presence of very high levels of iron, copper and nickel and low levels of gold and silver, which doesn't comply with the state regulations that limit the use of metals to one. Further, the levels of copper in the LEDs were found to be 3892 mg per kg, which exceeds the California limit of 2500 mg per kg and the lead levels were in excess of 7103 mg per kg compared to the limit of 1000 mg per kg. However, only the lead concentration in landfills from low intensity red LEDs exceeded the limit set by federal regulations, which places cap at 5 mg per litre, as opposed to the 186 mg per litre that the current trend seems to be. This throws light on the many discrepancies in the policies and regulations set by the national and state authorities in the assessment of the use and toxicity of LEDs. The research then goes on to highlight the need to develop policies that are consistent across national and international boundaries.
The study emphasises that while the presence of copper, iron, lead, nickel and silver in LEDs contribute to the toxicity, the use of silver and gold, despite in small amounts, have far reaching effects of depleting natural resources. Although the latter scenario seems negligible now, it has the potential to increase especially with the development of high power LEDs.
Further, the study also raises concern about the use of copper and nickel in particular as they significantly cause harm to the ecosystem, if leached from landfill, implying that this applies to all LEDs as they all contain these metals.
As the way forward the research recommends better recycling technologies and innovation in LEDs that uses fewer rare metals to reduce impact.