Potential environmental impacts of light-emitting diodes (LEDs): metallic resources, toxicity, and hazardous waste classification

Environ Sci Technol. 2011 Jan 1;45(1):320-7. doi: 10.1021/es101052q. Epub 2010 Dec 7.

Abstract

Light-emitting diodes (LEDs) are advertised as environmentally friendly because they are energy efficient and mercury-free. This study aimed to determine if LEDs engender other forms of environmental and human health impacts, and to characterize variation across different LEDs based on color and intensity. The objectives are as follows: (i) to use standardized leachability tests to examine whether LEDs are to be categorized as hazardous waste under existing United States federal and California state regulations; and (ii) to use material life cycle impact and hazard assessment methods to evaluate resource depletion and toxicity potentials of LEDs based on their metallic constituents. According to federal standards, LEDs are not hazardous except for low-intensity red LEDs, which leached Pb at levels exceeding regulatory limits (186 mg/L; regulatory limit: 5). However, according to California regulations, excessive levels of copper (up to 3892 mg/kg; limit: 2500), Pb (up to 8103 mg/kg; limit: 1000), nickel (up to 4797 mg/kg; limit: 2000), or silver (up to 721 mg/kg; limit: 500) render all except low-intensity yellow LEDs hazardous. The environmental burden associated with resource depletion potentials derives primarily from gold and silver, whereas the burden from toxicity potentials is associated primarily with arsenic, copper, nickel, lead, iron, and silver. Establishing benchmark levels of these substances can help manufacturers implement design for environment through informed materials substitution, can motivate recyclers and waste management teams to recognize resource value and occupational hazards, and can inform policymakers who establish waste management policies for LEDs.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Conservation of Natural Resources
  • Electronic Waste / analysis*
  • Electronic Waste / classification
  • Electronic Waste / statistics & numerical data
  • Environment
  • Environmental Monitoring
  • Hazardous Substances / analysis*
  • Hazardous Substances / toxicity
  • Hazardous Waste / analysis*
  • Hazardous Waste / classification
  • Hazardous Waste / statistics & numerical data
  • Lead / analysis
  • Lead / toxicity
  • Lighting*
  • Metals / analysis*
  • Metals / toxicity
  • Risk Assessment
  • Water Pollutants, Chemical / analysis
  • Water Pollutants, Chemical / toxicity

Substances

  • Hazardous Substances
  • Hazardous Waste
  • Metals
  • Water Pollutants, Chemical
  • Lead