Debate on mercury in energy-saving light bulbs
Take-back obligation for waste light bulbs
At the end of their life, energy-saving bulbs, which contain small quantities of mercury, must be collected separately from other wastes and disposed of properly. Lightcycle Retourlogistik und Service GmbH was founded by leading German light manufacturers, in order to organise the statutory take-back obligation for waste light bulbs (including fluorescent tubes, energy-saving bulbs and LED bulbs) Germany-wide on the basis of the Electrical and Electronic Act. This enables the raw materials of these bulbs to be reprocessed in an environmentally friendly way in recycling facilities.
Risks at the collection
When the energy saving bulbs are collected a small quantity of the lamps are unavoidably broken, and therefore a fraction of the mercury they contain is released. bifa carried out investigations on behalf of Lightcycle with the objective of evaluating the health risks to employees and customers due to the resulting potential mercury contamination.
Release rate of mercury
To this end it was necessary to determine the underlying data, missing until now – the release rate of mercury from broken old bulbs and the resulting mercury concentrations at the installation site. In order to enable the results to be applied to different installation locations and to enable any subsequent changes to the collection systems to be taken into account, the release rates were determined in several runs, as realistically as possible, but independently of the basic conditions in possible installation sites. In order to simulate different installation conditions, test series on the mercury release from broken energy-saving bulbs were performed under different basic conditions. From the measured release rates, based on the room size and ventilation, it was possible to calculate the average concentration in the room air for predefined scenarios. Breakage rates not relevant in practice were also generated to simulate concentration peaks.
Measurements on recycling depots
In addition to the supermarket and administration/public building scenarios, indicative measurements were also taken in various recycling depots with different local operating conditions. The result of the tests showed that only by applying massive force is it possible to break several lamps simultaneously and even if several bulbs are broken at the same time, the relevant workplace exposure limits are not exceeded. The mercury concentration peak lies within the first 15 minutes and then falls rapidly. This dilution is accelerated still further by fresh air supply. At increased temperature the release rates rise and therefore the concentrations in the room air rise too.
In the case of the indicative measurements only very small traces of mercury up to maximum 3 μg/m³ were detected. Apart from presenting the results and subsequent assessment, specific action recommendations were given for various collection points. The report was discussed with the client and representatives of the Federal Environmental Agency in a meeting of experts.