The RoHS requirement came into being as a way to remove potentially hazardous materials from coming into contact with people and from entering the world ecology through improper disposal. Beryllium (Be), cadmium (Cd), chromium (Cr), mercury (Hg), arsenic (As), and lead (Pb) are among the most common metals that bear discussion. They have not nearly the lethal level of polonium (Po) which is deadly at less than a billionth of a gram, but because of the amount produced every year their use and disposal needs to be controlled.
We in the chemicals industry have dealt with these metals and a host of other materials. As their hazardous nature became evident we have worked to minimize their use. Asbestos served admirably as a heat insulator and a reinforcement for plastic and metal composites. When asbestosis was researched that mineral’s use was rapidly curtailed and protective measure were implemented in its few remaining applications.
During the 19th century arsenic was used as an embalming fluid which subsequently polluted the ground and water supply near burial sites. This has now been replaced by formaldehyde (which has its own issues). The bright cadmium yellow in plastics have been replaced by organic azo compounds. Each time an issue was considered and proven, steps for amelioration were taken.
Closer to our industry, the lead in our solder-flowed printed circuit boards has been replaced by formulations high in tin (Sn) with small additions of copper (Cu) or silver (Ag). Formulations that meet the RoHS regulations are today so common as to be considered as the standard build, with lead-containing PCBs now a special order.
Still, with the widespread use of circuit boards at the end of their useful life we need to investigate methods of disposal that both reclaim the reusable constituents and minimize the toxic effects of the portion that must be discarded.
Many ecology-oriented investigations are European as is a paper written in Italy by Maria Paola Luda at the Dipartimento di Chimica IFM dell’Università di Torino. That paper on recycling PCBs was published by Intech Open who makes available works of over 100,000 authors on-line in a searchable database.
Awareness of our ecology is not strictly the pervue of tree-huggers. They demonstrate; we solve problems. Attached here for your perusal is Luda’s paper.