The dilemma of processing gold with cyanide

In the last decades, limit concentration values for environmentally dangero us synthetic and natural chemical substances have been established in the i ndustrialized countries. According to the range of application, state of ag gregation, propagation velocity, specific action on living organisms, long or short time effect, etc., different terms specify these limit concentrati ons (adi, TLV, LD50, immissions values, water quality standards, etc.). Sev eral parameters (e.g. range of application, ethic and social valuation, env ironmental factors, scientific knowledge) have lead to nationally and inter nationally varying values depending on region and time. The veracity of the thus developed system of evaluation cannot necessarily be improved by list ing further analytical data but rather by furnishing sufficiently secured s cientific data for a serious discussion with the public influenced more and more by the mass media. The best-established scientific knowledge has been acquired in the field of the chemical industry(1). National and internatio nal groups demand to deal with ecological-chemical problems in other fields of industry as well and this research could without doubt be intensified. Using the example of the mining industry which has to employ chemical metho ds in order to isolate small concentrations (ppm) we show the environmental conflict caused by the increasing world population requiring the adaptatio n of the process to the modem environmental concept. This is illustrated by the evolution of the gold recovery process.