Based on new data and requests from interested users, the revised second edition of the paper Pollutants in tannery effluents was prepared drawing on technical inputs by J. Buljan, I. Král, M. Bosnić, R. Daniels. This training material is primarily intended to meet the needs of tanners and people of different profiles associated with environmental protection in the leather industry in developing countries.

The environment is under increasing pressures from solid and liquid wastes as by-products from leather manufacture and tannery effluent create significant pollution unless there has been a form of treatment before discharge.  The industry has gained a negative image in the society with respect to its pollution potential and therefore the leather processing activity is facing a serious challenge.

The paper presents the main sources of pollution and typical pollution loads generated by tanning processes adopted by the tanneries in developing countries, volume(s) of wastewater discharged, the corresponding concentrations of main pollutants as well as the the table of widely prevailing discharge standards.

In this edition the main pollutants' parameters are elaborated in great detail, together with descriptions of their negative environmental impact. Air pollution and toxicity aspects are expanded and a concise chapter on Substances of Very High Concern, SVHC ( carcinogenic, mutagenic, bioaccumulative, persistent etc.) introduced. One can also find photos of equipment used for laboratory analysis.

For the country-wise overview of discharge standards (admittedly somewhat obsolete) please refer to Part II of the first edition.