How to Remediate Pollution with Mercury and Hexachloro-Cyclohexane Residues in a Chemical Plant

Pollution of soil and underground water in a major chemical plant situated in Macedonia’s capital Skopje started some 30 years ago. Brine electrolysis plant was inevitably a source of pollution due to the (i) use of enormous quantities of mercury as a cathode in the electrolysis cells and (ii) a long and complex scheme of mercury circulation through the unit segments. Spilling of mercury is still present in soil and groundwater in concentrations that significantly exceed the legal allowances, no matter that plant’ operation was ceased 15 years ago.

Synthesis of hexachloro-cyclohexane (HCH), whose γ-isomer was the active component of insecticide ‘lindane’, was also a source of significant soil and groundwater pollution. 86 – 88% of each HCH-batch was of non-γ-isomers, so that some 30.000 - 35.000 tons of HCH-isomers did accumulate during the 14 years of HCH-unit operation. The by-products were temporary disposed in a concrete pool constructed specially for the purpose and covered with nonpermeable cover and top soil layer. As usually happens, nothing is as longlasting as the temporary attempts are, and today, some 30 years latter, the HCH residues are still in their concrete pool. Unfortunately, the pool’s content became accessible to rainfalls and the pool bottom started to leak, so that the soil and groundwater show results of heavy contamination with chlorinated hydrocarbons and products of HCH-decay.

In the meantime, with the rise of environmental concern, the problem was recognized, precisely identified and documented. Some proposals for its solution were elaborated, but the main objective remains untouched - how to provide funding for such an expensive treatment in a country that faces a lot of serious economic problems.

This paper deals with a number of details aimed at helping remediation of above described pollution. The aim is, if there is no possibility for urgent solving of the problem, just to keep it present on the agenda, and to stress it permanently until the solution is applied.