PCB´s (and II): management barriers

No safe options for PCB treatment

PCBs are treated using thermal, chemical and biological methods. All generate problems on the one hand or on the other. Among them, incineration is the worst, since PCBs, because they contain chlorine in their molecule, are pioneers of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans. The process of thermochemical destruction called CTZ is based on the exothermic reaction between halogenated organic compounds and calcium silicates, in an oxygen-free environment and at a temperature of 600-800 °C. Any change of conditions in this system can result in the leakage of hazardous substances. Therefore, it is not entirely safe.

Among the chemical treatments there are several. The Sun Ohio PCBX is based on the use of organic sodium compounds, generating sodium chloride and degraded polymer residues. This system also disinfects in concentrations below 2 ppm. This system is being used in Canada and New Zealand.

On the other hand, the system called Basic Catalytic Dechlorination (BCD) uses high-pressure hydrogen gas for product dechlorination. The most negative is the risk of hydrogen gas explosion. In Euskal Herria there is a project that works with this system, which has not yet been launched and which is designed to transform lindane instead of treating PCBs. Greenpeace considers the most recommended among all PCB treatment systems.

PCBs can also be eliminated by biological degradation processes. This has been demonstrated through numerous studies to date. But this system has not yet been widely applied.

Storage can also be considered a treatment system. This does not eliminate the PCB, as it is a temporary option. However, keeping PCBs well isolated from the environment as appropriate treatments are invented seems an acceptable option. This method always requires adequate control mechanisms.

Ways to deal with the problem

Given the high danger of these compounds, an international agreement was signed to eliminate all PCBs by 2010. The Spanish State also adhered to the agreement called Parco Convention 92/3. For its part, the European Union published a Directive forcing all Member States to remove all PCBs before that year.

As for Spain and Hego Euskal Herria, the situation is quite dark. Although there are inventories of transformers and capacitors containing PCBs, the scope of the problem is still unclear for two reasons: on the one hand, inventories are not made public and on the other hand, estimates data are very different. Some say there are 65,000 tons of transformers and capacitors throughout the state and others give a figure of 115.00.

The little credibility of inventories is evident. There is currently a draft law under debate. In addition to an excessively generalist proposal, it leaves the management criteria of PCBs in the hands of autonomous associations. This can lead to situations of uncontrol. Furthermore, although it seems reasonable that the development of a good inventory is a primary condition for the correct management of this toxic compound, the legislative proposal does not clearly indicate that it is necessary to do so.