Inventory of PCBs
Developing an inventory of persistent organic pollutants, contaminated locations, POP-containing materials and wastes is one of the first and most important steps towards the implementation of the Stockholm Convention on POPs at the national and regional levels, which shall be also complemented by a strategy to reduce POPs emissions and/or to eliminate them.
Following the obligations under the Stockholm Convention on POPs, a number of countries have developed a classification for PCB-containing liquids and substances. For example, Australia, the USA, Canada, the UK and Germany have the following norms in place:
- Substances, containing more than 500 ppm of PCB, are considered pure PCB;
- Substances and equipment, containing 50-500ppm of PCB, are classified as PCB-containing;
- Substances and equipment, containing 5-50ppm of PCB, are considered to be potential sources of PCB;
- Substances and equipment, containing less than 5ppm of PCB, are not considered to contain PCB.
The Swedish system to estimate the content of hazardous substances employs mass percentage as a criterion. The mass percentage of 0.1% of PCB is regarded as critical.
Up until now, Russia has had no standards on the content of PCBs in equipment and substances subject to special regulation, as well as no regulations on an inventory of PCBs and on the management of this type of hazardous objects. Nevertheless, a certain work in this field is conducted by the Federal Supervisory Service for natural resource management and by the Ministry of natural resources and ecology of the Russian Federation. For example, the Government of Russia is currently considering a number of draft normative legal acts on the inventorization procedure of equipment and substance containing or using PCBs, as well as on introducing regulations on the treatment of such equipment and substances. It was proposed to introduce special regulatory measures, such as developing a national inventory of POPs and supervising the compliance with the treatment requirements for this group of hazardous substances.
Yet, as important as special regulations for the management of PCBs are, the identification of PCB-contaminated objects appears to be even of a higher importance. As a first step to it, systems that might contain PCBs shall be identifies. Such systems may include:
- Closed systems: electrical transformers, capacitors, some electrical engines in cooling systems and electromagnets;
- Partially closed system: oil switches, vacuum pumps, hydraulic liquids of drilling equipment, heat transfer fluids etc.;
- Open systems: lubricants, plasticizers used in the production of polyvinylchloride (PVC) and sealers; surface coatings, casting wax and adhesive coatings.
In addition, such substances and objects as used oils, out-of-service oil-filled equipment, vapours and spills at disposal sites, buildings to be wrecked (fine cement kiln dust and impregnation components, fire-resistant coatings of integral panels), waste burning systems, excavation of mud and water during bottom fortification works, and other instances of unintended PCB emissions shall be subject to inventorization.
Although the list of potential sources of PCBs appears quite long, a number of studies has identified that not more than 7-10% of all equipment and substances are in fact contaminated with PCBs. The majority of contaminated objects was put into service in the 1960-1970ss. However, there are also cases of cross-contamination of newer materials and equipment. For example, the mineral oil which is used to refill PCB-contaminated power transformers gets contaminated with PCB as well.
In this regard, highly relevant appears the issue of instrumental control and analysis of potentially PCB-contaminated objects. Since the 1980s when the danger of PCBs to the health of humans and animals came to the attention of wider public, multiple analytical methods were developed to control for the content of PCB in respective substances. The methods included express-analysis which could identify only the presence of chlorinated molecules in the compound, as well as methods of deeper analysis – gas chromatography, thin layer chromatography and high-performance liquid chromatography. The latter three methods are able to not only estimate the mass percentage of hazardous substances in the analysed mixture, but also identify individual components. However, these methods are quite money and time consuming and require special equipment and skilled personnel.
To identify potential sources of PCB in closed and partially closed systems, a number of express-analysis methods were developed based on:
- Measuring the density of oil. The method compares the density of pure and PCB-containing oil in water. In the latter case, components subside in the water solution or float within the water column. Pure oil does not mix with water and forms as a thin layer at the surface (the method was invented by the company Tredi Int.);
- Measuring the chlorine content in transformer oil. There are several variations of this method - photometric identification of chlorine presence (based on the colour of the flame of burning oil), or potentiometric identification (based on the difference of potentials or of electrical conductivity of the oil solution). The methods were invented by Hach Comoany and Dexsil Corporation.
These express-methods help to identify a potential presence of PCBs in the oil. However, the actual presence of hazardous substances and their concentration can be determined by the chromatography methods described above.
For a long time, Russia had no methodology documents to analyse the surrounding environment and materials for PCB-contamination. Although scientists in the USSR and then in Russia have developed methods to identify PCB in transformer oils, there were no unified national standards. Only in 2008-2012 there were introduced national standards (GOSTs) for the identification of PCB content in soil, water and food; and in 2013 – national standards for the identification of PCB in insulating fluids (GOST R MEK 61619-2013 “Insulating fluids. Identification of contamination with polychlorinated biphenyls with the method of gas chromatography with a capillary column”).
The Stockholm Convention on POPs sees the identification of contaminated objects as a primary step to create a framework for PCB management and their phase-out. Given the incompleteness of the analytical and normative methodological frameworks in this field in the past, a full scale identification of contaminated equipment, substances and wastes did not seem possible to be realized. However, today there are all prerequisites in place to initiate it, also thanks to the UNIDO project on the environmentally sound management of PCBs and elimination of more than 3800t of contaminated oil and waste.
Within the project, 50.000 samples of condenser oil will be analysed. In addition to a methodological framework, there shall be also a network of certified laboratories. In Russia, given its size, it is one of the critical challenges to be addressed. To fulfil the obligations under the Stockholm Convention on time (the phase-out of PCB-containing equipment by 2025, final disposal – by 2028) it is necessary to create such a network of laboratories, as well as train the personnel and introduce a monitoring system over such measurements (interlab analysis on a regular basis).
At the moment, there are only a few laboratories in Russia certifies to conduct the analysis of PCBs in condenser oils and in the environment. These laboratories are located in the Central, Privolzhsky, North-Caucasian and Far-Easter federal district. For a huge country like Russia it is extremely few. It shall be mentioned that not a single centre of laboratory analysis and technological inspection of the Federal Supervisory Service for the management of natural resources and of the Federal Service of technological, environmental and nuclear supervision is certified to control for PCBs in insulating fluids. There can be no successful inventorization of PCBs without a broad network of laboratories and reference centres, including those under the authority of executive bodies.
Hence, the issue of POPs inventorization and POPs monitoring system, also exclusively for PCBs (which is stated in the Stockholm Convention on POPs), cannot be tackled without a state interference. Developing a normative methodological framework and making inventorization of equipment obligatory will require a network of laboratories equipped up-to-date, a pool of trained chemists, and the involvement of the proprietors of power equipment into the inventorization process. All of these issues shall be addressed already today.