The purpose of this study is; inventory, verification, and testing the oil transformers in a closed system, for the presence of PCBs oil or mineral oil with PCBs; and to see if PCBs wasted quantities meet the requirements of the Stockholm Convention. Albania is a part of the Stockholm Convention since 1994. Mainly, this study tends to make an inventory of PCBs and assessment of the existing infrastructure of transformers and capacitors, and awareness of the staff in charge of transformers maintenance about the risks that PCBs cause in humans and the environment.
We analyzed mainly oil transformers which administrated from Armed Forces (AF) and some that were under the administration of Electricity Distribution Operator Albania (EDOA). Our study is performed during the years 2006, 2008 and 2011. Total analyzed samples were 194. Based on data, only three samples contained PCBs above 50 ppm.
Key-words: transformers, capacitors, PCBs, oil contaminated
Polychlorinated biphenyl (PCBs) are a class of organ chlorine aromatic compounds, which have been used for a long time in many countries in chemical industry, additive oils in electrical equipment, hydraulic machinery and many thermo stability applications ( WHO 1993; Bogdevich & Cadociniov 2004).
Polychlorinated biphenyls or PCBs are a subset of the synthetic organic chemicals known as chlorinated hydrocarbons. The chemical formula for PCBs is C12H(10-n) Cln, where is a number of chlorine atoms within the range of 1-10. The class includes all compounds with a biphenyl structure (i.e., two benzene rings linked together) that have been chlorinated to varying degrees. Theoretically, 209 congeners are, but only about 130 of these are likely to occur in commercial products (WHO 1993; Neumeier 1998).
Congeners of PCBs have low water solubility, non-flammable, chemically stable and lipophilic (WHO 1993; Fiedler, 1997). Based on their properties, they dispersed globally at environment do to food chain and accumulate mainly in fatty tissues or preferentially (WHO 1993; Tanable 1998). PCBs are presented in the environment anywhere, air, sediments, soil, water, fish, and mammals at adipose tissue and breast milk. Some studies reported PCBs mainly oral, inhalation and dermal exposure. They accumulate in liver and adipose tissues of mans, aqueous organism, birds, and animals. Some effects are reported in sea animals, rabbit and monkeys in reproductive system (WHO 1993). Chronic effects of low-level PCB exposures reported include liver damage, reproductive and developmental effects, and possibly cancer. The US Department of Health and Human Services as well as the International Agency for Research on Cancer (IARC) considers PCBs to be probable carcinogens in humans (ATSDR, 1997: IARC, 1987). Much of the data on effects of PCB exposure on humans comes from incidents of PCB contamination in cooking oil or food or from the long-term exposure to PCBs of capacitor manufacturing workers (IARC, 1987; ATSDR, 1989). Countries that have manufactured PCBs are United States, United Kingdom, Austria, China, Czechoslovakia, France, Germany, Italy, Japan, the Russian Federation, and Spain (Fiedler, 1997; Jakobi, 1996; Pesiakova et al 2018). These PCBs generally used in dielectric fluids from all state production and distribution. This shown that transformer oil is primary source pollution of PCBs in environmental.
All testing samples were done at Sector of Fuels and Oil Analyses at the Central Laboratory of Army Force. The study consists of three stages:
Sample analysis is done by using the test-kit, type Clor – N – OIL ®50. The Clor-N-Oil Test Kit works on principle of chlorine determination. Since PCBs are chlorine-based materials, the test kit is able to detect them. However, the test cannot distinguish between any another chlorine-containing compounds such as trichlorobenzene which may also be found in transformer oil. Clor-N-Oil 50 test kit classify them as either PCB or non-PCB (i.e., containing more or less than 50 µg/g) (EPA, 1996). With regard to the elimination of the use of polychlorinated biphenyls in equipment (e.g. transformers, capacitors or other receptacles containing liquid stocks) by 2025, subject to review by the Conference of the Parties, take action in accordance with the following priorities:
In table 1 show the origins of the transformers and the amount of oil that is located in each transformer. As seen in the table the highest numbers of transformers that are administered by the Armed Forces are manufactured in China and the latter are manufactured in Albania. Greater amount of oil we have to transformers China, and for this reason they are more in number. Chinese transformers are 45 years old, Albanian transformers aged 27-30 years and the Russian transformers have over 32 years. Considering that most of the transformers have been provided from Asia and Eastern Europe, the expectations that their oil is contaminated with PCBs.
The oil contained in all transformers by AF and EDOA is imported from various countries of Europe and Asia. The old transformers studied during this inventory are manufactured in China in 1963. In some transformers was noticed small leak at the concrete area and in-ground from transformers located in concrete pillars. Given the age of the transformers, it was first thought they might be contaminated with PCB, knowing that the largest amount of PCB has been produced during the period 1960-1980. But these results have shown that most part of the transformers is PCBs-free mineral oil. Only in three oil samples, the PCBs contain were above 50 ppm. All tested samples of capacitors oil resulted PCBs free mineral oil. We can’t come to a conclusion regarding the transformer’s maintenance issue about oil change, oil treatment, as far as there doesn’t exist any written data at all. The main purpose of this inventory meets the requirements of the Stockholm Convention. This study informs the staff for maintenance and treatment of transformer oil. Staff was informed about the risk that PCBs cause in humans and in the environment, the soil, surface water, groundwater and air.