Transformer Oils Potential for PCBs Contamination

Abstract

Polychlorinated biphenyls (PCBs) are a class of synthetic organic chemicals consisting of from one to ten chlorine atoms bonded totwo phenyl rings that create up 209 possible variations referred to as congeners. PCBs were commercially produced world-wide on a large scale between the 1930s and 1980sthat had been used widely in variety of commercial equipment like transformers, capacitors and other electrical equipment because of their useful quality as being a fire retardant. But due to their persistence and ubiquitous distribution in the environment, PCBs were banned from the U.S in the 1970s and internationally through the Stockholm Convention on Persistent Organic Pollutants. Although banned by law and punished heavily, large numbers of PCB-contaminated transformers are still in service. Thus, there remains a huge reservoir of PCBs with the potential to serve as sources of contamination to the environment. In this study, using EN 12766 test method: "Petroleum products and used oils-Determination of PCBs and related products", PCBs were analyzed in the random samples collected from different regions of Turkey. The samples also used for screening for the presence of total halogens and chlorine. Test results of the study showed that PCBs were present in certain transformers but concentrations in the most of samples did not exceed the limit value of 50 ppm.However, there was a significant relationship between the PCB concentrationsand the halogens.Finally, the contaminated transformer oils were evaluated according to Regulation on Control ofWaste Oils.

Levels and temporal trends of organochlorine contaminants in mussels from Spanish Mediterranean waters

“…PCBs were commercially produced world-wide on a large scale between the 1930s and 1980s. Given their extraordinary chemical stability and heat resistance, they were extensively employed as components of electrical and hydraulic equipment and as lubricants (Pelitli et al, 2015). Current sources of PCBs are landfills, open burning of products containing PCBs, waste incineration, accidental fires and volatilization from formerly exposed soils (Castro-Jiménez et al, 2008).…”

A simple and reliable method for separation of mineral oil/polychlorobiphenyl mixtures

“…Since the phaseout of PCBs, mineral oil (MO) has been used as an alternative in power transformers, especially due to its electromagnetic insulating power equivalent to that of PCBs ( Rouse, 1998 ), its wide distribution and its low cost compared to other fluids, such as silicone and synthetic or vegetable ester oils, available in the market ( Borsi and Gockenbach, 2005 ). However, transformer oils often contain variable amounts of PCBs ( Pelitli et al, 2015 ).…”

Improvement of Some Chemical and Electrical Properties of Aged Transformer Oil using Eco-Friendly Fillers

“…Many international convections forbid the usage of such additives in insulating oils with restricted terms in handling and selling any used oils containing PCBs, among those conventions is Stockholm convention in 2004. New studies approved that toxicity of PCBs lies in their damage effect to the reproductive, neurological and immune systems, also are known as carcinogenic compounds (Pelitli et al, 2015). These previous reasons were the base of new direction established by treatment of aged transformer oils via different techniques.…”