3. Controls and Solutions
In this section the need for the safe destruction of the vast quantities of PCBs currently in use and in storage is examined. The environmental and health problems are summarized and a brief historical background is provided for the Canadian experience. Finally the actual size of the current PCB problem in Canada is given.
3.1 Environmental and Health Problems
Certain synthetic substances included in the class collectively known as chlorinated organic compounds, and used extensively in a number of industries today, are the subject of growing concern as environmental pollutants because of both their persistence and their wide dispersal. Prominent among them are polychlorinated biphenyls (PCBs). Because of this excessive persistence in the environment and the harmful effects of long-time, low-level exposure, PCB have become a global environmental problem.
For many years, isolated reports of the toxic effects of PCB in the industrial medical literature caused little general interest. More recently, public concern was aroused by a number of incidents, the most serious being the contamination of rice oil in Japan in 1969 which affected 1 000 people.
3.2 Production, Distribution and Historic Disposal of PCBs
Ail PCBs produced in North America were manufactured by a single company called Monsanto. The production and distribution of PCB including disposal is shown in detail in Table 1. The export figures include exports to Canada which amounted to 22 000 tonnes between 1954 and 1975 when most of this commercial activity took place. Presently there remains approximately 16 000 tonnes in use and in storage in Canada, as explained in Section 3.3.
In the past, practices used in the United States and Canada for the disposal of PCBs were normal, accepted industrial practices. PCBs were incinerated as a manufacturing waste (probably to recover the chlorine content) or as a component of waste oil burned for its heat content or even as a component of ordinary solid waste. PCBs were sent to landfills and other municipal disposal facilities as part of the waste from capacitor and transformer manufacturing processes or as obsolete electrical equipment or associated with paper, plastics or oily wastes.
Table 1 American Production and Distribution of PCBs*
| |
|
(tonnes x 103) |
|
| Use: |
Transformers |
150 |
|
| (Total) |
Capacitors |
290 |
|
| |
Plasticizers |
52 |
570 originally used in the |
| |
Hydraulics and Lubricants |
36 |
USA prior to controls |
| |
Carbonless Copy Paper |
20 |
implementation |
| |
Misc. Industrial |
12 |
|
| |
Heat transfer |
9 |
|
| |
Petroleum additives |
1 |
|
| Use: |
Transformers |
136 |
|
| (Present) |
Capacitors |
205 |
345 in use following |
| (1975) |
Other Electrical |
4 |
implementation of regulatory controls |
| Disposal: |
Degraded Environmentally |
14 |
25 destroyed |
| |
Incinerated |
11 |
|
| |
Landfills - Cap. & Trans. Prod. |
50 |
|
| |
Waste |
|
|
| |
Elect. Equip. |
36 |
199 in environment |
| |
Paper, Plastics etc. |
45 |
|
| |
Free in Environment |
68 |
|
* EPA 1977
PCBs still in the environment amount to some 68 000 tonnes. Of this amount slightly less than half is found in the atmosphere. This suggests a fairly rapid exchange between atmosphere and land and water reservoirs. Atmospheric inputs to lakes and remote areas are therefore thought to be significant.
In the future, the disposal/destruction of PCBs will concentrate largely upon the 345 000 tonnes of PCB contained inside of various electrical equipment. Some PCB from the worst of the old chemical landfill sites across North America will be also destructed but this will not probably be a significant amount. A number of technologically sophisticated chemical landfills exist in the United States. They are approved to accept solid and liquid PCB waste (so called Annex II landfills) |
