Wood preservation facilities, chromated copper arsenate: chapter B-10


10. Environmental and Workplace Monitoring

10.1 Baseline Environmental Evaluation

Considerable variability in natural concentrations of copper, chromium and arsenic occurs in soils and waters. Therefore, it is important to determine background levels of the site immediately prior to operating a facility, to enable meaningful future assessments of pollution control at the facility. Older facilities may not have this information available. A comparative site from a nearby property can be used as a reference. The facility may use the template provided in Part 1, Section 10, Table 24 from Chapter A.

Copper, chromium and arsenic, the components of CCA, are natural elements that at normal background concentrations (generally in Canada) do not have discernible adverse effects on biota. Table 24 presents a typical concentration of CCA constituents in a Canadian non-polluted environment (7, 13).

 

10.2 Environment Monitoring

There have been few studies of CCA releases from wood preservation facilities to the adjacent environment. Data compiled for regulatory purposes (19) indicate that when proper precautions are not taken, groundwater in the immediate vicinity of CCA facilities may be contaminated to levels that render it unsafe for human use. To a limited extent, stormwater runoff from CCA facilities has also been analyzed, and the results indicate that this water may contain at least one of the elements copper, chromium or arsenic at levels in excess of existing water quality limits (9). The studies also indicate that ratios of copper/chromium/arsenic are not consistent within runoff waters. The inconsistency may be due to differences in the ability of the components to bind to the yard soils or due to different sources within the yards (i.e. stored lumber washoff versus dripped material from freshly treated loads). Arsenic is persistent in the environment and close monitoring studies (such as surface water discharges, groundwater and contaminated soil) are recommended to properly assess the degree of such releases. Arsenic, copper and chromium are the minimum components that should be monitored for CCA facilities.

10.3 Workplace Exposure Monitoring

Workplace monitoring generally falls under provincial jurisdiction. Worker health programs should be developed with provincial and/or local regulatory agencies in consultation with a provincial workers’ compensation board and/or department of labour and/or industrial physician/industrial hygienist.

Studies of air quality at several CCA facilities have been reported (19, 20, 21); concentrations of arsenic, copper and chromium at those facilities were found to be below regulatory workplace standard action levels. The treatment process requires no external heat sources (except for kiln drying and in facilities applying accelerated fixation processes) and no vapours should be created. Air releases, if any, would be in the form of localized mists. The effect of a normal CCA facility on air quality of the surrounding environment is expected to be non-detectable.

The appropriate components of a site and worker exposure monitoring program are contained in Section 10.2 of Part I, Chapter A - General Recommendations for All Wood Preservatives: Table 25 - Recommended Routine Environmental Monitoring and Table 26 - Recommended Routine Workplace Monitoring.

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