"Pulp and paper mills use a variety of chemical substances potentially hazardous to human health.
Compounds of both short- and long-term toxicological significance are found in workplaces, air emissions, and water effluent.
In this paper we evaluate the body of published literature on cancer associated with working in pulp and paper mills as well as in surrounding communities.
However, a new generation of study sophistication, international in scale and coordinated by the International Agency for Research on Cancer (IARC), has catalogued tens of thousands of exposure measurements made at a large number of work stations within the pulp and paper industry, allowing for greatly improved individual-level exposure assessments.
This approach reduces non-differential misclassification of exposure, increasing the power of these studies to detect exposure disease relationships, especially for rarer cancers.
Spent digester fluid is concentrated in evaporators and fed into the recovery furnace, which recycles solid sodium sulphide and combusts the organic component as a source of energy.
A lime kiln recovers calcium oxide for regeneration of the caustic component of the digester fluid.
Both chemical processes produce a relatively dark-coloured pulp that requires bleaching. The vast majority of the 47 bleached pulp mills operating in Canada through 1993 used the kraft method.7 Five mills employed the sulphite process.
Since about the 1960s, mills were required to perform primary treatment of effluent (i.e., settling out of large particulates before discharge). Today, however, Canadian mills are required by federal regulations to perform secondary treatment in addition. Most mills in Canada use aerated stabilization basins or activated sludge to remove oxygen-consuming materials and decrease the effluent toxicity, and this toxicity is monitored.8a
|Production area/job||Potential exposures|
|Raw wood preparation (i.e., debarking, chipping)||Wood volatiles, wood dust, spores, fungi, microbes|
|Production of cooking liquor||Sulphate: ammonia, hydrogen sulphide, sulphur dioxide, mercaptan, chromate and other contaminants|
Sulphite: sulphur, sulphur dioxide, calcium carbonate, zinc, sulphuric acid, lead fumes, asbestos, sulphurous acid
|Pulp production, cooking||Sulphate: lime, magnesium, wood volatiles|
Sulphite: pigments, dyes, wood volatiles
Ground wood: wood volatiles, aniline
|Pulp bleaching, bleach plant||Chlorine compounds, ozone, hydrogen peroxide, boron compounds, caustic acids|
|Wet pulp, paper additives||Talc, clays, titanium dioxide, urea and melamine formaldehyde, pigments, dyes|
|Paper rolling, sizing, dying, drying, glazing, coating||Urea and melamine formaldehyde, paper dust, coating and pigment dusts|
|Maintenance||General plant exposures, asbestos, welding fumes|
|Unknown jobs, power, utility||General plant exposures, asbestos|
|Unexposed jobs||No significant exposures|