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Disease and Injury Patterns

Monday, 28 March 2011 20:24

Injuries and Non-malignant Diseases

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Injuries

Only limited statistics are available on accident rates in general in this industry. Compared to other manufacturing industries, the 1990 accident rate in Finland was below the average; in Canada, the rates from 1990 to 1994 were similar to other industries; in the United States, the 1988 rate was slightly above average; in Sweden and Germany, the rates were 25% and 70% above the average (ILO 1992; Workers’ Compensation Board of British Columbia 1995).

The most commonly encountered risk factors for serious and fatal accidents in the pulp and paper industry are the papermaking equipment itself and the extreme size and weight of pulp or paper bales and rolls. In a 1993 United States government study of occupational fatalities from 1979 to 1984 in pulp, paper and paperboard mills (US Department of Commerce 1993), 28% were due to workers being caught in or between rotating rolls or equipment (“nip-points”) and
18% were due to workers being crushed by falling or tumbling objects, especially rolls and bales. Other causes of multiple deaths included electrocution, hydrogen sulphide and other toxic gas inhalation, massive thermal/chemical burns and one case of heat exhaustion. The number of serious accidents associated with paper machines has been reported to decrease with the installation of newer equipment in some countries. In the converting sector, repetitive and monotonous work, and the use of mechanized equipment with higher speeds and forces, has become more common. Although no sector-specific data are available, it is expected that this sector will experience greater rates of over-exertion injuries associated with repetitive work.

Non-Malignant Diseases

The most well documented health problems encountered by pulp mill workers are acute and chronic respiratory disorders (Torén, Hagberg and Westberg 1996). Exposure to extremely high concentrations of chlorine, chlorine dioxide or sulphur dioxide may occur as a result of a leak or other process upset. Exposed workers may develop acute chemical-induced lung injury with severe inflammation of air passages and release of fluid into the air spaces, requiring hospitalization. The extent of damage depends on the duration and intensity of the exposure, and the specific gas involved. If the worker survives the acute episode, complete recovery may occur. However, in less intense exposure incidents (also usually as a result of process upsets or spills), acute exposure to chlorine or chlorine dioxide may trigger the subsequent development of asthma. This irritant-induced asthma has been recorded in numerous case reports and recent epidemiological studies, and current evidence indicates that it may persist for many years following the exposure incident. Workers similarly exposed who do not develop asthma may experience persistently increased nasal irritation, cough, wheezing and reduction in airflow rates. Workers most at risk for these exposure incidents include maintenance workers, bleach plant workers and construction workers at pulp mill sites. High levels of chlorine dioxide exposure also cause eye irritation and the sensation of seeing halos around lights.

Some mortality studies have indicated increased risk of death from respiratory disease among pulp mill workers exposed to sulphur dioxide and paper dust (Jäppinen and Tola 1990; Torén, Järvholm and Morgan 1989). Increased respiratory symptoms have also been reported in sulphite mill workers who are chronically exposed to low levels of sulphur dioxide (Skalpe 1964), although increased airflow obstruction is not normally reported among pulp mill populations in general. Symptoms of respiratory irritation are also reported by workers exposed to high air concentrations of terpenes in turpentine recovery processes often present at pulp mill sites. Soft paper dust has also been reported to be associated with increased asthma and chronic obstructive pulmonary disease (Torén, Hagberg and Westberg 1996).

Exposure to micro-organisms, especially around wood chip and waste piles, debarkers and sludge presses, creates an increased risk for hypersensitivity responses in the lungs. Evidence for this appears to be limited to isolated case reports of hypersensitivity pneumonitis, which can lead to chronic lung scarring. Bagassosis, or hypersensitivity pneumonitis associated with exposure to thermophylic micro-organisms and bagasse (a sugar cane by-product), is still seen in mills using bagasse for fibre.

Other respiratory hazards commonly encountered in the pulp and paper industry include stainless steel welding fumes and asbestos (see “Asbestos,” “Nickel” and “Chromium” elsewhere in the Encyclopaedia). Maintenance workers are the group most likely to be at risk from these exposures.

Reduced sulphur compounds (including hydrogen sulphide, dimethyl disulphides and mercaptans) are potent eye irritants and may cause headaches and nausea in some workers. These compounds have very low odour thresholds (ppb range) in individuals not previously exposed; however, among long-time workers in the industry, odour thresholds are considerably higher. Concentrations in the range of 50 to 200 ppm produce olfactory fatigue, and subjects can no longer detect the distinctive “rotten eggs” odour. At higher concentrations, exposure will result in unconsciousness, respiratory paralysis and death. Fatalities associated with exposure to reduced sulphur compounds in confined spaces have occurred at pulp mill sites.

Cardiovascular mortality has been reported to be increased in pulp and paper workers, with some exposure-response evidence suggesting a possible link with exposure to reduced sulphur compounds (Jäppinen 1987; Jäppinen and Tola 1990). However, other causes for this increased mortality may include noise exposure and shift work, both of which have been associated with increased risk for ischaemic heart disease in other industries.

Skin problems encountered by pulp and paper mill workers include acute chemical and thermal burns and contact dermatitis (both irritant and allergic). Pulp mill workers in kraft process mills frequently experience alkali burns to the skin as a result of contact with hot pulping liquors and calcium hydroxide slurries from the recovery process. Contact dermatitis is reported more frequently among paper mill and converting workers, as many of the additives, defoaming agents, biocides, inks and glues used in paper and paper-product making are primary skin irritants and sensitizers. Dermatitis may occur from exposure to the chemicals themselves or from handling freshly treated paper or paper products.

Noise is a significant hazard throughout the pulp and paper industry. The US Department of Labor estimated that noise levels over 85 dBA were found in over 75% of plants in the paper and allied products industries, compared to 49% of plants in manufacturing in general, and that over 40% of workers were exposed regularly to noise levels over 85 dBA (US Department of Commerce 1983). Noise levels around paper machines, chippers and recovery boilers tend to be well over 90 dBA. Conversion operations also tend to generate high noise levels. Reduction in worker exposure around paper machines is usually attempted by the use of enclosed control rooms. In converting, where the operator is usually stationed next to the machine, this type of control measure is seldom used. However where converting machines have been enclosed, this has resulted in decreased exposure to both paper dust and noise.

Excessive heat exposure is encountered by paper mill workers working in paper machine areas, with temperatures of 60°C being recorded, although no studies of the effects of heat exposure in this population are available in the published scientific literature.

 

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Monday, 28 March 2011 20:25

Cancer

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Exposures to numerous substances designated by the International Agency for Research on Cancer (IARC) as known, probable and possible carcinogens may occur in pulp and paper operations. Asbestos, known to cause lung cancer and mesothelioma, is used to insulate pipes and boilers. Talc is used extensively as a paper additive, and can be contaminated with asbestos. Other paper additives, including benzidine-based dyes, formaldehyde and epichlorohydrin, are considered probable human carcinogens. Hexavalent chromium and nickel compounds, generated in stainless-steel welding, are known lung and nasal carcinogens. Wood dust has recently been classified by IARC as a known carcinogen, based mainly on evidence of nasal cancer among workers exposed to hardwood dust (IARC, 1995). Diesel exhaust, hydrazine, styrene, mineral oils, chlorinated phenols and dioxins, and ionizing radiation are other probable or possible carcinogens which may be present in mill operations.

Few epidemiological studies specific to pulp and paper operations have been conducted, and they indicate few consistent results. Exposure classifications in these studies have often used the broad industrial category “pulp and paper”, and even the most specific classifications grouped workers by types of pulping or large mill areas. The three cohort studies in the literature to date involved fewer than 4,000 workers each. Several large cohort studies are currently under way, and IARC is coordinating an international multicentric study likely to include data from more than 150,000 pulp and paper workers, allowing much more specific exposure analyses. This article will review the available knowledge from studies published to date. More detailed information may be obtained from earlier published reviews by IARC (1980, 1987, and 1995) and by Torén, Persson and Wingren (1996). Results for lung, stomach and haematological malignancies are summarized in table 1.

Table 1. Summary of studies on lung cancer, stomach cancer, lymphoma and leukaemia in pulp and paper workers

Process
description

Location
of study

Type of
study

Lung
cancer

Stomach
cancer

Lymphoma
NHL/HD
§

Leukaemia

Sulphite

Finland

C

0.9

1.3

X/X

X

Sulphite

USA

C

1.1

0.7

0.9

Sulphite

USA

C

0.8

1.5

1.3/X

0.7

Sulphite

USA

PM

0.9

2.2*

2.7*/X

1.3

Sulphate

Finland

C

0.9

0.9

0/0

X

Sulphate

USA

C

0.8

1.0

2.1/0

0.2

Sulphate

USA

PM

1.1

1.9

1.1/4.1*

1.7

Chlorine

Finland

C

3.0*

Sulphite/paper

Sweden

CR

2.8*

Paper dust

Canada

CR

2.0*

Paper mill

Finland

C

2.0*

1.7

X/X

Paper mill

Sweden

C

0.7*

Paper mill

USA

C

0.8

2.0

2.4

Paper mill

Sweden

CR

1.6

Paper mill

USA

PM

1.3

0.9

X/1.4

1.4

Board mill

Finland

C

2.2*

0.6

X/X

X

Power plant

Finland

C

0.5

2.1

Maintenance

Finland

C

1.3

0.3*

1.0/X

1.5

Maintenance

Sweden

CR

2.1*

0.8

Pulp and paper

USA

C

0.9

1.2

0.7/X

1.8

Pulp and paper

USA

C

0.8

1.2

1.7/X

0.5

Pulp and paper

Sweden

CR

0.8

1.3

1.8

1.1

Pulp and paper

Sweden

CR

2.2/0

Pulp and paper

Sweden

CR

1.1

0.6

Pulp and paper

USA

CR

1.2*

Pulp and paper

USA

CR

1.1

Pulp and paper

USA

CR

—/4.0

Pulp and paper

Canada

PM

1.2

3.8*/—

Pulp and paper

USA

PM

1.5*

0.5

4.4/4.5

2.3

Pulp and paper

USA

PM

0.9

1.7*

1.6/1.0

1.1

Pulp and paper

USA

PM

0.9

1.2

1.5/1.9*

1.4

Pulp and paper

USA

PM

1.7*

1.4

1.6*

C = cohort study, CR = case-referent study, PM = proportionate mortality study.
* Statistically significant. § = Where separately reported, NHL = non Hodgkin lymphoma and HD = Hodgkin’s disease. X = 0 or 1 case reported, no risk estimate calculated, — = No data reported.

A risk estimate exceeding 1.0 means the risk is increased, and a risk estimate below 1.0 indicates decreased risk.

Source: Adapted from Torén, Persson and Wingren 1996.

Respiratory System Cancers

Maintenance workers in paper and pulp mills experience an increased risk of lung cancer and malignant mesotheliomas, probably because of their exposure to asbestos. A Swedish study showed a threefold increased risk of pleural mesothelioma among pulp and paper workers (Malker et al. 1985). When the exposure was further analysed, 71% of the cases had been exposed to asbestos, the majority having worked in mill maintenance. Elevations in lung cancer risk among maintenance workers have also been shown in Swedish and Finnish pulp and paper mills (Torén, Sällsten and Järvholm 1991; Jäppinen et al. 1987).

In the same Finnish study, a twofold increased risk of lung cancer was also observed among both paper mill and board mill workers. The investigators made a subsequent study restricted to pulp mill workers exposed to chlorine compounds, and found a threefold increased risk of lung cancer.

Few other studies of pulp and paper workers have shown increased risks for lung cancer. A Canadian study showed an increased risk among those exposed to paper dust (Siemiatycki et al. 1986), and US and Swedish studies showed increased risks among paper mill workers (Milham and Demers 1984; Torén, Järvholm and Morgan 1989).

Gastro-intestinal Cancers

Increased risk of stomach cancer has been indicated in many studies, but the risks are not clearly associated with any one area; therefore the relevant exposure is unknown. Socio-economic status and dietary habits are also risk factors for stomach cancer, and might be confounders; these factors were not taken into account in any of the studies reviewed.

The association between gastric cancer and pulp and paper work was first seen in a US study in the 1970s (Milham and Demers 1984). The risk was found to be even higher, nearly doubled, when sulphite workers were examined separately. US sulphite and groundwood workers were also found in a later study to run an increased risk of stomach cancer (Robinson, Waxweiller and Fowler 1986). A risk of the same magnitude was found in a Swedish study among pulp and paper mill workers from an area where only sulphite pulp was produced (Wingren et al. 1991). American paper, paperboard and pulp mill workers in New Hampshire and Washington state ran an increased mortality from stomach cancer (Schwartz 1988; Milham 1976). The subjects were probably a mixture of sulphite, sulphate and paper mill workers. In a Swedish study, threefold increased mortality due to stomach cancer was found in a group comprising sulphite and paper mill workers (Wingren, Kling and Axelson 1985). The majority of pulp and paper studies reported excesses of stomach cancer, though some did not.

Due to the small number of cases, most studies of other gastrointestinal cancers are inconclusive. An increased risk of colon cancer among workers in the sulphate process and in paper board production has been reported in a Finnish study (Jäppinen et al. 1987), as well as among US pulp and paper workers (Solet et al. 1989). The incidence of biliary tract cancer in Sweden between 1961 and 1979 was linked with occupational data from the 1960 National Census (Malker et al. 1986). An increased incidence of cancer of the gallbladder among male paper mill workers was identified. Increased risks of pancreatic cancer have been observed in some studies of paper mill workers and sulphite workers (Milham and Demers 1984; Henneberger, Ferris and Monson 1989), as well as in the broad group of pulp and paper workers (Pickle and Gottlieb 1980; Wingren et al. 1991). These findings have not been substantiated in other studies.

Haematological Malignancies

The issue of lymphomas among pulp and paper mill workers was originally addressed in a US study from the 1960s, where a fourfold increased risk of Hodgkin’s disease was found among pulp and paper workers (Milham and Hesser 1967). In a subsequent study, the mortality among pulp and paper mill workers in the state of Washington between 1950 and 1971 was investigated, and a doubled risk of both Hodgkin’s disease and multiple myeloma was observed (Milham 1976). This study was followed by one analysing mortality among pulp and paper union members in the United States and Canada (Milham and Demers 1984). It showed almost a threefold increased risk for lymphosarcoma and reticulum cell sarcoma among sulphite workers, while sulphate workers had a fourfold increased risk of Hodgkin’s disease. In a US cohort study, sulphate workers were observed to have a twofold risk of lymphosarcoma and reticulosarcoma (Robinson, Waxweiller and Fowler 1986).

In many of the studies where it was possible to investigate the occurrence of malignant lymphomas, an increased risk has been found (Wingren et al. 1991; Persson et al. 1993). Since the increased risk occurs both in sulphate and sulphite mill workers, this points towards a common source of exposure. In the sorting and chipping departments, the exposures are rather similar. The workforce is exposed to wood dust, terpenes and other extractable compounds from the wood. In addition, both pulping processes bleach with chlorine, which has the potential to create chlorinated organic by-products, including small amounts of dioxins.

Compared with lymphomas, studies on leukaemias show less consistent patterns, and the risk estimates are lower.

Other Malignancies

Among US paper mill workers with presumed exposure to formaldehyde, four cases of urinary tract cancer were found after 30 years’ latency, although only one was expected (Robinson, Waxweiller and Fowler 1986). All of these individuals had worked in the paper-drying areas of the paper mills.

In a case-control study from Massachusetts, central nervous system tumours in childhood were associated with an unspecified paternal occupation as a paper and pulp mill worker (Kwa and Fine 1980). The authors regarded their observation as a random event. However, in three subsequent studies, increased risks were also found (Johnson et al. 1987; Nasca et al. 1988; Kuijten, Bunin and Nass 1992). In studies from Sweden and Finland, two- to threefold increased risks of brain tumours were observed among pulp and paper mill workers.

 

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Monday, 28 March 2011 20:27

Environmental and Public Health Issues

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Because the pulp and paper industry is a large consumer of natural resources (i.e., wood, water and energy), it can be a major contributor to water, air and soil pollution problems and has come under a great deal of scrutiny in recent years. This concern appears to be warranted, considering the quantity of water pollutants generated per tonne of pulp (e.g., 55 kg of biological oxygen demand, 70 kg of suspended solids, and up to 8 kg of organochlorine compounds) and the amount of pulp produced globally on an annual basis (approximately 180 million tonnes in 1994). In addition, only about 35% of used paper is recycled, and waste paper is a major contributor to total worldwide solid waste (about 150 million of 500 million tonnes annually).

Historically, pollution control was not considered in the design of pulp and paper mills. Many of the processes used in the industry were developed with little regard for minimizing effluent volume and pollutant concentration. Since the 1970s, pollution abatement technologies have become integral components of mill design in Europe, North America and other parts of the world. Figure 1 illustrates trends over the period 1980 to 1994 in Canadian pulp and paper mills in response to some of these environmental concerns: increased use of wood waste products and recyclable paper as fibre sources; and decreased oxygen demand and chlorinated organics in wastewater.

Figure 1. Environmental indicators in Canadian pulp and paper mills, 1980 to 1994, showing use of wood waste and recyclable paper in production, and biological oxygen demand (BOD) and  organochlorine compounds (AOX) in wastewater effluent.

PPI140F1

This article discusses the major environmental issues associated with the pulp and paper process, identifies the sources of pollution within the process and briefly describes control technologies, including both external treatment and in-plant modifications. Issues arising from wood waste and anti-sapstain fungicides are dealt with in more detail in the chapter Lumber.

Air Pollution Issues

Air emissions of oxidized sulphur compounds from pulp and paper mills have caused damage to vegetation, and emissions of reduced sulphur compounds have generated complaints about “rotten egg” odours. Studies among residents of pulp mill communities, in particular children, have shown respiratory effects related to particulate emissions, and mucous membrane irritation and headache thought to be related to reduced sulphur compounds. Of the pulping processes, those with the greatest potential to cause air pollution problems are chemical methods, in particular kraft pulping.

Sulphur oxides are emitted at the highest rates from sulphite operations, especially those using calcium or magnesium bases. The major sources include batch digester blows, evaporators and liquor preparation, with washing, screening and recovery operations contributing lesser amounts. Kraft recovery furnaces are also a source of sulphur dioxide, as are power boilers which use high-sulphur coal or oil as fuel.

Reduced sulphur compounds, including hydrogen sulphide, methyl mercaptan, dimethyl sulphide and dimethyl disulphide, are almost exclusively associated with kraft pulping, and give these mills their characteristic odour. The major sources include the recovery furnace, digester blow, digester relief valves, and washer vents, though evaporators, smelt tanks, slakers, the lime kiln and waste water may also contribute. Some sulphite operations use reducing environments in their recovery furnaces and may have associated reduced sulphur odour problems.

Sulphur gases emitted by the recovery boiler are best controlled by reducing emissions at the source. Controls include black liquor oxidation, reduction in liquor sulphidity, low-odour recovery boilers and proper operation of the recovery furnace. Sulphur gases from digester blow, digester relief valves and liquor evaporation can be collected and incinerated - for example, in the lime kiln. Combustion flue gases can be collected using scrubbers.

Nitrogen oxides are produced as products of high-temperature combustion, and may arise in any mill with a recovery boiler, power boiler or lime kiln, depending on the operating conditions. The formation of nitrogen oxides can be controlled by regulating temperatures, air-fuel ratios and residence time in the combustion zone. Other gaseous compounds are minor contributors to mill air pollution (e.g., carbon monoxide from incomplete combustion, chloroform from bleaching operations, and volatile organics from digester relief and liquor evaporation).

Particulates arise mainly from combustion operations, though smelt-dissolving tanks can also be a minor source. More than 50% of pulp mill particulate is very fine (less than 1 μm in diameter). This fine material includes sodium sulphate (Na2SO4) and sodium carbonate (Na2CO3) from recovery furnaces, lime kilns and smelt-dissolving tanks, and NaCl from burning by-products of logs which have been stored in salt water. Lime kiln emissions include a significant amount of coarse particulates due to entrainment of calcium salts and sublimation of sodium compounds. Coarse particulate may also include fly ash and organic combustion products, especially from power boilers. Reduction of particulate concentrations can be achieved by passing flue gases through electrostatic precipitators or scrubbers. Recent innovations in power boiler technology include fluidized bed incinerators which burn at very high temperatures, result in more efficient energy conversion, and allow burning of less uniform wood waste.

Water Pollution Issues

Contaminated wastewater from pulp and paper mills can cause death of aquatic organisms, allow bioaccumulation of toxic compounds in fish, and impair the taste of downstream drinking water. Pulp and paper wastewater effluents are characterized on the basis of physical, chemical or biological characteristics, with the most important being solids content, oxygen demand and toxicity.

The solids content of wastewater is typically classified on the basis of the fraction that is suspended (versus dissolved), the fraction of suspended solids that is settleable, and the fractions of either that are volatile. The settleable fraction is the most objectionable because it may form a dense sludge blanket close to the discharge point, which rapidly depletes dissolved oxygen in the receiving water and allows the proliferation of anaerobic bacteria which generate methane and reduced sulphur gases. Although non-settleable solids are usually diluted by the receiving water and are therefore of less concern, they may transport toxic organic compounds to aquatic organisms. Suspended solids discharged from pulp and paper mills include bark particles, wood fibre, sand, grit from mechanical pulp grinders, papermaking additives, liquor dregs, by-products of water treatment processes and microbial cells from secondary treatment operations.

Wood derivatives dissolved in the pulping liquors, including oligosaccharides, simple sugars, low-molecular-weight lignin derivatives, acetic acid and solubilized cellulose fibres, are the main contributors to both biological oxygen demand (BOD) and chemical oxygen demand (COD). Compounds which are toxic to aquatic organisms include chlorinated organics (AOX; from bleaching, especially kraft pulp); resin acids; unsaturated fatty acids; diterpene alcohols (especially from debarking and mechanical pulping); juvabiones (especially from sulphite and mechanical pulping); lignin degradation products (especially from sulphite pulping); synthetic organics, such as slimicides, oils and greases; and process chemicals, papermaking additives and oxidized metals. The chlorinated organics have been of particular concern, because they are acutely toxic to marine organisms and may bioaccumulate. This group of compounds, including the polychlorinated dibenzo-p-dioxins, have been the major impetus for minimizing chlorine use in pulp bleaching.

The amount and sources of suspended solids, oxygen demand and toxic discharges are process-dependent (table 1). Due to the solubilization of wood extractives with little or no chemical and resin acid recovery, both sulphite and CTMP pulping generate acutely toxic effluents with high BOD. Kraft mills historically used more chlorine for bleaching, and their effluents were more toxic; however, effluents from kraft mills which have eliminated Cl2 in bleaching and use secondary treatment typically exhibit little acute toxicity if any, and subacute toxicity has been greatly reduced.

 

Table 1. Total suspended solids and BOD associated with the untreated (raw) effluent of various pulping processes

Pulping Process

Total Suspended Solids (kg/tonne)

BOD (kg/tonne)

Groundwood

50–70

10–20

TMP

45–50

25–50

CTMP

50–55

40–95

Kraft, unbleached

20–25

15–30

Kraft, bleached

70–85

20–50

Sulphite, low-yield

30–90

40–125

Sulphite, high-yield

90–95

140–250

De-inking, non-tissue

175–180

10–80

Waste paper

110–115

5–15

 

Suspended solids have become less of a problem because most mills utilize primary clarification (e.g., gravity sedimentation or dissolved air flotation), which removes 80 to 95% of the settleable solids. Secondary wastewater treatment technologies such as aerated lagoons, activated sludge systems and biological filtration are used for reducing BOD, COD and chlorinated organics in the effluent.

In-plant process modifications to reduce settleable solids, BOD and toxicity include dry debarking and log conveying, improved chip screening to allow uniform cooking, extended delignification during pulping, changes to digestion chemical recovery operations, alternative bleaching technologies, high-efficiency pulp washing, fibre recovery from whitewater and improved spill containment. However, process upsets (particularly if they result in intentional sewering of liquors) and operational changes (particularly the use of unseasoned wood with a higher percentage of extractives) may still cause periodic toxicity breakthroughs.

A relatively recent pollution control strategy to eliminate water pollution entirely is the “closed mill” concept. Such mills are an attractive alternative in locations that lack large water sources to act as process-supply or effluent-receiving streams. Closed systems have been successfully implemented in CTMP and sodium-base sulphite mills. What distinguishes closed mills is that liquid effluent is evaporated and the condensate is treated, filtered, then reused. Other features of closed mills are enclosed screen rooms, counter-current washing in the bleach plant, and salt control systems. Although this approach is effective at minimizing water pollution, it is not yet clear how worker exposures will be affected by concentrating all contaminant streams within the mill. Corrosion is a major issue facing mills using closed systems, and bacteria and endotoxin concentrations are increased in recycled process water.

Solids Handling

The composition of solids (sludges) removed from liquid effluent treatment systems varies, depending on their source. Solids from primary treatment principally consist of cellulose fibres. The major component of solids from secondary treatment is microbial cells. If the mill uses chlorinated bleaching agents, both primary and secondary solids may also contain chlorinated organic compounds, an important consideration in determining the extent of treatment required.

Prior to disposal, sludges are thickened in gravity sedimentation units and mechanically dewatered in centrifuges, vacuum filters or belt or screw presses. Sludges from primary treatment are relatively easy to dewater. Secondary sludges contain a large quantity of intracellular water and exist in a matrix of slime; therefore they require the addition of chemical flocculants. Once sufficiently dewatered, sludge is disposed of in land-based applications (e.g., spread on arable or forested land, used as compost or as a soil conditioner) or incinerated. Although incineration is more costly and can contribute to air pollution problems, it may be advantageous because it can destroy or reduce toxic materials (e.g., chlorinated organics) that could create serious environmental problems if they were to leach into the groundwater from land-based applications.

Solid wastes can be generated in other mill operations. Ash from power boilers can be used in road beds, as construction material and as a dust suppressant. Waste from lime kilns can be used to modify soil acidity and improve soil chemistry.

 

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Contents

Preface
Part I. The Body
Part II. Health Care
Part III. Management & Policy
Part IV. Tools and Approaches
Part V. Psychosocial and Organizational Factors
Part VI. General Hazards
Part VII. The Environment
Part VIII. Accidents and Safety Management
Part IX. Chemicals
Part X. Industries Based on Biological Resources
Agriculture and Natural Resources Based Industries
Beverage Industry
Fishing
Food Industry
Forestry
Hunting
Livestock Rearing
Lumber
Paper and Pulp Industry
Major Sectors and Processes
Disease and Injury Patterns
Resources
Part XI. Industries Based on Natural Resources
Part XII. Chemical Industries
Part XIII. Manufacturing Industries
Part XIV. Textile and Apparel Industries
Part XV. Transport Industries
Part XVI. Construction
Part XVII. Services and Trade
Part XVIII. Guides

Paper and Pulp Industry Additional Resources

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Paper and Pulp Industry References

Canadian Pulp and Paper Association. 1995. Reference Tables 1995. Montreal, PQ: CPPA.

Food and Agriculture Organization (FAO) of the United Nations. 1995. Pulp and Paper Capacities, Survey 1994-1999. Rome: FAO.

Henneberger, PK, JR Ferris, and RR Monson. 1989. Mortality among pulp and paper workers in Berlin. Br J Ind Med 46:658-664.

International Agency on the Research of Cancer (IARC). 1980. Monographs on the Evaluation of Carcinogenic Risks to Humans: Wood, Leather and Some Associated Industries. Vol. 25. Lyon: IARC.

—.1987. Monographs on the Evaluation of Carcinogenic Risks to Humans, Overall Evaluations of Carcinogenicity: An Updating of IARC Monographs. Vol. 1-42 (supplement 7). Lyon: IARC.

—.1995. Monographs on the Evaluation of Carcinogenic Risks to Humans: Wood Dust and Formaldehyde. Vol. 62. Lyon: IARC.

International Labour Organization (ILO). 1992. Social and Labour Issues in the Pulp and Paper Industry. Geneva: ILO.

Jäppinen, P. 1987. Exposure to Compounds, Cancer Incidence and Mortality in the Finnish Pulp and Paper Industry. Thesis, Helsingfors, Finland.

Jäppinen, P and S Tola. 1990. Cardiovascular mortality among pulp mill workers. Br J Ind Med 47:259-261.

Jäppinen, P, T Hakulinen, E Pukkala, S Tola, and K Kurppa. 1987. Cancer incidence of workers in the Finnish pulp and paper industry. Scand J Work Environ Health 13:197-202.

Johnson, CC, JF Annegers, RF Frankowski, MR Spitz, and PA Buffler. 1987. Childhood nervous system tumors—An evaluation of the association with paternal occupational exposure to hydrocarbons. Am J Epidemiol 126:605-613.

Kuijten, R, GR Bunin, and CC Nass. 1992. Parental occupation and childhood astrocytoma: Results of a case-control study. Cancer Res 52:782-786.

Kwa, SL and IJ Fine. 1980. The association between parental occupation and childhood malignancy. J Occup Med 22:792-794.

Malker, HSR, JK McLaughlin, BK Malker, NJ Stone, JA Weiner, JLE Ericsson, and WJ Blot. 1985. Occupational risks for pleural mesothelioma in Sweden, 1961-1979. J Natl Cancer Inst 74:61-66.

—. 1986. Biliary tract cancer and occupation in Sweden. Br J Ind Med 43:257-262.

Milham, SJ. 1976. Neoplasias in the wood and pulp industry. Ann NY Acad Sci 271:294-300.

Milham, SJ and P Demers. 1984. Mortality among pulp and paper workers. J Occup Med 26:844-846.

Milham, SJ and J Hesser. 1967. Hodgkin’s disease in woodworkers. Lancet 2:136-137.

Nasca, P, MS Baptiste, PA MacCubbin, BB Metzger, K Carton, P Greenwald, and VW Armbrustmacher. 1988. An epidemiologic case-control study of central nervous system tumors in children and parental occupational exposures. Am J Epidemiol 128:1256-1265.

Persson, B, M Fredriksson, K Olsen, B Boeryd, and O Axelson. 1993. Some occupational exposures as risk factors for malignant melanomas. Cancer 72:1773-1778.

Pickle, L and M Gottlieb. 1980. Pancreatic cancer mortality in Louisiana. Am J Public Health 70:256-259.
Pulp and Paper International (PPI). 1995. Vol. 37. Brussels: Miller Freeman.

Robinson, C, J Waxweiller, and D Fowler. 1986. Mortality among production workers in pulp and paper mills. Scand J Work Environ Health 12:552-560.


Schwartz, B. 1988. A proportionate mortality ratio analysis of pulp and paper mill workers in New Hampshire. Br J Ind Med 45:234-238.

Siemiatycki, J, L Richardson, M Gérin, M Goldberg, R Dewar, M Désy, S Campell, and S Wacholder. 1986. Association between several sites of cancer and nine organic dusts: Results from an hypothesis-generating case control study in Montreal, 1979-1983. Am J Epidemiol 123:235-249.

Skalpe, IO. 1964. Long-term effects of sulfur dioxide exposure in pulp mills. Br J Ind Med 21:69-73.

Solet, D, R Zoloth, C Sullivan, J Jewett, and DM Michaels. 1989. Patterns of mortality in pulp and paper workers. J Occup Med 31:627-630.

Torén, K, S Hagberg, and H Westberg. 1996. Health effects of working in pulp and paper mills: Exposure, obstructive airways diseases, hypersensitivity reactions, and cardiovascular diseases. Am J Ind Med 29:111-122.

Torén, K, B Järvholm, and U Morgan. 1989. Mortality from asthma and chronic obstructive pulmonary diseases among workers in a soft paper mill: A case referent study. Br J Ind Med 46:192-195.

Torén, K, B Persson, and G Wingren. 1996. Health effects of working in pulp and paper mills: Malignant diseases. Am J Ind Med 29:123-130.

Torén, K, G. Sällsten, and B Järvholm. 1991. Mortality from asthma, chronic obstructive pulmonary disease, respiratory system cancer among paper mill workers: A case referent study. Am J Ind Med 19:729-737.

US Department of Commerce. 1983. Pulp and Paper Mills. (PB 83-115766). Washington, DC: US Department of Commerce.

—.1993. Selected Occupational Fatalities Related to Pulp Paper and Paperboard Mills as Found in Reports of OSHA Fatality/Catastrophe Investigations. (PB93-213502). Washington, DC: US Department of Commerce.

Weidenmüller, R. 1984. Papermaking, the Art and Craft of Handmade Paper. San Diego, CA: Thorfinn International Marketing Consultants Inc.

Wingren, G, H Kling, and O Axelson. 1985. Gastric cancer among paper mill workers. J Occup Med 27:715.

Wingren, G, B Persson, K Torén, and O Axelson. 1991. Mortality patterns among pulp and paper mill workers in Sweden: A case-referent study. Am J Ind Med 20:769-774.

Workers’ Compensation Board of British Columbia. 1995. Personal communication.