This article was downloaded by: [University of Southern Queensland]On: 09 October 2014, At: 06:11Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registeredoffice: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK

Human and Ecological Risk Assessment:An International JournalPublication details, including instructions for authors andsubscription information:http://www.tandfonline.com/loi/bher20

Health Risk Assessment of Workers'Exposure to Organic Compounds in a TireFactoryErtan Durmusoglu a , Seda Aslan a , Esra Can a & Zehra Bulut aa Department of Environmental Engineering , University of Kocaeli ,Kocaeli, TurkeyPublished online: 24 Jan 2007.

To cite this article: Ertan Durmusoglu , Seda Aslan , Esra Can & Zehra Bulut (2007) Health RiskAssessment of Workers' Exposure to Organic Compounds in a Tire Factory, Human and Ecological RiskAssessment: An International Journal, 13:1, 209-222, DOI: 10.1080/10807030601105134

To link to this article: http://dx.doi.org/10.1080/10807030601105134

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the“Content”) contained in the publications on our platform. However, Taylor & Francis,our agents, and our licensors make no representations or warranties whatsoever as tothe accuracy, completeness, or suitability for any purpose of the Content. Any opinionsand views expressed in this publication are the opinions and views of the authors,and are not the views of or endorsed by Taylor & Francis. The accuracy of the Contentshould not be relied upon and should be independently verified with primary sourcesof information. Taylor and Francis shall not be liable for any losses, actions, claims,proceedings, demands, costs, expenses, damages, and other liabilities whatsoever orhowsoever caused arising directly or indirectly in connection with, in relation to or arisingout of the use of the Content.

This article may be used for research, teaching, and private study purposes. Anysubstantial or systematic reproduction, redistribution, reselling, loan, sub-licensing,systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

Human and Ecological Risk Assessment, 13: 209–222, 2007Copyright C© Taylor & Francis Group, LLCISSN: 1080-7039 print / 1549-7680 onlineDOI: 10.1080/10807030601105134

RISK COMMUNICATIONS: AROUND THE WORLD

Health Risk Assessment of Workers’ Exposure

to Organic Compounds in a Tire Factory

Ertan Durmusoglu, Seda Aslan, Esra Can, and Zehra BulutDepartment of Environmental Engineering, University of Kocaeli, Kocaeli, Turkey

ABSTRACTThis study focuses on a health risk assessment related to chemical exposure via in-

halation for workers in a tire factory. Specifically, several volatile organic compounds(VOCs) and semi-volatile organic compounds (SVOCs) were measured in the fourdifferent points of the vulcanization unit. A chemical transport model was devel-oped in order to better represent the workers’ exposure to the chemicals. Then, arisk assessment methodology was employed to evaluate the potential adverse healtheffects of the chemicals according to their carcinogenicities. Concentrations mea-sured near the milling machine and press in the vulcanization unit were generallyhigher than the respective occupational exposure limit values. The correspondingestimated cumulative cancer risks for the carcinogens at the each sampling pointwere higher than the designated acceptable risk level of 1 × 10−4. With respect tonon-carcinogenic risks, the hazard indexes, both individually and cumulatively, werelower than the specified level of one. The high cancer risk estimated in this studysuggests that the VOCs and SVOCs exposure for workers in the vulcanization unitshould not be neglected. The results obtained in this study are valuable to plantmanagers, government officials, and regulators in the risk evaluation process.

Key Words: volatile organic compounds (VOCs), semi-volatile organic compounds(SVOCs), health risk assessment, occupational health, rubber indus-try, vulcanization.

INTRODUCTION

Many factors related to the work environment, job content, and organizationalconditions interact with workers’ personal characteristics, their cultures, habits, andinfluence their work performance, job satisfaction, and health (Fischer et al. 1998).Certain jobs and even work environments are riskier for workers‘ health than others.

Received 9 September 2005; revised manuscript accepted 6 December 2005.Address correspondence to Dr. Ertan Durmusoglu, Assistant Professor, University of Kocaeli,Department of Environmental Engineering, Veziroglu Campus, 41040, Kocaeli, Turkey.E-mail: ertan@kou.edu.tr

209

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

E. Durmusoglu et al.

Many chemical hazards pose important threats to health, mainly in production areasof factories (Weeks et al. 1981; Vermeulen et al. 2001). During the last decade, therehas been increasing concern within the scientific community over the effects ofindoor air quality on workers‘ health (Jones 1999; Vermeulen 2001; Gromiec 2002;Chien et al. 2003). However, workers employed in the various industries are still atrisk despite the continuous measures adopted to improve their work conditions andenvironment (Fracasso et al. 1999). The tire industry is one of these industries thatpose significant threat to workers‘ health.

Tire industries are usually formed by five main components, namely general ser-vice department, compounding (weighing, mixing, reforming, washing, milling)department, inner tire tube department, vulcanizing department, and componentassembly department (Ke and Shunzhang 2000). Chemicals are released mainly dueto the several processes including the creation of the rubber mixture, mastication,shaping, vulcanization, and finishing. The tire manufacturing process includes themanufacture of rubber and placing additives in the rubber. It also includes the coat-ing of fabrics for the radial belts and bias plies and integrating them into the rubber.Additives are added before and during the processing. After the initial compositionof the mixture is created with an internal mixer, the shaping of the semi-finishedproduct is made with an extruder. The compression process, the transfer molding,and injection molding are used for vulcanization in presses. The vulcanization is aprocess in which rubber, through a change in its chemical structure, is converted to acondition in which the elastic properties are conferred or re-established or improvedor extended over a greater range of temperature. Large air contaminant fractionsare released during the vulcanization process.

A wide range of chemicals used in the rubber industry has been the subject ofmany epidemiological studies in different countries and, thus, the rubber industry isacknowledged by the World Health Organization’s (WHO’s) International Agencyfor Research on Cancer (IARC) to be a cancer-risk technology (IARC 2002). Epi-demiological studies on cancer risk among workers in the rubber industry haveshown the presence of a widespread risk for stomach, bladder, lung, laryngeal, andoesophageal cancer and leukemia (Peters et al. 1976; Delzell and Monson 1984; Bour-guetet al. 1997; Ke and Shunzhang 2000; Kogevinas et al. 1998; Monarca et al. 2001;Vermeulen et al. 2001; Ke and Shunzhang 2002). Epidemiological studies did notprovide information associating specific exposure with cancer risk; however, manymaterials that occur in the work atmosphere in the rubber industry are experimen-tal mutagens and carcinogens (Hedenstedt et al. 1981; Donner et al. 1983; Spiegel-halder 1983; Baranski et al. 1989; Fracasso et al. 1999; Vermeulen et al. 2001). Thesematerials include mineral oils, carbon black (extracts) containing polycyclic aro-matic hydrocarbons (PAHs), vulcanization fumes, some monomers (1,3-butadiene,acetonitrile, styrene, vinyl chloride, ethylene oxide), solvents, nitroso compoundsand aromatic amines, thiurams and dithiocarbamate compounds, ethylenethiourea,di(2-ethylhexyl) phthalate, di(2-ethylhexyl) adipate and hydrogen peroxide (Van Ertet al. 1980; Fishbein 1991; Fracasso et al. 1999; Monarca et al. 2001; Sielken and Valdez-Flores 2001; Gromiec 2002; IARC 2002). In addition to the IARC, these chemicalshave been also classified as probable and possible carcinogens by the U.S. Environ-mental Protection Agency (USEPA) (Delzell et al. 2001; Sielken and Valdez-Flores2001; Tsai et al. 2001). The combination of chemical exposures occurring in the tire

210 Hum. Ecol. Risk Assess. Vol. 13, No. 1, 2007

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

Health Risk Assessment of Tire Factory Workers

industry is probably more relevant to the cancer pattern observed than are singlecompounds or groups of compounds. The variety of exposures increases the like-lihood that there are interactive effects between two or more such agents and, inturn, that there is interaction with non-occupational factors (IARC 2002).

The subject of determining the probability of getting an undesirable health ef-fect from exposure to hazards is called “risk assessment” (USEPA 1986a; Asante-Duah1993). Risk assessment is one of the fastest evolving tools to evaluate the impact of thehazards on human health and to determine the level of treatment required to solvea specific environmental problem. It is also becoming the technique for develop-ing appropriate management strategies relating to hazardous chemicals (LaGregaet al. 1994; NJDEP 1994; Batchelor 1997; Tsai et al. 2001). Risk assessment has fouressential elements: hazard identification, dose-response assessment, exposure assess-ment, and risk characterization (NRC 1983). The risk is characterized by comparingestimated (or measured) concentrations in air, on skin or total daily intakes to theresults of the hazard assessment (Rennen et al. 2004). In order to quantify the humanhealth risks, chemicals are characterized as carcinogens and non-carcinogens. Themathematical expressions of risk differ for the two categories of chemicals. Non-carcinogens have a threshold below which they do not induce any adverse healtheffect. On the other hand, some risk is assumed for carcinogens at any dose, regard-less of how small (USEPA 1986a; Asante-Duah 1993).

Knowledge of ambient levels of chemicals in a factory is necessary to evolve aproper strategy to control and maintain healthy air quality for workers. Informationon pollution levels for Turkish industries is lacking. Moreover, concentrations oftarget organic compounds specified in the USEPA’s Compendium Method TO-17(USEPA 1999) are almost totally lacking. In this study, several air pollutants namelyvolatile organic compounds (VOCs) (Benzene, Xylene) and semi-volatile organiccompounds (SVOCs) (Anthracene, Biphenyl, Hydrazine, Naphthalene, N-nitrosodi-n-propylamine, Phenanthrene, Phenol) in the vulcanization working environmentof a tire factory in Turkey were measured. Following the measurements, a chemicaltransport model was developed to better represent the workers’ exposure to thechemicals. A health risk assessment methodology was then employed to evaluate thepotential adverse health effects of the chemicals according to their carcinogenicities.

MATERIALS AND METHODS

Air Sampling

The ambient air samples were taken with stationary samplers in the vulcanizationunit near to the following locations: the milling machine (sampling point 1), thevulcanization press (sampling point 2), the entrance (sampling point 3), and the exit(sampling point 4). The sampling time ranged from 4 to 6 h. Samples were takenin the locations where workers generally reside, at a height of approximately 1.75 mabove the ground to ensure they reflected conditions in the breathing zone of theworkers. The sampling method for VOCs was modified from the Method of TO-17suggested by the USEPA (1999). The VOCs were sampled through multi-bed sorbenttubes (Carbotrap 300, Supelco Inc.) with a vacuum pump operated at the rate of20 L/min. The sampling method for SVOCs was modified from the Method of 0010

Hum. Ecol. Risk Assess. Vol. 13, No. 1, 2007 211

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

E. Durmusoglu et al.

suggested by the USEPA (1986b). The SVOCs were sampled into approximately 10 gof XAD-2 resin (Supelco Inc.) that was placed in a quartz glass adsorption columnwith a vacuum pump operated at 20 L/min. Before all filters were sampled, sorbenttubes and adsorption columns were cleaned and extracted with methyl alcohol andmethylene chloride with a soxhlet apparatus. Then, the filters were dried with liquidnitrogen.

Chemical Analyzes of VOCs and SVOCs

In VOCs analyses, all samples were analyzed using thermal desorption coupledwith a Gas Chromatography/Mass Spectrometry (GC/MS) (Model 6890 plus GC& 5973 N MSD, Hewlett Packard Inc.) according to the USEPA’s Method TO-17(USEPA 1999). The samples were desorbed at 200◦C for 20 min. The GC/MS wasequipped with a DB 624 capillary column having 60 m of length (0.32 mm intervaldiameter and 1.8 μm thickness, J&W Scientific). Helium gas was used as the carriergas with a flow rate of 1.0 ml/min and a split ratio of 1:25. The GC oven was pro-grammed to hold 35◦C for 2 min then rising to 200◦C at a rate of 5◦C/min, thenbeing held for another 8 min. The mass ion source utilized electron impaction, andwas operated at 70 eV and 180◦C. The transfer line between the GC and MS was alsoset at 180◦C. The collected chemicals were identified based on similarity of the massspectra index to that of the Wiley Library System.

XAD-2 resins used for sampling SVOCs were extracted for 18 h with a soxhletapparatus having a 100-ml of mixture containing equal amounts of methyl alcoholand methylene chloride, and the extracts were concentrated to 2 ml. This proceduremodified from the USEPA’s Method 3542 (USEPA 1996). All glass apparatus was pre-cleaned with methylene chloride. The extracts were analyzed by the GC accordingto the USEPA’s Method 8270D (USEPA 1998). The GC was equipped with a 30-mcapillary column (0.32 mm interval diameter and 0.5 μm thickness, Supelco Inc.PTA-5) and mass spectrometer (5973 N MSD Hewlett Packard Inc.). Helium gas wasused as the carrier gas with a flow rate of 1.0 ml/min. The GC oven was programmedfor 40◦C, held for 2 min, and increased from 40 to 280◦C at a rate of 10◦C/min. Theinjection volume was 1 μL, splitless injection at 275◦C. The mass ion source utilizedelectron impaction, and was operated at 70 eV. The transfer line temperature wasalso set at 250◦C. Substances were estimated on the basis of degree of similarity ofthe mass spectra index to that of the Wiley Library System.

RESULTS AND DISCUSSION

In Table 1 are presented the measurements obtained for VOCs and SVOCs inthe vulcanization unit of the factory. As indicated before, the measurements werecarried out in the four different points in the vulcanization unit. As seen in Table 1,the concentrations measured in the sampling points 3 and 4 are below the detectionlimits except the concentration of Phenol in the sampling point 3. In addition, allof the concentrations in the sampling points 3 and 4 are below the limits establishedby the international standards. On the other hand, some of the results of the mea-surements in the sampling points 1 and 2 exceeded the international limits. Amongthe chemicals measured in the sampling points 1 and 2, Naphthalene, Phenol, andXylenes were below the limits. The other chemicals, on the other hand, exceeded

212 Hum. Ecol. Risk Assess. Vol. 13, No. 1, 2007

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

Health Risk Assessment of Tire Factory Workers

Table 1. VOC and SVOC concentrations in sampling points in the vulcanizationunit.

Concentrations (Co ) inSampling Points∗

Chemical CASRN 1 2 3 4ACGIH†

(TWA)∗OSHA‡(TWA)∗

Carc.Class+

Anthracene 120-12-7 0.053 5.36 <0.01 <0.01 ** 0.2 DBenzene 71-43-2 27.2 1.92 <0.01 <0.01 1.5 3.2 ABiphenyl 92-52-4 0.003 1.07 <0.01 <0.01 1 1 DHydrazine 302-01-2 4.26 8.00 <0.01 <0.01 0.013 1.3 B2n-Nitrosodi- 621-64-7 1.086 <0.01 <0.01 <0.01 ** ** B2

n-propylamineNaphthalene 91-20-3 1.09 0.63 <0.01 <0.01 50 50 DPhenanthrene 85-01-8 0.063 1.52 <0.01 <0.01 ** 0.2 DPhenol 108-95-2 1.61 0.30 0.79 <0.01 19 19 DXylenes 1330-20-07 3.72 0.35 <0.01 <0.01 435 435 D

∗all in mg/m3.∗∗not established.†ACGIH (1999).‡OSHA (2001).+designated by USEPA (A—Human carcinogen; B2—Probable human carcinogen; D—Notclassifiable as to human carcinogenicity).CASRN—Chemical Abstract Service Registry Numbers.TWA—Time Weighted Average (Concentration for a normal 8-hour workday and a 40-hourworkweek).

the limits in either sampling point 1 or 2. Hydrazine was the only chemical that wasexceeded the limits in the both sampling points 1 and 2.

The vulcanization unit is a closed area having a total volume of 150,000 m3. Thearea is continuously ventilated with atmospheric air in the rate of 1,250,000 m3/hfor 24 h a day. It should be noted that the measurements were carried out underthis continuous ventilation. In addition to this ventilation, a continuous productionprocess was taking place in the vulcanization unit. Therefore, in order to representthe conditions in the unit, a mass balance equation was developed based on the boxmodels. That is

Mass storage velocity = (Mass imput velocity) − (Mass output velocity) ± (Transformation)(1)

In equation (1), the mass input velocity includes the continuous emission fromthe production process within the unit and any chemical coming to the unit fromthe atmosphere due to the ventilation. The mass output velocity, however, includesthe chemicals released to the sampling area considered after the emission and ven-tilation taken place. The transformation considers the degradation of the chemicalsbased on the first-order rate constants during transportation in the air. Hence, themathematical expression of equation (1) can be expressed as

VdCout

dt= (E + QinCin) − (QoutCout) − (kV Cout) (2)

Hum. Ecol. Risk Assess. Vol. 13, No. 1, 2007 213

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

E. Durmusoglu et al.

where V = total volume of the sampling area [L3]; Cin = concentration of chemicalsin the inflow [M/L3]; Cout = concentration of chemicals in the outflow [M/L3];E = emission [M/T]; Qin = inflow rate [L3/T]; Qout = outflow rate [L3/T]; k =first-order rate constant for transformation [1/T]; and t = time [T].

If the inflow rate is assumed to be equal to the outflow rate (e.g., Qin = Qout), therearrangement of equation (2) gives

dCout

dt+

(QV

+ k)

Cout = E + QCin

V(3)

Here, equation (3) is a first order linear differential equation in the form of

dydt

+ P(t)y = Q(t) (4)

If equation (4) is solved, the resulting final equation would be

Cout = E + QCin

Q + kV−

(E + QCin

Q + kV− Co

)exp

(−

(QV

+ k)

t)

(5)

and

Css = E + QCin

Q + kV(6)

where Co = initial concentration of chemicals [M/L3] and Css = steady-state con-centration of chemicals [M/L3]. It should be noted that the initial concentrations(Co) are the measured values presented in Table 1.

Here, it was assumed that there is no chemical input from the atmosphere dueto the ventilation (e.g., Cin = 0). In equation (6), the emission (E ) can be estimatedbased on the following expression (UBA 2003)

E = QprodQadditive

100.FrecipeF (7)

where Qprod = amount of product type produced per day [M/T], Qadditive = parts ofadditive introduced per parts of 100 rubber [wt%], Frecipe = recipe factor [−], F =emission factor [−].

In this study, a daily generic production (Qprod) of 300 tons was considered. TheQadditive and Frecipe were assumed to be 3.8 and 2, respectively (UBA 2003). The emis-sion factor (F ) was estimated to be 0.001 based on the A-Tables (emission factors)of the European Union Technical Guidelines (TGD 2002) from IC-11 (polymerindustry) life cycle step “polymer processing.”

Employing equations (6) and (7) into equation (5) gives the concentrations ofchemicals that workers were exposed during the work hours (see Figure 1). Theconcentrations of the chemicals are lower than 0.1 and 0.01 mg/m3 in the points3 and 4, respectively. On the other hand, in the points 1 and 2, the concentrationsare generally above the 0.1 mg/m3. As seen in Figure 1, the points 1 and 2 are themajor sources of chemicals. The point 3 is the only exception for the Phenol source.Figure 2 presents the comparisons of the percentage each chemical contributes tothe total concentration in sampling points. Although most of the chemicals werequite equally contributed to the total concentration in the points 1, 2, and 4, Phenolis the major chemical released in the point 3.

214 Hum. Ecol. Risk Assess. Vol. 13, No. 1, 2007

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

Health Risk Assessment of Tire Factory Workers

Figure 1. Concentrations of chemicals estimated based on transport model.

Following determination of concentrations by equation (5), cancer risks for indi-vidual chemicals were calculated based on the following

CancerRisk = I × CPF (8)

where I = daily intake (mg/kg of body weightday) and CPF = carcinogen potencyfactor. The CPF is basically the slope of the dose-response curve at very low ex-posures. The dimensions of the CPF are expressed as the inverse of daily intake

Figure 2. Percent contribution of chemicals based on their concentrations in sam-pling points.

Hum. Ecol. Risk Assess. Vol. 13, No. 1, 2007 215

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

E. Durmusoglu et al.

(mg/kg·day)−1. A number of databases exist that document CPFs and other toxico-logical data for carcinogens. The Integrated Risk Information System (IRIS) (USEPA2003), the USEPA’s preferred source of toxicity information for hazardous wastes,was employed in this study. The parameters considered in determining the intakeof contaminants include exposure frequency, duration of exposure, and the bodyweight of the receptor (or worker). The following generic equation was used tocalculate the intake

I = Cout × CR × EF × E DBW × AT

(9)

where CR = contact rate [L3/T]; EF = frequency [−]; ED = exposure duration [T];BW = body weight [M]; and AT = averaging time [T]. Considerable research hasbeen done to define the parameters in equation (9), and they may be found in theliterature (Asante-Duah 1993; LaGrega et al. 1994). In this study, it was consideredthat each worker works 8 h every day except Sundays. Considering the 30 days ofannual vacation, one may found the exposure frequency for workers (EF) as 74days (=52 × 6/3-30). The air breathing rate for workers (CR) was assumed to be20 m3/day (USEPA 1989). The BW and ED are other important parameters thatmust be defined for calculating daily intake requirements. The USEPA recommendsstandard values of 70 kg and 30 years for the BW and ED, respectively (USEPA 1989).In addition, if exposure to carcinogens is averaged over a lifetime, the AT becomes70 years or 25,500 days. In Table 2 are presented the daily intakes calculated basedon the concentrations of chemicals presented in Figure 1.

Cancer risks for individual chemicals were summed for a Cumulative Cancer Risk(CCR). That is

CCR =∑

Individual Cancer Risks (10)

The individual risk values for carcinogens (Benzene, Hydrazine, and n-Nitrosodi-n-propylamine) considered in this study are presented in Figure 3. The risk predictedto be less than or equal to 1 in 1,000,000 (=1 × 10−6) is usually considered negligible

Figure 3. Individual health risks determined for carcinogens.

216 Hum. Ecol. Risk Assess. Vol. 13, No. 1, 2007

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

Tab

le2.

Dai

lyin

take

sfo

rw

orke

rsca

lcul

ated

insa

mpl

ing

poin

tsin

the

vulc

aniz

atio

nun

it.

Dai

lyIn

take

sin

Sam

plin

gA

reas

∗

Ch

emic

al1

23

4C

PF†

RfD

∗k

(hr)

−1

An

thra

cen

e0.

46×

10−4

0.47

×10

−20.

87×

10−5

0.87

×10

−50.

300.

0173

Ben

zen

e0.

45×

10−2

0.32

×10

−30.

17×

10−5

0.17

×10

−50.

029

0.00

22B

iph

enyl

0.13

×10

−40.

46×

10−2

0.43

×10

−40.

43×

10−4

0.05

0.01

30H

ydra

zin

e0.

16×

10−2

0.31

×10

−20.

38×

10−5

0.38

×10

−517

.10.

1155

n-N

itro

sodi

-0.

46×

10−2

0.43

×10

−40.

43×

10−4

0.43

×10

−47

0.00

72n

-pro

pyla

min

eN

aph

thal

ene

0.29

×10

−20.

17×

10−2

0.27

×10

−40.

27×

10−4

0.02

0.13

86Ph

enan

thre

ne

0.18

×10

−30.

45×

10−2

0.29

×10

−40.

29×

10−4

**0.

0173

Phen

ol0.

28×

10−2

0.51

×10

−30.

13×

10−2

0.17

×10

−40.

300.

1730

Xyl

enes

0.41

×10

−20.

39×

10−3

0,11

×10

−40,

11×

10−4

0.03

0.34

65

∗ all

inm

g/kg

·day.

† all

in(m

g/kg

·day)

−1.

∗∗n

otes

tabl

ish

ed.

217

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

E. Durmusoglu et al.

(USEPA 1991; Tam and Neumann 2004). On the other hand, the risk predictedto be greater than or equal to 1 in 1,000 (=1 × 10−3) was defined as a significantrisk by the U.S. Supreme Court in 1980 (Rodrics et al. 1987). In addition to thissetting, more recently, the level of the unacceptable risk was considered to be 1 ×10−4 (NJDEP 1994; Tam and Neumann 2004). As seen in Figure 3, the individualrisks for all of the carcinogens in sampling points 1 and 2 are exceeded 1 × 10−6.The risk levels exceeding 1 × 10−6 ranged between 5.16 × 10−2 for Hydrazine to8.97 × 10−6 for Benzene both at the sampling point 2. The individual risk levelsfor Benzene and Hydrazine in the sampling points 3 and 4 are lower than 1 ×10−4 and, thus, they may be considered acceptable. The risk of Benzene in thesampling points 3 and 4 is the only one that is considered to be negligible. TheCCRs estimated by equation (10) in the sampling points 1, 2, 3, and 4 are 5.96 ×10−2, 5.19 x 10−2, 4 × 10−4 and 4 × 10−4, respectively. It can be seen that all valuesare clearly higher than the designated acceptable risk level of 1 × 10−4. Therefore,the cancer risks predicted in the four sampling points are considered significant.It should be concluded that the current ventilation is not enough, being the onlycontrol measure for carcinogens. Therefore, a risk management decision needs tobe implemented in order to prevent or limit the workers’ exposure. Because the risksare higher in the sampling points 1 and 2, it would be better to isolate these two areasfrom the rest of the unit. Another suggestion might be increasing the outflow rate bymeans of more ventilation. It should be noted that workers were assumed not to bewearing any individual respiratory equipment in the aforementioned calculations,based on knowledge of the manufacturing process.

An assessment of the toxicity of non-carcinogens is based on the concept of thresh-old below which no adverse health effects can be observed. Instead of establishinga threshold value, it is common to use the term Reference Dose (RfD) to representthe level of daily intake of a particular substance that should not produce an adversehealth effect (LaGrega et al. 1994). Non-carcinogenic risk is characterized in termsof a Hazard Index (HI). This index for non-carcinogenic chemicals is calculatedusing reference doses (RfD) as follows

HI = IRfD

(11)

The hazard indexes were summed to calculate a Hazard Ratio (HR). That is

HR =∑

Individual Hazard Indexes (12)

The hazard indexes calculated for non-carcinogens (Anthracene, Biphenyl, Naph-thalene, Phenanthrene, Phenol, and Xylenes) in each sampling points are presentedin Figure 4. In order to evaluate the non-carcinogenic effects of the chemicals, it iscommon to consider the risk to be negligible if the HI is less than or equal to 1.0(USEPA 2003). The non-carcinogenic risks predicted for each individual chemicalin the four sampling points are negligible because all of the HIs are less than one.Similar to the risks from carcinogens, the non-carcinogenic risks are also higher inthe sampling points 1 and 2. The exceptions are the HIs of Biphenyl and Phenol inthe sampling point 3. The HRs estimated by equation (12) in the sampling points 1,2, 3, and 4 are 3 × 10−1, 4.2 × 10−1, 8.5 × 10−3, and 6.3 × 10−5, respectively. It shouldbe noted that the chemicals considered in this study have different target organs of

218 Hum. Ecol. Risk Assess. Vol. 13, No. 1, 2007

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

Health Risk Assessment of Tire Factory Workers

Figure 4. Individual hazard indexes determined for non-carcinogens.

the workers. Because the HR method assumes dose additivity, it is more suitable forchemicals with similar effects. Therefore, the HRs here indicate only approximatevalues. For instance, the HRs for respiratory irritation are only an approximation ofthe aggregate effect on the respiratory system (i.e., lungs and air passages) because itis possible that some of the substances cause irritation by different (i.e., non-additive)mechanisms. Because the HRs are less than one, the non-carcinogen risk is consid-ered to be negligible in the vulcanization unit. If the additional control measuressuggested earlier were implemented, the HRs would be further reduced.

The measurements and the risk determination performed for the vulcanizationunit are thought to represent the worst case situations in the factory. Results of thisstudy may either overestimate or underestimate the health risks caused by carcino-gens and non-carcinogens. Health risks may have been overestimated due to thefact that the risks calculated based on the chemical concentrations measured ina short time were compared to specified risks developed based on the toxicologi-cal data established for exposures over a lifespan. Cancer risks may have also beenoverestimated given that the USEPA’s (2003) unit risk values were generally basedon 95% upper confidence limits of cancer slopes from dose-response curves ratherthan estimates of central tendency. The USEPA’s approach was intended to providea conservative and protective health toxicity factor. With respects to underestimatingpotential health risks, only nine chemicals were analyzed in this study. Incompletetoxicity data (e.g., RfDs) for compounds also contributed to underestimating risks.For instance, because the inhalation RfDs for Naphthalene and Phenol have notbeen established yet, the oral RfDs were employed instead. Moreover, due to noexisting RfD for Phenanthrene, the one for Naphthalene was assumed. Health risksmay have also been underestimated because only inhalation exposures were consid-ered in this study. Dermal exposure for workers may be a major route of exposure,especially for certain chemicals. Another uncertainty arises from the addition ofthe cancer risks and hazard ratios to calculate a cumulative cancer risk and hazard

Hum. Ecol. Risk Assess. Vol. 13, No. 1, 2007 219

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

E. Durmusoglu et al.

index. This approach does not reflect toxicological mechanisms of action but ratheris assumed to be a screening approach to identify VOCs and SVOCs of concern forthe factory. Finally, in this study, the modeled chemical concentrations were used asactual exposure concentrations when assessing health risks.

CONCLUSIONS

This study attempted to determine potential health risks in the vulcanizationunit of a tire factory. Permanent progress and differences in instrumental methodsof analysis and measurements in the various work environments and conditionsmake exposures even measured in the same industries practically incomparable.However, it can be concluded that the levels of VOCs and SVOCs observed in thisstudy is appreciably high. Most of the exposures were associated with the millingmachine and the press in the vulcanization unit. The cumulative cancer risks werefound as 5.96 × 10−2, 5.19 × 10−2, 4 × 10−4, and 4 × 10−4 in the four differentsampling points. The non-carcinogenic health risk, on the other hand, is found tobe acceptable because the hazard ratios were lower than the specified level of 1.0.These findings reveal that vulcanization unit imposes a health threat to workers.This study identifies the potential health risks for workers in a tire industry and mayprovide a basis for developing future control measures.

REFERENCES

ACGIH (American Conference of Government Industrial Hygienists). 1999. The ThresholdLimit Values and Biological Exposure Indices Booklet, Cincinnati, OH, USA.

Asante-Duah DK. 1993. Hazardous Waste Risk Assessment, pp 21–112. Lewis Publishers, BocaRaton, FL, USA

Baranski B, Indulski J, Janik-Spiechowicz E, et al. 1989. Mutagenicity of airborne particulatesin the rubber industry. J Appl Toxicol 9:389–93

Batchelor B. 1997. A framework for risk assessment of disposal of contaminated materialstreated by solidification/stabilization, Environ Eng Sci 14:3–13

Bourguet CC, Checkoway H, and Hulka BS. 1997. A case-control study of skin cancer in thetire and rubber manufacturing industry. Am J Ind Med 11:461–73

Chien YC, Ton S, Lee MH, et al. 2003. Assessment of occupational health hazards in scrap-tireshredding facilities. Sci Total Environ 309:35–46

Delzell E and Monson R. 1984. Mortality among rubber workers. Am J Ind Med 6:273–79Delzell E, Macaluso M, Sathiakumar N, et al. 2001. Leukemia and exposure to 1,3-butadiene,

styrene and dimethyldithiocarbamate among workers in the synthetic rubber industry.Chem Biol Interact 135/136:515–34

Donner M, Husgafvel-Pursiainen K, Jessen D, et al. 1983. Mutagenicity of rubber additives andcuring fumes. Results from five short-term bioassays. Scand J Work Environ Health 9:27–37

Fischer FM, Paraguay AI, Bruni AC, et al. 1998. Working conditions, work organization andconsequences for health of Brazilian petrochemical workers. Scand J Work Environ Health21:209–19

Fishbein L. 1991. Chemicals used in the rubber industry. Sci Total Environ 101:33–43Fracasso ME, Franceschetti P, Mossini E, et al. 1999. Exposure to mutagenic airborne particu-

late in a rubber manufacturing plant. Mutat Res 441:43–51

220 Hum. Ecol. Risk Assess. Vol. 13, No. 1, 2007

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

Health Risk Assessment of Tire Factory Workers

Gromiec JP, Wesolowski W, Brzeznicki S, et al. 2002. Occupational exposure to rubber vulcan-ization products during repair of rubber conveyor belts in a brown coal mine. J EnvironMonit 4:1054–59

Hedenstedt A, Ramel C, and Wachtmeister CA. 1981. Mutagenicity of rubber vulcanizationgases in Salmonella typhimurium. J Toxicol Environ Chem 8:805–14

IARC (International Agency for Research on Cancer). 2002. Monographs on the Evaluationof the Carcinogenic Risks to Humans. Available at http://www-cie.iarc.fr

Jones AP. 1999. Indoor air quality and health. Atmos Environ 33:4535–64Ke Y and Shunzhang Y. 2000. Oesophageal cancer and occupational exposure to rubber: A

nested case-control study. Annu Occup Hyg 44:355–59Ke Y and Shunzhang Y. 2002. Leukemia mortality and occupational exposure to rubber: A

nested case-control study. Int J Hyg Environ Health 204:317–21Kogevinas M, Sala M, Boffetta P, et al. 1998. Cancer risk in the rubber industry: a review of the

recent epidemiological evidence. Occup Environ Med 55:1–12LaGrega MD, Buckingham PL, and Evans JC. 1994. Hazardous Waste Management, pp 837–

885. McGraw Hill, New York, NY, USAMonarca S, Feretti D, Zanardini A, et al. 2001. Monitoring airborne genotoxicants in the

rubber industry using genotoxicity tests and chemical analyses. Mutat Res 490:159–69NJDEP (New Jersey Department of Environmental Protection). 1994. Guidance on Preparing

a Risk Assessment for Air Contaminant Emissions. Available at http://www.state.nj.us/dep/aqpp/downloads/techman/1003.pdf

NRC (National Research Council). 1983. Risk Assessment in the Federal Government: Man-aging the Process, National Academy Press, Washington, DC, USA

OSHA (Occupational Health and Safety Administration). 2001. Occupational Health andSafety Standards of the United States. 29 CFR Chapter XVII, Subpart-Z-Toxic and Haz-ardous Substances. Available at http://www.osha.gov/pls/oshaweb/owadisp.showdocument?p table=STANDARDS&p id=10147

Peters JM, Monson RR, Burgess WA, et al. 1976. Occupational disease in the rubber industry.Environ Health Perspect 17:31–4

Rennen MAJ, Bouwman T, Wilschut A, et al. 2004. Oral-to-inhalation route extrapolationin occupational health risk assessment: a critical assessment. Regul Toxicol Pharm 39:5–11

Rodrics JV, Brett SM, and Wrenn GC. 1987. Significant risk decisions in Federal regulatoryagencies. Regul Toxicol Pharm 7:307–20

Sielken RL and Valdez-Flores C. 2001. Dose–response implications of the University of Al-abama study of lymphohematopoietic cancer among workers exposed to 1,3-butadieneand styrene in the synthetic rubber industry. Chem Biol Interact 135/136:637–51

Spiegelhalder B. 1983. Carcinogens in the workroom air in the rubber industry. Scand J WorkEnviron Health 9:15–25

TGD (Technical Guidance Document). 2002. Commission Regulation (EC) No 1488/94 onRisk Assessment for Existing Chemicals. Available at http://ecb.jrc.it/existing-chemicals

Tam BN and Neumann CM. 2004. A human health assessment of hazardous air pollutants inPortland, OR. J Environ Manage 73:131–45

Tsai PJ, Shieh HY, Lee WJ, et al. 2001. Health-risk assessment for workers exposed to polycyclicaromatic hydrocarbons (PAHs) in a carbon black manufacturing industry. Sci Total Environ278:137–50

UBA (Umweltbundesamt—Federal Environmental Agency). 2003. Exposure Assessment ofthe Environmental Releases of Chemicals in the Rubber Industry. Available at http://www.oekopro.de/bilder/UBA ESD Rubber final 27June2003.pdf

USEPA (US Environmental Protection Agency). 1986a. Guidelines for Carcinogen Risk As-sessment. U.S. Federal Register, Vol. 51, No. 185 (9/24/86)

Hum. Ecol. Risk Assess. Vol. 13, No. 1, 2007 221

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014

E. Durmusoglu et al.

USEPA. 1986b. Method 0010, Modified Method 5, Sampling Train, Center for EnvironmentalResearch Information. Office of Research and Development, Cincinnati, OH, USA

USEPA. 1989. Risk Assessment Guidance for Superfund, Volume I: Human Health EvaluationManual (Part A). EPA/540/1-89/002. Office of Solid Waste and Emergency Response,Washington, DC, USA

USEPA. 1991. Risk Assessment for Air Pollutants: A Citizen’s Guide. EPA-450/3-90-024. AirRisk Information Support Center, Research Triangle Park, NC, USA

USEPA. 1996. Method 3542, Extraction of Semi Volatile Analytes Collected Using Method 0010(Modified Method 5 Sampling Train). Center for Environmental Research Information,Office of Research and Development, Cincinnati, OH, USA

USEPA. 1998. Method 8270 D, Semi Volatile Organic Compounds by Gas Chromatogra-phy/Mass Spectrometry (GC/MS). Center for Environmental Research Information, Of-fice of Research and Development, Cincinnati, OH, USA

USEPA. 1999. Compendium of Methods for the Determination of Toxic Organic Compoundsin Ambient Air, Second Edition. EPA/625/R-96/010b. Center for Environmental ResearchInformation, Office of Research and Development, Cincinnati, OH, USA

USEPA. 2003. Integrated Risk Information System (IRIS). Available at http://www.epa.gov/iriswebp/iris/index.html

Van Ert MD, Arp EW, Haris RL, et al. 1980. Worker exposure to chemical agents in themanufacture of rubber tires: Solvent vapor studies. Am Ind Hyg Assoc J 41:212–19

Vermeulen R, Bosb RP, and Kromhouta H. 2001. Mutagenic exposure in the rubber manu-facturing industry: An industry wide survey. Mutat Res 490:27–34

Weeks JL, Peters JM, and Monson RR. 1981. Screening for occupational health hazards in therubber industry. Am J Ind Med 2:125–41

222 Hum. Ecol. Risk Assess. Vol. 13, No. 1, 2007

Dow

nloa

ded

by [

Uni

vers

ity o

f So

uthe

rn Q

ueen

slan

d] a

t 06:

11 0

9 O

ctob

er 2

014