**4.2 Occupational exposure limit values and threshold effects**

OELVs are established to prevent occupational illnesses in general but they are not specific to a health effect or target organ. Thus, even though the TCE and PCE concentrations are below the OELVs, some serious adverse health effects may occur [31]. Furthermore, since the general population is also involved, people, including the occupationally exposed ones, are more effectively protected if the air concentrations are below the toxicological reference values (TRV). These TRVs are exclusively established based on scientific considerations [31]. In this section, we are only discussing TRVs that are protecting populations from threshold effects.

Since there are no Tunisian values, we are checking TRVs that are conceived from French and American agencies. The French values are constructed by the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) [32]. The TCE chronic TRV via inhalation is constructed based on noncarcinogenic renal effect because of a well-established nephrotoxicity mechanism [33]. The TRV is fixed on 3.2 mg/m3 . The mean value of all TCE concentrations is 13.4 times the French TRV, which means that there is a great risk of nephrotoxicity for workers. Among the American TRVs, we can mention, for instance, the ones that are established by the Environmental Protection Agency (US EPA) [34]. The TCE

*Solvents, Ionic Liquids and Solvent Effects*

*ND, not detected; F, dry cleaning facility.*

**Table 3.**

it still is 18% lower than the mean value of TCE concentrations in the workplaces' atmospheres, which confirms its connection with the lowest consumed quantity. Regarding PCE, the personal sampling concentrations are higher than workplaces' atmospheres, particularly in P3 where the PCE level has doubled. Thus, the employees who are carrying personal sampling devices (particularly in F3 and F29) are exposed to greater levels of solvents. This is obviously due to their specific movement patterns where they could be moving closer to the emission sources. This consequently justifies our judgment to use the personal sampling in these job tasks. As we can notice in **Table 3**, almost all TCE concentrations are close to the selected OELV (**Table 2**). These results are quite surprising because all facilities have declared to only use PCE. In fact, we suspected to have found TCE in trace amounts as impurity content. But, these high concentrations are an alarming finding. Thus, even though all PCE concentrations are lower than one-tenth of the OELV (except for both measurements in F29 and for F3 personal sampling level), we believe that urgent corrective actions should be carried out in all facilities.

*Indoor air measured concentrations of TCE and PCE in dry cleaning facilities.*

**Fixed monitoring Personal sampling TCE PCE TCE PCE**

**F mg/m3 ppm mg/m3 ppm mg/m3 ppm mg/m3 ppm** F3 26.35 4.98 12.60 1.89 35.38 6.69 25.08 3.76 F4 40.58 7.67 7.86 1.17 — — — — F5 44.67 8.45 ND ND — — — — F13 42.06 7.95 ND ND 41.60 7.87 — — F19 49.61 9.38 ND ND — — — — F21 43.57 8.24 ND ND — — — — F22 49.72 9.40 ND ND — — — — F28 42.22 7.98 ND ND — — — — F29 41.10 7.77 54.34 8.14 44.06 8.33 65.40 9.80 F30 41.45 7.84 ND ND — — — — F31 48.89 9.25 7.98 1.19 — — — — F35 43.21 8.17 8.47 1.27 — — — — F36 45.86 8.67 ND ND — — — — F39 46.21 8.74 ND ND — — — — F41 43.74 8.27 12.27 1.84 — — — — F43 42.27 7.99 ND ND — — — —

**4.1 Location of dry cleaning facilities in Sfax and residential exposure**

First of all, since there was no list of dry cleaning facilities in Sfax city, we encountered some difficulties during the identification and location steps. That is why, it was decided to conduct a door-to-door canvassing in the study area.

**34**

**4. Discussion**

chronic Reference concentration (RfC) is fixed on 2 10<sup>−</sup><sup>3</sup> mg/m3 [35] based on both developmental and immune effects. The mean value of all TCE concentrations is 21,385 times the RfC, which means that there is also an enormous risk related to the increase of congenital cardiac malformations and a decrease of thymus weight [36]. This developmental effect could be also alarming because 70% of the workers are women.

Regarding PCE, the chronic French TRV via inhalation is developed based on neurological effects. Among them, the ANSES distinguished the visual alterations as the most sensitive effect toward the lowest exposure levels [30]. The TRV is fixed on 0.4 mg/m3 [30, 32], which is over 60 times the mean value of all PCE concentrations. Since the PCE concentration distribution is highly dispersed, the ratio, and consequently the risk, is even higher (108 times) if we use the upper bound of the 95% confidence interval for mean. As for the RfC, it is set at the tenth of the French TRV (0.04 mg/m3 [37]) based also on neurological effects, notably neurobehavioral effects and color vision impairment induced by neurotoxicity [29]. Thus, the risk of neurotoxicity could be even 10 times higher for workers. It is worth to note that these risks maybe also extrapolated to the general population with lower intensity, but with great significance and likely adverse consequences.

### **4.3 Carcinogenic effects**

Chronic exposure can also induce carcinogenic effects. Thus, there are nonthreshold TRVs as well. Each value is established for a specific tumor site or sites based on a lifetime exposure.

As shown in **Table 1**, according to World Health Organization (WHO) [13, 38], TCE was proved to cause kidney cancer to humans. Indeed, the French carcinogen TRV via inhalation, established by ANSES, is the ERU "excès de risque unitaire," and is equal to 10<sup>−</sup><sup>6</sup> (μg.m<sup>−</sup><sup>3</sup> ) −1 [32]. It was constructed based on kidney cancer, specifically the renal cell carcinoma [33].

Yet, other solid scientific evidences indicate other potential carcinogenic effects of TCE. In fact, the US EPA established the Inhalation Unit Risk for three different cancer sites: the hematologic, liver, and kidney cancers. Its value is more protective and equal to 4.1 10<sup>−</sup><sup>6</sup> (μg/m3 ) −1 [35, 36]. According to the latter value, the lifetime cancer risk, which is defined as the product of multiplying the carcinogen TRV by the exposure concentration, is equal to 17.5 10<sup>−</sup><sup>2</sup> , when compared with the mean value of all TCE concentrations. This means that, more than 17 additional cases of hematologic, hepatic, and renal cancers are estimated to occur during a lifetime exposure to TCE in a population of 100 people. This value is considerably high even for an occupationally exposed population.

Furthermore, other international agencies have also demonstrated the carcinogenic effect of TCE for other target organs, such as in testes or in lungs [33].

As for PCE, according to WHO [38], it is probably inducing urinary bladder cancer to humans.

Elsewhere, ERU established by ANSES is based on liver cancer (hepatocellular adenoma and carcinoma) [30] and is equal to 2.6 × 10<sup>−</sup><sup>7</sup> (μg/m3 ) −1 [32]. Additionally, the Inhalation Unit Risk by US EPA has the same value, but only for the hepatic cancer. According to this carcinogen TRV, the lifetime cancer risk is 6.3 × 10<sup>−</sup><sup>3</sup> . It means that six additional cases of liver cancer are expected to take place during a lifetime exposure in a population of 1000 people. Due to the high variability of PCE concentrations, this value could be even higher (more than 11 cases if the upper bound of the 95% confidence interval for mean is used) in some cases. Although these findings are slightly better than those for the TCE, they are still high and troubling. In fact, the inhalation cancer risk could be worse

**37**

interdicted [7].

*Per- and Trichloroethylene Air Monitoring in Dry Cleaners in the City of Sfax (Tunisia)*

if we consider a total cancer risk due to the cumulative exposure to both solvents,

In Tunisia, chemical risk assessment studies have started in many industrial sectors that are handling solvents, such as adhesive [39] and shoe manufacturing [40] industries. Yet, the occupational exposure in dry cleaning industry is not explored. The exposure assessment was achieved using questionnaires and indoor air measurements. In fact, air samplings were carried out for the first time in the region of Sfax. We consider that this study will help for better understanding the dry cleaning industrial sector in Tunisia, which will lead to further improvement in health risk

All the 33 dry cleaning facilities in Sfax have announced to use PCE as a dry cleaning product; however, due to the high TCE concentrations, we assume the

• The dry cleaning products are contaminated by TCE but in significant amounts, so either the product manufacturers did not inform their customers about TCE or solvent handlers are mixing PCE with TCE to reduce cost since it is cheaper.

• TCE could be coming from a different emission source, as it could be used as a

• Both managers and workers are not aware of the chemical risks and the adverse

It is worth to note that in our study, the air monitoring was conducted during the warm season (in June and the temperature was ~30°C) when the workplaces were relatively highly ventilated; doors and windows were open. However, in winter season, they are rather closed. So, we suppose that the exposure levels will be even

The suggested corrective measures could start with the substitution. It consists

of eliminating the use of the hazardous products by replacing them with less dangerous ones, especially because they are suspected to contain a high amount of TCE or by switching to a different process. Among the substitution processes, there are the (i) wet cleaning that consists of using a mixture of water, detergents, and surfactants whose risks are little or currently unknown, (ii) hydrocarbon dry cleaning that involves solvents that are less volatile than PCE, and (iii) siloxane D5 dry cleaning that are using the latter product as a liquid solvent that is barely volatile. These alternative machines may be quite costly; however, other easier corrective

For the second level of the corrective actions, we highly recommend the implementation of collective protection measures (CPM). In every facility, general mechanical ventilation ought to be installed immediately, with fume extraction systems positioned toward every job task. It should be noted that the polluted air needs to be rejected after purification [7]. In addition, the mechanical ventilation has to be supplied by outdoor fresh air and the reuse of the same air after gas scrubbing is

The third level of the corrective actions involves the mandatory use of PPE in some job tasks. The wearing of protective clothing is advisable for every worker. Elsewhere, we noticed that the loading of solvents in the cleaning machines is generally introduced by manual pouring on the back or through the porthole,

*DOI: http://dx.doi.org/10.5772/intechopen.86725*

assessment studies in this sector.

following:

especially when the target organ is the same.

degreaser in maintenance operations.

higher in poor ventilation conditions.

actions could be carried out.

health effects of both solvents, especially TCE.

**4.4 Health risk assessment and chemical risk prevention**

if we consider a total cancer risk due to the cumulative exposure to both solvents, especially when the target organ is the same.
