Publications which conducted health risk assessment

Publications which conducted health risk assessment

Tong et al. (2018) conducted a probabilistic health risk assessment based on the model recommended by USEPA and the Monte-Carlo simulation. Health risk assessment was performed among workers in a superstructure residential building in Beijing. Five zones (office zone, floor zone, concrete zone, steel zone, and template zone) were selected to measure PM from, and TSP was used as a dust monitoring indicator. The USEPA risk assessment model was used to convert PM concentration into average daily exposure dose (ADD). The reference value for the inhalation rate of the workers given in the Chinese Exposure Manual was used. Following that, the hazard index (R) was determined to show the dust risk.

Results showed that workers in the template zone had the highest health risk (1.42 × 10^-6), while workers in the office zone had the lowest health risk (4.9 × 10^-8). The steel zone was the second riskiest zone (6.76 × 10^-7) followed by the concrete and floor zones (3.4 × 10^-7 and 3.27 × 10^-7, respectively). Disability-adjusted life years (DALY) were used to describe health impairment more comprehensively. One DALY means one healthy year lost due to disability or mortality caused by a particular disease

Workers in tunnel construction are also exposed to a high concentration of PM. Chen et al. (2019) conducted a health risk assessment of silica dust in a tunnel construction site at Chongqing, China. The health risks of five different trades (tunneling, slag-out, arching, shotcrete, and lining) were assessed. Similar to other studies, the health risk assessment model by the USEPA was used. Silica dust samples were collected for each activity separately. R was calculated after converting dust concentration into ADD. While calculating for the ADD, the actual value of C was used by considering the isolation effect of dust masks according to inward leakage (IL) and filtration efficiency (FE). The results showed that health risk was reduced significantly (26–82%) due to the isolation effect. The health risk assessment results were shown in both cases with and without considering the isolation effect of the masks. In both cases, tunneling, followed by slag-out, shotcrete, and arching, had more health risks. Meanwhile, lining was the least risky activity compared to the others. The health risk was represented in DALY, wherein the DALYs for tunneling, slag-out, shotcrete, arching, and lining were 1.25, 0.46, 0.12, 0.12, and 0.18, respectively. The reason why the DALY of lining was higher than shotcrete and arching was that there were more people involved in lining.

Yeheyis et al. (2012) conducted a probabilistic human health risk assessment of crystalline silica exposure among construction workers. In their probabilistic risk assessment, Yeheyis et al. (2012) assessed the incremental lifetime cancer risk (ILCR) and non-cancer hazard quotient (HQ) using the approach recommended by the USEPA along with the Monte-Carlo simulation. Reference values were used for both C and IR, which were borrowed from values used in other studies (Flanagan et al. 2006; USEPA 1997). The health risk for five different trades (abrasive blasting, cement finishing, labor work, stone/brick masonry, and hod carrying) was estimated. The authors of this study considered the 70–80% reduction in silica exposure as an outcome of engineering controls, which has also been reported in other studies (Lahiri et al., 2005). Therefore, ILCR and HQ were calculated both with and without control measures. The results of the health risk assessment showed that the ILCR and HQ values ranged from 1×10^-5 to 4.5×10^-5 and from 3.23 to 14.1, respectively. Among the trades, abrasive blasting was the riskiest activity, whereas hod carrying had the lowest health risk. Cement finishing, labor work, and masonry were second-, third-, and fourth-most dangerous activities, respectively. The sensitivity analysis showed that the concentration of PM, followed by inhalation rate, were the most significant factors that affected the results of the health risk assessment.

Azari et al. (2009) and Normohammadi et al. (2016) assessed the risk of mortality from silicosis and lung cancer due to exposure to silica at construction sites. This type of risk assessment was based on the cumulative exposure of 45 years of work experience. In order to conduct a risk assessment based on cumulative exposure, findings from other studies were used by the researchers to assess the risk of mortality from lung cancer and silicosis, respectively (Rice et al., 2001; Mannetje et al., 2002). Mannetje et al. (2002) analyzed data from six cohorts: US diatomaceous earth workers, Finnish granite workers, US granite workers, US industrial sand workers, US gold miners, and Australian gold miners. In their results, they categorized cumulative exposure based on ranges from 0 to 28.8 mg/m³-year (total of 10 ranges), and excess risk of silicosis mortality varied from 1 to 63 per one thousand exposed people, respectively (see table 1). Rice et al. (2001), in a cohort study on 2,342 diatomaceous earth workers, predicted the excess lifetime risks of mortality from lung cancer, assuming 45 years of respirable crystalline silica exposure. Their results showed that the excess lifetime risk of lung cancer was 19 and 37 per thousand people for 0.05 mg/m³ and 0.1 mg/m³ (see table 1) exposure to silica, respectively.

Based on the aforementioned model, Azari et al. (2009) conducted a health risk assessment on a total of 200 workers in ten industrial fields (stone milling and cutting, foundry work, glass manufacturing, asphalt, construction, sand and gravel mining, sandblasting, ceramics, bricks and cement manufacturing) in the east zone of Tehran. Four employees from 50 workshops (five from each workshop) were selected to measure dust exposure. A gravimetric sampling method was used to measure construction dust. To determine the level of silica exposure, infrared absorption spectroscopy based on the NIOSH method No. 7602 was used. The occupational exposure to crystalline silica was measured for each field. The geometric mean (GM) of exposure to crystalline silica among construction workers was 0.193 mg/m³ and ranged from 0.124 to 0.301. The risk of mortality from silicosis among construction workers was 22.6 per thousand exposed people. Following that, the excess lifetime risk of lung cancer was estimated based on Rice et al.’s (2001) model. The results of the risk assessment of lung cancer showed that excess lifetime risk of lung cancer from crystalline silica exposure was 73 per one thousand people among construction workers.

Subsequently, a study conducted by Normohammadi et al. (2016) assessed the health risks of building demolition workers. The risk of mortality because of silicosis and lung cancer was estimated based on models recommended by Mannetje et al. (2002) and Rice et al. (2001), respectively. Four sites in Tehran were selected, and samples of dust were collected from breathing zones of 60 demolition workers. The gravimetric method was used to measure the concentration of construction dust, and NIOSH method No. 7601 was used to determine the level of silica dust in samples. Occupational exposures to crystalline silica were measured, and the highest exposure to silica was found to be at Site 1 (0.158mg/m³ (GM)). In contrast, workers were exposed to the lowest amount of crystalline silica at Site 3. Eighty percent of the workers’ exposure was higher than occupational exposure levels. The results of the risk of mortality from silicosis were 1 for the lowest exposure and 22.64 per thousand people for the highest exposure to crystalline silica dust. The risk of mortality from lung cancer ranged from 32 to 60 per thousand exposed people. According to Occupational Safety and Health Administration (OSHA), the results showed that the risk of silicosis for 28% of the workers was acceptable. Meanwhile, 72% of the workers’ risk for silicosis mortality was unacceptable.

In a more recent publication, Yang et al. (2020) assessed the health risk of heavy metals in urban construction dust falls. The authors of this study determined heavy metal concentrations, enrichment factors, bioaccessibility, carcinogenic, and non-carcinogenic health risks. A total of 114 dust samples from three types of construction (road, subway, and building construction) were collected. Dust samples were collected by using shovel, brush, and bags. Bioaccessibility of the heavy metals showed the following trend: Zn (50.5%) > Cd (35.3%) > Cu (29%) > Pb (27.7%) > Ni (16.1%) > Cr (9.27%). Non-carcinogenic and carcinogenic health risks of heavy metals were determined using the health risk assessment model recommended by US EPA. The mean concentrations of all heavy metals except for Ni were higher than the Chinese background soil values. Concentrations of Cr, Ni, Cu, Zn, Pb, Cd, and Hg were in the range of 13-355, 0.72-68, 18-272. 35-4130, 20-320, 0.24-7.44 and 00.2-0.84 mg/kg, respectively. The results showed that ingestion was the primary exposure pathway, followed by dermal contact and inhalation. Higher mean values of hazard index were observed at road construction sites compared to subway construction and building construction sites. Carcinogenic health risk values of Cr, Ni, and Cd were lower than 10-6, indicating an acceptable level of health risk.