Dust exposure risk from stone crushing to workers and locally grown plant species in Quetta, Pakistan.

The aim of this study was to assess the effects of stone crushing dust pollution on three commonly cultivated fruit plant species (Vitis vinifera L., Morus alba L., and Prunus armeniaca L.) and on the health of workers working at crushing plants. The trial was carried out on fruit plant species grown close to the stone crushing units located near the northwestern (Brewery) bypass of Quetta city, Pakistan, near National Highway NH-25. Plant materials were collected from three polluted sites at a distance of 500, 1000, and 1500 m, respectively, away from the stone crushing units and one locality of comparatively clean air considered a control at 4000 m away from these crushing components. To know the status of air disorder near the experimental sites, the suspended particulate matters and both oxides of sulfur and nitrogen were also noted during operating hours. Consequences of the study indicated that during the crushing process, a fine aerosol of stone dust is often generated which could cause a significant health hazard to workers and also affect plant productivity due to the smothering of plant stomata. Environmental data designated that the average highest evaluated total suspended particulate matter (TSPM), NO_x, and SO_x were 7400 μg/m³, 803.7 μg/m³, and 216 μg/m³, respectively, at 500-m distance which gradually decreases as the distance increases-all of these pose a health risk to operators. The maximum deposit dust washed from the plant leaf surface under study was found to be 8.2, 4.6, and 4.4 at the distance of 500 m in all the investigated plant species which was highly significantly higher than that of the control site (4000 m). Among the plant species, the maximum dust fall was noted on the leaves of Vitis vinifera L., and minimum was on the leaves of Prunus armeniaca. The locations affected by more stone dust pollution (500 m) were leading to a reduction in the yield and quality of fruits. The studied stone crushing units had high percentages of closed stomata both on the upper sides (Us) and lower sides (Ls) of leaves at 500-m distance from stone crushing installations. Data regarding workers' health indicated the maximum age distribution among the workers was between the age groups of 20-35 years (46.15%). Results also showed that stone crushing workers suffered from symptoms of respiratory diseases (82.17%), allergies (72.13%), headaches (75.09%), coughing (78.36%), and tiredness (92.31%).