Master of Environmental Health and Infection Control Committee Leader, Al-Amal Hospital (Palestine Red Crescent Society), Gaza, Palestine, IsraelIsrael
Associate Professor in Public Health, Islamic University of Gaza, Gaza, Palestine, IsraelIsrael
Professor of Environmental Resources Management, Islamic University of Gaza, Gaza, Palestine, IsraelIsrael
Also available as PDF (figures and tables appear in the PDF).
Case-control study was conducted during the period from April to August, 2013 on all gravel crushers at Middle Gaza Governorates. There were 87 individuals participants inv-loved in this study, out of which 40 were case (exposed) and 47 control (non-exposed) groups respectively. PM10 (Particulate matter with an aerodynamic diameter of 10 micrometer or less) concentration level was measured in the six crushers, and all participants were subjected to Complete Blood Counts (CBC). This was conducted to evaluate the level of PM10 air pollution in crusher’s plants, and their impacts on complete blood counts (CBC) for crushers workers. Results showed that an average of particulate matter contributions is 15153 μg/m3 (microgram/cubicmeter), which is about 100 times higher than PM10 existing standard of 150 μg/m3. As well as, it showed clear links between PM10 exposure and CBC changes among exposed group. Increasing in white blood cells count were more common among the exposed group, whereas in the non-exposed group, CBC did not change. Therefore, we can conclude that PM10 con-centration level in crushers plants were much higher than the existing standard. Occupational exposure to PM10 leads to CBC changes especially increasing in white blood cells count.
Keywords: PM10; Complete Blood Count (CBC); Crushers; WBCs; HGB; RBCs; Gaza; Palestine; Pal- estine
what was destroyed by the occupation in Gaza governorates. This study conducted on all crushers and workers who The researchers attempt to measure the concentration continuously exposed to dust without using any protective deof PM10 in crusher’s plants during operation and to examine efvices in the Middle Governorate which has six crushers distribfects on the complete blood counts that have occurred as a result uted on all areas. (Figures 1-3) of direct exposure of workers to particulate matter air pollution for contentious long hours of work. Due to that there is limited available data about the complete blood counts effects that caused to crushers workers, and limited available data associated with concentration of PM10 in crushers plants.
The general objective of this study is to evaluate the level of PM10 air pollution in crushers plants, and their effects on complete blood count for crusher workers.
The target population of the study were (87) individuals. Case (exposed) group were 40, and control (non-exposed) group were 47. This case-control study was conducted between the participants who are under age of 15-65 and have no medical history and who works in crushers at Middle Governorate, and the participants those who are under the age of 15 years or more than 65, and have past medical history and do not work in the Middle Governorate were considered.
This case-control study was conducted during the period from April-August 2013 in gravel crushers, at Middle Governorate, Southern Governorates, Palestine.
All workers in the six crushers at Middle Governorate who accomplished criteria, the number of workers is 40, as they worked in gravel crushers and continuously exposed to dust without using any protective devices, the exposed workers were male, their age ranged from 15-65 years, and does not have any past medical history.
The control group contain 47 individuals who live in the same area of case group, their ages ranged from 15-65 years, do not have any past medical history, but they do not work in the gravel crushers.
3 6-8 matter (PM10) existing daily average standard of 150 μg/m .
The results in Figure (3) show the percentage of ages for both cases and control groups. Furthermore, it shows the elevated level of ages rapprochement between the two groups, which increase the accuracy of the study.
Results of Complete Blood Counts between Case Group (40) and Control Group (47) are shown in Table 1.
Case 40 5.04 0.51 RBCS -1.260 0.211 Control 47 5.17 0.44 Case 40 8.67 1.24 WBCS 6.975 0.000 Control 47 7.22 0.64 Case 40 14.75 0.92 HGB -1.170 0.245 Control 47 14.97 0.81
Table 1. The results of independent samples T-test for complete blood counts results between (40) case group and (47) control group.
Red blood cells (RBCs): The mean of RBCs for case and control group is (5.04, with SD of 0.51) and (5.17, with SD of 0.44), respectively. The value of the T-test equals -1.260, with p-value equals 0.211. This means that there is sufficient evidence to conclude that mean of RBCs is insignificantly different between the two groups. In other words, there is insignificant difference in the mean RBCs between case and control group.
White blood cells (WBCs): The mean of WBCs for case and control group is (8.67, with SD of 1.24) and (7.22, with SD of 0.64), respectively. The value of the T-test equals 6.975, with p-value equals 0.000. This reveals that there is an evidence to conclude that mean of WBCs is significantly different between the two groups. Since the sign of the T-test is positive, then mean of WBCs for case group is significantly greater than control group.
Hemoglobin (HGB): The mean of HGB for case and control group is (14.75, with SD of 0.92) and (14.97, with SD of 0.81), respectively. The value of the T-test equals -1.170, with p-value equals 0.245. This implies that there is sufficient evidence to conclude that mean of HGB is insignificantly different between the two groups. In other words, there is insignificant difference in the mean HGB between case group and control group.
Positive relationship is observed between PM air pollution and increasing White Blood Cells (WBCs) (leukocytosis) in this study. The statistical strength of relationship between
PM10 air pollution exposure and increasing WBCs is in line with the study conducted by Tan, et al.4 have demonstrated leukocytosis in young military recruits exposed to an acute episode of particles air pollution during forest fires of south east Asia in the summer of 1997, suggesting that an episode of acute exposure to PM10 air pollution causes bone marrow stimulation in humans.2
Furthermore, Van and Tem studies showed that an acute exposure of PM10 air pollution causes leukocytosis in humans and proinflammatory cytokines in the blood collect in the south east Asia.2
This is supported by other independent longitudinal studies linking elevation of the peripheral blood count to increase mortality during exposure of PM10 air pollution. In consistent, Wells, et al. have shown that an increase in leukocyte count is predictor of total mortality, independent of smoking in large population-based studies9
Examination Survey in the United States, conducted among adults aged 20-89 years, which showed significant association between WBC count and estimated local PM10 levels 3,10 during 1 year. Also, our findings are consistent with animal experiments showing an increase release of WBCs and their precursors from the bone marrow in response to the deposition of particles in the lungs.
These findings suggest that inflammatory mediators released from lung are capable of irritating not only a local inflammatory response, but also a systematic response when PM10 are deposited in the lungs, resulting in leukocytosis.
In the present study, it observed significant relationship between PM10 air pollution and increasing WBCs, these results are consistent with physiologic and related studies results. Insignificant relationships are observed between PM10 air pollution and hemoglobin and red blood cells.
A cross-over study among 29 participants with or without biking exercise and exposed to particulate air pollutants did not find any significant association of particulate air pollutants with hemoglobin, RBC and platelet count and markers of inflammation in healthy adolescents and childs.11
The associations of particulate air pollutants with hematologic parameters are consistent with the chronic effects of air pollutants on hematological factors.1
In the present study, it shows insignificant relationship due to the short duration of exposure to PM10 for target groups (1-3) years compared with appearance of significant impact on hemoglobin and red blood cells, which need long term period to appear clearly.
In summary, our findings are consistent with the results of studies that have mentioned and other, which showed positive
and significant relationship between exposure of PM10 air pollution and increasing white blood cells (leukocytosis).
The particulate matter that emitted from the crushers varies widely from 10008 to 19807 μg/m3, with an average particulate matter contribution of 15153 μg/m3, which is about more than 100 times higher than the particulate matter (PM10) existing standard.
Increasing in white blood cells count reported in this study among the exposed workers. This increasing was found to be related to exposure of PM10 air pollution, as a result of the inflammatory process.
Data analysis shows insignificant relationship between (Red blood cells and Hemoglobin) and PM10 air pollution exposure, due to the short duration of exposure to PM10 for target groups (1-3) years compared with appearance of significant impact on hemoglobin and red blood cells, which need long term period to appear clearly.
The authors declare that they have no conflicts of interest.
The authors reiterate their endless acknowledgement and high appreciation to all who helped in conducting this study.
The authors has received written permission for publication of the case details.