Risk assessment of lead exposure in radiology personnel in Menoufia hospitals,Egypt

Abstract

Lead shielding is used as a guard against scatter radiation. Lead aprons can emit particulate lead into the occupational environment, resulting in the accumulation of lead dust on the skin and garments of workers. This study aimed to assess the risk of lead exposure among radiologists working in the radiology departments by estimating hair and blood lead levels. A total of 40 radiology personnel (18 wearing aprons and 22 not wearing aprons) with a comparable control group (20 personnel not working in a radiology department) underwent a pre-designed questionnaire with estimation of blood and hair levels. The hair and blood lead levels in radiologists wearing aprons were significantly higher than those of the control group and that of the radiologist not wearing aprons. The lead levels in hair and blood were correlated significantly with the duration of wearing aprons in years and weekly working hours. Health care workers in radiology departments demonstrated high hair and blood levels that were higher among workers wearing aprons than those not wearing protective equipment. Hair lead levels can be detected quickly, cheaply, and non-invasively, and could be a helpful screening test for occupational exposure.

Keywords

Lead aprons lead toxicity radiology specialists blood lead hair lead

Introduction

The World Health Organization (WHO) has identified lead as one of the ten chemicals of major public health concern. It is the most dangerous metallic element as no identified lead level has been proven safe (WHO 2022). Lead is used in many different applications, including lead acid batteries, dyes, cosmetics, ceramic glazes, ammunition, glass, paint manufacturing, ore mining, recycling processes, and smelting (Félix et al. 2013) (WHO 2022).

Lead can be ingested or inhaled into the body through residues that are adhered to items like food, clothing, and hands (Hsieh et al. 2017). Even at low concentrations, lead exposure poses a serious, irreversible, acute, and chronic health hazard affecting all organ systems (mainly CNS, hemopoietic, reproductive, and urinary). The impacts of lead poisoning differ based on the person’s age and the duration of exposure (Shoaget al., 2020).

Lead is also considered a hazard in some workplaces. It is employed in a variety of radiology applications, including X-ray imaging and PET rooms. Lead shielding is used as a guard against scatter radiation. Lead aprons and other lead-based shields can emit particulate lead into the occupational environment, resulting in the accumulation of lead dust on the skin and garments of workers. This subsequently enables “take-home exposure” of lead dust, which has been associated with elevated lead blood levels (Bushong 2020).

As radiological departments are frequently located in small, poorly ventilated areas of hospitals, the ambient lead concentrations in the X-ray rooms could readily accumulate, increasing the lead exposure of the radiological practitioners. Additionally, lead sheets are fitted into plasterboards fastened to the walls to shield radiation in the radiology departments (Iball, et al., 2008) Table 1.

Table 1.

Descriptive data of the studied groups.

Parameter	Radiologist with apron (n = 18)	Radiologist without apron (n = 22)	Control (n = 20)	Total	Test of significance (Chi square test)	p-Value
Sex Male Female	14 (77.8%) 4 (22.2%)	15 (68.2%) 7 (31.8%)	15 (75.0%) 5 (25.0%)	44 (73.3%) 16 (26.7%)	0.509	0.775
Residence Rural Urban	11 (61.1%) 7 (38.9%)	15 (68.2%) 7 (31.8%)	13 (65.0%) 7 (325.0%)	39 (65.0%) 21 (35.0%)	0.218	0.897
Marital status Married Single	14 (77.8%) 4 (22.2%)	20 (90.9%) 2 (9.1%)	16 (80.0%) 4 (20.0%)	50 (83.3%) 10 (16.7%)	1.469	0.480
Smoking Yes No	8 (44.4%) 10 (55.6%)	10 (45.5%) 12 (54.5%)	9 (45.0%) 11 (55.0%)	27 (45.0%) 33 (55.0%)	0.004	0.998
Hospital University hospital Teaching hospital Fever hospital	5 (27.8%) 7 (38.9%) 6 (33.3%)	9 (40.9%) 6 (27.3%) 7 (31.8%)		14 (35.0%)13 (32.5%)13 (32.5%)	0.906	0.636
Age in years (mean±SD)	31.5 ± 5.94 (25–45)	32.04 ± 6.60 (25–49)	32.7 ± 8.32 (23–51)	32.10 ± 6.94 (23–51)	ANOVA 0.138	0.871
Duration of working as radiologist in years	10.27 ± 5.77 (4–24)	12.27 ± 6.10 (5–28)			tiTest 1.06	0.229
Working hours per week (mean±SD)	84.44 ± 19.97 (38–1 06)	77.00 ± 17.33 (48–108)			tiTest 1.24	0.215

Lead is eliminated in urine and feces. However, it also appears in hair, nails, sweat, and breast milk. Hair serves as a significant route for the detoxification of lead, making it a good indicator of a long-term buildup of lead exposure (Hung &Chang 2021). A blood lead test is the most useful screening and diagnostic test of ongoing or recent lead exposure but does not give accurate information about the total body burden of lead, like the hair analysis (Spivey 2007) Table 2.

Table 2.

Correlation between the hair lead level and different parameters.

	Hair lead level in ug/g	t-Test	p-Value
SexMaleFemale	11.31 ± 2.2111.11 ± 1.67	0.33	0.742
Radiologist with apron Radiologist without apron Control	13.38 ± 1.67(10.7–16.40)10.95 ± 1.52(7.8–13.98)9.67 ± 1.06(8–12)	32.315*ANOVA test	<0.001 Post hoc (Scheffe test)P1 < 0.001P2 < 0.001*P3 < 0.02
ResidenceRuralUrban	10.93 ± 2.0011.86 ± 2.09	1.69	0.096
Marital statusMarriedSingle	11.32 ± 2.1010.94 ± 1.94	0.533	0.596
SmokingYesNo	11.32 ± 2.5511.21 ± 1.60	3.43	0.001*
HospitalUniversity hospitalTeaching hospitalFever hospital	11.61 ± 1.7113.05 ± 2.0211.52 ± 2.01	2.64*ANOVA test	0.084

P1: Difference between radiologist with apron and radiologist without aprons.

P2: Difference between radiologist with apron and control.

P 3: Difference between radiologist without apron and control.

^**p < 0.001 highly significant; *p ≤ 0.05 significant; p > 0.05 insignificant.

The aim of this study was to assess the risk of lead exposure in the radiologists working in the radiology departments by estimating the lead level in hair samples (for long-term exposure) and blood samples (for ongoing exposure) Table 3.

Table 3.

Pearson correlation between hair lead level and different parameters.

	Hair lead level
	Correlation coefficient (r)	p Value
Age in years	0.098	0.458
Total duration of working as radiologists in years	0.221	0.171
Duration of wearing aprons in years	0.764	<0.001*
Working hours per week	0.407	0.009*

**p < 0.001 highly significant; *p ≤ 0.05 significant; p > 0.05 insignificant.

Materials and methods

The current study was carried out at three hospitals on radiologists who are at risk of lead exposure in their radiology department (study group) at Menoufia University hospital, Shebin Elkoom teaching hospital and the fever hospital in Menoufia governorate, Egypt and employees from other departments (control group). Radiologists of both sexes who worked at least 6–8 h per day, not less than 4 days per week, and worked in the radiology department for at least the previous 2 years were chosen at random from the three general hospitals. Radiologists with a past history of lead poisoning or exposed to lead at home in the past 6 months as well as those with colored hair were excluded from the study Table 4.

Table 4.

Blood lead levels of the studied groups.

	Blood lead level in ug/dl	ANOVA test	p Value
Radiologist with apronRadiologist without apronControl	3.33 ± 0.93 (1.92–5.34)1.45 ± 0.52 (0.7–2.9)0.96 ± 0.37 (0.37–1.71)	73.43	p < 0.001 Post hoc (Scheffe test)P1 < 0.001^ P2<0.001^P3 < 0.053

P1: Difference between radiologist with apron and radiologist without aprons.

P2: Difference between radiologist with apron and control.

P3: Difference between radiologist without aprons and control.

^**p < 0.001 highly significant; *p ≤ 0.05 significant; p > 0.05 insignificant.

A pre-designed questionnaire was completed by all participants, including data about their age, sex, residence, marital status, smoking, working hours per week, duration of working in the radiology department, lead shield usage, and time spent wearing a shield. The hair and blood samples were taken from both control and study groups after obtaining their informed consent.

This study was approved by the Menoufia Faculty of Medicine ethical committee (Approval number 10/2022 FORE31).

The hair samples were collected and taped to a card and sealed in a polyethylene envelope. Hair was cut into 5–10 mm lengths and weighed to at least 10 mg. Hair was washed in deionized water on a mechanical shaker and then boiled. Each sample was transferred to a 100 mL Teflon beaker and digested with a 1:5 mixture of HClO4: HNO3 until only a few drops of clear liquid remained. The sample was diluted with deionized water at a ratio of 1:50. Determination of lead concentration was made using a PerkinElmer A Analyst 800 Atomic Absorption Spectrometer.

Each study participant gave 10 mL of blood, which was collected in heparinized tubes for lead estimation. The blood was added into sodium EDTA-containing tubes that had been verified as lead-free. SM 3500 PBA atomic absorption spectrometry with a graphite furnace was used to determine the lead concentration of the blood samples (Drobyshev et al., 2017).

Statistical analysis

The collected data were organized, tabulated, and analyzed using SPSS Version 16 software (SPSS Inc, Chicago, ILL Company). The t-test was used to compare between mean ± SD of two groups. Also, normally quantitative data were expressed as mean ± SD and were compared using an F-test (ANOVA), and the significance between groups was determined using a post hoc test (Tukey). The abnormally distributed quantitative data were expressed as medians (min. and max.) and compared using the Kruskal–Wallis test, where the significance between groups was determined using another post hoc test (Dunn’s multiple comparisons test). The accepted level of significance was considered as p ≤0.05. The Pearson correlation coefficient (r) is a descriptive statistic that describes the strength and direction of the linear relationship between two quantitative variables.

Results

The present study was a prospective one involving 60 participants. The participants were divided into two groups based on their possible exposure to lead: the control group: 20 persons, who were not working in the radiology department in the three studied hospitals, and the study group: 40 persons who were working in the radiology department in the three studied hospitals; Eighteen of them were wearing aprons and 22 were not wearing an apron.

There were no statistically significant differences between the control group and the studied group regarding age, sex, residence, marital status, smoking status, and type of the hospital (p > 0.05). There was no significant difference between radiologists wearing aprons and those not wearing aprons regarding the duration of working (in years) and working hours per week (p > 0.05) as depicted in table (1).

Radiologists wearing aprons had a significantly higher hair lead level than both the controls and radiologists without aprons (p < 0.001). The lead hair level in the radiologists without aprons was significantly higher than that of the control group (p < 0.02). There were no statistically significant differences between the hair lead level of the participants regarding the sex, residence, marital status, and type of hospital (p-values: 0.74, 0.096, 0.596, and 0.084, respectively), while smoker participants showed higher hair lead levels than non-smokers, and the difference (p-value: 0.001) is shown in table (2) and Figure 1.

The hair lead level was correlated significantly with the duration of wearing aprons in years and weekly working hours (p-values: <0.001 and 0.009, respectively) as revealed in table (3).

The blood lead level in radiologists wearing aprons was higher than that of the control group and higher than that of the radiologists without aprons (p < 0.001 and p < 0.001, respectively), and the blood lead level in the radiologists without aprons was significantly higher than the control group (p < 0.05) as shown in table (4) and Figure 2.

There was a highly significant positive correlation between the blood lead level and the hair lead level (r = 0.743, p-value <0.001) as shown in Figure 3. There was a highly significant positive correlation between the hair lead level and the duration of wearing an apron (in years) (r = 0.764, p-value <0.00) as shown in Figure 4.

There is a significant positive correlation between the hair lead level and the duration of working hours per week (r = 0.407, p-value <0.009) as shown in Figure 5.

Discussion

Environmental lead exposure continues despite knowledge of the harmful effects of lead on all body systems and World Health Organization (WHO) warning that there was no safe blood lead level. Most adult lead exposures occur at work. The current study explored the possible risk of lead exposure in radiologists by studying the hair and blood lead levels.

In the current study, the majority of workers at radiology departments were of male gender (72.5%), which may be primarily attributed to the deleterious risks of ionizing radiations on female workers. This is in accordance with a recent study involving a total of 213 radiologists of which only 36% of participants were females; who were included in the analysis of gender differences in the scope of work practice (Alcaide-Leon et al., 2022).

More than half of the present study participants (65%) were from rural areas, as the majority of Menoufia Governorate is rural. About half of the participants in the current study were smokers, as most of them were males in young and middle age, and the smoking habit is common among males in this age group.

Radiologists wearing aprons in this study were only 45%, which could be explained by the lack of health instructions and supervision of workers to decrease the risks of exposure to ionizing radiation. A recent study of 195 radiologists to assess awareness and practice of ionizing radiation protection procedures among health-care workers (HCWs) occupationally exposed to ionizing radiation at Zagazig University Hospitals revealed that satisfactory awareness of radiation protection procedures among HCWs was 51.3%, but HCWs had inadequate practice scores (only 18%) regarding the use of safety measures of radiation exposure during work (Salah Eldeen and Farouk, 2020).

The mean lead level in the blood and hair of radiographers wearing aprons was 3.33 ± 0.93μg/dl and 13.38 ± 1.67 μg/g, respectively; hence, this represents a health hazard for those workers. This is in accordance with the findings of Schwartz et al. who concluded that even if the workers' blood lead levels were low, lead exposure could harm their health (Schwartz et al., 2007).

Telisman et al., have shown in their study that lead had an adverse impact on male reproductive function at blood lead levels (BLL) < 5 μg/dL (Telisman et al., 2007). Also, Lanphear et al., reported that BLLs >3 μg/dL have been linked to an elevated risk of cardiovascular and stroke deaths (Lanphear et al., 2018).

The age of the participants in the present study did not influence their hair lead levels. This is in accordance with the result of Niculescu et al., on occupationally exposed subjects (Niculescu et al., 1983). Sanna also found non-significant correlations between the hair lead level and age (Sanna et al., 2007).

In the current study, the hair lead level in the radiologists was higher than the control group. It was also high in radiologists wearing apron group compared with those who did not wear aprons, as lead shielding materials disintegrate over time and the lead dusts can escape the capillary pores of plasterboards or cracks of aprons and enter the X-ray room environments. Therefore, environmental lead accumulated in the hairs of radiologists during the working period.

These results correlated with those of Hung and Chang, who observed increased hair lead level in radiographers using lead aprons and working in the space with installed lead shielding (Hung and Chang, 2021).

Burns et al., also reported that 63% of radiation-protection aprons had lead dust on the exterior of them (Burns et al., 2017).

The blood lead levels of the radiologists in the current study were greater than those of the control group, and they were also considerably higher in apron-wearing radiologists than in non-wearing radiologists. This may be due to the presence of lead particles in the work environment. The apron use increases exposure. No blood lead level has been demonstrated to be safe, according to the WHO (2021).

These findings were not correlated with those of Shoag et al., who found no correlation between the BLLs and the use of radiation shields with low BLLs of adult radiation shield wearers (Shoag et al., 2020).

Smoker participants in the present study showed higher hair lead levels compared with non-smokers. Smoking increases the risk of lead poisoning, as tobacco leaves trap lead from the atmosphere on their surface, and according to the WHO, 2–6% of lead in cigarettes is inhaled by the smoker.

Al-Ghabban found a significant increase in the blood–lead level associated with smoking in the general population (Al-Ghabban, 2006).

In the current study, there was a correlation between the lead hair level and the blood lead level, as the blood lead level denotes acute and ongoing exposure as the radiologists were still in the same working environment. This is in accordance with the work of Niculescu et al., who observed that the lead content in hair in workers occupationally exposed was correlated with the blood lead concentration (Niculescu et al., 1983). Also, Sanna et al., in their study, showed a significant correlation between blood lead and hair lead values (Sanna et al., 2007).

The hair lead level was positively correlated with both working hours and working years wearing apron in the present study. Rianto et al., observed a significant correlation between work duration and lead hair levels in their study on gas station workers (Rianto et al., 2018), while Hung and Chang found no correlation between working years and hair lead levels in their studied groups (Hung and Chang, 2021).

The multicenter design of the study in addition to the inclusion of a control group of normal personnel constitutes the main strengths of this study. Inability to conduct a larger trial and to include a larger number of participants was an unintended limitation of the current study.

Future research should focus on aprons used in radiology departments as a potential source of lead poisoning among health care workers. Testing for lead dust on the surface of radiation shields should still be considered to assess for occupational exposure that may have clinical implications to workers and their families.

Conclusion

Health care workers in radiology departments increased high hair and blood levels, which were higher among workers wearing aprons than those not wearing protective equipment. Wearing aprons, smoking, long working hours per week, and long working duration (in years) were independent risk factors for lead exposure in radiologists. Lead levels in hair may be detected quickly, cheaply, and non-invasively, and they are thought to be a helpful screening test for assessing occupational exposure.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Ethical approval

This study was approved by the Menoufia Ethical Committee (approval no. 10/2022 FORE 31).

ORCID iD

Aziza Elbadry

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