Date of Award

5-2000

Document Type

Thesis

Degree Name

Master of Environmental Studies (MES)

Department

Environmental Science

First Advisor

Dr. Abdulbari Bener

Second Advisor

Dr. A. G. Nicolas

Third Advisor

Dr. Ahmad Ayoob Alqadal

Abstract

Lead, which is considered to be as a toxic metal without any useful physiological or biochemical function in human body was widely used since the evolution of the industrialized era as a chemical part of much machinery and commodities. Lead containing gasoline, lead paints, lead-soldered cans, lead-glazed earthenware and tobacco are examples of sources of lead. Therefore, lead continues to be a significant public health concern globally.

Nowadays it is particularly impossible to find a person with blood lead level lower than 0.48μmol/L (100 μg/ dL) especially in city areas. Changes in neurobehavioral, cardiovascular, hematological, and renal functions are found to be associated with lead even low blood lead levels. At the molecular levels, lead tends to cause damages to multitude of enzymes and essential cellular structures.

The aim of the present study is to determine the Blood Lead Levels (BLLs) among expatriate industrial (exposed) and non-industrial (unexposed) workers and investigate predictor factors that are influencing BLLs in UAE population. Additionally, the present study aiming to determine the effect of lead exposure on the plasma levels of amino acids and serum liver enzymes, cardiac enzymes and renal functions protein in industrial workers in Al-Ain, UAE. Finally, to study acute and chronic respiratory symptoms occurred exposure among industrial.

Although this study is not intended for generalization of the lead population problem to the whole UAE population, but without any doubt this study would be a representative sample of concurrent measures of lead exposures in the specific community. The first part of the study was screening of blood lead levels among industrial versus non-industrial individuals taking in consideration age, ethnic group, and smokers and non-smokers criteria. The second part of the study is focusing on the correlation between blood lead levels and levels of amino acids, liver function enzymes, cardiovascular enzymes and renal function proteins.

The study was based on matched exposed and unexposed study of subject selected from Al-Ain City. The study included 100 exposed and 100 unexposed, matched for age, sex and nationality. The field survey was conducted during the period from 1st of February to July 1999.

The relative importance of some factors on the likelihood of industrial workers having lead exposure was assessed using statistical methods and models.

This matched case-control was conducted in three parts, namely:

a) An epidemiological study of eating habits, life style, reported symptoms and lead level in industrial and non-industrial workers.

b) Plasma amino acid profiles among industrial and non-industrial workers.

c) Laboratory analysis of serum liver enzymes, cardiac enzymes and renal function proteins for cases and controls.

The Socio-demographic characteristics of industrial and non-industrial workers were similar among the population surveyed. Most of the industrial workers were not certain about lead exposures. Both groups, industrials and non-industrials workers were demographically similar with regards to age groups, nationality and marital status. The majority of industrial workers (38%) were illiterate, which was the expected result. The majority of non-industrial workers (48%) were educated with secondary or high school educational certificates. Most industrial workers were not aware of the amount of lead they might have been exposed.

Few industrial workers reported exposure to lead. One type of exposure derives from the working in jobs related to 40% of industrial workers reported being involved with smelling spraying of toxic gases and chemical directly, 13% of the subjects reported working in radiation areas or magnetic fields, and 14% of them reported dealing with battery recycling.

The exposure to lead among industrial and non-industrial workers was investigated. The majority of industrial workers reported not using masks as the main method of protection during their work. The majority of industrial workers reported different clinical symptoms. Reported symptoms among industrial workers were higher than non-industrial workers had. It was observed that, most of the symptoms occurred among industrial and non-industrial were significant differences as follows Nausea/vomiting [OR= 4.235, 95% Cl (1.35-13.25)], (p=0.008), Red/irritated eye/blurred vision [OR=1.61, 95% Cl(0.731-3.547)],(p=0.235)], Increased anxiety [OR = 2.68, 95% Cl (1.16-6.20)], (p= 0.017), Dizziness [OR = 1.926, 95% Cl (0.808-4.592)], Headache [OR = 1.176, 95% Cl (0.617-2.243)], (p= 0.622), Muscular symptoms [OR = 3.146, 95% Cl (1.46-6.75)], (p= 0.002), Memory loss [OR= 11.0, 95% Cl (1.38-87.64)], (p= 0.005), Fatigue [OR= 3.439, 95% Cl (1.303-9.074)], (p=0.009), Insomnia [ OR = 2.16, 95% Cl (0.834-5.612)], (p= 0.106), Chest pain [OR = 1.0, 95% Cl (0.41-2.42)], (p= 1.000). Kidneys [OR= 3.20, 95% Cl (1.20-8.51)], (p=0.008), Gastrointestinal [OR= 2.55, 95% Cl (1.17-5.55)], (p= 0.016), Anemia [OR = 3.43, 95% Cl (1.30-9.07)], (p= 0.009), Difficulty in breathing [OR = 2.72, 95% Cl (1.07-6.88)], (p = 0.030), Cardiovascular [OR = 3.61, 95% Cl (1.27-10.30)], (p= 0.011), Mania [OR = 6.62, 95% Cl (1.87-23.39)], (p= 0.0016), Abdominal pain [OR = 1.18, 95% Cl (0.53-2.63)], (p= 0.684), Myalgia and Anorexia [OR = 1.26, 95% Cl (0.32-4.84)], (p= 0.733).

Furthermore, we have investigated plasma amino acid profiles among industrial workers (exposed) and non-industrial workers (unexposed). Most plasma amino acid tests showed higher values among industrial than non-industrial workers did. There were statistically very highly significant differences between industrial and non-industrial with the respect of some amino acids levels as can be seen as follows: Taurine (112.02 ±38.70 μmol/l, Mean ± S.D) in non- industrial workers, N=100, (p= 0.0001), Serine (159.33 ± 34.68 μmol/l, Mean ± S.D) in industrial workers and (108.09 ± 26.42 μmol/l, Mean ± S.D) in non-industrial workers, (p= 0.003), Glutamic acid (236.89±149.91 μmol/l, Mean ± S.D) in industrial workers and (82.26 ± 57.09 μmol/l) in non-industrial workers, (p=0.000), Glycine, (236.89 ± 149.91 μmol/l, Mean ± S.D) in industrial workers and Mean ± S.D (244.25 ± 72.88 μmol/l in non-industrial workers, (p= 0.0001), Histidine Mean ± S.D (107.50 ± 29.61 μmol/l) in industrial and Mean ± S.D (95.90 ±18.53 μmol/l) in non-industrial workers, Ornithine Mean ± S.D (178.94 ± 59.16 μmol/l) in industrial workers and (104.84 ± 30.64 μmol/l) in non-industrial workers (p= 0.001), Lysine Mean ± S.D (218.71 ±51.73 μmol/l) in industrial workers and (176.77 ± 36.71 μmol/l) in non-industrial workers (p=0.006), Leucine Mean ± S.D (162.49.99 ±38.73 μmol/l) in industrial workers and non-industrial workers (135.57 ± 26.94 μmol/l), (p = 0.002), Valine Mean ± S.D (264.15 ±65.88 μmol/l) in industrial workers and (234.05 ±58.02 μmol/l) in non-industrial workers (p = 0.62), Threonine Mean ± S.D (161.67 ± 42.04 μmol/l) in industrial workers, (p = 0.055) and Mean ± S.D (130.34 ± 34.55 μmol/l) in non-industrial workers, (p = .055), Alanine Mean ±S.D (526.59 ± 151.35 μmol/l) among the industrial workers and non-industrial workers Mean ± S.D (417.64 ± 92.08 μmol/l), (p= 0.0001), Glutamine Mean ± S.D (622.86 ± 139.85 μmol/l) in industrial workers and (583.86 ± 146.50 μmol/l) in non-industrial workers, (p= 0.346) and Proline Mean ± S.D (339.31 ± 137.29 μmol/l) in industrial workers and (261.15 ± 82.464 μmol/l) in non-industrial workers (p=0.006).

Finally, the liver function tests were estimated among industrial (exposed) and non-industrial (unexposed) workers. Only Lactate Dehydrogenase and Alkaline Phosphates were higher in industrial workers than non-industrial workers. And there were statistically significant differences between industrial and non-industrial workers, for Lactate Dehydrogenase in industrial workers (211.27 ± 57.27u/l, Mean ± S.D); versus in non-industrial workers (194.77 ± 48.69 u/l, Mean ± S.D), (P=0.029) and Alkaline Phosphates (84.27 ± 24.64 u/l, Mean ± S.D) for u/l) for industrial and (76.18 ± 20.48u/l, Mean ±S.D) in non-industrial workers, (p=0.012).

Also kidney proteins such as Blood Urea Nitrogen and Creatinine were estimated among industrial and non-industrial workers without any statistically significant differences.

The results of this study determined the exact Blood Lead Levels among industrial and non-industrial workers, in UAE population. Also lead and associated environmental risk factors will hold great promise for future planning, prevention and programming in Al-Ain City for the Ministry of Health, Universities, Federal Environmental Agency, WHO, Municipality and other concerned academic researcher institutions.

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