Abstract
Trace element levels (B, V, Cr, Mn, Fe, Cu, Zn, As, Sr and Cd) in environmental (water and cigarette tobacco) and biological (tear drop, saliva, scalp hair and fingernail) samples collected from Iraqi individuals resident in Karbala (Iraq) and London (UK) were determined by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Multi-element analysis was carried out on drinking (commercial, domestic bottled and tap) and irrigation (river, artesian and well) water samples. It was found that most trace element levels (ug/1) were lower than the permissible guidelines for drinking water recommended by the World Health Organisation (WHO) and Iraqi government. The only exceptions were for B in artesian and well waters; and Cd in river, artesian and well waters. The highest levels in drinking and irrigation waters were found for Sr when compared with other trace elements. Trace element levels in tap water from Karbala were higher than those from London. The levels of trace elements in cigarette tobacco were found to be at higher to lower levels through the following sequence: Fe > Mn > Sr > Zn > Cu > As > Cd > Cr > V. Moreover, multi-element analysis was undertaken for tear drop, saliva, washed scalp hair and fingernail samples for Iraqi individuals from Karbala (Iraq) and London (UK). Discriminant analysis suggested that Sr, Mn, B, V, As, Cd and Zn levels could be used to discriminate between healthy and diabetic populations (83% of cases correctly classified). Higher trace element levels were found in the tear drop, saliva, scalp hair and fingernail samples from Karbala than those from London. The influence of various factors (health status, gender and smoking activity) and covariates (individual’s age and drinking water) on elemental levels in tear drops was investigated using the analysis of covariance (ANCOVA). Significant differences (at P < 0. 05) were found between the healthy and diabetic individuals for B, Mn and Sr; males and females in terms of the levels of Fe; and smokers and non-smokers for Cd. Trace element levels in drinking water were found to have significant effects on the levels of V, Mn and Sr, whilst an individual’s age has a significant effect in terms of Zn and As. Interelement interactions were evaluated for each pair of trace elements in tear drops, and between tear drops and saliva, washed scalp hair and fingernails. There were 32 and 27 statistically significant correlations of the total 45 tested using tear drops from healthy and diabetic individuals, respectively. Similar results were observed for saliva, washed scalp hair and fingernails in terms of residential location, health status and inter-element interactions. The use of tear drops as a potential biomarker for assessing human health status has been evaluated using several studies in this research, namely; drinking water analysis, smoking activity and type 2 diabetes.