ABSTRACT
This study comprised 40 patients with chronic renal failure [CRF] with undefined leading cause and 40 apparently healthy subjects of comparable age and sex [control group]. Blood sample [7 ml] was taken from every one and divided into two parts: the first was heparinized for determination of cadmium, lead, and mercury in the whole blood using atomic absorption spectrophotometry and the second part was allowed to clot and centrifiged to separate serum for estimation of serum levels of urea and creatinine. There was a significant [P<0.05] increase of estimated blood levels of cadmium and lead and non-significant increase of blood level of mercury in the patients group compared to the control levels. Also, there was a positive significant [P<0.001] correlation between serum levels of urea and creatinine and blood levels of both cadmium [r=0.608 and 0.742] and lead [r=0.547, 0.688], respectively, in the control group. A similar positive significant correlation with blood cadmium [r=0.504, 0.503] and lead [r=0.473, 0.44 7], was found in patients group. The 95[th] percentile of blood levels of cadmium and lead in patients groups was 0.6875 and 16.645, respectively, there were 8 control subjects [20%] having a blood cadmium level >/=0.6875 microg/dl, while there was only one control subject [2.5%] having blood lead level >/= 16.645 microg/dl. In a trial to determine the dominant heavy metal leading to CRF, blood cadmium was found to be the variable that closely related to CRF manifested by increased serum creatinine with a significant standardized coefficient [beta=0.503, P=0.001]. We can conclude that environmental pollution with heavy metals especially cadmium, lead and mercury is responsible for the occurrence of interstitial nephritis that may progress to CRF, and that cadmium is the main causative pollution factor. We recommend considering a blood cadmium level of >/=0.6875 microg/dl as an indicator for impending renal failure, also we recommend inquiring for possible sources of drinking water pollution with cadmium