Study on clinical and biochemical toxicity biomarkers in a zinc-lead mine workers

Abstract

The aim of this study was to determine oxidative stress status as well as blood lead (Pb) and zinc (Zn) levels and clinical markers in workers of a Zn-Pb mine. A comparative cross-sectional analysis was performed in 67 mine workers who have been in contact with Zn and Pb in comparison to a control group containing 67 healthy subjects with the same age and sex. Lipid peroxidation, superoxide dismutase, catalase, glutathione reductase, myleoperoxidase, DNA damage, total antioxidant capacity, Zn, and Pb levels were measured in blood of workers and controls. Clinical examination was accomplished to record any abnormal sign or symptoms. Comparing with controls, the workers showed higher blood levels of superoxide dismutase, myleoperoxidase, glutathione reductase, lipid peroxidation, Pb, and Zn. Workers showed lower DNA-damage as compared with controls. Workers showed clinical symptoms such as memory impairment, less of concentration, insomnia, headache, claudication, epigasteric, inappetence, agitation, tremor, decreasing of reflection of deep tendon, conduction deafness of ear, and fatigue. The workers had extra normal levels of Pb (0.9-3 microg/dL) and showed oxidative stress. Taken together, the results indicate that exposure to combination of Pb and Zn in mine elevates total antioxidant capacity of body in a reflex to overcome to oxidative stress. Especially, in the present case, it seems that toxic effect of Pb has been greater than positive effects of Zn, but the combination exposure has resulted in not such a critical toxicity situation.

Clinical, Haematological, and Neurocognitive Findings in Lead-Exposed Workers of a Battery Plant in Iran

“…Supporting these data, our previous study (29) in lead/zinc mine workers showed clinical symptoms such as memory loss, diminished concentration, sleeplessness, headache, limping, epigastric pain, lack of appetite, anxiety, tremor, low DTR, deafness, and fatigue. Lead exposure can also end up with abdominal cramps, peripheral and central neuropathy, anaemia, or with vague symptoms such as myalgia, tiredness, bad temper, and headache, or with no symptoms at all (29). In another study, by Zhang et al (30), petrol workers exposed to tetraethyl lead had a signifi cantly higher incidence of tremor and sinus bradycardia than controls, which is similar to our fi ndings.…”

“…Our earlier study (29) indicated that the key reason for increased BLL in lead/zinc mine workers is inappropriate use of safety equipment. The workers did use masks, but failed to use protective clothing or take regular showers, even though suitable facilities were available.…”

Lead Exposure and Oxidative Stress: A Systematic Review

“…Four studies reported that TBARS were detected measuring LPO in body fl uids. Three studies reported that the TBARS concentration was signifi cantly higher in workers exposed to lead than in control groups (Ito et al 1985 ;Sugawara et al 1991 ;Wasowicz et al 2001 ), and another study showed no signifi cant differences among subjects with higher BLLs (Malekirad et al 2010 ). A higher correlation of serum LPO was observed with the duration of lead exposure than with aging (Ito et al 1985 ).…”

“…Among these, 6 studies observed that SOD and CAT activities were signifi cantly lower in groups exposed to lead (Sugawara et al 1991 ;Patil et al 2006a , b ;Mohammad et al 2008 ;Grover et al 2010 ;Conterato et al 2013 ). Four studies found that SOD activity was higher in exposed groups (Kasperczyk et al 2004b(Kasperczyk et al , 2012Malekirad et al 2010 ;Conterato et al 2013 ), and 1 of these studies reported that the increase was greater in the low lead-exposed subgroup (BBL, 35.0 ± 9.3 μg/dL) than in the high leadexposed subgroup (BBL, 44.2 ± 8.1 μg/dL) (Kasperczyk et al 2004b ). No significant difference was noted in CAT activity in these studies (Kasperczyk et al 2004b(Kasperczyk et al , 2012Malekirad et al 2010 ).…”

Association of Blood Lead Level With Clinical and Renal Parameters in a Group of Egyptian Lead Exposed Workers

“…Chronic exposure leads to loss of short term memory, inability to concentrate, increased excitability, depressive mood, paresthesia of extremities, generalized abdominal pain and nausea (Pearce, 2007). Patients may also complain of headaches, weakness, myalgia, anemia and lead line which are common signs in chronic lead poisoning (Malekirad et al, 2010).…”