Lead exposure by E-waste disposal and recycling in Agbogbloshie, Ghana.

BACKGROUND: Agbogbloshie in Ghana is the world's biggest dumpsite for the informal recycling of electronic waste (e-waste). E-waste is dismantled by rudimentary methods without personal or environmental protection. Workers and occupants are exposed to lead. There are no data so far about the extent and the consequences. We therefore analyzed blood lead levels (BLL) and creatinine levels (CL). METHODS: Full blood samples and basic data (i.e. age, job, length of stay) were collected from dumpsite volunteers. BLL were measured by atomic absorption spectrometry; CL were assessed using the standard clinical laboratory procedures of Aachen Technical University. European BLL reference values were used as Ghana lacks its own. Statistical analysis was by non-parametric tests (Mann-Whitney U test), with p < 0.05. RESULTS: Participants of both sexes (n = 327; 12-68 years; median age 23 years) were assessed. Most workers were aged <30 years. The collective's BLL was in pathological range for 77.7%; 14% had a BLL >10.0 µg/dl with symptoms consistent with high lead exposure including severe (6.5%) and intermediate (39%) renal disorder. BLL above 15.0 µg/dl were found in 5.9% of all workers which is the German threshold for those working with lead. Elevated CL in a pathological range were found in 254 participants. This is problematic as 75% of the lead entering the body is excreted via urine. CONCLUSION: Most of our volunteers had pathological BLL and CL. Preventive strategies are necessary to reduce health risks, particularly for vulnerable populations (i.e. children, pregnant women).

Contractile activity is required for sarcomeric assembly in phenylephrine-induced cardiac myocyte hypertrophy.

Agonist-induced hypertrophy of cultured neonatal rat ventricular myocytes (NRVM) has been attributed to biochemical signals generated during receptor activation. However, NRVM hypertrophy can also be induced by spontaneous or electrically stimulated contractile activity in the absence of exogenous neurohormonal stimuli. Using single-cell imaging of fura 2-loaded myocytes, we found that low-density, noncontracting NRVM begin to generate intracellular Ca2+ concentration ([Ca2+]i) transients and contractile activity within minutes of exposure to the alpha 1-adrenergic agonist phenylephrine (PE; 50 microM). However, NRVM pretreated with verapamil and then stimulated with PE failed to elicit [Ca2+]i transients and beating. We therefore examined whether PE-induced [Ca2+]i transients and contractile activity were required to elicit specific aspects of the hypertrophic phenotype. PE treatment (48-72 h) increased cell size, total protein content, total protein-to-DNA ratio, and myosin heavy chain (MHC) isoenzyme content. PE also stimulated sarcomeric protein assembly and prolonged MHC half-life. However, blockade of voltage-gated L-type Ca2+ channels with verapamil, diltiazem, or nifedipine (10 microM) blocked PE-induced total protein and MHC accumulation and prevented the time-dependent assembly of myofibrillar proteins into sarcomeres. Inhibition of actin-myosin cross-bridge cycling with 2,3-butanedione monoxime (7.5 mM) also prevented PE-induced total protein and MHC accumulation, indicating that mechanical activity, rather than [Ca2+]i transients per se, was required. In contrast, blockade of [Ca2+]i transients and contractile activity did not prevent the PE-induced increase in cell surface area, activation of the mitogen-activated protein kinases ERK1 and ERK2, or upregulation of atrial natriuretic factor gene expression. Thus contractile activity is required to elicit some but not all aspects of the the hypertrophic phenotype induced by alpha 1-adrenergic receptor activation.

An experimental manipulation of food and water: growth and time-space utilization of hatchling lizards (Sceloporus undulatus).

At a site in western Nebraska, we studied the effects of supplemental food and water on growth, survival, and habitat utilization of hatchling iguanid lizards, Sceloporus undulatus. Hatchlings were randomly assigned to one of four experimental groups and received either (1) supplemental food only, (2) supplemental water only, (3) supplemental food and water, or (4) neither supplemental food nor water (control). Neither supplemental food nor supplemental water affected growth rate in length, growth rate in mass, or size-specific body mass (i.e. robustness) at the end of the treatment period. Over the 45 day treatment pierod, there were no significant differences among treatment groups in survival, home-range size, or habitat utilization. There were, however, significant differences in the index of activity. Hatchlings in the treatment groups receiving supplemental water were sighted more often than hatchlings in the control group. We conclude that, during our study, neither food nor water limited growth but that water limited activity.

Study of an analytical method for hexavalent chromium.

The diphenylcarbazide colorimetric method was evaluated by analyzing spiked PVC filters prepared by an AIHA-accredited consultant laboratory for chromium (VI). All seven participating laboratories received the samples and performed the analyses at the same time. Three laboratories simultaneously tested three alternative analytical procedures. Reduced amounts of chromium (VI) were found by both the consultant and participating laboratories when using the test procedure and one of the alternative methods. Two of the alternative analytical methods, both of which involve an alkaline extraction procedure, provided higher recoveries and more precise values for the test filters. It appears that the alkaline extraction procedure may be more appropriate for occupational health samples taken in steel industry environments which may include several interferents. Suggestions are made for further studies to determine the most appropriate analytical method.