Microbial Bioleaching of Ag, Au and Cu from Printed Circuit Boards of Mobile Phones.

Electronic waste (E-Waste) is consumed at high speed in the world. These residues contain metals that increase their price each year, generating new research on the ability of microorganisms to recover the metals from these wastes. Therefore, this work evaluated the biologic lixiviation of Cu, Ag and Au from printed circuit boards (PCB) of mobile phones by three strains of Aspergillus niger, Candida orthopsilosis, Sphingomonas sp. and their respective consortia, in addition to leaching with citric acid. The microorganisms were cultured in mineral media with 0.5 g of PCB, and the treatments with 1M citric acid were added the same amount of PCB. All treatments were incubated for 35 days at room temperature. The results showed that Sphingomonas sp. MXB8 and the consortium of C. orthopsilosis MXL20 and A. niger MXPE6 can increase their dry biomass by 147% and 126%, respectively, in the presence of PCB. In the bioleaching of metals, the inoculation of A. niger MXPE6, the consortium of Sphingomonas sp. MXB8/C. orthopsilosis MXL20 and Sphingomonas sp. MXB8 leached 54%, 44.2% and 35.8% of Ag. The consortium of A. niger MX5 and A. niger MXPE6 showed a leaching of 0.53% of Au. A. niger MX5 leaching 2.8% Cu. Citric acid increased Cu leaching by 280% compared to treatments inoculated with microorganisms. Although further research is required, A. niger MXPE6 and the consortium of Sphingomonas sp. MXB8/C. orthopsilosis MXL20 could be an alternative to recover Ag from PCB of mobile phones.

[Socioeconomic status and resource consumption in primary care]. / Nivel socioeconómico y consumo de recursos sanitarios en atención primaria.

OBJECTIVE: To determine the influence of socioeconomic status on healthcare demand and resource consumption in our population. PATIENTS AND METHODS: We performed a cross sectional, retrospective study of socioeconomic status and healthcare and pharmaceutical consumption in randomly selected patients from five primary care pediatric clinics in Madrid. The chi-square test was used to compare percentages. For the remaining analyses, nonparametric tests were used after confirming that the data followed non-normal distribution. RESULTS: We compared 684 questionnaires. Patients in the most disadvantaged socioeconomic levels consumed a greater number of drugs than those in more privileged levels (mean 0.79 vs. 0.47, p = 0.04). The mean pharmacological expenditure was also higher in the lowest socioeconomic levels than in the highest levels (5.28 Euros vs. 2.21 Euros, respectively; p = 0.001). No significant differences were found among socioeconomic levels in the number of consultations or diagnostic tests requested. The number of consultations was higher in younger patients (p < 0.001) or in those with chronic diseases (p = 0.001). Drug consumption was increased in the most disadvantaged levels (p = 0.002) and in patients with chronic diseases (p < 0.001). Lastly, pharmacological expenditure expressed in Euros was also higher in the lowest socioeconomic levels (p = 0.001) and in patients with chronic diseases (p < 0.001) but was lower if one of the parents was a foreigner (p = 0.031). CONCLUSIONS: We found a relationship between socioeconomic level and drug consumption and its attributable cost. These data should be confirmed by broader studies.