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The San Jos6 Mine is a mothballed Ag-Sn mine near Oruro on the Bolivian Altiplano. A groundwater risk assessment has been carried out considering: (i) the current mine water pumping operation; (ii) potential future mine flooding; and (iii) mine waste leachate, at risk sources. Mine flooding rates have been simulated using two models (MIFIM and MODFLOW), with input data based on the observed water inflow distribution and calculated mine volumes. Mine water chemistry has been characterized by field analyses. Transport of contaminants in groundwater in the Quaternary sedimentary aquifer complex surrounding the mine has been assessed by empirical data and hydraulic-geochemical modelling using MODFLOW and MPATH. Empirical and modelled data suggest that no risk is (or will be) posed to Oruro's public water supply wellfields at Challapampa. Continued pumping and discharge of mine water poses a potential risk to surface water recipients and private groundwater abstractions located alongside these.

The extraction of anthocyanins present in the skin of the dragon fruit was performed using trifluoroacetic acid (TFA) plus a mixture of methanol, acetic acid and water; the anthocyanins were then purified with a LC-18 cartridge, using methanol acidified with TFA as eluent, reaching concentrations of 44.3865 ± 1.3125 mg/100g of sample. The extracts were put through stability tests under different storage conditions, modifying the pH of the extracts (pH of 1, 4 and 6), the temperature (4˚C, 25˚C and 68˚C) and the absence and presence of light for a time period of 4 days; the tests indicated that anthocyanins remain more stable at a temperature of 4˚C with a pH of 4 in the absence of light, retaining up to 80% of the pigment. Three anthocyanins were partially identified in the extracts by high performance liquid chromatography (HPLC); they were: cyanidin 3-O-glucoside, cyanidin 3,5 O-glucoside and pelargonidin 3,5 O-glucoside.

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