Environmental assessment of mercury pollution in urban tailings from gold mining.

It is well-known that small-scale artisanal mining is a source of mercury emissions into the environment, mainly from the use of rudimentary technologies that use mercury amalgamation in the extraction process. Mines near Andacollo, which is located in the Coquimbo region of Chile, use primitive methods to mine gold and copper. In this study, we determined the mercury content of gold mining wastes from Andacollo. At each site, we randomly sampled the soil at the surface and at a depth of 2 m following the ISO 10381 guidelines. Mercury analysis was performed with a direct mercury analyzer. At least one site was contaminated at a mercury concentration of 13.6±1.4 mg kg(-1), which was above the international recommendations that were set by the Canadian Council of Ministers of the Environment's soil quality guidelines (CA-SQG) and the Dutch guidelines (NL-RIVM). At least four of the fourteen sites in this study were within the control and tolerance levels of these recommendations. Better characterization of these sites is required to establish whether they represent a risk to the local community. Based on the US-EPA recommendations, which have a higher tolerance limit, none of the fourteen sites should pose a risk to humans.

Uncertainty of ozone measurements with the primary standard reference photometer (SRP45).

A comparison of the ozone primary reference standard photometer serial number 45 (SRP45) against the National Institute of Standards and Technology (NIST) instruments, serial number 0 (SRP0) and 2 (SRP2), has been performed in order to establish the traceability and comparability of ozone measurements made by the Chilean atmospheric science community. A complete uncertainty budget was developed for SRP45, using a GUM approach. The results of the comparisons allow us to conclude that SRP45, SRP0 and SRP2 are comparable according to international criteria over an ozone mole fraction range of 0 nmol mol(-1) to at least 500 nmol mol(-1). The official result for the validation of SRP45 is x(ozone)(SRP45)=[0.013+0.99806x(ozone)(SRP2)] nmol mol(-1) with an expanded uncertainty of [Formula in text] from 0 to 500 nmol mol(-1).