Browsing by Subject "mine"

Arsenic (As) is a metalloid naturally present in the environment. Arsenic species vary in toxicity. Metal mining has contributed to the anthropogenic input of arsenic to groundwaters and surface waters. In this study, water samples were collected from 20 sample points in three mining-impacted study areas in Finland: the former Ylöjärvi Cu–W–As and Haveri Au–Cu mines, and the active Pyhäsalmi Zn–Cu mine. Six groundwater well samples, eleven surface water samples and three tailings seepage collection ditch samples were analyzed for dissolved arsenic speciation by HPLC-ICP-MS and for geochemical composition by ICP-MS, titration, and ion chromatography. Dissolved arsenic concentrations ranged from 14.2 to 6649 µg L-1 in samples collected at the Ylöjärvi study area, from 0.5 to 6.2 µg L-1 in samples collected at the Haveri study area, and from 0.2 to 9.4 µg L-1 in samples collected at the Pyhäsalmi study area. In all study areas, measured dissolved arsenic concentrations showed a general decrease from the tailings to the surroundings. Speciation analysis showed that two of the samples collected at the Ylöjärvi study area had arsenite [As(III)] as the dominant form of dissolved inorganic arsenic (iAs), three had arsenate [As(V)] as the dominant form of dissolved iAs, and four had a mixture of both. In the water samples collected at the Haveri and Pyhäsalmi study areas, all concentrations of dissolved arsenic species were below method detection limits. Also, none of the 22 water samples analyzed for arsenic speciation had dissolved MMA or DMA concentrations above method detection limits. Identification of dissolved arsenic species in the sampled waters in Haveri and Pyhäsalmi, and of MMA and DMA in all sampled waters requires more detailed study. A significant 2-tailed Pearson correlation between dissolved arsenic and dissolved molybdenum (Mo) (r=0.80**, n=20), and dissolved arsenic and dissolved potassium (K) (0.68**, n=19) suggests that in these three study areas the distributions of dissolved arsenic and Mo, as well as dissolved arsenic and K may be controlled by the same environmental variables. Anomalously high maximum concentrations of dissolved Al, Ca, Co, Cu, Fe, Ni, and SO4 were measured in surface water samples collected at the Ylöjärvi and Haveri study areas, and in a seepage collection ditch sample collected at the Pyhäsalmi study area.