Contribution of nitrogen and phosphorus by precipitation in the drainage basin of the Santillana Reservoir (Madrid)

The contribution of nitrogen and phosphorus due to precipitation constitutes the second most important route after superficial runoff. The sampling carried out during a two-year period by means of a precipitation collector allows us to determine the contribution of this route both qualitatively and quantitatively. Nitrogen is mainly supplied in an inorganic form, while phosphorus is principally supplied as orthophosphate. During the period of this study (March 1986–February 1988) it was found that in the Santillana Reservoir Watershed the level of nitrogen supplied by precipitation constitutes an average of 4.87% and the level of phosphorus constitutes 8.01%. The contribution of nitrogen varies in inverse ratio to precipitation and the contribution of phosphorus varies in direct ratio.     

Minor improvement for intertidal seaweeds and invertebrates after acid mine drainage diversion at Britannia Beach, Pacific Canada

In December 2001, acid mine drainage (AMD) from an abandoned copper mine at Britannia Beach (British Columbia, Canada) was diverted to flow from Britannia Creek into an outfall at 30 m depth in Howe Sound. Britannia Beach was studied in early 2003 to determine whether AMD diversion resulted in improved conditions for intertidal organisms. Species number and abundance have increased at the intertidal zone since AMD diversion, although they were still lower than at an unpolluted control site nearby (Furry Creek). Survivorship and growth rates of transplanted Mytilus trossulus (mussel) have increased since AMD diversion, although they were still significantly lower than at the control site. Transplanted Fucus gardneri (seaweed) performed better than before the AMD diversion; at Britannia Beach the chlorophyll a concentration in tissues was not significantly different from that at the control site, although the concentration of chlorophyll c in tissues and the chlorophyll c to a ratio was lower than at the control site six weeks after transplantation. Britannia Beach is still subject to leaching of metals from surrounding soils, low levels of AMD coming down the creek, and AMD discharge from the deep outfall. Although there has been an improvement, the intertidal environment at Britannia Beach still seems unable to support normal growth and survival of organisms.     

Fractionation of the noble metals by physical processes

During partial melting in the earth’s mantle, the noble metals become fractionated. Os, Ir, Ru, and Rh tend to remain in the mantle residue whereas Pt, Pd, and Re behave mildly incompatible and are sequestered to the silicate melt. There is consensus that sulfide plays a role in the fractionation process; the major noble metal repository in the mantle is sulfide, and most primitive mantle melts are sulfide-saturated when they leave their mantle sources. However, with sulfide–silicate partitioning, the fractionation cannot be modeled properly. All sulfide–silicate partition coefficients are so extremely high that a silicate melt segregating from a mantle source with residual sulfide should be largely platinum-group elements free. We offer a physical alternative to sulfide–silicate chemical partitioning and provide a mechanism of generating a noble metal-rich melt from a sulfide-saturated source: Because sulfide is at least partially molten at asthenospheric temperature, it will behave physically incompatible during melt segregation, and a silicate melt segregating from a mantle residue will entrain molten residual sulfide in suspension and incorporate it in the basaltic pool melt. The noble metal abundances of a basalt then become independent of sulfide–silicate chemical partitioning. They reflect the noble metal abundances in the drained sulfide fraction as well as the total amount of sulfide entrained. Contrary to convention, we suggest that a fertile, sulfide-rich mantle source has more potential to generate a noble metal-enriched basaltic melt than a refractory mantle source depleted by previous partial melting events.     

Contamination of some reservoirs and lakes in Republic of Bulgaria by microcystins

This paper presents the results from analyses of water samples from 15 Bulgarian reservoirs and lakes for detection of microcystins presence by high‐performance liquid chromatography (HPLC) coupled to a ultraviolet (UV) and photo diode array (PDA) detector. In 3 of the studied drinking water reservoirs cyanobacterial blooms were not detected. Cyanobacterial blooms were observed in 6 of 12 investigated water bodies used for fishing and water sports. Microcystis was the dominant cyanobacterial genus. The concentration of total microcystins in the biomasses ranged from 8 to 1070 μg g^–1 (d.w.). Microcystin‐LR and microcystin‐RR were the predominant microcystins, followed by microcystin‐YR. Presence of dissolved microcystins was obtained in one water sample with concentration of total microcystins 1.64 μg L^–1. Presence of microcystin‐LF and ‐LW or unknown peaks possessing characteristic microcystin‐like UV‐spectra were not detected. Those first results for occurrence of microcystins in some Bulgarian reservoirs and lakes are a contribution to the knowledge on their distribution.