Snowmelt Samples Research Articles

Fate of lincomycin in snowmelt runoff from manure-amended pasture

Livestock manure containing antimicrobials becomes a possible source of these compounds to surface and ground waters when applied to agricultural land as a plant nutrient source. The potential for the transport of the veterinary antimicrobial, lincomycin, to surface waters via snowmelt runoff was assessed following field-scale fall injection of liquid swine manure into perennial grassland in Saskatchewan, Canada. This was achieved by monitoring snow melt runoff which accumulated in nineteen closed basin depressions, four ephemeral wetlands and two dugouts (small constructed reservoirs), approximately 6 months after manure injection. Following solid-phase extraction of the snowmelt runoff samples, LC–MS–MS was used to quantify lincomycin in the extracts. Lincomycin was detected in all snowmelt samples and concentrations in the closed basin depressions, ephemeral wetlands and dugouts ranged from 0.008 to 0.84 μg L −1. Significantly higher concentrations in the closed basin depressions most likely occurred because the liquid manure was injected directly into the depressions and because snow, which had accumulated in the ephemeral wetlands, and water, which remained in the dugouts from the previous year, would have diluted snowmelt runoff entering these water bodies. The time for 50% dissipation (DT 50) of lincomycin concentrations in the two dugouts and in two of the ephemeral wetlands which retained snowmelt runoff for greater than 4 weeks ranged from 18 to 49 d. This study demonstrates that the management practice of fall incorporation of liquid manure from confined animal feeding operations into pasture land may result in antimicrobial transport to surface waters via snowmelt runoff.

Organochlorine Pesticide and Polychlorinated Biphenyl Concentrations in Snow, Snowmelt, and Runoff at Bow Lake, Alberta

We present analyses of the concentrations of organochlorine (OC) contaminants (including organochlorine pesticides and PCBs) in snow, snowmelt, and runoff in glacier and snowmelt fed streams at Bow Lake, Alberta in two contrasting hydrological years (1997 and 1998). The study investigates the variability in OC burdens in snow across the catchment, the elution of OCs from the snowpack, and the relationship between OC concentrations in streams and the annual snowpack. Snowpacks in forested sites were thinner and had lower OC concentrations than snowpacks in open or sparsely vegetated sites. The first snowmelt samples exhibited very high contaminant concentrations relative to the snowpack, and even the more hydrophobic compounds (Dieldrin, DDTs, and PCBs) were highly concentrated in meltwater. Interannual changes in the mean OC concentrations in streams did not reflect year-to-year changes in the snowpack contaminant concentrations. The results indicate that the extent of glacial ice melt may be more important than mean snowpack burdens as a control on OC concentrations in runoff in glacial catchments.

Biogeochemical pools and fluxes of carbon and nitrogen in a maritime tundra near penguin colonies along the Antarctic Peninsula

There is limited information regarding biogeochemical pools and fluxes in maritime tundra ecosystems along the Antarctic Peninsula. To collect baseline information on biogeochemical processes in a tundra ecosystem dominated by two vascular plant species (Colobanthus quitensis and Deschampsia antarctica) at Biscoe Point off the coast of Anvers Island, we measured pools and fluxes of C and N in transplanted tundra microcosm cores, complemented with sampling of precipitation and surface runoff. Snow and snowmelt from the tundra collection site and soil leachates from the cores were enriched with N and dissolved organic carbon compared to precipitation and snowmelt samples collected at Palmer Station, indicating high loading of N and organic matter from the penguin colonies adjacent to the tundra site. Relatively high values of δ15N in the live and dead biomass of D. antarctica and C. quitensis (5.6–25.1‰) indicated an enrichment of N in this tundra ecosystem, possibly through N inputs from adjacent penguin colonies. Stepwise multiple linear regressions found that ecosystem respiration and gross primary production were best predicted by live biomass of D. antarctica, suggesting a disproportionately high contribution of D. antarctica to CO2 fluxes. The cores with higher δ15N and lower δ13C in the soil organic horizon exhibited higher CO2 fluxes. The results suggest that abundant N inputs from penguin colonies and the competitive balance between plant species might play a critical role in the response of tundra ecosystems along the Antarctic Peninsula to projected climate change.

Snowmelt dominance of dissolved organic carbon in high‐latitude watersheds: Implications for characterization and flux of river DOC

Transport of dissolved organic carbon (DOC) from land to water is an important but poorly known component of northern carbon cycles. We examined seasonal patterns of arctic river DOC flux, focusing on the largely uncharacterized snowmelt period. High‐intensity sampling of the Kolyma River showed rapid increases in DOC concentration during peak discharge, yielding unique DOC‐water flux relationships compared to summer, fall and winter. Our annual DOC flux estimates were 31% higher than previous estimates for the basin based on few or no snowmelt samples. Synthesis of the sparse literature show that 55% of arctic river DOC flux occurs during snowmelt. Biogeochemical characterizations of DOC in large rivers are usually done after snowmelt runoff, and are thus unrepresentative of most DOC transported to the Arctic Ocean. Finally, the proportion of annual DOC flux at snowmelt is considerably higher than for water, suggesting that cold season production is an important but little known process regulating arctic DOC transport.

A new technique to provide high time resolution snowpack dating for stratigraphy and chemistry assessments

A new technique has been developed to provide quantitative, high temporal resolution information of snow accumulation dynamics in remote polar, alpine, and high-latitude environments which can be used to identify episodic mechanical forcings and chemical inputs to a snowpack. This technique uses a device; which disperses inert, colored (high albedo) glass microspheres onto a snow surface at known time intervals to act as a tracer and time marker. Dating individual layers of the snowpack is obtained by using a sequence of several microsphere colors. The time interval between microsphere dispersal can range from hours for investigations of individual storms, to months for investigations in polar regions with small snow accumulations. The resulting spatial distribution of microspheres in the snowpack is determined by either core sampling or snow pit sampling, and extracting the microspheres from the snow melt samples for optical analyses. A field test of this technique was successfully conducted at an alpine site and the results of this test along with a chemical analysis of the snow profile are provided.

Manganese accumulation along Utah roadways: a possible indication of motor vehicle exhaust pollution

An organic manganese compound is currently added to gasoline to replace tetraethyl lead as an antiknock fuel additive in the USA and Canada. Combustion exhaust gases contain manganese oxides. Manganese oxides are known to cause various deleterious health effects in experimental animals and humans. A field survey of roadside soil and plants in central Utah revealed that soil manganese concentrations in high traffic areas were up to 100-fold higher than historic lead levels. Soil manganese concentrations were highly correlated with distance from the roadway. Lead concentrations seem to have changed little from values reported twenty years ago but may have moved deeper into the soil profile. In addition, roadside aquatic plants were higher in leaf tissue manganese than herbs or grasses. Plant tissue manganese content was better correlated with plant type, traffic volume and microhabitat than with distance from the roadway. Submerged and emergent aquatic plants were sensitive bioindicators of manganese contamination. Roadside snow melt and water samples were low in manganese and lead content. We conclude that roadside soil and plants were apparently contaminated by manganese oxides from Mn-containing motor vehicle exhaust. Manganese concentrations in soil and in some plant species along impacted roadsides often exceeded levels known to cause toxicity.

Urban snow dump quality and pollutant reduction in snowmelt by sedimentation

Four snow dump sites in the Ottawa-Carleton region were analyzed for BOD, total and fecal coliforms, chlorides, sulfates, specific conductance, suspended solids, metals, and other parameters. Sites were sampled at various depths during the months of February through May. There was no trend in variation of quality in the dump piles with time. The black crust that formed on the top of the pile was heavily laden with solids and metals.Snowmelt samples were also taken over the same time period and analyzed for the above parameters. The process of snowmelt reduced the concentrations of most metals and suspended solids from the dump by 50–70%. Dissolved constituents in snowmelt are discharged at very high levels during the initial stages of snowmelt and rapidly decrease to low concentrations. Suspended solids and associated metals in snowmelt exhibited variability with snowmelt conditions and the state of the dump pile. The concentrations of a number of metals in settled snowmelt exceeded provincial objectives for surface waters.An analysis of settled snow dump and snowmelt samples for suspended solids and metals was conducted for settling periods of 1, 6, 12, and 24 h. A settling time from 2 to 6 h would achieve most of the removal that could be expected from sedimentation. The overall removal of suspended solids and the metals in settled snowmelt would generally be better than 90%. There were no significant trends in removal behavior as the snowmelt season progressed. The removal of metals lagged slightly behind the removal of suspended solids after settling because of the stronger association of metals with smaller sediment particles. The residue at the dump site is highly contaminated. Key words: snowmelt, runoff, stormwater, sedimentation, road deicing, snow dump, pollution.

Oxidation of S(IV) in rain-water collected in Japan

Rates of S(IV) oxidation in 48 rain-water and snowmelt samples collected at 15 sites in Japan were determined to assess the significance of the autoxidation in the sulfate formation channels of the aqueous phase. Sodium bisulfite aqueous solution was added to each of the samples, and the S(IV) concentration was followed by a modified West-Gaeke method. Most sample systems showed pseudo-first order kinetics, with rate constants ranging from 1 × 10 −5 to 3 × 10 −3 s −1. In several cases, however, the logarithmic concentration-time plot definitely deviated from a straight line. Some other kinetics such as rate = k a[ S(IV)] + k b[ S(IV)] 1 2 could reproduce these non-linear plots of the reactions. Strong correlations were found between the first-order rate constant and the concentrations of some transition metals (Cr, Fe, Co, V and Mn, in order of decreasing correlation coefficients). The experimental rate constants agreed typically within a factor of three with calculations for the Mn concentration, but were much smaller than the predictions for the Fe levels. The experimental rates in the rain-water samples were applied to the atmospheric oxidation rate of SO 2 and were compared with those of H 2O 2 and O 3.