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1.
Philip L. Verplanck D. Kirk Nordstrom Dana J. Bove Geoffrey S. Plumlee Robert L. Runkel 《Applied Geochemistry》2009
Acidic, metal-rich waters produced by the oxidative weathering and resulting leaching of major and trace elements from pyritic rocks can adversely affect water quality in receiving streams and riparian ecosystems. Five study areas in the southern Rocky Mountains with naturally acidic waters associated with porphyry mineralization were studied to document variations in water chemistry and processes that control the chemical variations. Study areas include the Upper Animas River watershed, East Alpine Gulch, Mount Emmons, and Handcart Gulch in Colorado and the Red River in New Mexico. Although host-rock lithologies in all these areas range from Precambrian gneisses to Cretaceous sedimentary units to Tertiary volcanic complexes, the mineralization is Tertiary in age and associated with intermediate to felsic composition, porphyritic plutons. Pyrite is ubiquitous, ranging from ∼1 to >5 vol.%. Springs and headwater streams have pH values as low as 2.6, SO4 up to 3700 mg/L and high dissolved metal concentrations (for example: Fe up to 400 mg/L; Cu up to 3.5 mg/L; and Zn up to 14.4 mg/L). Intensity of hydrothermal alteration and presence of sulfides are the primary controls of water chemistry of these naturally acidic waters. Subbasins underlain by intensely hydrothermally altered lithologies are poorly vegetated and quite susceptible to storm-induced surface runoff. Within the Red River study area, results from a storm runoff study documented downstream changes in river chemistry: pH decreased from 7.80 to 4.83, alkalinity decreased from 49.4 to <1 mg/L, SO4 increased from 162 to 314 mg/L, dissolved Fe increased from to 0.011 to 0.596 mg/L, and dissolved Zn increased from 0.056 to 0.607 mg/L. Compared to mine drainage in the same study areas, the chemistry of naturally acidic waters tends to overlap but not reach the extreme concentrations of metals and acidity as some mine waters. The chemistry of waters draining these mineralized but unmined areas can be used to estimate premining conditions at sites with similar geologic and hydrologic conditions. For example, the US Geological Survey was asked to estimate premining ground-water chemistry at the Questa Mo mine, and the proximal analog approach was used because a mineralized but unmined area was located adjacent to the mine property. By comparing and contrasting water chemistry from different porphyry mineralized areas, this study not only documents the range in concentrations of constituents of interest but also provides insight into the primary controls of water chemistry. 相似文献
2.
Use of stream response functions to determine impacts of replacing surface-water use with groundwater withdrawals 总被引：1，自引：0，他引：1
Erik B. Pruneda Michael E. Barber Diana M. Allen Joan Q. Wu 《Hydrogeology Journal》2010,18(5):1077-1092
A regional-scale numerical groundwater model is used to study the impacts of replacing surface-water use with groundwater wells to improve low-flow stream conditions for endangered species within the Bertrand and Fishtrap watersheds, southern British Columbia, Canada and Washington, USA. Stream response functions ranging from 0 to 1.0 were calculated for individual wells placed within a steady-state groundwater flow model at varying distances from the streams to determine the impact that these replacement wells, operating under sustained pumping rates, would have on summer instream flows. Lower response ratios indicate groundwater pumping will have less of an impact on streamflow than taking an equivalent amount of water directly from a surface-water source. Results show that replacing surface-water use with groundwater withdrawals may be a viable alternative for increasing summer streamflows. Assuming combined response factors should be ≤0.5 for irrigators to undergo the expense of installing new wells, ~57% of the land area within 0.8 km of Bertrand Creek would be suitable for replacement wells. Similarly, 70% of the land area within 0.8 km of Fishtrap Creek was found to be appropriate. A visual analysis tool was developed using STELLA to allow stakeholders to quickly evaluate the impact associated with moving their water right. 相似文献
3.
Geochemical fluxes from watersheds are typically defined using mass-balance methods that essentially lump all weathering processes operative in a watershed into a single flux of solute mass measured in streamflow at the watershed outlet. However, it is important that we understand how weathering processes in different hydrological zones of a watershed (i.e., surface, unsaturated, and saturated zones) contribute to the total geochemical flux from the watershed. This capability will improve understanding of how geochemical fluxes from these different zones may change in response to climate change. Here, the geochemical flux from weathering processes occurring solely in the saturated zone is investigated. This task, however, remains exceedingly difficult due to the sparsity of subsurface sampling points, especially in large, remote, and/or undeveloped watersheds. In such cases, springflow is often assumed to be a proxy for groundwater (defined as water residing in fully saturated geologic formations). However, springflow generation may integrate different sources of water including, but not limited to, groundwater. The authors’ hypothesis is that long-term estimates of geochemical fluxes from groundwater using springflow proxies will be too large due to the integrative nature of springflow generation. Two conceptual models of springflow generation are tested using endmember mixing analyses (EMMA) on observations of spring chemistries and stable isotopic compositions in a large alpine watershed in the San Juan Mountains of southwestern Colorado. In the “total springflow” conceptual model, springflow is assumed to be 100% groundwater. In the “fractional springflow” conceptual model, springflow is assumed to be an integration of different sources of water (e.g., groundwater, unsaturated flow, preferential flow in the soil, etc.) and groundwater is only a fractional component. The results indicate that groundwater contributions in springflow range from 2% to 100% overall and no springs are consistently composed of 100% groundwater; providing support for the fractional springflow conceptual model. Groundwater contributions are not strongly correlated with elevation, spring contributing area, spring discharge, or seasonality. This variability has a profound effect on long-term geochemical fluxes. The geochemical fluxes for total springflow overestimate long-term solute release by 22–48% as compared to fractional springflow. These findings illustrate that springflow generation, like streamflow generation, integrates many different sources of water reflecting solute concentrations obtained along many different geochemical weathering pathways. These data suggest that springs are not always ideal proxies for groundwater. Springs may be integrating very distinct portions of the groundwater flow field and these groundwater contributions may become mixed at the spring emergence with much younger sources of water that have never resided in the groundwater system. 相似文献
4.
Baseflow in urban streams remains an under-researched topic, given the critical roles it plays and the extensive and ever-increasing pace of urbanization and its impacts on stream ecosystems. This study is designed to characterize the complexity of baseflow in Dry Run, an urban stream in Columbus, Ohio. A hierarchical modeling approach combined with observations of streamflow discharge (Q) and specific conductance (SC) of the stream water was applied. The streamflow measurements showed that baseflow in Dry Run is small (below 1 m3 s?1) and being impacted by anthropogenic activities that directly discharge water into the stream. Model analyses using IHACRES and SWMM showed that baseflow is mainly composed of two different components—groundwater inflow and slowly released flows from storm-water detention ponds. The complex origins of baseflow are exemplified by hysteresis, which can be described with a plot of SC versus discharge. Overall, the study shows the value of geochemical measurements that constrain conceptual models of source-water inflows to the stream. 相似文献
5.
6.
《Applied Geochemistry》2003,18(1):1-24
A combined approach involving evaluations of historical information, compositional trends, site mineralogy, and forward and inverse geochemical modeling was used to assess the effects of Au mining on ground water quality at the Cripple Creek Mining District. The District is located in a Tertiary volcanic diatreme complex surrounded by Precambrian granite. Historically, mining activity was underground whereas present-day mining occurs in surface mines. Between 1896 and 1941, a series of tunnels was excavated to drain the underground mining areas. The Carlton Tunnel, located about 900–950 m below the surface, is the primary ground water drain for the mining areas. Ground water flowing from the Carlton Tunnel has historically been of good quality. The geochemical processes controlling the quality of the Carlton Tunnel water were the focus of this study. Mineralogical and acid/base accounting data indicate that the diatreme is zoned vertically from an oxidized condition with acidic paste-pH, acidic ground water, and elevated metal concentrations near the surface to an alkaline condition with high pH, elevated SO4, and low metal concentrations at depth. The average travel time of water from the surface to the Carlton Tunnel is estimated to be at least 25a based on 3H determinations. Forward geochemical modeling results indicate that this travel time is sufficient for ground water to reach equilibrium with calcite, gypsum, and fluorite by the time it exits through the Carlton Tunnel. Equilibrium processes have effectively fixed the pH, alkalinity, and SO4 in the Carlton Tunnel water to near-constant levels for at least 24–70a based on comparisons to historically reported water compositions. Inverse geochemical modeling results indicate that there is sufficient neutralization capacity at depth in the diatreme to maintain the current good quality of the ground water flowing from the Carlton Tunnel for the forseeable future, assuming no significant changes in hydrogeochemical conditions. 相似文献
7.
Methods for assessing natural background water quality of streams affected by historical mining are vigorously debated. An empirical method is proposed in which stream-specific estimation equations are generated from relationships between either pH or dissolved Cu concentration in stream water and the Fe/Cu concentration ratio in Fe-precipitates presently forming in the stream. The equations and Fe/Cu ratios for pre-mining deposits of alluvial ferricrete then were used to reconstruct estimated pre-mining longitudinal profiles for pH and dissolved Cu in three acidic streams in Montana, USA. Primary assumptions underlying the proposed method are that alluvial ferricretes and modern Fe-precipitates share a common origin, that the Cu content of Fe-precipitates remains constant during and after conversion to ferricrete, and that geochemical factors other than pH and dissolved Cu concentration play a lesser role in determining Fe/Cu ratios in Fe-precipitates. The method was evaluated by applying it in a fourth, naturally acidic stream unaffected by mining, where estimated pre-mining pH and Cu concentrations were similar to present-day values, and by demonstrating that inflows, particularly from unmined areas, had consistent effects on both the pre-mining and measured profiles of pH and Cu concentration. Using this method, it was estimated that mining has affected about 480 m of Daisy Creek, 1.8 km of Fisher Creek, and at least 1 km of Swift Gulch. Mean values of pH decreased by about 0.6 pH units to about 3.2 in Daisy Creek and by 1–1.5 pH units to about 3.5 in Fisher Creek. In Swift Gulch, mining appears to have decreased pH from about 5.5 to as low as 3.6. Dissolved Cu concentrations increased due to mining almost 40% in Daisy Creek to a mean of 11.7 mg/L and as much as 230% in Fisher Creek to 0.690 mg/L. Uncertainty in the fate of Cu during the conversion of Fe-precipitates to ferricrete translates to potential errors in pre-mining estimates of as much as 0.25 units for pH and 22% for dissolved Cu concentration. The method warrants further testing in other mined and unmined watersheds. Comparison of pre-mining water-quality estimates derived from the ferricrete and other methods in single watersheds would be particularly valuable. The method has potential for use in monitoring remedial efforts at mine sites with ferricrete deposits. A reasonable remediation objective might be realized when the downstream pattern of Fe/Cu ratios in modern streambed Fe-precipitates corresponds to the pattern in pre-mining alluvial ferricrete deposits along a stream valley. 相似文献
8.
Douglas B. Yager Raymond H. Johnson Barnaby W. Rockwell Jonathan Saul Caine Kathleen S. Smith 《Environmental Earth Sciences》2013,70(3):1057-1082
Hydrothermally altered bedrock in the Silverton mining area, southwest Colorado, USA, contains sulfide minerals that weather to produce acidic and metal-rich leachate that is toxic to aquatic life. This study utilized a geographic information system (GIS) and statistical approach to identify watershed-scale geologic variables in the Silverton area that influence water quality. GIS analysis of mineral maps produced using remote sensing datasets including Landsat Thematic Mapper, advanced spaceborne thermal emission and reflection radiometer, and a hybrid airborne visible infrared imaging spectrometer and field-based product enabled areas of alteration to be quantified. Correlations between water quality signatures determined at watershed outlets, and alteration types intersecting both total watershed areas and GIS-buffered areas along streams were tested using linear regression analysis. Despite remote sensing datasets having varying watershed area coverage due to vegetation cover and differing mineral mapping capabilities, each dataset was useful for delineating acid-generating bedrock. Areas of quartz–sericite–pyrite mapped by AVIRIS have the highest correlations with acidic surface water and elevated iron and aluminum concentrations. Alkalinity was only correlated with area of acid neutralizing, propylitically altered bedrock containing calcite and chlorite mapped by AVIRIS. Total watershed area of acid-generating bedrock is more significantly correlated with acidic and metal-rich surface water when compared with acid-generating bedrock intersected by GIS-buffered areas along streams. This methodology could be useful in assessing the possible effects that alteration type area has in either generating or neutralizing acidity in unmined watersheds and in areas where new mining is planned. 相似文献
9.
Mercury (Hg) and methylmercury (CH3Hg+) concentrations in streambed sediment and water were determined at 27 locations throughout the Sacramento River Basin, CA. Mercury in sediment was elevated at locations downstream of either Hg mining or Au mining activities where Hg was used in the recovery of Au. Methylmercury in sediment was highest (2.84 ng/g) at a location with the greatest wetland land cover, in spite of lower total Hg at that site relative to other river sites. Mercury in unfiltered water was measured at 4 locations on the Sacramento River and at tributaries draining the mining regions, as well as agricultural regions. The highest levels of Hg in unfiltered water (2248 ng/l) were measured at a site downstream of a historic Hg mining area, and the highest levels at all sites were measured in samples collected during high streamflow when the levels of suspended sediment were also elevated. Mercury in unfiltered water exceeded the current federal and state recommended criterion for protection of aquatic life (50 ng/l as total Hg in unfiltered water) only during high streamflow conditions. The highest loading of Hg to the San Francisco Bay system was attributed to sources within the Cache Creek watershed, which are downstream of historic Hg mines, and to an unknown source or sources to the mainstem of the Sacramento River upstream of historic Au mining regions. That unknown source is possibly associated with a volcanic deposit. Methylmercury concentrations also were dependent on season and hydrologic conditions. The highest levels (1.98 ng/l) in the Sacramento River, during the period of study, were measured during a major flood event. The reactivity of Hg in unfiltered water was assessed by measuring the amount available for reaction by a strong reducing agent. Although most Hg was found to be nonreactive, the highest reactivity (7.8% of the total Hg in water) was measured in the sample collected from the same site with high CH3Hg+ in sediment, and during the time of year when that site was under continual flooded conditions. Although Hg concentrations in water downstream of the Hg mining operations were measured as high as 2248 ng/l during stormwater runoff events, the transported Hg was found to have a low potential for geochemical transformations, as indicated by the low reactivity to the reducing agent (0.0001% of the total), probably because most of the Hg in the unfiltered water sample was in the mercury sulfide form. 相似文献
10.
Alicia M. Kinoshita Terri S. Hogue Janet Barco Christopher Wessel 《Environmental Earth Sciences》2014,72(3):879-889
The goal of the current study is to better understand the role of storm dynamics on stream water chemical variability in a highly polluted urban-fringe watershed. The study was conducted in the upper reach of the Arroyo Seco watershed located on the eastern edge of the densely urbanized Los Angeles basin in California. During the 2008–2009 study period, high-frequency stream water observations of chloride, fluoride, sulfate, and nitrate were monitored through a series of storm events and were compared to pre- and post-winter storm season geochemical soil profiles. Of the four solutes measured, nitrate demonstrated hydrologically enhanced behavior. Chloride, fluoride, and sulfate exhibited enhanced behavior initially (first flush), but transitioned to dilution behavior as the season progressed. Soil chemistry analyses in the riparian zone confirmed the abundance of nitrate on the soil surface, serving as a source for stream water nitrate. Observations and analyses collectively suggest that the chemical variability observed during the storms is dependent not only on discharge, but also on the magnitude and intensity of rainfall, the length of the antecedent dry period, and riparian soil composition. A further understanding of these factors will ultimately improve geochemical models for prediction of downstream chemical loads from regional urban-fringe watersheds. 相似文献
11.
W. W. -S. Yim 《Environmental Geology》1981,3(5):245-256
Tin-mine tailings containing high concentrations of Sn, Cu, Zn, Fe, Mn, As, and W are discharged into the Red River of cornwall,
England and are then transported into St. Ives Bay under normal flow conditions. Most of the tin-bearing particles in the
fluvial sediments are smaller than 170 μm, but tin-bearing composite grains or mineral grains with tin interspersed in the
crystal lattices also occur in coarser size fractions. Tin distribution in the sediments is controlledby: (1) the distance
from the source of the tailings, and (2) the concentration processes operating on the river bed. Suspended sediment and sediment
transported by saltation filtered from river water samples also showed high concentrations of metals although, in contrast
to the bottom sediments, they vary within a narrow range. Distributions of Cu, Zn, Fe, As, and Pb in the filtered sediments
probably are related to the physical and chemical behavior of their sulphide minerals during fluvial transportation.
A regional stream-sediment geochemical reconnaissance survey for tin did not show the highest concentration in the Red River;
this indicated that in other rivers and streams tin reconcentration by selective removal of light minerals had taken place
in the bottom sediments after mining operations had ceased. These rivers and streams also can transport large quantitiies
of land-derived sediment including tin-mine tailings discharged into them when mines were operating. The minimum distance
of tin transported by the Red River is at least 10 km; however, most of the tin was derived from mine tailings and is considered
to be unnatural. 相似文献
12.
Alexandria B. Boehm Kevan M. Yamahara Sarah P. Walters Blythe A. Layton Daniel P. Keymer Rachelle S. Thompson Karen L. Knee Matt Rosener 《Estuaries and Coasts》2011,34(5):925-936
This study quantifies dissolved inorganic nitrogen (DIN), soluble reactive phosphorous (SRP), and microbial pollutant inputs
to a tropical embayment, Hanalei Bay, Kaua'i, Hawai'i from rural watersheds during two field excursions during non-storm conditions.
We employ land cover analysis and a suite of nucleic acid fecal source tracking markers (host-specific Bacteroidales and human enterovirus) to identify sources of pollutants to the bay. The highest concentrations of DIN and SRP are in streams
draining watersheds with large areas of cultivated land, suggesting fertilizer is a source of these nutrients to the streams
and coastal waters. Pollutant areal loading correlates with the fractions of urban and cultivated land cover. Microbial source
tracking indicates the presence of human, pig, and ruminant feces in the streams. This work provides preliminary evidence
that human development affects loading of DIN, SRP, and microbial pollutants to tropical coastal waters; further study is
needed to confirm this. Additionally, results point to a mix of microbial pollutant sources. 相似文献
13.
Climatic and tectonic controls on chemical weathering in the New Zealand Southern Alps 总被引：2，自引：0，他引：2
Climatic and tectonic controls on the relative abundance of solutes in streams draining the New Zealand Southern Alps were investigated by analyzing the elemental and Sr isotope geochemistry of stream waters, bedload sediment, and hydrothermal calcite veins. The average relative molar abundance of major cations and Si in all stream waters follows the order Ca2+ (50%) > Si (22%) > Na+ (17%) > Mg2+ (6%) > K+ (5%). For major anions, the relative molar abundance is HCO3− (89%) > SO42− (7%) > Cl− (4%). Weathering reactions involving plagioclase and volumetrically small amounts of hydrothermal calcite define the ionic chemistry of stream waters, but nearly all streams have a carbonate-dominated Ca2+ and HCO3− mass-balance. Stream water Ca/Sr and 87Sr/86Sr ratios vary from 0.173 to 0.439 μmol/nmol and from 0.7078 to 0.7114, respectively. Consistent with the ionic budget, these ratios lie solely within the range of values measured for bedload carbonate (Ca/Sr = 0.178 to 0.886 μmol/nmol; 87Sr/86Sr = 0.7081 to 0.7118) and hydrothermal calcite veins (Ca/Sr = 0.491 to 3.33 μmol/nmol; 87Sr/86Sr = 0.7076 to 0.7097).Streams draining regions in the Southern Alps with high rates of physical erosion induced by rapid tectonic uplift and an extremely wet climate contain ∼10% more Ca2+ and ∼30% more Sr2+ from carbonate weathering compared to streams draining regions in drier, more stable landscapes. Similarly, streams draining glaciated watersheds contain ∼25% more Sr2+ from carbonate weathering compared to streams draining non-glaciated watersheds. The highest abundance of carbonate-derived solutes in the most physically active regions of the Southern Alps is attributed to the tectonic exhumation and mechanical denudation of metamorphic bedrock, which contains trace amounts of calcite estimated to weather ∼350 times faster than plagioclase in this environment. In contrast, regions in the Southern Alps experiencing lower rates of uplift and erosion have a greater abundance of silicate- versus carbonate-derived cations. These findings highlight a strong coupling between physical controls on landscape development and sources of solutes to stream waters. Using the Southern Alps as a model for assessing the role of active tectonics in geochemical cycles, this study suggests that rapid mountain uplift results in an enhanced influence of carbonate weathering on the dissolved ion composition delivered to seawater. 相似文献
14.
During more than a century of gold mining in South Africa large amounts of tailings were produced, which now cover vast areas
in densely populated regions. These dumps contain elevated levels of uranium and other toxic heavy metals associated with
gold in the mined ore. Large-scale extraction of uranium from auriferous ore only took place during the cold war, leaving
tailings with high uranium concentrations that were deposited before and after this period. Recent studies found elevated
levels of the radioactive heavy metal in groundwater and streams, mainly attributed to the discharge of contaminated water
from mines. In this paper the contribution of seepage from slimes dams to the uranium pollution of adjacent streams is analysed.
Based on geochemical analyses of samples, field observations and long-term in situ measurements of hydraulic and hydrochemical parameters at selected mining sites across the Witwatersrand goldfields, the
extent, mechanisms and dynamics of diffuse stream contamination by tailings seepage is characterised. Temporal and spatial
variations of the process and the associated hazard potential are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
Based on this preliminary study, existing sand and gravel mining regulations (in Maine, USA) can be inferred to provide some
protection to water resources. Sand and gravel deposits are important natural resources that have dual uses: mining for construction material and pumping for drinking water. How the mining of sand and gravel affects aquifers and change aquifer vulnerability to contamination
is not well documented. Mining regulations vary greatly by state and local jurisdiction. This study test metrics to measure
the effectiveness of mining regulations. The sand and gravel aquifer system studied is covered with former and active gravel
pits to nearly 25% of its areal extent. Data from homeowner interviews and field measurements found scant evidence of changes
in water quantity. Water quality analyses collected from springs, streams, ponds and wells indicate that the aquifer was vulnerable
to contamination by chloride and nitrate. However, water quality changes can not be related directly to mining activities. 相似文献
16.
Post-mine metal transport and attenuation in the Keno Hill mining district, central Yukon, Canada 总被引：6，自引：0，他引：6
The Keno Hill mining district in central Yukon was the second largest silver producer in Canada with mines operating from
1913 to 1989 on more than 65 vein silver deposits. The seven and a half decades of mining activities have generated large
volumes of mine waste disposed on the land surface, resulting in elevated metal contents in numerous small drainages. To assess
the extent of metal mobilization, old mine workings and the associated mine waste were examined and the water courses draining
to a major river valley sampled. The results of field observations and an array of water and sediment analyses led to three
major conclusions. 1. Acid mine drainage is not widespread because of galvanic protection of pyrite from oxidative dissolution
and neutralization by carbonates in the country rock. 2. Mechanisms operative to limit aqueous metal transport in small streams
in the district include cryogenic precipitation, coprecipitation and sorption. 3. The near-surface concentration of metals
limits the options of waste disposal in future mining developments due to potential metal-leaching problems.
Received: 12 December 1995 · Accepted: 26 March 1996 相似文献
17.
The aim of this study was to investigate temporal trends and controlling factors of As and V in running waters throughout Sweden. For this purpose, data on stream water chemistry from 62 streams of varying catchment size and characteristics, included in the Swedish environmental monitoring programmes were evaluated. The geochemical software Visual MINTEQ was used to model the speciation and trend analyses were performed on total concentrations of As and V as well as modelled fractions (dissolved species as well as arsenate and vanadate adsorbed to ferrihydrite). The trend analyses showed increasing total concentrations of As and V in southern Sweden. Concentrations of As and V correlated significantly to Fe concentrations in 59 and 60 of the 62 streams respectively, indicating that Fe is an important determining factor for As and V concentrations in Swedish streams. This was confirmed by the geochemical modelling that indicated that the adsorbed fraction is the dominant form of As and V and that the concentrations of As and V in Swedish streams are thus highly determined by concentrations of colloidal or particulate Fe. It is therefore suggested that the increasing trends of As and V are to a large extent due to increasing concentrations of colloidal Fe, which is stabilised by increasing concentrations of DOC. Further the geochemical modelling indicates that the dissolved fraction of As and V generally is small, with the exception of a few streams with high pH and/or phosphate concentrations. 相似文献
18.
19.
Effect of widespread severely acidic soils on spatial features and abundance of trace elements in streams 总被引：1，自引：0，他引：1
In the coastal area of western Finland, a large number of streams are strongly acidic and contaminated with metals. The reason for this is not historical and present industrial, mining and urban activities, but a current high rate of weathering and leaching of widespread acid sulphate soils (pH 2.5–4.0) developed in artificially drained Holocene marine and lacustrine sulphide-bearing sediments. Evaluation of existing hydro- and geochemical field and experimental data revealed that: (1) cobalt, Ni and Zn are extensively leached from the acid sulphate soils and thus exist abundantly in streams affected by such soils, (2) copper and Tl are also leached abundantly from the acid sulphate soils, although not to the same extent as are Co, Ni and Zn, (3) vanadium is in general depleted and Cr only weakly enriched in streams draining ‘the average acid sulphate soil’, but they increase substantially in severely acidic streams in catchments underlain with particularly acidic soil, (4) arsenic and Pb are not leached more abundantly from the acid sulphate soils than from the common types of soils and sediments (till, glaciofluvial deposits, peat) resulting in aquatic abundance and distribution patterns unrelated to the acid sulphate soil occurrences. 相似文献
20.
E. Heinen De Carlo Daniel J. HooverCharles W. Young Rebecca S. HooverFred T. Mackenzie 《Applied Geochemistry》2007
Storm runoff in the steep watersheds in Hawaii leads to sediment and freshwater pulses to coastal waters that quickly affect nearshore water quality. This is particularly true in semi-enclosed embayments, such as Kaneohe Bay, Oahu, where water has a relatively long residence time compared to more open coastal areas of the islands. In this paper the authors discuss water quality and productivity in Kaneohe Bay after back-to-back rain events in late November and early December 2003, following a particularly dry summer. The short-term biogeochemical response of coastal waters and the ecosystem to runoff and physical forcing was evaluated through a combination of continuous in situ measurements and adaptive synoptic sampling carried out on a variety of temporal and spatial scales. 相似文献