preliminary seismic hazard assessment for los angeles ventura and orange counties california affected by the 17 january 1994 northridge earthquake abstract the seismic ground motion hazard is assessed for a 10 probability of exceedance in 50 years for the three counties los angeles ventura and orange impacted by the 1994 northridge earthquake m w 6 7 the earthquake source model of the southern california earthquake center has been modified with additional slip rate information for mapped faults and blind thrusts and incorporated into seismic hazard maps that will be used for making regional hazard and risk mitigation decisions by state and local government agencies peak horizontal ground acceleration pga and 5 damped spectral acceleration sa 0 3 and 1 sec were calculated with three equally weighted attenuation relationships of boore et al 1993 campbell and bozorgnia 1994 and sadigh written comm 1994 the results of this assessment indicate high hazard over the entire tri county area with ground motions exceeding 0 4 g pga 1 0 g 0 3 sec sa and 0 5 g 1 sec sa nearly everywhere a monte carlo uncertainty analysis is described for two sites located in los angeles and northridge this analysis yields 95 confidence limits for peak ground acceleration at the two sites that range between 0 1 and 0 2 g our calculations indicate that the uncertainty in the magnitude rupture length relations magnitude distribution moment magnitude relation attenuation relation and slip rate contribute most to the hazard uncertainty at these sites and that the highest uncertainties in the mapped ground motion are associated with the strongest anticipated ground motions

a terrain based site conditions map of california with implications for the contiguous united states abstract we present an approach based on geomorphometry to predict material properties and characterize site conditions using the v s 30 parameter time averaged shear wave velocity to a depth of 30 m our framework consists of an automated terrain classification scheme based on taxonomic criteria slope gradient local convexity and surface texture that systematically identifies 16 terrain types from 1 km spatial resolution 30 arcsec shuttle radar topography mission digital elevation models srtmdems using 853 v s 30 values from california we apply a simulation based statistical method to determine the mean v s 30 for each terrain type in california we then compare the v s 30 values with models based on individual proxies such as mapped surface geology and topographic slope and show that our systematic terrain based approach consistently performs better than semiempirical estimates based on individual proxies to further evaluate our model we apply our california based estimates to terrains of the contiguous united states comparisons of our estimates with 325 v s 30 measurements outside of california as well as estimates based on the topographic slope model indicate our method to be statistically robust and more accurate our approach thus provides an objective and robust method for extending estimates of v s 30 for regions where in situ measurements are sparse or not readily available

stable isotope geochemistry of ground and surface waters associated with undisturbed massive sulfide deposits constraints on origin of waters and water rock reactions abstract stable isotopes h o c were determined for ground and surface waters collected from two relatively undisturbed massive sulfide deposits halfmile lake and restigouche in the bathurst mining camp bmc new brunswick canada additional waters from active and inactive mines in the bmc were also collected oxygen and hydrogen isotopes of surface and shallow groundwaters from both the halfmile lake and restigouche deposits are remarkably uniform 13 to 14 and 85 to 95 for 18ovsmow and 2hvsmow respectively these values are lighter than predicted for northern new brunswick and combined with elevated deuterium excess values suggest that recharge waters are dominated by winter precipitation recharged during spring melting deeper groundwaters from the restigouche deposit and from active and inactive mines have heavier 18ovsmow ratios up to 10 8 than shallow groundwaters suggesting recharge under warmer climate or mixing with shield type brines some of the co variation in cl concentrations and 18ovsmow ratios can be explained by mixing between saline and shallow recharge water end members carbon isotopic compositions of dissolved inorganic carbon dic are variable ranging from 15 to 5 13cvpdb for most ground and surface waters much of the variation in the carbon isotopes is consistent with closed system groundwater evolution involving soil zone co2 and fracture zone carbonate minerals calcite dolomite and siderite average 6 5 13cvpdb the dic of saline restigouche deposit groundwater is isotopically heavy 12 13cvpdb indicating carbon isotopic fractionation from methanogenesis via co2 reduction consistent with the lack of dissolved sulfate in these waters and the observation of ch4 degassing during sampling

ground motion amplification in the santa monica area effects of shallow basin edge structure abstract the 1994 northridge earthquake produced ground motions in the northwest portion of the los angeles basin that were significantly larger than rock site motions observed at locations just north of the basin the santa monica area was hit particularly hard with numerous structures being damaged or destroyed by the strong ground shaking in this region the basin edge geology is controlled by the active strand of the east west striking santa monica fault and virtually all of the structural damage occurred at or south of the fault location we have used 2d finite difference ground motion simulations to investigate the effect of the basin edge structure in amplifying ground response constraints on the basin edge structure come from geologic cross sections geophysical data and seismological observations our simulations indicate that the shallow basin edge structure 1 km deep formed by the active strand of the santa monica fault creates a large amplification in motions immediately south of the fault scarp in very good agreement with mainshock damage patterns recorded ground motions and locations of elevated site response this large amplification results from constructive interference of direct waves with the basin edge generated surface waves and is quite similar to the basin edge effect associated with the 1995 kobe earthquake in addition we find that focusing effects created by the deeper basin structure 3 to 4 km deep cannot explain the large motions observed immediately south of the fault scarp this strongly suggests that the deep basin focusing models proposed by gao et al 1996 and alex and olsen 1998 are not likely explanations of the observed pattern of ground motion amplification in the santa monica area

the effect of acid rain and altitude on concentration δ34s and δ18o of sulfate in the water from sudety mountains poland abstract the analyses of sulfate content 34s and 18o of dissolved sulfate and 18o of water were carried out in a 14 km2 crystalline massif located in the sudety mountains sw poland to 1 assess the amount of the sulfate delivered to the surface and groundwater systems by modern atmospheric precipitation 2 determine the effect of altitude on these parameters and 3 investigate their seasonal variations in april and november of 2002 august 2003 and march and september of 2005 samples of water were collected from springs and streams of the massif during these seasons sulfate contents and 18o so42 values varied from 5 80 to 18 00 mg l and from 3 96 to 8 23 respectively showing distinctively higher values of 18o so42 in wet seasons the 34s so42 values had a relatively narrow range from 4 09 to 5 28 and were similar to those reported for organic matter in soil and the canopy throughfall in the sudety mountains sulfate content 34s so42 18o so42 and 18o h2o values revealed a remarkable dependence on the altitude the calculated altitude effects for five season averages of these parameters were 1 00 mg l 100 m 0 18 100 m 0 27 100 m and 0 17 100 m respectively this dependence on the altitude resulted mainly from the mixing of sulfates of different origins such as anthropogenic sulfate sulfate produced in the soil within the weathered zone of the massif and that one from the tree canopy the oxygen isotope mass balance indicates that in the study area about one third of the sulfate delivered to the surface and groundwater by modern precipitation comes from anthropogenic pollution further interaction of meteoric water within the weathered rocks causes a continuous decrease of 18o so42 values resulting from biological transformation of the sulfate due to plant vegetation and decomposition of organic matter

variability in north pacific intermediate and deep water ventilation during heinrich events in two coupled climate models the responses of north pacific intermediate and deep water ventilation and ocean biogeochemical properties to northern north atlantic glacial freshwater perturbations are evaluated with a coupled atmosphere ocean general circulation model miroc and an earth system model of intermediate complexity loveclim when the atlantic meridional overturning circulation amoc is weakened as a result of the north atlantic freshwater discharge both models simulate subthermocline and intermediate water warming in the pacific ocean the sensitivities of the pacific meridional overturning circulation pmoc to amoc weakening differ significantly between the two models miroc simulates a small enhancement of the deep sinking branch of the pmoc in the north pacific on the contrary the loveclim freshwater experiment exhibits intensified deep water formation in the north pacific associated with a maximum transport change of 19 sv despite the significant differences in ocean circulation response both models successfully reproduce high oxygen and low nutrient conditions of intermediate and deep waters in accordance with sediment core based paleoproxy reconstructions from the north pacific and bering sea during heinrich event 1 emergence of younger intermediate and deep water in the north pacific can be partly attributed to an overall enhanced mixing as well as intensified overturning circulation of the subpolar north pacific our models simulate broad features observed in several paleoproxy data of the pacific ocean biological production decrease in northern japan cooling in the western north pacific ocean and the southward shift of the pacific intertropical convergence zone

application of multiple isotopic and geochemical tracers for investigation of recharge salinization and residence time of water in the souss massa aquifer southwest of morocco summary groundwater and surface water in souss massa basin in the west southern part of morocco is characterized by a large variation in salinity up to levels of 37 g l 1 the high salinity coupled with groundwater level decline pose serious problems for current irrigation and domestic water supplies as well as future exploitation a combined hydrogeologic and isotopic investigation using several chemical and isotopic tracers such as br cl 18 o 2 h 3 h 87 sr 86 sr 11 b and 14 c was carried out in order to determine the sources of water recharge to the aquifer the origin of salinity and the residence time of water stable isotope 3 h and 14 c data indicate that the high atlas mountains in the northern margin of the souss massa basin with high rainfall and low 18 o and 2 h values 6 to 8 and 36 to 50 is currently constitute the major source of recharge to the souss massa shallow aquifer particularly along the eastern part of the basin localized stable isotope enrichments offset meteoric isotopic signature and are associated with high nitrate concentrations which infer water recycling via water agricultural return flows the 3 h and 14 c data suggest that the residence time of water in the western part of the basin is in the order of several thousands of years hence old water is mined particularly in the coastal areas the multiple isotope analyses and chemical tracing of groundwater from the basin reveal that seawater intrusion is just one of multiple salinity sources that affect the quality of groundwater in the souss massa aquifer we differentiate between modern seawater intrusion salinization by remnants of seawater entrapped in the middle souss plains recharge of nitrate rich agricultural return flow and dissolution of evaporate rocks gypsum and halite minerals along the outcrops of the high atlas mountains the data generated in this study provide the framework for a comprehensive management plan in which water exploitation should shift toward the eastern part of the basin where current recharge occurs with young and high quality groundwater in contrast we argued that the heavily exploited aquifer along the coastal areas is more vulnerable given the relatively longer residence time of the water and salinization processes in this part of the aquifer

a test of various site effect parameterizations in probabilistic seismic hazard analyses of southern california we evaluate the implications of several attenuation relationships including three customized for southern california in terms of accounting for site effects in probabilistic seismic hazard studies the analysis is carried out at 43 sites along a profile spanning the los angeles basin with respect to peak acceleration and 0 3 1 0 and 3 0 sec response spectral acceleration values that have a 10 chance of being exceeded in 50 years the variability among currently viable attenuation relationships espistemic uncertainty is an approximate factor of 2 biases between several commonly used attenuation relationships and southern california strong motion data imply hazard differences that exceed 10 however correcting each relationship for the southern california bias does not necessarily bring hazard estimates into better agreement a detailed subclassification of site types beyond rock versus soil is found to be both justified by data and to make important distinctions in terms of hazard levels a basin depth effect is also shown to be important implying a difference of up to a factor of 2 in ground motion between the deepest and shallowest parts of the los angeles basin in fact for peak acceleration the basin depth effect is even more influential than the surface site condition questions remain however whether basin depth is a proxy for some other site attribute such as distance from the basin edge the reduction in prediction error sigma produced by applying detailed site and or basin depth corrections does not have an important influence on the hazard in fact the sigma reduction is less than epistemic uncertainties on sigma itself due to data limitations it is impossible to determine which attenuation relationship is best however our results do indicate which site conditions seem most influential this information should prove useful to those developing or updating attenuation relationships and to those attempting to make more refined estimates of hazard in the near future

nonlinearity at california generic soil sites from modeling recent strong motion data the average strong to weak motion amplification ratios during the 1989 loma prieta and 1987 whittier narrows earthquakes in california are estimated by modeling strong ground motions at soil sites in the linear response assumption and comparing the simulated and observed records the linear amplification function used to synthesize ground motions is the generic transfer function developed for california soil the database consists of 22 and 80 soil stations for the loma prieta and whittier narrows events respectively a statistically significant at 95 confidence reduction in amplification for the loma prieta event within 40 km from the fault is observed between approximately 1 and 3 hz examining individual strong to weak motion amplifications as a function of peak acceleration at the base of soil within this frequency range shows that detectable reduction in amplification occurs at accelerations above about 200 cm sec2 the strong motion amplification is reduced by a factor of 1 7 2 on average relative to a generic weak motion response the results of this study suggest the magnitude of the reduction in amplification caused by soil nonlinearity at large strain that can be expected on average at california soil sites

sulphur cycling in the drinking water catchment area of torgau mockritz germany insights from hydrochemical and stable isotope investigations the hydrochemical composition of groundwater and the isotopic composition of sulphur compounds in sediments 3 4 s of sulphide inorganic sulphate and groundwater 3 4 s 1 8 o of dissolved sulphate have been investigated to reveal the reasons for elevated concentrations of dissolved groundwater sulphate in the drinking water catchment area of torgau mockritz germany the three most important anthropogenic sources of sulphate identified in this study are historic atmospheric sulphate deposition predominantly of anthropogenic origin inorganic fertilization and dissolution of gypsum from waste dumps owing to their overlapping isotopic range no clear differentiation between the individual anthropogenic sources is possible sulphate from the oxidation of sedimentary sulphides however was recognized by its negative sulphur isotope signature 3 4 s 5 the mobilization of sulphate from different soil sulphur species is closely connected with variable isotopic fractionations resulting in a wide isotopic variation range for the sulphate entering the saturated zone generally sulphur and oxygen isotope ratios of the dissolved groundwater sulphate range from 19 to 37 vienna canon diablo troilite and from 2 to 19 vienna standard mean ocean water respectively sulphate from the majority of groundwater samples can be assigned to anthropogenic sources sulphate from sulphide oxidation is especially present in samples from the upper sampling level and the groundwater surface sulphate concentrations above 700 mg l 1 are mostly caused by the oxidation of sulphide sulphate that occurs in low and moderate concentrations dominantly originates from anthropogenic sources 3 4 s distribution patterns were used to locate the sources for the elevated sulphate concentrations in the raw water it was shown that the sulphate is not mobilized in the immediate vicinity of the production wells rather it originates in an area 1 5 km west of the intake the main mobilization mechanism there is the oxidation of reduced sedimentary sulphur species beyond its local significance this study presents a general example how changes in the sulphur cycle indicate major anthropogenically induced alterations of the hydrochemical situation in catchment areas

geochemistry and stable isotope composition of fresh alkaline porphyry copper tailings implications on sources and mobility of elements during transport and early stages of deposition abstract prevention of acid mine drainage amd in sulfide containing tailings requires the identification of the geochemical processes and element pathways in the early stages of tailing deposition however analyses of recently deposited tailings in active tailings impoundments are scarce because mineralogical changes occur near the detection limits of many assays this study shows that a detailed geochemical study which includes stable isotopes of water 2h 18o dissolved sulfates 34s 18o and hydrochemical parameter ph eh doc major and trace elements from tailings samples taken at different depths in rainy and dry seasons allows the understanding of weathering oxidation dissolution sorption and desorption water and element pathways and mixing processes in active tailings impoundments fresh alkaline tailings ph 9 2 10 2 from the cu mo porphyry deposit in el teniente chile had low carbonate 0 8 1 1 wt caco3 equivalent and sulfide concentrations 0 8 1 3 wt mainly as pyrite in the alkaline tailings water mo and cu up to 3 9 mg l mo and 0 016 mg l cu were mobile as moo42 and cu oh 20 during the flotation tailings water reached equilibrium with gypsum up to 738 mg l ca and 1765 mg l so4 the 34s vs 18o covariations of dissolved sulfate 2 3 to 4 5 34s and 4 1 to 6 0 18o revealed the sulfate sources the dissolution of primary sulfates 12 0 to 13 2 34s 7 4 to 10 9 18o and oxidation of primary sulfides 6 7 to 1 7 34s sedimented tailings in the tailings impoundment can be divided into three layers with different water sources element pathways and geochemical processes the deeper sediments 1 m depth were infiltrated by catchment water which partly replaced the original tailings water especially during the winter season this may have resulted in the change from alkaline to near neutral ph and towards lower concentrations of most dissolved elements the neutral ph and high doc up to 99 4 mg l c of the catchment water mobilized cu up to 0 25 mg l due to formation of organic cu complexes and zn up to 130 mg l due to dissolution of zn oxides and desorption at 1 m depth tailings pore water obtained during the winter season was chemically and isotopically similar to fresh tailings water ph 9 8 10 6 26 7 35 5 mg l cl 2 3 6 0 mg l mo during the summer a vadose zone evolved locally and temporarily up to 1 2 m depth resulting in a higher concentration of dissolved solids in the pore water due to evaporation during periodical new deposition of fresh tailings the geochemistry of the surface layer was geochemically similar to fresh tailings in periods without deposition sulfide oxidation was suggested by decreasing ph 7 7 9 5 enrichment of moo42 and so42 and changes in the isotopic composition of dissolved sulfates further enrichment for na k cl so4 mg cu and mo up to 23 8 mg l mo resulted from capillary transport towards the surface followed by evaporation and the precipitation of highly soluble efflorescent salts e g mirabilite syngenite at the tailing surface during summer

seismic hazard estimate from background seismicity in southern california abstract we analyzed the historical seismicity in southern california to develop a rational approach for calculating the seismic hazard from background seismicity of magnitude 6 5 or smaller the basic assumption for the approach is that future earthquakes will be clustered spatially near locations of historical mainshocks of magnitudes equal to or greater than 4 we analyzed the declustered california seismicity catalog to compute the rate of earthquakes on a grid and then smoothed these rates to account for the spatial distribution of future earthquakes to find a suitable spatial smoothing function we studied the distance r correlation for southern california earthquakes and found that they follow a 1 r power law relation where increases with magnitude this result suggests that larger events are more clustered in space than smaller earthquakes assuming the seismicity follows the gutenberg richter distribution we calculated peak ground accelerations pga for 10 probability of exceedance in 50 yr pga estimates range between 0 25 and 0 35 g across much of southern california these ground motion levels are generally less than half the levels of hazard that are obtained using the entire seismic source model that also includes geologic and geodetic data we also calculated the overall uncertainty for the hazard map using a monte carlo method and found that the coefficient of variation is about 0 24 0 01 for much of the region

provisional seismic zoning for ground failures in portions of los angeles and ventura counties following the 17 january 1994 northridge earthquake abstract provisional seismic hazard zones for earthquake induced ground failures have been delineated for portions of the three county area most affected by the northridge earthquake using a simplified hazard assessment methodology the procedure integrates surface geology topography and groundwater information using gis technology while not a replacement for official seismic hazard zones which are based on a more detailed and comprehensive analysis of hazard these provisional zones will assist in the immediate and cost effective distribution of postearthquake hazard mitigation funds

hazard consistent ground motions generation on the basis of uniform hazard fourier spectra design seismic forces depend on peak ground acceleration pga values and on the shape of response spectra rs dictated by building codes or that need to be evaluated on a site specific basis the pga values and rs strictly depend on earthquake magnitude and distance style of faulting and in cases near source effects e g rupture directivity as well as on the regional and local geological conditions at present there is no doubt that it is necessary to construct so called site and region specific building code provisions reflecting the influence of different magnitude events at different distances that may occur during the lifetime of the construction as well as the variety of local ground conditions a scheme of uniform hazard response spectra and pga estimation considering local site response is described in this article the assessments of these design parameters are obtained on the basis of uniform hazard fourier spectra using the concept of dominant earthquakes the effect of local geology is included by means of the soil reference site spectral ratios the results of using the method are presented for the regions characterized by different seismicity and tectonics and compared with the data obtained during the recent strong earthquakes the caucasus armenia the 1988 spitak earthquake region and the turan plate central asia the 1979 and 1984 gazli earthquakes region

rare earth element patterns as process indicators at the water solid interface of a post mining area abstract rare earth element ree la lu patterns in groundwater are the result of complex solid water interactions and can therefore be applied as process indicators in this system at a remediated basement area of a heap in a post u mining area ronneburg germany ree patterns in near surface groundwater were studied for 10 years 2005 2014 along a groundwater flow path the groundwater passed through quaternary sand silt and again sand resulting in increased element and ion concentrations e g al co mg mn ree so42 along the flow path most of which decreased steadily over the 10 years the decline in concentrations was more pronounced for observation points in the downstream area it is likely that during mining operations elements were retained by sorption or buffering reactions in the silty loamy material and have been gradually mobilized with fading subsequent delivery the ree patterns in groundwater were enriched in middle sm dy and heavy ree ho lu and featured a positive ce anomaly the basic pattern without ce anomaly in groundwater was attributed to mobilization from the silurian black shale that had been dumped this signature was also retained in the silty central part currently being leached resulting in increasing concentrations of heavy ree along the flow path efflorescent salts at gessenhalde indicated capillary rise because they reflected the major groundwater characteristics in the ree patterns moreover especially in the downstream area mn oxide coatings occurred in the zone of capillary rise above the groundwater table these mn phases birnessite and todorokite preferentially accumulated ce over other ree positive ce anomalies in groundwater indicate at least partial dissolution of these mn phases ferric phases like schwertmannite and goethite were found to slightly enrich light ree however based on this dataset it was possible to relate specific features of the ree patterns to the input pattern of the heap and local geology as well as the formation dissolution of secondary phases

seismic ground motion hazard mapping incorporating site effects for los angeles orange and ventura counties california a geographical information system application abstract the seismic ground motion hazard with site conditions incorporated is mapped for a 10 probability of exceedance in 50 years for the three counties affected by the 1994 northridge earthquake mw 6 7 the source model of petersen et al 1996 was used to calculate peak horizontal acceleration pga and 5 damped spectral acceleration sa levels at 0 3 and 1 sec periods for alluvium soft rock and hard rock site conditions a geologic map that differentiates the three site conditions was produced using shear wave velocity maps of tinsley and fumal 1985 and extended into other areas that were not mapped by tinsley and fumal using 1 250 000 scale geologic maps ground motion maps for each site condition were overlaid with the geologic map to produce the resulting hazard maps the effect of geology on the hazard is observed only slightly in the peak ground acceleration map more in the 0 3 sec sa map and significantly more in the 1 sec sa map the uncertainties for ground motions represented on these three maps ranges from 0 1 to 0 3 g for pga and 0 2 to 1 0 for sa in general 95 confidence limits are about 50 of the mean ground motion value

flow dynamics of groundwater and soil water in the former heap gessenhalde at the uranium mining area of ronneburg a stable isotope approach stable isotopes 2hwater 18owater as well as 18osulphate and 34ssulphate were used to study the flow system of shallow groundwater and soil water at the base area of a former leaching heap at the uranium mining area of ronneburg germany the flow paths and water retention times were estimated by comparison of 2h and 18o values in groundwater and soil water to the 2h and 18o signature of precipitation giving distinctive inputs of summer or winter precipitation the points of measuring the groundwater were divided into three categories with different flow conditions rapid flow stagnant conditions and a transition zone by hierarchical cluster analysis of 2h and 18o values of groundwater the transit time of groundwater in the rapid flow area is less than 6 months whereas water in the stagnant zone is stored for at least 1 year in soil water a clear response to different input signals is detectable only in the 30 cm horizon retention time is about 6 months whereas at deeper levels a mixing with older water is taking place the isotopic composition of the dissolved sulphate was used to identify oxidation of sulphides as the source of sulphate copyright 2010 john wiley sons ltd

drought induced pulses of so42 from a canadian shield wetland use of δ34s and δ18o in so42 to determine sources of sulfur abstract following summer drought periods pulses of elevated so 4 2 concentrations are frequently observed in streams draining forested catchments that contain wetlands delays in the recovery of freshwater streams and lakes in eastern canada from historically high levels of acidic precipitation have been partially ascribed to these periodic pulses of so 4 2 climate in eastern canada has also changed within the last 25 a with a documented increase in summer dryness and duration of droughts in small forested catchments in the turkey lakes watershed tlw so 4 2 concentrations in streams draining wetlands can be elevated by up to a factor of 7 during post drought discharge events compared to the annual average two neighbouring catchments one with a series of cascading wetlands and one without any wetlands were selected for comparison stable s and o isotope ratios were analyzed in samples of bulk precipitation streams and groundwaters to examine sources of so 4 2 in post drought pulses 34 s so 4 2 in the streams and groundwaters show that so 4 2 is retained in the wetland via so 4 2 reduction and stored in the upper peat profile nitrate is elevated in soil and groundwaters at tlw due to high rates of nitrification in forest soils and the presence of no 3 can be used to identify piezometers unaffected by so 4 2 reduction 18 o so 4 2 shows that higher concentrations of so 4 2 in deeper groundwater are likely due to oxidation of organic s and not a geologic source of reduced s following drought the low 34 s so 4 2 in streams is consistent with wetland retention by so 4 2 reduction and much lower than so 4 2 released by weathering in deep glacial till and bedrock high so 4 2 groundwaters and geologic sources do not contribute to the so 4 2 pulses in streams isotopic patterns over 6 a were similar pulses of so 4 2 in the wetland catchments following drought are a result of the oxidation of s previously reduced and stored in the wetland

sulfur cycling in an acid mining lake and its vicinity in lusatia germany the sulfur cycle plays a key role in the hydrochemical development of lignite and coal mining districts which are often characterized by acid mine drainage identification of sulfur sources and transformations is essential if we are to understand the current status of acid lakes and propose successful remediation strategies we utilized stable isotope 34ssulfate 18osulfate 34sdissolved sulfide 18owater and hydrochemical data of lake and groundwater samples as well as the concentrations and isotope ratios of various sedimentary sulfur compounds acid soluble sulfate ass acid volatile sulfur avs chromium reducible sulfur crs in aquifer and lake sediments for assessing the biogeochemical sulfur cycle in a lusatian acidic mining lake ml111 and the surrounding area pyrite oxidation is the dominant source of sulfate and iron in the two aquifers west and east of mining lake ml111 concentration and isotope data for dissolved sulfate suggest that bacterial dissimilatory sulfate reduction became an increasingly important process in the flow direction of the western aquifer thereby improving water quality in contrast bacterial sulfate reduction was only of local importance in the dump aquifer on the eastern side of the lake oxygen isotope ratios of the lake water sulfate and mass and isotope balances demonstrate that 80 of the sulfate in mining lake ml111 is derived via groundwater influx from the dump aquifer with the remainder contributed by the western aquifer in lake pyrite oxidation or bacterial sulfate reduction in the water column are insignificant the latter process is restricted to the monimolimnion which represents less than 1 of the lake volume hence the potential for natural generation of alkalinity by bacterial dissimilatory sulfate reduction is presently low for successful remediation of ml111 it is essential to reduce significantly the continuous input of sulfate and acidity from inflowing dump groundwater

geochemistry and stable sulfur and oxygen isotope ratios of the podwiśniowka pit pond water generated by acid mine drainage holy cross mountains south central poland abstract the paper presents the results of a geochemical and isotopic study of acidic pond water in the abandoned podwi niowka quarry poland the scope of investigations also encompassed mineralogical and isotopic studies of pyrite and related supergene minerals compared to similar sites throughout the world the pit pond water examined is characterized by a very low ph averaging 2 64 0 33 and simultaneously very low concentrations of so 4 2 geometric mean of 237 57 mg l 1 fe ii 4 8 3 4 mg l 1 fe iii 10 0 6 2 mg l 1 and other trace elements this acidity has been generated by complex processes of as rich pyrite oxidation combined primarily with hydrolysis precipitation and transformation of fe oxyhydroxysulfates and oxyhydroxides into goethite the specific mineralogy of ore and gangue minerals but especially the lack of acid buffering constituents has additionally contributed to the very low ph and element concentrations of the toxic elements the high content of as 1111 1879 mg kg 1 in the western part of pit pond sediment may be of great concern especially when using lime as a neutralizing agent of the acidic water the 34s of soluble so4 varied from 19 8 to 11 1 and was different from that of efflorescent sulfates 25 7 to 25 4 and host pyrite 25 4 2 5 the comparison of the 18o so 4 2 2 0 1 2 and 18o h2o 6 2 3 5 values indicated that the pyrite underwent bacterially catalyzed oxidation by two natural oxidants primarily by fe3 and to a lesser extent o2

isotope geochemistry of drainage from an acid mine impaired watershed oakland california abstract oxidation of sulfides at the leona heights sulfur mine has resulted in the liberation of acid so4 and metals to leona creek previous research at the site has indicated fe ii oxidation at rates faster than would be predicted by abiotic oxidation alone particularly in the segment of stream between the adit and leona street sample stations in order to assess the mechanisms responsible for sulfide oxidation samples were collected for isotopic analysis of water and so4 the results of which were used to develop a stoichiometric isotope balance model this exercise indicated that the percentage of water derived oxygen in so4 increased spatially from between 56 and 64 at the adit to between 71 and 72 at leona street illustrating that increased sulfide oxidation via fe iii was occurring within or as water flows over the waste rock relative to water emanating directly from the former mine the incorporation of water derived oxygen in so4 during pyrite oxidation is a process controlled by fe oxidizing bacteria such as a ferrooxidans at low ph the role of bacteria was further supported by estimates of the rate constant for fe oxidation between sampling stations yielding values that were approximately 106 faster than abiotic fe oxidation alone stable isotopic analysis of water further indicates a close correlation of adit spring water to the local meteoric water line while 3h data indicate a groundwater apparent age or time of travel from its primary zone of recharge of

a stable isotope study of recharge processes in the english chalk the 2h and 18o values of water contained in unsaturated chalk have been measured in drillcore profiles taken over a period of 28 months on arable land in cambridgeshire eastern england the isotopic composition of rainfall and lysimeter drainage on the same site has also been monitored over a period of four years the distribution of isotope values in the upper few metres of soil and unsaturated chalk shows that the mechanism of infiltration is not simple piston like downward displacement since the scale of vertical fluctuations is incompatible with estimated annual infiltration and the apparent rates of movement of matrix water derived from thermonuclear tritium studies lysimeter drainage is not isotopically identical to matrix water at the same depth suggesting that different routes to water table are associated with consistently different isotopic content although there is an apparent difference between matrix water beneath arable and permanent grassland these differences appear to cancel out in the composition of bulk recharge beneath these land types the regional aquifer has a uniform isotopic composition similar in value to weighted average rainfall and lysimeter drainage suggesting that the recharge abstraction system has been in isotopic equilibrium for many years despite changes in pumping rates and land use two other chalk sites in southern england have been investigated in less detail but indicate clear difference in infiltration behaviour from that seen in cambridgeshire this seems to be related to a higher matrix conductivity and annual rainfall amount