trace metal contamination in sediments from u k estuaries an empirical evaluation of the role of hydrous iron and manganese oxides abstract concentrations of reducible trace metals available to hydroxylamine hydrochloride acetic acid ha have been determined in sediments from contrasting estuaries around the united kingdom specifically estuaries receiving contemporary anthropogenic inputs from catchments which are urbanized and industrialized to varying degrees clyde dee forth loughor mersey and poole harbour and estuaries receiving inputs from mineralized catchments where working of sulphidic ore deposits was important in the past fal hayle helford and tavy mean estuarine ratios of fe mn ranged from less than 10 dee mersey loughor to about 100 fal poole harbour inter estuarine variations in the mass contributions of fe and mn were attributed to differences in geological and hydrological catchment characteristics while intra estuarine variations were attributed to local differences in hydraulic sorting of sediment and redox conditions the relative contributions of hydrous fe and mn oxides to the accumulation of trace metals cr cu pb zn was evaluated by applying different regression analyses to each estuarine dataset overall the most significant correlations were with fe and in estuaries draining mineralized catchments where well defined contaminant metal sources exist poor correlations in other cases were related to the dissolution of additional metal bearing phases including carbonates by the digest dee loughor or the inability of low energy environments clyde poole harbour to buffer the impacts of local sources of contaminant metals mean estuarine concentrations of pb and zn ranged from about 25 g g 1 poole harbour to 200 g g 1 hayle and 80 g g 1 forth to 1500 g g 1 hayle respectively pooled pb and zn data were defined by a single regression equation which was not controlled by the availability or abundance of oxidic material suggesting common environmental and anthropogenic sources and similar sorptive and post depositional behaviours for these metals pooled cr and cu data however exhibited distinct groupings which were attributed to the differential sources and sorptive behaviours of these metals naturally occurring cr is highly resistant to the ha digest and excess concentrations above a baseline of about 2 5 g g 1 which characterises sediment from mineralized catchments are the result of contamination from contemporary or historical industrial processes e g mean concentrations in the clyde and forth are about 30 g g 1 copper is available to the ha digest in sediments of estuaries draining mineralized catchments where concentrations locally exceed 750 g g 1 but is highly resistant to the ha digest in sediments of industrialized estuaries where concentrations are typically between 5 and 40 g g 1 this is because cu derived from the dissolution of sulphidic minerals adsorbs readily to hydrous fe oxides while cu derived from contemporary industrial and municipal sources appears to interact with anthropogenic organic matter and the resulting complexes partition into sediment organic matter which is relatively resistant to the ha digest although the ha digest cannot readily resolve geochemical and anthropogenic metals in hydrous oxides and other sorbents dissolved by ha the availability of metals like cr and cu may give some indication of the history of the contaminant e g its source and subsequent particle water interaction mechanism more generally from a management and assessment standpoint this approach affords a first order estimate of contaminant metal loading which is geochemically and biologically available

direct observation of heavy metal mineral association from the clark fork river superfund complex implications for metal transport and bioavailability two sets of samples from riverbeds and adjacent floodplains separated by 80 river kilometers were collected from the clark fork river superfund complex montana the largest superfund site in the united states and studied primarily with transmission electron microscopy tem with several supporting techniques to determine heavy metal mineral association seven of the eight samples studied were strongly influenced by material that once resided in mining and smelting dumps and impoundments this material was transported downstream sometime during the last century and a half from the butte anaconda areas the eighth sample was from a deeper floodplain level and dates to premining days the tem observations afford a direct look down to the nanometer level at secondary mineral formation as a result of the breakdown of sulfides and silicates in the acid environment of this massive mine drainage system in the shallow oxic floodplain sediments heavy metals of concern in this system as cu pb and zn are taken up by the formation of sulfates particularly pb in jarosite as well as hydrous metal oxides as cu pb and zn in and on ferrihydrite and a possibly new vernadite like mineral the oxides are long lived in these systems as they were also found in the anoxic riverbeds metals are also taken up by the formation of sulfides in sulfate reducing environments as observed in the formation of nanoclusters of chalcopyrite and sphalerite in all samples clays make up between 5 and 20 of the sediment and carry significant amounts of cu and zn the hydrous oxides secondary sulfides and clays provide several routes for metal transport downstream over long distances besides the potential bioavailability of heavy metals exchanged on and off the hydrous metal oxides and clays nanometer sized sulfides may also be highly reactive in the presence of biologic systems

geochemical characterization of mangrove sediments of the zuari estuarine system west coast of india abstract the grain size clay mineralogy and geochemistry were studied in the sediment cores collected from the mangrove environments of the zuari estuary to understand sources and factors affecting accumulation mobility bioavailability and toxicity of metals finer sediments organic matter and metals were higher in the middle estuary and canal sediments while coarser sediments with fewer metal concentrations were seen in the lower estuary kaolinite smectite illite and traces of chlorite constituted the clay mineral assemblage and had a minor influence on metal distributions in the study area the hydrodynamic conditions changed from lower estuary towards the upstream regions owing to mixing of riverine and sea water that led to finer sediment deposition in the middle estuary the variations in metal abundance were attributed to a difference in hydrodynamic conditions regulated by the tide freshwater flow and geomorphology of the zuari estuary the results revealed that the estuary received material from natural weathering of rocks as well as from anthropogenic sources such as mining and industrial domestic discharges enrichment factor and geo accumulation index showed that fe mn and cr were enriched in the mangrove sediments whereas fractionation of metals revealed that concentrations of bioavailable mn pose a considerable risk to biota increased accumulation of fe and mn in the upper middle estuary and canal sediments trap trace metals that may considerably affect sediment quality and dredging of these sediments can cause re suspension and mobilize metals from loosely bound sedimentary forms to the water column

structure of a paleoproterozoic continent continent collision zone a lithoprobe seismic reflection profile across the trans hudson orogen canada abstract an 800 km reflection seismic profile across the trans hudson orogen northern saskatchewan and manitoba images crustal scale tectonic imbrication in an unprecedented picture of paleoproterozoic crustal accretion and continent continent collisional tectonism the profile is crudely symmetric about a crustal scale culmination in the western part of an accreted juvenile collage reindeer zone geologic and isotopic data suggest that this culmination is cored by microcontinental archean basement west of the culmination highly reflective juvenile crustal elements dip westward into the lower crust beneath the wathaman batholith and archean continental crust of hearne craton to the east strong reflections in the juvenile reindeer zone crust and reworked archean foreland of the thompson belt have eastward dips persisting into the middle crust and extending beneath the superior craton a continuous reflection moho well defined for 500 km in the western part of the profile shows marked relief 12 15 s including a prominent root below the crustal culmination these imaged structures give evidence of substantial crustal shortening and thickening via large scale imbrication consistent with collisional orogeny w dipping structures below the wathaman batholith and reworked hearne craton may reflect subduction polarity in this part of the orogen however geological evidence suggests that e dipping structures below superior craton are largely related to late post collisional deformation rather than to prior oceanic subduction polarity

the kapuskasing uplift a geological and geophysical synthesis over the past decade the kapuskasing uplift has been the subject of intense geological and geophysical investigation as lithoprobe s window on the deep crustal structure of the archean superior province enigmatic since its recognition as a positive gravity anomaly in 1950 the structure has been variably interpreted as a suture rift transcurrent shear zone or intracratonic thrust diverse studies including geochronology geothermobarometry and various geophysical probes provide a comprehensive three dimensional image of archean 2 75 2 50 ga crustal evolution and proterozoic 2 5 1 1 ga cooling and uplift the data favour an interpretation of the structure as an intracratonic uplift related to hudsonian collision eastward across the southern kapuskasing uplift erosion levels increase from 10 km in the michipicoten greenstone belt through the wawa gneiss domain 10 20 km into granulites 20 30 km of the kapuskasing structural zone juxtaposed against the low grade swayze greenstone belt al

geochemical trends in metal contaminated fiord sediments near a former lead zinc mine in west greenland abstract disposal of sulfidic waste in marine environments implies an environmental risk due to potential release and spreading of heavy metals to sediments and biota on a regional scale however tailings disposal in marine systems is practised in several places fiord sediments near black angel mine in west greenland are contaminated by pb and zn as a result of mining activity and marine disposal in the period 1973 1990 chemical analyses were performed on 6 fiord sediment cores collected up to 10 km away from the disposal area and included heavy metal analysis high resolution stable pb isotope stratigraphy and radiochemical dating 210pb the results were used for evaluating spatial and temporal distribution of anthropogenic heavy metals from the marine disposal a significant accumulation of pb and zn on a regional scale is still observed 9 years after mine closure stable pb isotope data provide a unique fingerprint of the mining related pb sources in the area today spreading of mining related pb up to 10 km away from the mining area accounts for more than 80 of total pb in sediment deposited within the last 100 years

role of sediment composition in trace metal distribution in lake sediments sediment cores were collected from 20 lakes from the muskoka region of ontario canada to study vertical changes in trace metal concentrations with depth and the distribution of metals amongst humic material amorphous and crystalline fe and mn oxides insoluble organics sulphides and silicates based on their total concentrations trace elements displayed different degrees of affinity for the organic fraction represented by organic c and the mineral fraction represented by al certain elements hg as sb pb cd and zn displayed a positive correlation with organic c a negative correlation with al and enrichment in surface sediments with enrichment factors ranging from 2 to 24 detailed speciation studies revealed that these elements were associated mainly with humic material and to a lesser extent with oxides in surface sediments other elements al cr co fe and mn displayed a negative correlation with organic c a positive correlation with al and no consistent enrichment in their total concentration at the surface the speciation study revealed that metals of the latter group were mainly associated with the silicate fraction in both surface and deep sediments this study shows that relative affinities for organic and mineral fractions play an important role in the distribution of trace metals during burial and diagenesis and hence in the shape of their vertical profiles

magma sources for mesozoic anorogenic granites of the white mountain magma series new england usa the magma sources for granitic intrusions related to the mesozoic white mountain magma series in northern new england usa are addressed relying principally upon nd isotopes many of these anorogenic complexes lack significant volumes of exposed mafic lithologies and have been suspected of representing crustal melts sm nd and rb sr isotope systematics are used to evaluate magma sources for 18 felsic plutons with ages ranging from about 120 to 230 ma the possibility of crustal sources is further examined with analyses of representative older crust including paleozoic granitoids which serve as probes of the lower crust in the region multiple samples from two representative intrusions are used to address intrapluton initial isotopic heterogeneities and document significant yet restricted variations 1 in end overall mesozoic granite plutons range in end t from 4 2 to 2 3 with most 2 to 0 and in initial 87sr 86sr from 0 7031 to 0 709 the isotopic variations are roughly inversely correlated but are not obviously related to geologic geographic or age differences older igneous and metamorphic crust of the region has much lower nd isotope ratios with the most radiogenic paleozoic granitoid at end 180 ma of 2 8 these data suggest mid proterozoic separation of the crust in central northern new england moreover the bulk of the mesozoic granites cannot be explained as crustal melts but must have large mantle components the ranges of nd and sr isotopes are attributed to incorporation of crust by magmas derived from midly depleted mantle sources crustal input may reflect either magma mixing of crustal and mantle melts or crustal assimilation which is the favored interpretation the results indicate production of anorogenic granites from mantle derived mafic magmas

upper mantle velocity temperature conversion and composition determined from seismic refraction and heat flow 1 we compile upper mantle pn velocities from seismic refraction wide angle reflection surveys in the southern superior province of the canadian shield and compare them with temperatures at the moho deduced from heat flow data calculated moho temperatures and pn velocities correlate well showing that in this area pn depends primarily on temperature the obtained values of v pn t depend weakly on the assumed value of moho heat flow and are on the order of 6 0 10 4 10 km s 1 k 1 within the range of temperature derivatives obtained in laboratory studies of ultramafic rocks comparison between observed pn velocities and predicted values for several mineralogical models at moho temperatures allows constraints on both the moho heat flow and the shallow mantle composition for all moho heat flows undepleted clinopyroxene rich mantle compositions do not allow a good fit to the data for depleted mantle compositions temperatures consistent with the observed pn velocities correspond to values of moho heat flow larger than 12 mw m 2 for our preferred moho heat flow of 15 mw m 2 the best fit mantle composition is slightly less depleted than models for average archean subcontinental lithospheric mantle this may be due to rejuvenation by melt related metasomatism during the keweenawan rifting event the similarity in pn t conversion factors estimated from this empirical large scale geophysical study and those from laboratory data provides confidence in the absolute temperature values deduced from heat flow measurements and seismic studies

sediment properties and heavy metal pollution assessment in the river estuary and lake environments of a fluvial plain china abstract a better understanding of the relationships between heavy metal pollution and sediment sources in different aquatic environments is needed in this study some geochemical properties major elements and trace metals of sediments from a river an estuary and a lake were researched in the yangtze river delta plain a fluvial plain nj river sediments sediments from the nanjing section showed a relatively coarse size and tl lake sediments sediments from the taihu lake showed a fine size as a whole nj river sediments revealed higher concentrations of toc cao and mgo while tl lake sediments revealed higher sio2 and al2o3 ye estuary sediments sediments from yangtze estuary had medium ranges of major elements for metal speciation nj river sediments had high concentrations of acid extractable cd and pb ye estuary sediments showed high reducible fractions of cu pb and zn and tl lake sediments revealed a high oxidizable fraction of cu ye estuary sediments showed strong correlations between trace metals and major elements but tl lake sediments showed weak correlations the heavy metal contamination levels were evaluated by enrichment factors based on existing heavy metal forms in sediments the risk assessments were also manifested by the proportion of the first metal form risk assessment code rac the comprehensive racs of sediments followed the order of river sediments estuary sediments lake sediments among heavy metals cd and pb revealed the highest risks for sediments the results of primary component analysis and cluster analysis showed that the metal speciation was associated with sediment sources and components it is apparent that the metal contaminations are associated with sediment sources which significantly influence the geochemical properties of sediments in the different aquatic environments of the yangtze river delta plain

sequential extraction procedure as a tool to investigate pthe geochemistry and potential geoavailability of dam sediments almaden mining district spain sediments from castilseras reservoir almaden were collected to assess the potential environmental hazards associated with the availability of potentially toxic or harmful elements pthe in this freshwater environment pthe concentrations in sediments were investigated using a four step f1 f4 sequential extraction procedure sep and the results were evaluated using principal component analysis pca and different risk indexes and criteria considering the fractions results and the pca treatment two groups of elements can be differentiated in the easily leached by weak acids fraction f1 and these indicate the presence of sulfate and secondary precipitates of carbonates as the main sink for easily accessible metallic elements in reducible fraction f2 chemical analysis revealed a significant relationship between the majority of the analyzed elements and the fe oxy hydroxides with the exception of co hg and ni which are preferentially associated with mn oxy hydroxides in the oxidizable fraction f3 a significant relationship between cu fe hg and zn representative metals of the existing ore deposits and sulfides organic matter was observed the environmental assessment based on the aforementioned criteria provides risk levels varying from moderate to high the risk appears to be higher near the dam where the higher pthe levels in sediment are due to a selective accumulation of fine grained particles

the use of various methods for the study of metal pollution in marine sediments the case of euvoikos gulf greece this study presents the results on heavy metal mn fe cu zn analyses of sediments taken from euvoikos gulf greece which is a semi enclosed system receiving pollution loads from several urban and industrial sources and is affected by a strong tidal current a sequential extraction schema and two single step methods were used for the determination of trace metals the data of the 1997 period are compared with data from previous studies carried out in the authors laboratory in the area 1980 1993 using various analytical techniques in an attempt to evaluate both the evolution of pollution in the area and the effectiveness of analytical methods it has been confirmed that a significant part of the pollution load remains in coastal localities in the vicinity of the land based pollution sources whereas there are also some more remote sites where small polluted particles are transported deposited and accumulated the sedimentology regime of the area affects the concentration of metals in a rather complex way depending also on its content of carbonates organic c and clay minerals the study of sediment cores has indicated elevated metal concentrations in recent surface sediments on the other hand some environmentally positive trends were also observed i e the reduction of mobile metals a systematic monitoring is needed in the marine environment coupled with some reduction in pollution inputs and integrated management on the coastal zone because the overall hydrological characteristics of the area favour its rapid self restoration 2002 elsevier science ltd all rights reserved

heat flow in the nipigon arm of the keweenawan rift northwestern ontario canada 1 in the archean superior province the nipigon embayment in the area of lake nipigon north of lake superior is covered by midproterozoic sediments intruded by keweenawan diabase sills it has been interpreted as a failed arm of the ca 1100 ma keweenawan rift six new heat flow values in this area show that the region of low heat flow associated with the keweenawan rift in lake superior extends northwards along the western margin of the nipigon embayment the average heat flow in the nipigon area 39 5 mwm 2 is only slightly lower than

low mantle heat flow at the edge of the north american continent voisey bay labrador heat flow measurements in 4 deep drillholes near voisey bay labrador have yielded the lowest value ever reported in the canadian shield 22 mw m 2 this very reliable estimate is also one of the lowest continental heat flow values world wide it requires the crust to be very poor in radioelements in this part of the archean nain province it also strongly supports the view that mantle heat flow is low 15 mw m 2 throughout the canadian shield with no trend of increasing mantle heat flow near the edges of the continent it also raises questions about the controlling mechanism for rifting and the opening of the labrador sea at 100 ma

evolution of soils on quaternary reef terraces of barbados west indies soils on uplifted quaternary reef terraces of barbados 125 000 to 700 000 yr old form a climo chronosequence and show changes in physical chemical and mineralogical properties with terrace age parent materials are dust derived from the sahara volcanic ash from the lesser antilles island arc and detrital carbonate from the underlying reef limestone although some terrace soils are probably eroded soils or their remnants are redder and more clay rich with increasing terrace age profile average al2o3 and fe2o3 content increases with terrace age which partially reflects the increasing clay content but dithionite extractable fe also increases with terrace age profile average k2o tio2 na2o tio2 and p2o5 tio2 values decrease with terrace age reflecting the depletion of primary minerals average sio2 al2o3 values also decrease with terrace age and reflect not only loss of primary minerals but also evolution of secondary clay minerals although they are not present in any of the parent materials the youngest terrace soils are dominated by smectite and interstratified kaolinite smectite which gradually alter to relatively pure kaolinite over 700 000 yr comparisons with other tropical islands where precipitation is higher and rates of dust fall may be lower show that barbados soils are less weathered than soils of comparable age it is concluded that many soil properties in tropical regions can be potentially useful relative age indicators in quaternary stratigraphic studies even when soils are eroded or changes in soil morphology are not dramatic

crustal scale shortening and extension across the grenville province of western quebec a deep seismic reflection survey shot in 1993 crosses almost the full width of the grenville province in western quebec the seismic transect provides a very clear image of the crust mantle boundary and the most precise definition to date of the various grenvillian terranes the crust is around 44 km thick beneath the grenville front but thins rapidly to 36 km some 60 km to the southeast it is also notable that the greatest crustal thickness of 50 km occurs at the southeast end of the transect far from the inferred location of the main grenvillian collision the grenville front zone in which nw directed thrusting at about 1 ga was followed by se directed extension is defined by discontinuous se dipping reflections which extend down to the moho to the southeast the overlying migmatitic archean parautochthon almost half of the transect is characterised instead by nw dipping reflectors extending into the lower crust these reflectors are in turn truncated to the southeast by a 12 km thick zone of intense se dipping reflections the baskatong crustal ramp the base of the allochthonous terranes allochthon boundary thrust is likely located at this ramp which flattens out at around 30 km depth into the base of the relatively transparent intermediate crust a highly reflective upper crustal deck corresponding to rocks of the mont laurier terrane was thrust over the baskatong crustal ramp and is represented further to the northwest by the klippelike cabonga allochthon the synformal transparent morin anorthosite charnockite complex belongs to the same upper crustal level ramp anticlines and the overriding basal thrust of the upper allochthons demonstrate the nw directed propagation of tectonic transport during the grenvillian orogeny involving deformation and displacement along the baskatong ramp with a relay into the grenville front zone postaccretional extension appears to have been primarily accommodated along the latter two crustal discontinuities thinning the crust immediately south of the grenville front and affecting the crust up to 350 km away from the front

thermal regime of the lithosphere in the canadian shieldthis article is one of a series of papers published in this special issue on the theme lithoprobe parameters processes and the evolution of a continent geothermal studies were conducted within the framework of lithoprobe to systematically document variations of heat flow and surface heat production in the major geological provinces of the canadian shield one of the main conclusions is that in the shield the variations in surface heat flow are dominated by the crustal heat generation horizontal variations in mantle heat flow are too small to be resolved by heat flow measurements different methods constrain the mantle heat flow to be in the range of 12 18 mw m 2 most of the heat flow anomalies high and low are due to variations in crustal composition and structure the vertical distribution of radioelements is characterized by a differentiation index di that measures the ratio of the surface to the average crustal heat generation in a province determination of mantle temperatures requires the knowledge of both the surface heat flow and di mantle temperatures increase with an increase in surface heat flow but decrease with an increase in di stabi

deep seismic profile across a proterozoic collision zone surprises at depth collisions between continents generate the world s most striking mountains the deep structure of these collision zones inferred from seismic reflection profiles1 3 can be equally dramatic if less well understood improved knowledge of the structure of ancient collisional belts now known to have developed through plate tectonic processes4 5 can provide important new insights into the mechanisms of crustal growth although many such belts have been partly destroyed by severe post collisional deformation6 7 or magmatism8 some have been preserved in the stable interiors of continents9 one example is the early proterozoic trans hudson orogen9 10 in western canada here we present seismic reflection images across the entire orogen which reveal a broadly symmetric structure with reflections linked to island arc rocks dipping beneath both bounding archaean cratons the observed reflection geometries imply a doubling of crustal thickness during the collision along crust penetrating faults the presence of a significant amount of archaean crust at depth the extent of which could not have been determined from surface mapping suggests the need for caution in inferring crustal growth rate from the surface area of juvenile crust11 12

geochemical behavior assessment and apportionment of heavy metal contaminants in the bottom sediments of lower reach of changjiang river abstract heavy metal contamination of bottom sediments of the changjiang river is widely reported however the potential source and methods of transportation of these heavy metals in the contaminated sediments is poorly defined this paper examines the correlation between heavy metals and geochemical indices including fe2o3 al2o3 total organic carbon toc and black carbon bc as well as magnetic susceptibility ms using these indices we investigate the contamination characteristics of heavy metals in the sediments by with principal component analysis pca results from 83 sediment samples collected in the lower reach of changjiang river from nanjing to shanghai show that the first principal component accounts for 52 23 of the total variance corresponding to the heavy metals co cr cu ni and zn and conservative components of fe2o3 al2o3 and toc this result indicates that heavy metal distributions are controlled by the transportation and sedimentation of fine particles which is also confirmed by particle size analysis the second principal component explains 24 81 of the variance and is dominated by cd pb and ms which collectively result chiefly from industrial and transportation activities and for ms fly ash production the third principal component accounts for 7 91 of the variance and corresponds solely to hg principal component analysis multiple linear regression pca mlr was used to estimate the contribution of the three principal components to each heavy metal pca mlr results suggest that more than 50 of co cr cu ni and zn were influenced by the particle size effect particle size effect and fly ash account for 37 1 and 27 7 of as cd and pb were mainly explained by fly ash 98 9 of hg was related to pc3 which represented black carbon bc our study indicates that the combination of geochemical and multivariable statistical methods clearly characterizes the geochemistry of heavy metals in sediment of the lower reaches of the changjiang river and suggests that power plants are the main source of heavy metal pollution

more seismic evidence on the location of grenville basement beneath the appalachians of quebec maine summary high quality multichannel seismic 133 fold and refraction wide angle reflection 1 to 3 km receiver spacing and 30 to 60 km shot spacing data have been collected across the northern appalachians in quebec and maine an integrated interpretation of the seismic data from the southeastern quebec western maine region provides strong evidence that the rocks of the predominantly oceanic dunnage zone are allochthonous having been thrust westwards over precambrian grenville basement during and subsequent to the closing of the iapetus ocean

anthropocene footprint in the nalon estuarine sediments northern spain abstract four boreholes drilled at depths ranging from 9 to 27 m and retrieved from the nalon estuary asturias northern spain were investigated to assess the impact of the historical human footprint on the sedimentary sequence analytical measurements of grain size geochemical composition major and trace elements and stable pb isotopic ratios were performed two different sections of the sedimentary profile were identified throughout the sedimentary sequence using pb isotopic ratios and then corroborated with grain size characteristics and as hg pb and zn concentrations the upper sediment layer of the boreholes variable depth ranging between 3 and 9 m exhibited an increase in 208pb 206pb ratios and a decrease in 206pb 207pb ratios whereas in the deepest layers these ratios remained unchanged these variations reflected the anthropogenic input of pb into estuarine sediments which can be attributed to mining activities when compared to pb isotopic ratios from coal mined in the region the anthropogenic input can be also noted on the basis of the variability of the trace element concentrations with depth the enrichment factors of as max 7 5 hg max 45 4 pb max 10 3 and zn max 8 6 calculated using local geochemical background values helped distinguish the impact of intense anthropogenic activities which can be attributed to mining exploitation in the nalon river drainage basin despite the closure of several of these mines during the second half of the 20th century geochemical characteristics have revealed the ongoing input of as hg pb and zn into the coastal zone thus the legacy of contamination from these elements mainly from leaching slags and tailing dams is still being recorded in estuarine sediments and requires careful scrutiny on the part of local authorities in terms of its possible effects on the aquatic biota

tsunamis within the eastern santa barbara channel several locally generated tsunamis have been reported in southern california during the past 200 years yet the hazard from locally generated tsunamis has received considerably little attention we consider here tsunamis generated by coseismic displacements on the channel islands thrust cit system as well as waves generated by slope failures along the walls of the santa barbara channel we find that purely tectonic sources could generate regional tsunamis with 2m runup whereas combinations of tectonic sources and submarine mass movements could generate local runup as large as 15m