Al Concentrations In Water Research Articles

Occurrence, source identification and ecological risk assessment of heavy metals in water and sediments of Uchalli lake – Ramsar site, Pakistan

Uchalli Lake is an internationally significant Ramsar site that needs protection for supporting migratory birds. The current study aimed to assess wetland health by examining water and sediments utilizing total and labile heavy metals concentration, pollution indices, ecological risk assessment, water recharge and pollution induction sources through isotope tracer techniques. Al concentration in water was of serious concern as it was 440 times higher than the maximum acceptable concentration of Environmental Quality Standard of the UK for aquatic life in saline waters. Labile concentration predicted very severe enrichment of Cd, Pb, and moderate enrichment of Cu. Modified ecological risk index predicted very high ecological risk in sediments. The δ 18O, δ2H and D-excess values indicate that the lake was mainly recharged by local meteoric water. Enriched values of δ 18O and δ2H suggest a high evaporation of lake water, making lake sediments more enriched with metals. Isotopic and D-excess values of groundwater suggest a quick rainwater recharge to groundwater around the Uchalli Lake. Nitrates isotopes indicate that the rainwater runoff is main source of induction of fertilizers, pesticides and soil bonded metals in the lake system. The lake is recharged by rainwater runoff, from catchment areas, that erode the soil particles and agricultural residual waste dumped in the lake.

Suppression of performance of activated carbon filter due to residual aluminum accumulation

Extending the lifetime of granular activated carbon (GAC) filters with no significant loss in their effectiveness is a considerable challenge for drinking water supply utilities. However, the effects of residual Al from coagulants on GAC performance are rarely considered. Herein, in-service GAC samples obtained from full-scale water treatment plants were investigated to evaluate the amount of accumulated Al. Although the Al concentration in water was two to three times lower than the Ca concentration, Al exhibited considerable accumulation (second to Ca accumulation) in in-service GAC samples (0.68–8.63 mg g−1). Surface characterization results indicated that Al accumulation could have been caused by the co-precipitation of Al with Ca and Si to form Ca4Al2Si3O10·H2O and Ca4Al6O12SO4, self-precipitation or complexion with −OH/−COOH on the GAC or biofilm surfaces. Correlation analysis of the accumulated Al and GAC properties implied that Al accumulation considerably reduced the surface area of GAC by ∼30%. Lab simulation experiments indicated that the removal of dissolved organic matter was reduced by 6–10% when additional Al was loaded. In addition, results showed that the residual Al (up to 200 μg L−1) considerably affected the extracellular polymeric substance component and microorganism community structure. In summary, strict control of residual Al is beneficial for maintaining the efficacies of GAC and biologically activated carbon.

Evaluation of cardiotoxicity in Amazonian fish Bryconops caudomaculatus by acute exposure to aluminium in an acidic environment.

Aluminium (Al) is soluble in acidic waters and may become toxic to organisms. In this study, the acute effects of two Al concentrations were evaluated in the Amazonian fish Bryconops caudomaculatus. Antioxidant responses and lipid damage were assessed in gills, liver and muscle, along with the electrocardiography (ECG) and characterization of cardiac complex and wave intervals. Fish were essayed as follows: two control groups at neutral and acidic pH and two exposure groups at acidic pH (0.3 mg/L and 3.0 mg/L Al). Water samples were collected at 0h, 24h and 48h, for chloride (Cl-), fluoride (F-) and sulphate (SO42-) ion analyses, while total Al was quantified in muscle. Concentrations of Cl- and SO42- were constant over time whereas F- was not detected. Total Al concentrations in water and muscle were concentration-dependent. Antioxidant responses, total antioxidant capacity against peroxyl radicals (ACAP) and glutathione S-transferase were not triggered in fish tissues exposed to 0.3 mg/L Al; however, fish exposed to 3.0 mg/L Al presented increased and reduced ACAP in gills and liver, respectively. No changes in lipoperoxidation levels occurred among groups. Fish exposed to 0.3 mg/L Al showed prolonged intervals in ECG as a reflection of low heart rate (HR), with sinus bradycardia. Moreover, there was a marked prolongation of the PQ interval (time between the atrial activity and the start of ventricular activity), indicating interference on the cardiac cell automaticity. Fish exposed to the highest concentration of Al showed reduced wave intervals as a consequence of increased HR, with sinus arrhythmia, while ECG tracings did not present P waves (atrial contraction), indicating an atrioventricular blockade. In conclusion, 48h exposure sufficed to cause cardiotoxicity in B. caudomaculatus at either Al concentration. However, as oxidative stress was not observed, such cardiac alterations seem to be reversible under the experimental conditions established herein.

Study of aluminium in groundwater using chemometric methods

ABSTRACTThe field dataset including physico-chemical characteristics of Khibiny alkaline massif groundwater aquifer was analysed for the first time by applying chemometric methods to explore the relationships between investigated parameters in both time and frequency domains. Elevated Al concentration in water of this aquifer is described as a serious health concern when used for the household water supply. The time series of 12 physico-chemical parameters were examined by using Pearson correlation, multiple linear regression and spectral analysis based on fast Fourier transform (FFT) algorithm. Computed pairwise correlation coefficients matrix revealed that pH values, NO3−, SO42−, Cl− and TDS correlate with Al concentrations at a statistically significant level (α-level = 0.05). The multiple regression model including Cl−, NO3− and pH explains up to 54% of Al concentrations temporal variation in groundwater. Fourier coefficients, power spectral density (PSD) and cumulative spectral power (CSP) were calculated for Al, pH, NO3− and Cl− time series to identify and analyse the strength of their variations as a function of frequency. Calculations revealed the spectrums of these variables include three main frequency bands corresponding approximately to 5–7, 13–17 and 20–34 month periods. The fluctuations within these bands contribute mostly to the total temporal variation of Al, Cl−, NO3− concentrations and pH values.

Development of a Dispersive Liquid-Liquid Microextraction Method Combined with UV-Visible Spectrophotometry for Determination of Trace Aluminum(III) in Water, Wastewater, Food, Biological, and Pharmaceutical Samples.

A simple and sensitive method was proposed for the preconcentration of trace levels of Al(III) prior to its determination by spectrophotometry, based on dispersive liquid-liquid microextraction. The complexation of the Al(III) was performed by chelation with Eriochrome Cyanine R (ECR). In this method, cetyltrimethyl ammonium bromide (CTAB) as a dispersant was dissolved in chloroform as an extractant solvent, and then the solution was rapidly injected by a syringe into the samples containing Al(III), which had already been complexed by ECR at optimized pH. Various parameters were studied and optimized for a 10 mL sample volume. Under the optimum conditions, the LOD (3 times the SD of 10 replicate readings of the reagent blank) and the dynamic range of the calibration obtained were 0.2 ng mL-1 (7 nM) and 1.0-80.0 ng mL-1, respectively. The RSDs for eight replicate determinations of 10 and 60 ng mL-1 of Al(III) were 3.3 and 1.8%, respectively. This strategy was successfully applied to determine the Al concentration in water, wastewater, yogurt, apple, carrot, celery, bread, potato, urine, and Al-Mg syrup samples.

High tolerance of aluminum in the grass species Cynodon aethiopicus

Concentrations of aluminum (Al) were determined in leaves of native terrestrial plants, macrophytes and fruit parts (watermelon and tomato) using inductively coupled plasma mass spectrometry. Al concentrations in water and soil were determined by inductively coupled plasma optical emission spectrometry. Potamogeton thunbergii (macrophyte) and Cynodon aethiopicus (terrestrial grass) had the highest leaf Al concentrations (2 and 1 g kg−1 dw, respectively). Transfer factors (mg kg−1 dw plants/mg kg−1 dw soil) based on total Al concentrations in soil varied from 2 × 10−3 to 0.05 and from 1.9 to 78 based on mobile Al concentrations determined after sequential extraction. Bioconcentration factors (mg kg−1 dw plants/mg L−1 water) varied from 19 to 9.5 × 103 L kg−1 dw. Plants can accumulate high concentrations of Al when growing in neutral pH soils and slightly alkaline lakes in the Ethiopian Rift Valley. Controlled experiments showed that C. aethiopicus can accumulate high levels of Al both in root and shoot. Compared to Arabidopsis thaliana, C. aethiopicus was more tolerant to Al exposure as ≥400 μM AlCl3 was needed to inhibit root growth compared to 200 μM in A. thaliana. After exposing C. aethiopicus and A. thaliana in 800 μM AlCl3, alkaline comet assay indicates significant DNA (deoxyribonucleic acid) damage in A. thaliana while C. aethiopicus was unaffected. No significant induction of reactive oxygen species (ROS), in terms of leaf H2O2 levels, could be observed in C. aethiopicus. C. aethiopicus has mechanisms to suppress both Al-induced ROS and DNA damage, thereby increasing tolerance of the species to high Al concentrations.

The impact of aluminium sacrificial anodes on the marine environment: A case study

Cathodic protection using Al sacrificial anodes is a method of corrosion control that is often applied to submerged metallic structures. This technique leads to the progressive dissolution of the sacrificial anode and the metal(s) constituting the anode are inevitably released into the surrounding aquatic environment with potentially detrimental effects. The chemistry of sediments and waters from a French harbour where Al sacrificial anodes are deployed is examined in this study. In order to assess the potential influence of Al dissolution from the anode on the aquatic environment, total Al concentrations in water and sediment were determined and corresponding Al enrichment factors were calculated. Single and sequential extractions were also undertaken in order to evaluate the mobility of Al in the sediments. Results showed that whilst anodic dissolution does not significantly increase the concentration of Al in the water, both enrichment and an increase in the mobility of Al were evident in sediments sampled from the vicinity of the sacrificial anodes.

Patterns of Mercury Accumulation among Seston in Lakes of the Adirondack Mountains, New York

Mercury (Hg) concentrations in seston (biotic and abiotic particles < 200 microm) were measured during summer thermal stratification in nine lakes in the Adirondack Mountains of New York State that exhibit a range of physical and chemical characteristics. Fractionation of Hg bound to particulate matter was conducted to identify the influences of seston density and water chemistry on Hg accumulation among various ecologically important seston size classes (0.2-2, 2-20, 20-200, and > 153 microm). Total dissolved Al (< 0.45 microm) in lake water was significantly related to Hg concentrations in the 20-200 microm size class, and was positively correlated with Hg concentrations in the other seston size classes. Seston density was negatively correlated with seston Hg concentrations and significantly related to Hg bound by seston in the 0.2-2 microm size class. The results suggest that surface water Al concentrations and seston density influence Hg accumulation at the base of the aquatic food chain.

Dissolved Al distribution, particulate Al fluxes and coupling to atmospheric Al and dust deposition in the Arabian Sea

Abstract Concentrations of dissolved aluminium (Al) were measured in the Arabian Sea during three different seasons. Atmospheric Al concentrations and particulate Al fluxes at 100 m depth were measured during the northeast monsoon. Particulate Al fluxes in the deep Arabian Sea were determined from a 16 months sediment trap mooring. Surface water Al concentrations were higher in the more oligotrophic southern Arabian Sea (10–15 nM) than in the north-western Arabian Sea (3–9 nM). Seasonal variability was observed in the central and northern Arabian Sea with elevated concentrations during spring/summer. Mixed-layer residence times of 0.4–4 years for dissolved Al estimated with respect to both atmospheric input and particle flux exports indicate rapid removal from surface layers. Scavenging removal exerts major control on Al cycling. There are indications of a sediment source for dissolved Al. Atmospheric Al concentration during the northeast monsoon were 10–30 nmol m−3 and up to 81 nmol m−3 during dust pulses. The Al content in aerosol particles was variable with an average of 950 μmol g−1 (or 2.6% by weight), which is about threefold lower than in average continental crust (8.04%). Using available aerosol Al concentrations combined with satellite data, the annual atmospheric deposition rate of Al is estimated to ∼16000 μmol m−2 yr−1. Depending on the Al content in aerosol material (2.6–8.04%), this converts to a dust deposition rate of 5.4–16.7 g m−2 yr−1 that agrees with sediment trap results and sediment accumulation data. A simple model based on dissolved Al concentrations in surface waters is used to estimate dust deposition rates. We demonstrate that a relatively short residence time of ⩽3 yr and an aerosol Al content of only 2.6% provide improved constraints under steady-state conditions. The strong seasonality in particulate Al flux in the deep central Arabian Sea was dominated by the southwest monsoon sedimentation signal; about 46% of the annual Al flux is provided within only ca. 2 1 2 months. The estimated total atmospheric Al input and the observed deep-water flux of particulate Al of about 14000 μmol m−2 yr−1 agree closely. This suggests that the atmosphere is the major Al source to the Arabian Sea.

Hydrologic Pathways during Snowmelt in First-order Stream Basins at the Turkey Lakes Watershed

The chemical composition of stream and soil water collected from two first-order stream basins in the Turkey Lakes Watershed (TLW) during the spring melt periods of 1992-1996 was examined to determine the flowpaths of snowmelt to the stream channel. Soil water was intensively sampled from within the soil organic layers as well as above (shallow soil water) and within (deep soil water) a compact basal till. Stream SiO 2 concentrations of the high-elevation basin 47 were the same as the levels found in shallow soil water, and forest-floor percolate SiO 2 concentrations were elevated to these levels during intense melting periods. The SiO 2 concentrations from the stream and the shallow and deep soil water were similar at the low-elevation basin 31. With the exception of deep soil water, water collected from the soil and stream at basin 47 had higher H + and Al and lower base cation concentrations than basin 31. Stream Al concentrations were significantly correlated with forest-floor percolate Al concentrations at the high-elevation basin, whereas stream Al concentrations were correlated with mineral soil water Al concentrations at the low-elevation site. There were significant positive correlations between stream and shallow soil water H + at both basins. Shallow soil water pathways, therefore, were an important contributor to streamflow, and influenced stream chemical response during the spring snowmelt at TLW.

On the use of dissolved aluminum in surface waters to estimate dust deposition to the ocean

The concentration of dissolved Al in surface waters from various oceanic regimes is used in a simple model to calculate the annual amount of dust deposited to the surface ocean. Calculated values range from 0.015 to 9.9 g dust m−2 yr−1. Comparison of these calculated dust depositions with independent dust deposition estimates obtained from direct measurements, suspended atmospheric dust loads, or sediment traps show remarkably good agreement over approximately 3 orders of magnitude. In regions where the agreement between the model and other estimates is weakest, it is anticipated that local scaling of model parameters such as mixed layer depth and surface water residence time, will lead to improved agreement. Since surface water Al concentrations appear to be driven primarily by dust deposition, the distribution of dissolved Al in surface waters can be used to investigate the systematics of the delivery of other biologically important trace elements, for example, Fe, to the surface of the remote ocean by this route. In addition, temporal variations in surface water Al concentrations can be used to investigate the biogeochemical consequences to the surface ocean of large‐scale changes in atmospheric dust loads driven by decadal‐scale climatic variations.

The distribution of Al in the IOC stations of the North Atlantic and Norwegian Sea between 52° and 65° North

The vertical distribution of dissolved and reactive aluminium was determined at nine stations in the eastern and western North Atlantic, the Norwegian Sea and on a surface water transect during the International Oceanographic Commission's second open ocean baseline survey. The profile results show that the distribution of dissolved Al is primarily the result of advective movement of the various water masses that appear in these stations. Control of the dissolved Al distribution in the central and upper waters of the eastern and western basin of the North Atlantic appears to be related to the mixing series forming these waters. Namely, in the eastern basin by mixing of low salinity, low Al core North Atlantic Central Water (NACW) with high salinity, high Al Mediterranean Water (MW). Dissolved Al concentrations in a series of remnant mixed layers seen immediately above the NACW are consistent with the production of this water mass by deep wintertime convection. In the western basin and Charlie Gibbs Fracture Zone, the influence of the MW is restricted by the invasion of eastward spreading Labrador Sea Water (LSW). The central waters of the western basin primarily reflect a two end-member mixing of core LSW and high salinity moderate to low Al surface waters. Dissolved Al in surface waters along the ship's track range between 0.88 and 3.3 nM and generally reflect the prevailing salinity distribution. We show that the elevated deep water Al concentrations seen in the North Atlantic cannot be supported by either advection of high Al waters from the Arctic seas or by addition of Al from resuspension of bottom material in the high energy overflow zones. We present a mass balance of Al in the North Atlantic. Our calculations show that there is a `missing' flux of some 6.1×109 mol of Al yr−1 entering the North Atlantic Ocean. We examine the potential for the partial dissolution of eolian dust to provide this missing Al and demonstrate that a dissolution of 3% provides a balance within the errors inherent in these calculations. We suggest that atmospherically deposited Al is rapidly scavenged from the surface waters and removed to the sediment–sea water interface where remobilisation of labile particulate Al occurs and leads to a basin-wide diffusive type profile enriching the deep waters of the North Atlantic.

Plasma Prolactin, Cortisol, and Thyroid Responses of the Brown Trout (Salmo trutta) Exposed to Lethal and Sublethal Aluminium in Acidic Soft Waters

Brown trout, with indwelling dorsal aortic cannulae, were exposed to various concentrations of aluminium (Al; 50 μg liter−1, 100% mortality over 48 hr; 25 μg liter−1, 50% mortality over 120 hr; 12.5 μg liter−1, 0% mortality over 120 hr) in acidic (pH 5.0) soft water. The plasma concentrations of prolactin (PRL), cortisol, thyroxine (T4), and triiodothyronine (T3) were monitored. Plasma PRL concentrations were transiently depressed (to less than 20% of resting concentrations) after 12 hr in trout in the two highest water Al concentrations, but were unchanged in the trout exposed to 12.5 μg liter−1Al. Plasma cortisol concentrations were elevated in response to all water Al levels and remained elevated in trout in the lethal conditions. The sublethally exposed trout showed a recovery in plasma cortisol concentrations by 120 hr. Plasma T4concentrations were significantly elevated in trout exposed to both the lethal and the sublethal Al concentrations (from mean resting concentrations of 1–2 ng ml−1to peaks of 8.9 and 9.0 ng ml−1in the 50 and 12.5 μg liter−1Al groups, respectively), although a recovery in plasma concentrations was evident in the sublethally exposed trout from 72 hr onwards. Plasma T3concentrations were relatively stable in the trout exposed to the two highest doses of Al, whereas the trout under the lowest, sublethal, Al conditions exhibited a sustained (12–72 hr) elevation in plasma T3concentrations (from a mean resting concentration of 0.9 ng ml−1to a peak of 4.2 ng ml−1at 48 hr). No clear relationship was apparent between the plasma PRL concentrations and the previously reported ionoregulatory status of the trout.

Contrasting the geochemistry of aluminum among peatlands

Aluminum concentrations were measured in surface waters, pore waters and surface peats of 15 wetlands in south-central Ontario. Wetlands were grouped floristically and chemically as mineralpoor, moderately-poor or mineral-rich fen. Mineral-poor fens were dominated bySphagnum, were low in alkalinity (0.31μeq L−1) and pH (4.5–6.3). Moderately-poor fens had a mixture of vegetation (Sphagnum, sedges and grasses), mid-alkalinity (23–91μeq L−1) and pH (5.8–6.4). Mineral-rich fens were dominated by sedges and grasses, had high alkalinity (104–181μeq L−1) and circumneutral pH (6.2–6.3). Surface water Al concentrations were less in mineral-poor versus moderately-poor and mineral-rich fens (F=32.0; P<0.05). Pore water Al concentrations were lower in 4 of 5 mineral versus the mineral-rich fens (F=92.15; P<0.05). In all but two cases pore water Al (all species <0.2μm) were greater within the fen peats versus the overlying surface waters suggesting that peats could act as a source of Al to the overlying waters. In all wetlands, 70 and 30% of peat Al was recovered by a hydroxylamine hydrochloride/acetic extract (primarily inroganic) and an ammonium hydroxide extract (primarily organic), respectively. Differences in “extractable” Al recovered by the two reagents (i.e., inorganic+organic Al) among the 15 wetlands were independent of wetland type. Distribution coefficients, k d , were different among the 3 types of wetlands (F=25.0; P<0.05) with theSphagnum dominated mineral-poor fens containing higher values versus the sedge and grass dominated mineral-rich fens. Lower surface and pore water concentrations of Al in mineralpoor versus mineral-rich fens may in part be a result of differences in the degree of minerotrophic influences between the two types of peatlands. As well, the greater binding capacity ofSphagnum peat as indicated by higher k d 's in the mineral-poor fens, may have contributed to the observed lower pore water and surface water Al concentrations in mineral-poor versus mineral-rich fens. It has been postulated that anthropogenic acidification of peatlands will accelerate the transformation of a mineral-rich fen to that of a mineral-poor fen and ultimately to bog. Changes in Al geochemistry that may ensue as this transition occurs include decreases in pore and surface water Al concentrations with concurrent increases in peat bound Al.

Freshwater benthic algal population and community changes due to acidity and aluminum‐acid mixtures in artificial streams

AbstractCommunities of freshwater benthic algae were exposed to water acidified daily to pH 4.8 alone and in mixtures with 50, 100, or 500 μg L−1 Al. Daily acidification to nominal pH 4.8 in acidified treatments exposed algae to a range of pHs that led to a variety of Al species of different toxicity. Calcium concentrations in stream water were higher in acidified and Al treatments on day 1, and dissolved Al in stream water was higher in the highest Al treatment on days 1, 7, and 28; otherwise acid and Al treatments did not significantly alter Al and Ca in the exposure water. Calcium bioaccumulation by periphyton was lower in acidified and Al treatments on all sampling days. Concentrations of Mg in water and periphyton did not differ between treatments. The artificial stream system generated alkalinity to buffer acidified water; the amount of generated alkalinity returned to approximately the same levels for the first week, but the amount of alkalinity generated during the second week appeared to decline, and acid‐only and acid‐Al mixtures diverged in their ability to generate alkalinity during the third and fourth weeks. Aluminum in acidified water inhibited abundance of diatoms and green and blue‐green algae more than the effects of acid stress alone. The green filamentous alga Mougeotia showed a slight (but not statistically significant) increase in abundance in the acid‐only treatment. The middle‐Al treatment (nominally 100 μg L−1 Al and acid) generated more alkalinity and had higher abundance of some algal taxa on days 14 and 28, even though measured Al concentrations in water and periphyton fell between low‐ and high‐Al‐treatment levels. Community‐level tests, combining a taxonomic analysis of algal population abundance with chemical analysis of water and bioaccumulation, provide valuable insight to assess anthropogenic stress.

Assessing Trends in Fishery Resources and Lake Water Aluminum from Paleolimnological Analyses of Siliceous Algae

Lake water aluminum concentrations have a significant influence on the composition of microfossil assemblages of diatoms and chrysophytes deposited in lake sediments. With the paleolimnological approach of multilake datasets in the Adirondack region of New York, USA, we use canonical correspondence analysis to describe past trends in lake water Al. Four lakes, previously investigated regarding acidification and fishery trends, are used to demonstrate that paleolimnological assessment can also provide direction, timing, and magnitude of trends for both toxic metals and fish resources. Additionally, we use weighted averaging regression and calibration to obtain quantitative reconstructions of past lake water Al concentrations. Such reconstructions provide further insight into fishery resource damage and can be compared with modelling results. According to paleolimnological reconstructions, some (albeit few) of the naturally most acidic lakes in the Adirondack region had preindustrial lake water concentrations of inorganic monomeric Al near 4 μmol∙L−1. Although these high concentrations are surprising from a geochemical point of view, they may partially explain the preindustrial absence of fish, as has been independently determined by paleolimnological analysis of phantom midges (Chaoborus). Fishery resource deterioration in acidified Adirondack lakes was coincident with major increases in lake water Al concentrations.

Episodic response of aluminum chemistry in an acid‐sensitive Massachusetts catchment

A field investigation was conducted to evaluate factors that regulate episodic variations of Al chemistry in an acid‐sensitive Massachusetts catchment. Stream water was collected from an upland subcatchment, a wetland subcatchment, and below the confluence of these two drainage areas in the West Wachusett Brook at 6 hour intervals during the first 2 weeks of November 1985. All major solutes and three Al fractions were analyzed. During the monitoring period, two different rainfall events of contrasting origin (i.e., a coastal storm and an inland storm) occurred. Rainfall volume, intensity, and duration were important factors regulating short‐term acidification of this stream. Ion exchange processes rather than mineral phase solubility appear to control stream water Al concentrations during high‐flow periods. The episodic acidification and subsequent release of Al in the upland stream were associated with a decrease in basic cations. In contrast, Al chemistry from the wetland drainage was regulated by the release of organic acids which served as mobile anions and were responsible for chelating and transporting Al. Chemical equilibrium calculations showed that waters draining the upland subcatchment were potentially toxic to fish during high‐flow periods, whereas the wetland stream exhibited minimal potential for Al toxicity.

Aluminum retention in a man-made Sphagnum wetland

Runoff from a highway interchange in western Maryland had Al concentrations averaging about 50 mg L−1, with a maximum of 206 mg L−1. As an alternative to expensive chemical treatment of this Al-rich water, in August 1984, the drainage was diverted through a 500 m2 man-made wetland, constructed from organic peat. For a 10 week period, Al concentrations in water leaving the wetland averaged 1.5 mg L−1. as compared to Al concentrations at the two major inflows to the wetland of 35.3 and 6.6 mg L−1. However, effective treatment of the drainage by the wetland was not observed over the entire 27 mo sampling period. Peat chemical analysis indicated that over the 27 mo, total Al concentration in the peat increased from 2375 μg g−1 to 13 634 μg g−1. Of this increase 5.5 % was contributed by exchangeable Al, 4.3% by adsorbed Al, 39.8% by organically bound Al, 33.1% by oxide bound Al, and 17.2% by precipitated and residual Al. Changes in Fe, Mn, Ca, Mg, K, and Na chemistry in the peat associated with Al retention are discussed.

Biogeochemistry of Aluminum in McDonalds Branch Watershed, New Jersey Pine Barrens

AbstractAluminum concentrations, fluxes, and storage were measured in the vegetation, forest floor, and acid, sandy mineral soil of a forested watershed in the New Jersey Pine Barrens. Volume‐weighted mean Al concentrations in solution increased as water passed through the upland ecosystem, from 0.012 mg L−1 in bulk precipitation to 0.14 mg L−1 in throughfall to 0.45 mg L−1 in E horizon mineral soil, 0.60 mg L−1 in the B horizon, and 0.73 mg L−1 in the C horizon. Weighted mean Al concentration of the stream water was 0.15 mg L−1. Solution Al concentrations in different compartments of the ecosystem were related to the magnitude of moisture flux, dissolved organic carbon concentration, and pH. Soil solution and stream water Al concentrations were high in the winter and spring and low in the summer and fall, inversely following solution pH. Soil solution and stream pH were independent of precipitation pH because of internal control of H+ concentration by the soil and an apparent 0.5‐yr time lag in flushing of atmospherically deposited acids through the soil. Aluminum was partitioned strongly into the lower mineral soil horizons, but large stores of potentially labile Al were found in the upper mineral horizons and forest floor. Standing vegetation represented a relatively small pool of Al but cycled substantial amounts of Al between mineral soil and the forest floor.