Aluminum Species Distribution Research Articles

Enhanced catalytic ozonation of toluene using supported MnOx/USY via regulating the distribution of aluminum species in USY by dealumination

Recently, the problem of VOCs pollution has become serious in many regions, especially developing countries. Herein, the distribution of aluminum species in USY was controlled by dealumination of Y zeolite under different conditions, and then the dealuminated samples were used to prepare five different supported catalysts MnOx/USY to achieve high-efficiency catalytic ozonation of toluene at low temperature. It was found that aluminum species were successfully leached from the zeolite framework to the extra-framework, which changed the properties of the manganese oxide nanoparticles loaded on the zeolite. Moreover, the oxygen vacancies and the acid sites in different catalysts showed great differences. As the extra-framework aluminum species increased, the amount of oxygen vacancies in the catalysts decreased, while the content of acid sites exhibited a “volcano-type” trend similar to toluene conversion. The best catalysts (Mn-Y-3) maintain > 90% toluene conversion at 30 °C but the worst catalysts (Mn-Y-5) deactivate rapidly. With the help of in situ DRIFTS, it is found that the activation ability of toluene on the acidic sites of the catalyst is the key to the toluene conversion when the amount of oxygen vacancies is sufficient to decompose ozone into active oxygen species, and the contribution of Lewis acid sites is greater than Brønsted acid sites. It provides some theoretical guidance in designing effective catalysts for ozone catalytic oxidation of VOCs.

Distribution of Aluminum Species in Zeolite Catalysts: 27Al NMR of Framework, Partially-Coordinated Framework, and Non-Framework Moieties.

The structure of aluminum-containing moieties in and within zeolite H-ZSM-5 catalysts is a complex function of the elemental composition of the catalyst, synthesis conditions, exposure to moisture, and thermal history. 27Al NMR data collected at field strengths ranging from 7.05 to 35.2 T, i.e., 1H Larmor frequencies from 300 to 1500 MHz, reveal that Al primarily exists as framework or partially coordinated framework species in commercially available dehydrated H-ZSM-5 catalysts with Si/Al ranging from 11.5 to 40. Quantitative direct-excitation and sensitivity-enhanced 27Al NMR techniques applied over the wide range of magnetic field strengths used in this study show that prior to significant hydrothermal exposure, detectable amounts of nonframework Al species do not exist. Two-dimensional 27Al multiple-quantum magic-angle spinning (MQMAS) along with 1H-27Al and 29Si-27Al dipolar correlation (D-HMQC) NMR experiments confirm this conclusion and show that generation of nonframework species following varying severities of hydrothermal exposure are clearly resolved from partially coordinated framework sites. The impact of hydration on the appearance and interpretation of conventional direct-excitation 27Al spectra, commonly used to assess framework and nonframework Al, is discussed. Aluminum sites in dehydrated catalysts, which are representative of typical operating conditions, are characterized by large quadrupole interactions and are best assigned by obtaining data at multiple field strengths. On the basis of the results here, an accurate initial assessment of Al sites in high-Al content MFI catalysts prior to any hydrothermal treatment can be used to guide reaction conditions, anticipate potential water impacts, and identify contributions from hydroxyl groups other than those associated with the framework bridging acid site.

Fluoride removal from water by composite Al/Fe/Si/Mg pre-polymerized coagulants: Characterization and application

Fluoride, an anionic pollutant, is possibly to be found in excessive concentrations especially in groundwaters and can show detrimental effects on human health, in concentrations higher than the commonly applied legislation limit of 1.5 mg/L The most commonly applied method for water de-fluoridation is performed by Al-based coagulants, which however presents some important limitations, such as the applied relatively high dosage, producing rather excessive amounts of chemical sludge. In this study, the use of novel pre-polymerized Al-based coagulants was examined, regarding their efficiency towards fluoride removal, as compared with the conventionally applied AlCl3. The novel coagulants were characterized by measuring the main physico-chemical properties, the aluminum species distribution, the zeta potential, the particles' size distribution and the produced flocs’ sizes. The results showed that the Mg-containing coagulant (PSiFAC-Mg30-10-15) was the most efficient, when applied in pH values relevant to fluoride-containing groundwaters; it was also the only coagulant, which increases its efficiency at pH values > 7. The uptake capacity of coagulants, regarding fluoride, to reach the residual/equilibrium concentration limit of 1.5 mg F/L (Q1.5-value) at the pH value 7.0 ± 0.1 were found 170, 134 and 94 mg F/g Al for the cases of PSiFAC-Mg30-10-15, AlCl3·6H2O and PSiFAC-Na1.5-10-15, respectively. Accordingly, at the pH value 7.8 ± 0.2 the Q1.5-values were found 189, 118 and 41 mg F/g Al for the same coagulants; whereas considering the residual aluminum concentration this was ranged at 15 ± 5, 25 ± 5 and 30 ± 5 μg Al/L, respectively. In addition, (beneficial) increase of residual magnesium concentration, when applying the coagulant PSiFAC-Mg30-10-15 was 15 ± 5 mg/L.

Coagulation/flocculation process with polyaluminum chloride for the remediation of oil sands process-affected water: Performance and mechanism study

This study investigated the application of polyaluminum chloride (PACl) for the treatment of the oil sands process-affected water (OSPW). These coagulants are commonly used in water treatment with the most effective species reported to be Al13. PACl with 83.6% Al13 was synthesized using the slow base titration method and compared with a commercially available PACl in terms of aluminum species distribution, coagulation/flocculation (CF) performance, floc morphology, and contaminant removal. Both coagulants were effective in removing suspended solids, achieving over 96% turbidity removal at all applied coagulant doses (0.5–3.0 mM Al). The removal efficiencies of metals varied among different metals depending on their pKa values with metal cations having pKa values (Fe, Al, Ga, and Ti) below OSPW pH of 6.9–8.1 (dose dependent) being removed by more than 90%, while cations with higher pKa values (K, Na, Ca, Mg and Ni) had removals of less than 40%. Naphthenic acids were not removed due to their low molecular weights, negative charges, and hydrophilic characteristics at the OSPW pH. At the highest applied coagulant dose of 3.0 mM Al, the synthetic PACl reduced Vibrio fischeri inhibition effect to 43.3 ± 3.0% from 49.5 ± 0.4% in raw OSPW. In contrast, no reduction of toxicity was found for OSPW treated with the commercial PACl. Based on water quality and floc analyses, the dominant CF mechanism for particle removal during OSPW treatment was considered to be enmeshment in the precipitates (i.e., sweep flocculation). Overall, the CF using synthesized PACl can be a valuable pretreatment process for OSPW to create wastewater that is more easily treated by downstream processes.

Hydraulically irreversible membrane fouling during coagulation–microfiltration and its control by using high-basicity polyaluminum chloride

The extent of hydraulically irreversible membrane fouling in a coagulation–filtration system depends on several factors, including properties of the coagulant. Effects of polyaluminum chloride (PACl) coagulant properties, specifically basicity and sulfation, were investigated by conducting long-term direct filtration experiments. Elemental analysis determined Al and Si to be the major foulants, though the Si/Al ratios of the foulants differed from those of coagulated floc particles. While floc particle size depended on the concentrations of sulfate ions and polymeric species in the PACls, floc-size changes did not affect transmembrane pressure (TMP) buildup and thus did not affect irreversible fouling. Differences in PACl basicity, which affected the distribution of aluminum species, resulted in changes to the degree of irreversible fouling.Pretreatment with high-basicity (71%) PACl was superior to pretreatment with normal-basicity (51%) PACl in reducing irreversible fouling and attenuating TMP buildup during filtration. Higher basicities resulted in less Al breakthrough and a decrease in the Si/Al ratio of the foulants. However, TMP buildup was the same for PACls with basicities of 71% and 90%; therefore, TMP buildup is not simply related to Al breakthrough and deposition. Increasing the basicity of PACls would be an effective way to reduce the amount of foulant deposited on the membrane by decreasing the amount of aluminum that passes through the membrane.

Removal of aqueous fullerene nC60 from wastewater by alum-enhanced primary treatment

This study examined the removal of nC60 from wastewater by alum-enhanced primary treatment at different pH levels and alum dosages and identified wastewater characteristics affecting the removal. The efficiency of the removal depended on the alum dosage, pH, alkalinity, and the concentrations of suspended solids, sewage organic matter and salinity. Alum dosage and pH influenced the removal efficiency by changing the hydrolyzed aluminum species distribution at acidic and near neutral pH levels. At pH 9–10, nC60 removal was associated with the formation of magnesium (or calcium) carbonate or hydroxide precipitates. Alkalinity dramatically enhanced the nC60 removal efficiency (by up to 71%) through the formation of sodium aluminum hydroxycarbonate precipitates. Increasing the concentration of suspended solids enhanced the nC60 removal efficiency by up to 46% at 25mg/L of alum as the solids act as adsorbents and the nuclei around which flocs can grow. Increasing the concentration of sewage organic matter decreased the nC60 removal efficiency (by 17% or less) while salinity improved it, albeit only slightly so. The results of this study demonstrate that nC60 can be effectively removed from wastewater by the alum-based chemically enhanced primary treatment process under appropriate conditions and better removal can be achieved by increasing alum dosage.

Influence of composite flocculant of PAC and MBFGA1 on residual aluminum species distribution

In general, majority of biomaterials have shown good biosorption capacities towards certain of metal ions. In this work, microbial flocculant GA1 (MBFGA1) compound with PAC was used to control the residual aluminum in flocculation water treatment. The fluorescence spectrophotometry combined with different pretreatment methods was employed to divide the species of aluminum and determine their concentration. The results indicated that non-labile monomeric aluminum was the dominant specie in residual aluminum and addition of MBFGA1 could efficiently eliminate them. Two quadratic polynomial models with the response variables of flocculating rate and labile monomeric aluminum concentration were established by response surface methodology, respectively. The optimal flocculating conditions were MBFGA1 at 109.37mg/L, PAC at 81.87mg/L, initial pH at 8.5, time duration of stir 72.5min and ambient temperature at 24.3°C. Fourier transform-infrared spectra and environmental scanning electron microscope analysis indicated that MBFGA1 holded a large number of functional groups, which had strong capacity on binding aluminum and reducing its residual level during coagulation–flocculation.

Humic Acid Removal from Water with Polyaluminum Coagulants: Effect of Sulfate on Aluminum Polymerization

Humic acid (HA) removal from water with inorganic polyaluminum coagulants is reported in this paper. Polyaluminum chloride (PAC) and three kinds of polyaluminum chloride sulfate (PACS) with a [SO42-]/[Al3+] (S) molar ratio of 0.02, 0.06, and 0.10 were prepared. The coagulation behaviors of these coagulants were investigated in the view of coagulant dosage, initial pH, and aging time. PACS (S=0.06) showed the best HA removal efficiency, and there was no restabilization within a broad effective dosage range. The proper initial pH range was broad and was 4.0–9.0 for PACS (S=0.06). The stability of PACS (S=0.06) reduced with a long aging time, so the proper aging time should not exceed 1 month. The aluminum species distribution, particle mean size, charge neutralization, and infrared spectrum of prepared coagulants were tested. Results showed that SO42- addition promoted the hydrolysis/polymerization of aluminum and reduced the charge neutralization capacity of PACS. Besides charge neutralization, the bridge-...

Aluminum speciation of coagulants with low concentration: Analysis by electrospray ionization mass spectrometry

Aluminum speciation of coagulants with low concentration was investigated in detail by electrospray ionization mass spectrometry (ESI-MS). In particular, comparison with 27Al nuclear magnetic resonance ( 27Al NMR) and Ferron colorimetric method for aluminum speciation of coagulants was discussed. The results indicated that various hydrolyzed aluminum species (monomeric, dimeric, trimeric and tetrameric aluminum species), which could not be identified by other methods, appeared in ESI-MS spectra. Thus, ESI-MS method was much better for hydrolyzed aluminum species in low concentration. In this paper, sample cone voltage was an important operating parameter during ESI-MS detection, and optimum voltage was 70 V. Too low (40 V) or high (150 V) sample cone voltage was not suitable for detecting all aluminum species. This study also evaluated the effects of coagulant concentration, aging, pH value and organic matter on aluminum species distribution. The results indicated that the distribution of hydrolyzed aluminum species at low concentration was largely dependent on the solution pH. At higher pH conditions, aging (8–12 h) may influence aluminum hydrolysis. Additionally, after adding salicylic acid into coagulant solutions, speciation and stability for both Al 13 species and aluminum–salicylate complexes varied significantly at different pH values.

Novel inorganic-organic composite coagulants based on aluminium

In this study, the preparation of a novel coagulant is examined, by introducing into PACl a cationic polyelectrolyte (CPE). For this purpose, poly-diallyldimethylammonium chloride (p-DADMAC) was used, a commonly applied cationic polyelectrolyte in water and wastewater treatment. Several possible derivatives of the composite coagulant were prepared, based on different CPE content (Al/CPE ratio, w/w). The products were characterized by means of polymerization degree (aluminium species distribution), chemical bonding (FT-IR spectroscopy), conductivity, turbidity and pH, in order to examine the impact of CPE addition in the properties of PACl. Moreover, their coagulation performance was evaluated for the treatment of contaminated tap water and compared to the respective performance of the combined application of PACl and CPE but as separated reagents. Finally, the kinetics of coagulation-flocculation was studied by aims of a Photometric Dispersion Analyzer (PDA). From the results obtained it was revealed that...

Factors effecting aluminum speciation in drinking water by laboratory research

Effects of aluminum on water distribution system and human health mainly attribute to its speciation in drinking water. Laboratory experiments were performed to investigate factors that may influence aluminum speciation in water supply system. The concentration of soluble aluminum and its transformation among other aluminum species were mainly controlled by kinetics processes of related reactions. Total aluminum concentration had a notable effect on the concentrations of mononuclear and soluble aluminum in the first 4 day; then its effect became weak. At pH above 7.50, both fluoride and orthophosphate had little effect on aluminum speciation; while, when the solution pH was below 7.50, the concentrations of mononuclear and soluble aluminum were proportional to the concentration of fluoride and inversely proportional to the concentration of orthophosphate. Both mononuclear and polynuclear silicic acids could complex with mononuclear aluminum by forming soluble aluminosilicates. In addition, the adding sequence of orthophosphate and aluminum into drinking water would also affect the distribution of aluminum species in the first 4 day. In order to minimize aluminum bioavailability in drinking water, it was suggested that orthophosphate should be added prior to coagulant process, and that the concentrations of fluoride and silicic acids should be controlled below 2.0 and 25 mg/L, respectively, prior to the treatment. The solution pH in coagulation and filtration processes should be controlled in the range of 6.50–7.50.

Alternative cost-effective preparation method of polyaluminium chloride (PAC) coagulant agent: Characterization and comparative application for water/wastewater treatment

An alternative preparation procedure for polyaluminium chloride (PAC), a common inorganic coagulant, is presented in this paper. The proposed procedure is based on the use of granular aluminium metal, a common by-product of several aluminium-processing secondary industries, instead of using Al2O3 (or of using a mineral containing Al2O3) which is commonly applied by most industrial producers, and exhibits important benefits such as energy and time saving during the preparation procedure. Several efforts have been made to produce the pre-polymerized coagulant with properties, similar to the properties of a commercially available PAC solution, using appropriate, commonly found laboratory equipment and without the application of extreme conditions (in terms of temperature or pressure). The laboratory prepared PAClab was characterized mainly by means of aluminium content, basicity, density and aluminium species distribution. Furthermore, the coagulation performance of PAClab was evaluated for the treatment of contaminated tap water and of wastewater samples and it was compared with the performance of a commercially available PAC solution. Finally, the coagulation–flocculation kinetics was examined with the use of Photometric Dispersion Analyzer instrument (PDA) and the floc growth rates between the two coagulants were compared. The results suggest that PAC can be alternatively produced under mild conditions, resulting in a product with better properties than the commercial PAC used for comparison. Additionally, if the preparation takes place in industrial scale, a greater improvement is further feasible, due to the common equipment used, instead of using e.g. autoclaving.

A systematic study for the characterization of a novel coagulant (polyaluminium silicate chloride)

The current research in coagulation–flocculation field has focused mainly in understanding the behavior and chemistry of pre-polymerized coagulants, such as polyaluminium chloride (PACl), and the improvement of their properties. A possible way to increase the efficiency of PACl is claimed to be the incorporation of silica in its structure, in the form of polysilicates. The new product is called polyaluminium silicate chloride (PASiC) and is supposed to be more effective than PACl, when applied in the coagulation–flocculation process. The purpose of this study was the synthesis and characterization of many possible derivatives of polyaluminium silicate chloride, based on different basicity (OH/Al molar ratio), silica content (Al/Si molar ratio) and preparation method (co-polymerization or composite polymerization) to get an overall picture of their major physico-chemical properties. Overall 32 silica based coagulants were prepared with different OH/Al (1–2.5) and Al/Si (5–20) ratios. Their properties were mainly evaluated by means of polymerization degree and aluminium species distribution employing either the ferron technique or the 27Al NMR method, in order to evaluate the impact of silica addition in the new coagulants. Moreover, the formation of new species was investigated with the use of X-ray diffraction, FTIR, and SEM methods. Finally, their stability was investigated over a time period of several months.

Influence of some additives to aluminium species distribution in aluminium coagulants

Aluminium ions hydrolyse and polymerise into different species in water. Main aluminium species in aluminium coagulant solutions are monomeric Al species (Al 1) and polymeric Al species Al 13 O 4 ( OH ) 24 7 + (Al 13). The aluminium species distribution in coagulant solutions can be influenced by many parameters. This paper studies influences of concentrations of total aluminium species (Al t) and other species—OH −, polysilicic acid and ferric species, which were added in aluminium coagulant solutions, on the aluminium species distribution through 27Al nuclear magnetic resonance (NMR) analysis. Results show that only Al 1 and no Al 13 exist in coagulant solutions at higher Al t concentrations (over 1 mol l −1), while both species exist at lower Al t concentrations (0.1 mol l −1). The increase of OH/Al value (molar ratio) increases the concentration of Al 13 in coagulant solutions, while the addition of polysilicic acid and ferric species decreases the concentration of Al 13.

Calculated Solubility of Trivalent Iron and Aluminum in Oxalic Acid Solutions At 25 °C.

Based on the principle of thermodynamic equilibrium, the solubility curves of trivalent iron and aluminum at 25 °C are presented and used as a guide for the prediction and understanding of the chemistry of these metal ions in oxalic acid solutions. The present paper proposes a framework derived from equilibrium thermodynamic data that was formulated to qualitatively correlate and predict the trivalent iron and aluminum species distribution in the Fe3+ − Al3+ − H2C2O4 − H2O system for oxalic acid concentrations varying between 1 and 10−6 M. The paper also advocates the use of graphical representations to visualise the importance of different appearing species in the system under study as a function of pH and oxalic acid concentration.La solubilité au 25 °C d' ions ferriques et aluminium dans de solutions d'acide oxalique a été calculée et représentée graphiquement, pour mieux comprendre et prédire la chimie de ces deux ions métalliques dans le millieu oxalique. Cet article propose un cadre, derivé des données d' équilibre thérmodynamique, pour correler et prédire la distribution des espèces ferriques et aluminium au système Fe3+ -Al3+ - H2C2O4 - H2O, pour des concentrations d' acide oxalique entre 1 et 10-6 M. Les avantages des représentations graphiques pour visualiser l'apparition de differentes espèces et leur importance rélative en fonction du pH et de la concentration d' ions oxalates sont aussi discutés dans cet article.

Distribution of aluminum species in normal urine as determined by chemical neutron activation analysis

A procedure developed for separating and quantifying non protein and protein fractions of aluminum species in urine was applied to four consecutive 24 hr collections of five healthy subjects. The total Al content of urine was determined by a chemical neutron activation analysis technique reported elsewhere. Results from the analysis of all subjects indicate that the majority of aluminum is bound to protein (>88%) with minor fractions as citrate complexes. These data are comparable with other speciation experiments with blood plasma indicating 90% of the aluminum was bound to plasma proteins.

Speciation of Aluminium in Environmental Water Samples Employing Microcolumn Chelating Ion-Exchange Chromatography - ETAAS

A microcolumn chelating ion-exchange chromatography-electrothermal atomic absorption spectrometry procedure (ETAAS) was developed for aluminium speciation at the nanogram per millilitre level in water samples from the environment. Chelex-100 resin (100-200 mesh, H+ form) was filled into a micro column and connected to a peristaltic pump. Before analysis, the resin column was equilibrated to the pH of the particular sample analyzed. Sample was then pumped through the column at a flow rate of 0.5 cm3 min−1. Labile aluminium monomeric species were retained by the resin column and, after elution with 5 cm3 of HCl (1 mol dm−3), determined by ETAAS. At pH higher than 5.0, prewashing with 0.025 mol dm−3 HCl was applied prior to elution with 1 mol dm−3 HCl, to remove Al(OH)3 adsorbed on the column resin. The distribution of aluminium species over a pH range from 3.0 to 8.0 in synthetic standard solutions was closely matched by the 8-hydroxyquinoline spectrophotometric method and reported calculated data. Good reproducibility of measurement (± 1.5%) was obtained (10 ng cm−3 of Al, pH 4.0). LOD (3[sgrave]) for separated aluminium species (50 cm3 of sample) was found to be 0.3 ng cm3. The influence of some inorganic and organic complexing ligands as well as the effect of high salinity, nonionic surfactants and an excess of alkaline-earth ions on aluminium speciation was investigated. The technique was successfully employed in determination of aluminium species in various water samples from the environment.

Phosphate, Fe and Mn uptake of N2 fixing red clover and ryegrass from an Oxisol as affected by P and model humic substances application. 2. Phosphate and aluminum species distribution as modified by plant roots

AbstractIn a previous paper we reported that model humic substances (0–50 mg kg−1 soil) increased P‐, Fe‐, and AI‐solubility as well as P uptake of red clover and ryegrass on a strongly P‐fixing soil. In this paper P‐ and Al‐species calculations under equilibrium assumptions were conducted to determine the species which were mobilized by the humics and red clover root exudates.Phosphate distribution between free ortho‐P and humic‐Al‐P complexes was calculated by an iterative procedure. In the soil without plants more than 50% of P in solution was present as humic associated P even at the lowest humic level. In soil under ryegrass the proportion of humic‐P complexes was much lower due to the relatively low concentrations of humic‐Al complexes in solution. In soil under red clover, between 55 and more than 84% of P in solution were present as humic‐P. This increase compared to soil without plants or with ryegrass is caused by the high concentrations of humic‐Al complexes in solution. The higher P‐influx of red clover compared to ryegrass and P species distribution indicate that red clover can take up P from solubilized humic‐P complexes.Aluminum species calculations showed that, even at the lowest level of humics addition, more than 60% of Al was complexed by the humics in soil without plants. The proportion of Al complexed by humics increased to about 90% at the highest level of humics addition. In soil under ryegrass cover, the proportion of humic‐Al complexes was lower, not exceeding 73% due to the reduced solubility of humic substances. In contrast, higher humics concentrations in soil solution under red clover increased the proportion of humic‐Al complexes to more than 80% of total Al even at the lowest humic level. It was concluded that the strong complexation of Al by the humics in the soil solution under red clover reduces Al toxicity.

Aluminium species distribution during mixing of acid coal and slate mine drainage with neutral stream waters

We measured the spatial variation of aluminium concentrations and computed its species distribution before and during mixing of acid mine drainage containing waters with near neutral receiving waters. Acid mine drainage was collected from the Loquitz Creek, Thuringia, Germany, and Garvey Creek, Westland, New Zealand, which drain slate mine workings and coal mine workings, resp. The acidneutralizing capacity (ANC) of the receiving streams and the mixing with waters having low Al-concentrations cause a decrease of aluminium concentrations below the confluence. Depending on volumes and ANCs involved, the content of free Al and sulphate bound Al decreases after mixing in favour of organic and hydroxide bound Al. In addition, below the junction of the Loquitz Creek and the Aue Creek with its high ANC, we observe the precipitation of aluminium hydroxides and Al hydroxysulphates.

Aluminum Contamination of Groundwater: Spring Melt in Chalk River and Turkey Lakes Watersheds — Preliminary Results

Two watersheds with seasonal pH depressions in the groundwater exhibit high aluminum concentrations associated with these acidification events. The watersheds receive similar atmospheric loadings of H+ and SO42− but are covered by different surficial deposits. The aluminum is measured in four fractions by varying the pH and time conditions during analysis. The resulting classes calculated from these fractions are Class a, containing fast-reacting monomeric aluminum, predominantly inorganic Al3+ and hydroxy compounds; Class b, containing fast-reacting complex aluminum species, mainly inorganic F− complexes and simple organic complexes; Class c, containing slow-reacting amorphous and some polymeric aluminum species; and a class containing a residue of unknown aluminum species adding to the total acid-extractable aluminum. There are significant differences in the distribution of the various aluminum species between the two watersheds, both with depth and in the predominant class identified. The generally higher values measured at one watershed are consistent with the lower carbonate content of the overburden. In both locations it appears that the controlling factor is the pH of the groundwater, with all but Class c species increasing with decreasing pH. The difference between the distributions of aluminum species in groundwater and surface water is under investigation to determine the influence of groundwater-bourne aluminum on the surface water into which it flows.