Aluminum Concentration In Water Research Articles

Effect of Aluminum Concentration in Water on Its Toxicity and Bioaccumulation in Zooplankton (Chaoborus and Chironomus) and Carp (Cyprinus carpio L.) Roe.

An attempt to evaluate aluminum toxicity to living organisms was undertaken in the study. A laboratory experiment was conducted to determine aluminum bioaccumulation and toxicity in Chironomus and Chaoborus larvae and in Cyprinus carpio L. roe depending on aluminum concentration in water reflecting natural chemical composition. Water was examined for temperature, pH, electrical conductivity, dissolved oxygen, color, nitrate nitrogen, nitrite nitrogen, sulfates by spectrophotometric method; total hardness and chlorides by titration method; and calcium, magnesium, sodium by flame atomic absorption spectrometry, total aluminum by electrothermal atomic absorption spectrometry. Determination of aluminum levels in water, roe, and zooplankton was carried out after mineralization using electrothermal atomic absorption spectrometry. Aluminum bioaccumulation factor in roe was determined with respect to concentration in water. Moreover, acute toxicity (LC50) was calculated. In the roe experiment, aluminum concentration in water at the end of the experiment was 0.0635-0.1283 mgAl∙dm-3. The lowest values were noted for the control sample and the highest for water with 0.03 mgAl∙dm-3 aluminum content. The final aluminum level in roe was, like in water, the highest in roe treated with 0.03 mgAl∙dm-3 (18.95 mgAl∙kg-1), and the lowest in roe treated with 3.00 mgAl∙dm-3 (6.96 mgAl∙kg-1). Aluminum bioaccumulation in roe was the strongest in the control. Survival rate ranged from 2.00 to 97.00%, which shows higher sensitivity of roe to aluminum concentration. LC50 value for Chaoborus was 0.6464 mgAl⋅dm-3, and for Chironomus 0.2076 mgAl⋅dm-3 indicating that Chironomus is more sensitive to aluminum toxic effects. Concentration of 3.0 mgAl∙dm-3 caused the highest mortality. Aluminum in both species at each concentration reached the highest levels after one day (24h), 254.58mg⋅kg-1 for Chaoborus and 3107mg⋅kg-1 for Chironomus. After another day, aluminum levels decreased. This demonstrated the differential accumulation of aluminum depending on the species, which predisposes Chironomus as a better indicator organism. This type of research is important from the point of view of aquaculture, which is a targeted activity with a high degree of economic importance, but is also important for aquatic organisms living in natural conditions. Fish reproduction takes place in both types of waters, so all these reservoirs regardless of their source of destination should be inspected.

Effect of clariflocculator and pulsator based sedimentation technology and poly-aluminium chloride coagulant type on the efficiency of the water treatment plant

Abstract Polyaluminium chloride (PAC) with different basicity is used as a coagulant in most drinking water treatment plants (WTP). The aluminium concentration in PAC and its hydrolysis mechanism varied with the basicity of PAC. Incremental addition of PAC changes various physico-chemical properties and turbidity removal mechanisms in water. Water treatment plants use the PAC concentration beyond its optimum dose without considering other aspects, including residual aluminium concentration. In the present work, the effect of high and medium basicity of PAC on different physico-chemical properties like pH, zeta potential, and residual aluminium concentration of water was investigated. The pH of treated water decreases with the incremental addition of PAC, and an increase in zeta potential and residual aluminium concentration in treated water was evidenced. The change in pH after PAC addition is responsible for deciding the coagulation mechanism and efficiency of the coagulation process. pH reduction is comparatively more in high basicity PAC than medium basicity. PAC hydrolysis mechanism is controlled by the zeta potential of water and can be used as an alternative method to decide the optimum coagulant dose. The performance of clariflocculator and pulsator-based WTP was also evaluated for raw water from the same source. To reduce down the turbidity below the acceptable level, the coagulant requirement for clariflocculator based WTP is comparatively less than pulsator based WTP. The floc blanket in the pulsator gets disturbed with a slight change in the coagulant chemistry and quantity.

BLOOD MINERAL COMPOSITION IN RESIDENTS OF THE ARCTIC REGION WITH LOW WATER MINERALIZATION RATES IN CENTRALIZED TAP WATER SUPPLY SYSTEMS

Introduction: Mineral content of tap water vary significantly between settings and may affect blood mineral composition in humans. The evidence from Arctic Russian settings is scarce. Aim: To assess blood mineral composition among residents of areas with low mineralization of water from underground sources distributed by centralized water supply systems in Arctic Russia. Methods: The study was performed in the town of Kirovsk, Murmansk region. Only permanent residents of the town aged 18-23 years participated. Concentrations of Ag, Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, Si, Sn, Sr, Ti, Tl, V, Zn, Y in tap water and whole blood were determined by atomic emission spectrometry. Results: Tap water in Kirovsk has an increased pH value, with a total mineralization of 65.0 mg/l with the legal limit of 1000 mg/l). Magnesium and calcium concentrations were 1 000-1 500 and 150-300 times below maximum permissible (MPC) concentrations, re spectively. The concentration of aluminum exceeded MPC by 30-50 % while concentrations of other elements were tens to hundreds times below MPC. In blood, calcium concentration was slightly below the average value for healthy individuals while and the magnesium content corresponded to normal values. An increased concentration of boron (2.45 ± 0.11 mg/l) was revealed. Conclusions: Contrary to expectations, residents of the area with low mineral content of tap water did not have a significant decrease in concentrations of calcium and magnesium in whole blood. No signs of increased concentration of heavy metals in blood of the residents were observed. Despite the high concentration of aluminum in water, its concentration in whole blood is within the physiological limits. At the same time, an increased blood concentration of boron was revealed warranting further research.

Changes in the concentration of aluminum in water after the treatment process - experience from technological research

Changes in the concentration of aluminum in water after the treatment process - experience from technological research

Residual Aluminium in Water Intended for Human Consumption

Aluminium is one of the environmental factors that may have an impact on Alzheimer’s and Parkinson’s disease. Some epidemiological studies show a relationship between the concentration of aluminium in drinking water and the incidence of Alzheimer’s disease. The article presents and discusses the results of research on the effect of the type and dose of non-prehydrolyzed aluminium coagulants on the concentration of residual aluminium in water intended for human consumption. Aluminium sulphate (VI) and sodium aluminate were tested as coagulants. Analysis of the obtained test results showed that lower concentrations of residual aluminium were found after coagulation with aluminium sulphate (VI), which is hydrolyzed acidally, lowering the pH of the water in the range of 7.47 to 7.12 providing good conditions for the formation of Al(OH)<sub>3</sub>. A less useful coagulant due to the concentration of residual aluminium was sodium aluminate, which undergoes basic hydrolysis creating conditions for the transition of Al(OH)<sub>3</sub> into soluble Al(OH)<sub>4</sub><sup>−</sup>.

Identifying contaminants of potential concern in remote headwater streams of Tennessee's Appalachian Mountains.

The susceptibility of Tennessee's Appalachian Mountains to anthropogenic stressors has remained largely uninvestigated likely due to a lack of known point source contamination. However, a growing body of scientific evidence suggests that depositional inputs can lead to concerning levels of contamination, even in remote areas. To investigate potential concerns, water quality parameters, contaminants in water (nitrogen, TSS, and metals), and contaminants in eastern brook trout (mercury, polychlorinated biphenyls [PCBs], organochlorine [OC] pesticides, dioxins, furans, and phthalates) were measured in four Appalachian Mountain streams from 2015 to 2017. Concentrations were compared to literature and/or model-derived (e.g., biotic ligand model) threshold values to determine whether levels exceeded those acceptable for stream health. Dioxins and furans were detectable in fish tissue at all sites with an average 2,3,7,8-tetrachlorodinbenzodioxin toxicity equivalence (TEQ) of 0.0015ng/kg. Concentrations of PCBs, phthalates, and organochlorine pesticides were never above analytical quantitation limits, although several OC pesticides (e.g., alpha-chlordane) were detectable in fish. Aluminum concentrations in water were found at levels shown previously to cause mortality in brook trout during acidic rain events. The average whole-body methylmercury concentrations in fish among sites were 0.037 ± 0.003μg/kg and were on average 75 ± 2% of total mercury.

Selective colorimetric/visual detection of Al3+ in ground water using ascorbic acid capped gold nanoparticles

A method for the selective and sensitive detection of aluminium (Al3+) in aqueous systems has been developed. The detection is achieved by the selective aggregation of ascorbic acid capped gold nanoparticles (AA-AuNPs) in the presence of aluminium which is observed by the change in colour of the colloidal solution from bright red to purple. The change in characteristic absorption peak can also be noticed spectrophotometrically; absorption of AA-AuNPs (λmax–520nm) decreased and a second peak at 652nm appeared after the addition of aluminium. The ratio of A652/A520 can be used to quantify the concentration of aluminium in water. The method gave a linear response from 20ppb − 100ppb (R2=0.996) of Al3+ in drinking water with a detection limit of 6.5 ppb. The proposed method did not suffer any interference from concomitant transition metal ions like: Mn2+, Ni2+, Zn2+, Sn2+, Li+, Co2+, Hg2+, Fe3+, and Pb2+ up to a concentration of 5ppm and anions (Cl−, F−, SO42−, NO3−, PO43−) up to a concentration of 250ppm. However, a concentration of Ca2+ (≥15ppm) was found to interfere with the detection of Al3+ in ground water. The interference was eliminated by passing the water through an anion exchange resin converted into oxalate form for the removal of the interferant as calcium oxalate precipitate in the resin phase. After this pre-treatment the linearity range in ground water was found to be 100–350ppb with R2=0.996 and LOD − 12.5ppb. The simplicity and rapidity of the developed method shows great potential in favour of its application for screening of drinking water samples to check its safety with respect to aluminium toxicity.

XANTHAN GUM AS A NOVEL FLOCCULANT AID EMPLOYED IN DRINKING WATER TREATMENT

Aluminum salts used for drinking water treatment are strongly related to environmental implications and health hazards. In order to reduce aluminum concentration in water and enhance the quality of the flocs formed, flocculant additives are employed. This paper evaluated polyaluminum chloride as coagulant in combination with xanthan gum as a novel flocculant to improve drinking water quality. Optimum results for color removal of 97.4 %, were observed with 5.0 ppm of polyaluminum chloride combined with 0.6 ppm of xanthan gum, prepared at 65 oC. Turbidity removal was complete with 5.0 ppm of polyaluminum chloride combined with xanthan gum solution, prepared at 65 oC in all evaluated concentrations. Moreover, PACl combined with xanthan gum at 0.6 ppm, prepared at 65 oC, enhanced the removal of other contaminants, which could improve posterior stages of water treatment, as filtration and disinfection, resulting in greater control of organic load and DBPs formation.

Geochemical controls on aluminium concentrations in coastal waters

Environmental context Aluminium may be released into coastal waters in dissolved and particulate forms from urban runoff, industrial discharges and acid sulfate soils. Aquatic organisms may experience toxic effects from exposure to dissolved and particulate aluminium. Therefore, the current study reports the geochemical controls such as speciation, precipitation and adsorption that influence the exposure to these aluminium forms in the field and the laboratory. Abstract A combination of field and laboratory investigations was conducted in order to gain an understanding of aluminium dynamics in coastal seawater environments. Filterable (<0.025 and <0.45µm) aluminium concentrations in waters collected from an industrialised coastal location at Gladstone, Central Queensland, Australia ranged from 0.8 to 39.4µgL–1. Size-based separation measurements made on field and laboratory-spiked coastal waters showed colloidal (>0.025 to <0.45µm) aluminium species were generally minimal, apart from one field sample collected close to a river mouth where aluminium was associated with iron-containing colloids. In seawater (pH 8.15, 22°C) spiked with small increments of aluminium so as not to attain supersaturation, the solubility limit was ~500µgL–1. However, at higher total aluminium concentrations the solution chemistry became highly dynamic. In the presence of aluminium precipitate it was not possible to measure a solubility limit over the 28-day duration of the experiment because the dissolved aluminium concentration varied with both reaction time and precipitate concentration. For instance, when seawater solutions were spiked with 10000µgL–1 of total aluminium, a pulse of dissolved aluminium up to 1250µgL–1 was sustained for several days before decreasing to below 100µgL–1 after 28 days. The initial precipitate appeared to be solely aluminium hydroxide and transformed over time to contain increasing magnesium, consistent with the formation of hydrotalcite (Mg6Al2CO3(OH)16·4H2O), reaching 21% of the precipitate mass after 28 days. Adsorption studies showed that at anticipated suspended particulate concentrations for coastal waters, natural particulate material has a fairly low affinity for dissolved aluminium. The results of the current study highlight the complex chemistry of aluminium in marine waters and the role of precipitation reactions.

Improvement of Coagulation Process for the Prut River Water Treatment using Aluminum Sulphate

The aim of presented research was to optimize the treatment process of the Prut River water. In order to realize the proposed goal, there were studied the following factors which can improve the process of coagulation: (i) the infl uence of stirring speed during coagulation and (ii) the infl uence of the concentration of the coagulant solution added in the process of coagulation. The optimal conditions of coagulation were established using the Jar-test method. Application of the recommended procedure contribute to the reduction of the coagulant dose, the contact time, the aluminum concentration in water and the expenses for water treatment.

Aluminium removal from water after defluoridation with the electrocoagulation process

Fluoride is the most electronegative element and has a strong affinity for aluminium. Owing to this fact, most of the techniques used for fluoride removal utilized aluminium compounds, which results in high concentrations of aluminium in treated water. In the present paper, a new approach is presented to meet the WHO guideline for residual aluminium concentration as 0.2 mg/L. In the present work, the electrocoagulation (EC) process was used for fluoride removal. It was found that aluminium content in water increases with an increase in the energy input. Therefore, experiments were optimized for a minimum energy input to achieve the target value (0.7 mg/L) of fluoride in resultant water. These optimized sets were used for further investigations of aluminium control. The experimental investigations revealed that use of bentonite clay as coagulant in clariflocculation brings down the aluminium concentration of water below the WHO guideline. Bentonite dose of 2 g/L was found to be the best for efficient removal of aluminium.

Bioaccumulation of Aluminium in Hydromacrophytes in Polish Coastal Lakes

Abstract The research on aluminium content was conducted in water and on aquatic flora of Polish lakes in the central part of the coast. The study included the lakes Sarbsko, Choczewskie, Bia.e, K.odno, D.brze and Salino investigated in the summer of 2013. The examined lakes belong mainly to the direct basin of the Baltic Sea. Samples of aquatic plants and lake waters were collected. In the water samples pH and electrolytic conductivity were measured. The aluminium content was determined both in water and aquatic plants. Submerged hydromacrophyte studies included Myriophyllum alterniflorum L., Potamogeton perfoliatus L. and Ceratophyllum demersum L. Emergent hydromacrophyte studies included Phragmites australis (Cav.) Trin. ex Steud., Juncus bulbosus L., Iris pseudacorus L., Eleocharis palustris (L.) Roem. % Schult., Phalaris arundinacea L., Carex riparia Curt., Mentha aquatic L., Stratiotes aloides L., Alisma plantago-aquatica L., Glyceria maxima (Hartman) Holmb., Sagittaria sagittifolia L., Scirpus lacustris L. and Typha angustifolia L. The purpose of this investigation was the determination of the aluminium content in submerged and emergent hydromacrophytes and also the definition of their bioaccumulative abilities. The average concentration of aluminium in water was 2.68 fęg Al dm.3. The average content of aluminium in plants was 2.8015 mg Al kg.1. The bioaccumulation factor ranged from BCF=19.74 to BCF=16619. On the basis of the analysis of the aluminium content in water and aquatic plants results show that both water and plants were characterized by a moderate level of aluminium. The recorded concentrations indicate a mid-range value and are much lower than those which are quoted for a variety of surface waters in various parts of the world.

Impacts of alum residues from Morton Jaffray Water Works on water quality and fish, Harare, Zimbabwe

Metal pollution of freshwater due to human activities is a major problem confronting most urban centres in developing countries. This study determined the extent to which aluminium in the residues from Morton Jaffray Water Works in Harare were affecting the water quality of Manyame River and Lake Manyame. The study also measured aluminium bioaccumulation in Nile Tilapia (Oreochromis niloticus) which is of importance to the commercial fisheries industry in Zimbabwe. Depth integrated water, and sediment grab samples and adult fish were collected per site in January and March, 2010. A total of six sites were selected on the Manyame River and in Lake Manyame. The levels of Total Aluminium (Al) were determined in sediments, water and fish tissues (liver, kidney, gill and muscle). Total solids, total dissolved solids, conductivity, pH, dissolved oxygen and temperature were also determined in water and residues. The texture of the sediments was also assessed. Aluminium concentration in water ranged from 2.19mg/L to 68.93mg/L during both sampling campaigns surpassing permissible maximum concentration limits of 0.087 to 0.75mg/L suggested by the Environmental Protection Agency and African Union. The site upstream of the discharge point of the residues always had the lowest levels though it was higher than acceptable levels indicated above, thus suggesting the existence of other sources of aluminium in the catchment besides Morton Jaffray Water Works. However, there was a 10-fold and 100-fold increase in levels of aluminium in water and sediments, respectively, at the site 100m downstream of the discharge point on the Manyame River. Mean aluminium concentrations in water and sediments at this site averaged 68.93±61.74mg/L and 38.18±21.54mg/L in water and 103.79±55.96mg/L and 131.84±16.48mg/L in sediments in sampling campaigns 1 and 2, respectively. These levels were significantly higher than levels obtained from all the other sites during both sampling campaigns (ANOVA: p<0.05). This also indicated that the contribution of aluminium pollution from the water works residues was higher than all the other sources in the catchment. Aluminium levels were generally in the order of; sediments>fish>water. Bioaccumulation occurred in the fish and the order of bioconcentration was; kidney>liver>gill>muscle. The amounts of aluminium in the fish tissues investigated were significantly higher (maximum=2.92mg/g) than was reported in other studies reviewed (maximum=0.18mg/g). Thus, the water treatment plant residues are greatly increasing the concentrations of aluminium in the water system downstream of the plant thus creating a great risk of aluminium toxicity for fish. Treatment of the residues before discharge, substitution of alum with other coagulants, and re-use of the residues in buffer strips, agricultural lands and in sewage works should be considered.

Aluminio en pacientes con terapia de reemplazo renal crónico con hemodiálisis en dos unidades renales en Bogotá

Determining aluminium concentrations in the serum of patients undergoing chronic renal replacement therapy with haemodialysis and concentration in distribution network water and dialysis in two renal units in Bogotá. This was a descriptive study of 63 haemodialysed patients and 20 healthy subjects. Aluminium concentration was determined in water and serum using graphite furnace atomic absorption spectrometry with deuterium lamp background corrector. Average aluminium concentration was 26.5 µg/L in patients (ranging from 11.2 to 49.2 µg/L; 8.03 standard deviation) and 8.05 µg/L in healthy individuals (ranging from undetectable to 17.2 µg/L; 4.31 standard deviation). Aluminium concentration in dialysis water and distribution network water was below 2 µg/L and 200 µg/L, respectively. Aluminium concentration in water and serum in this study was below international standard values, thereby indicating appropriate treatment. Additionally, aluminium concentration in pre-HD and post-HD sera was below that reported previously. Aluminium hydroxide uptake increases aluminium concentration in serum. Personal situation regarding age, gender, civil and work status were not risk factors determining aluminium concentrations in serum.

Aluminum Concentrations in Water of Elderly People’s Houses and Retirement Homes and Its Relation with Elderly Health

The purpose of this study was to determine the concentrations of aluminum (Al) and other metals in water samples from elderly people's houses and retirement homes. Forty-six duplicate water samples from kitchen taps were collected in Ribeirão Preto/SP, Brazil. Metal levels were measured by atomic absorption spectrophotometer. Aluminum concentration exceeded the maximum allowed values in 26% of samples according to the Decree 518/2004 of the Brazilian Health Ministry. It was noted that 11% of elderly living at monitored houses, as well as 19% living at retirement homes presented Alzheimer disease diagnostic. These results suggest taking into account Al risks among vulnerable elderly population groups.

The epidemiology of Alzheimer's disease in relation to aluminium.

The combination of an ageing population, an exponential increase in the incidence of dementing illness with age, and the high demands that demented patients place on health care resources makes Alzheimer's disease a major public health issue. So far, epidemiologists have made better progress in quantifying the frequency of the disease than in identifying strong risk factors, but evidence is accumulating to implicate environmental exposure to aluminium in the aetiology. The finding of a geographical correlation between death rates from dementia and water aluminium concentrations in Norway has since been replicated in several other surveys. Although ecological studies of this type should be interpreted cautiously, the association between Alzheimer's disease and aluminium in drinking water may prove to be an example of a potentially important biological effect of aluminium.

Inputs of iron, manganese and aluminium to surface waters of the Northeast Atlantic Ocean and the European continental shelf

Dissolved Fe, Mn and Al concentrations (dFe, dMn and dAl hereafter) in surface waters and the water column of the Northeast Atlantic and the European continental shelf are reported. Following an episode of enhanced Saharan dust inputs over the Northeast Atlantic Ocean prior and during the cruise in March 1998, surface concentrations were enhanced up to 4 nmol L − 1 dFe, 3 nmol L − 1 dMn and 40 nmol L − 1 dAl and returned to 0.6 nmol L − 1 dFe, 0.5 nmol L − 1 dMn and 10 nmol L − 1 dAl towards the end of the cruise three weeks later. A simple steady state model (MADCOW, [Measures, C.I., Brown, E.T., 1996. Estimating dust input to the Atlantic Ocean using surface water aluminium concentrations. In: Guerzoni. S. and Chester. R. (Eds.), The impact of desert dust across the Mediterranean, Kluwer Academic Publishers, The Netherlands, pp. 301–311.]) was used which relies on surface ocean dAl as a proxy for atmospheric deposition of mineral dust. We estimated dust input at 1.8 g m − 2 yr − 1 (range 1.0–2.9 g m − 2 yr − 1 ) and fluxes of dFe, dMn and dAl were inferred. Mixed layer steady state residence times for dissolved metals were estimated at 1.3 yr for dFe (range 0.3–2.9 yr) and 1.9 yr for dMn (range 1.0–3.8 yr). The dFe residence time may have been overestimated and it is shown that 0.2–0.4 yr is probably more realistic. Using vertical dFe versus Apparent Oxygen Utilization (AOU) relationships as well as a biogeochemical two end member mixing model, regenerative Fe:C ratios were estimated respectively to be 20 ± 6 and 22 ± 5 μmol Fe:mol C. Combining the atmospheric flux of dFe to the upper water column with the latter Fe:C ratio, a ‘new iron’ supported primary productivity of only 15% (range 7%–56%) was deduced. This would imply that 85% (range 44–93%) of primary productivity could be supported by regenerated dFe. The open ocean surface data suggest that the continental shelf is probably not a major source of dissolved metals to the surface of the adjacent open ocean. Continental shelf concentrations of dMn, dFe, and to a lesser extent dAl, were well correlated with salinity and express mixing of a fresher continental end member with Atlantic Ocean water flowing onto the shelf. This means probably that diffusive benthic fluxes did not play a major role at the time of the cruise.

Plasma aluminium: a redundant test for patients on dialysis?

Aluminium toxicity as a cause of dementia, osteodystrophy and anaemia in patients receiving renal dialysis was first described in the 1970s and led to the regular monitoring of aluminium in plasma and dialysate water. However, aluminium phosphate binders have now been replaced by calcium-based binders or sevelamer and reverse osmosis (RO) water is used in the preparation of dialysate fluid. This has reduced the exposure of dialysis patients to aluminium and it is therefore opportune to review aluminium monitoring in patients undergoing regular renal dialysis. Plasma and water aluminium results were audited over the period January 2000-January 2004, with results obtained from nine renal dialysis units in the UK. Patients with a plasma aluminium concentration in the toxic range (>3.7 micromol/L) were followed up by contacting the relevant consultant. Plasma aluminium results were collected on 1626 patients over the four-year period (mean=0.47 micromol/L, median=0.3 micromol/L, range 0.07-30.26 micromol/L, n=5918). Forty-six patients had an aluminium concentration >3.7 micromol/L and nine were not retested. Only three patients had a repeat aluminium concentration >2.2 micromol/L, one being a result of desferrioxamine treatment, with no further clinical information available on the other two. All renal units are using RO water to prepare dialysate and aluminium-based phosphate binders are no longer prescribed. Only one of 212 RO water aluminium concentrations measured was >10 microg/L. Patients with clinical symptoms of overt aluminium toxicity were not identified in this population. The role of aluminium monitoring in long-term renal dialysis patients needs re-evaluation. Regular monitoring of plasma aluminium may not be required, but should be considered in any patient showing signs or symptoms of aluminium toxicity or exposed to a contaminated water supply. It is more important that RO water supplies are maintained and monitored. Environmental aluminium as a source of sample contamination should be considered and eliminated during blood collection and sample processing.

Nitrogen additions (NaNO 3 and NH 4NO 3) at Aber forest, Wales: I. Response of throughfall and soil water chemistry

Nitrogen was sprayed weekly onto the forest floor of a Sitka spruce stand for 2.5 years in a replicated block design experiment to investigate the impacts of chronic atmospheric nitrogen deposition, in both oxidised and reduced form, on these ecosystems. The nitrogen was applied as sodium nitrate at 35 or 75 kg N ha −1 year −1 and as ammonium nitrate at 35 kg N ha −1 year −1, and the response of the throughfall and soil water chemistry determined. The response to increased water availability was also determined in a zero-N treatment. Increased water availability resulted in decreased concentrations of ammonium and phosphate and increased hydrogen ion concentration in the throughfall above the height of the spray, indicating tree growth is limited by water at this site. No effect of increased nitrogen availability on throughfall or stemflow chemistry above that of the water response was observed. Ambient nitrogen inputs in throughfall plus stemflow were 17 kg N ha −1 year −1 of which 11 kg N ha −1 year −1 was leached. Retention capacity of additional nitrogen applied to the forest floor was found to differ for nitrate-N and ammonium-N. There was no retention capacity for incoming nitrate-N but 100% retention capacity for applied ammonium-N. Nitrate leaching losses increased in parallel with nitrate inputs and were independent of ammonium addition. There was no apparent transformation of ammonium to nitrate in the ammonium nitrate treatment. Total dissolved nitrogen losses were therefore lower in the ammonium nitrate 35 kg N ha −1 year −1 treatment relative to the sodium nitrate 35 kg N ha −1 year −1. As the soil exchange complex is dominated by aluminium, the increase in salt loading and lack of nitrate retention in both treatments was associated with increased soil water aluminium concentrations due to ion exchange between the incoming sodium or ammonium ions and aluminium on the soil exchange complex. No increase in soil water concentrations of any other cation, with exception of sodium in the sodium nitrate treatments, was observed. These findings suggest that any increase in nitrate deposition will result in increased nitrate and aluminium leaching at this site which can perhaps best be described as ‘nitrate saturated’. Elevated ammonium deposition will also result in increased aluminium leaching if accompanied by a mobile anion. More long term monitoring is required to evaluate these changes in soil water chemistry on tree vitality and the internal nitrogen cycle.

Leaching of aluminium from aluminium dishes and packages.

A study was carried out of the leaching of aluminium from aluminium cooking vessels and packages. Very small or undetectable levels of aluminium leached from packaging materials into foodstuffs. In boiling tests with neutral porridge no migration of aluminium into the test matrix was observed from the pan. When boiling milk, the leaching of aluminium was 0.2-0.8 mg/kg. The aluminium content of tap water in aluminium pans when reaching boiling point was 0.54-4.3 mg/l and increased with increasing boiling time to 6.3-17 mg/l. Aluminium dissolved in foods based on acidic fruit juice rose to levels of 2.9-35 mg/kg when the foods were boiled in aluminium pans. Steaming of currant berries in an aluminium vessel gave aluminium concentrations of 19-77 mg/kg in the resulting juice. The highest aluminium concentration of 170 mg/kg was measured in rhubarb juice prepared in the steaming vessel. Aluminium dissolved in water to levels of 0.81-1.4 mg/l when heated for the first time in new coffee percolators. The aluminium concentration of water heated in older percolators was 0.09-0.78 mg/l.