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Bioaccumulation: aquatic / sediment

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Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
GLP compliance:
not specified
Test organisms (species):
other: the fish species Channa marulius, Mystus seenghala and Wallago attu
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
Significant differences were observed among the three carnivorous fish species for the acute toxicity of metals, in terms of 96 h LC and lethal concentration values. Al was found more toxic to all the fish species than Co. During 96 h-LC50 and lethal concentrations exposure, C. marulius exhibited higher propensity to accumulate both the metals in its body than W. attu and M. seenghala. All these carnivorous fish species showed a greater tendency to concentrate the metals in liver followed by the kidney, gills, heart, gut, intestine, bones and skin and the lowest in their muscles.
Executive summary:

The acute toxicity of aluminum (Al) and cobalt (Co), in terms of both 96 h LC50 and lethal concentrations, was determined for three fish species viz. Channa marulius, Mystus seenghala and Wallago attu under controlled laboratory conditions. The experiments were performed at constant water temperature (28oC), pH (8) and total hardness (250 mg L-1). At the end of toxicity trials, the dead fish were dissected, digested and then analyzed for respective exposure metal’s concentrations in various body organs viz. gills, liver, kidney, heart, gut, intestine, muscles, bones and skin. There existed statistically significant variations at p<0.05 among the three fish species toward Al and Co acute toxicities (96 h LC50 and lethal concentrations) that followed the order: C. marulius>W. attu>M. seenghala. Statistically all the three species of fish were found more sensitive to Al than Co toxicity. During acute concentrations exposure, C. marulius exhibited significantly higher potential to accumulate Al and Co in its body followed by W. attu and M. seenghala. At both 96 h LC50 and lethal concentration exposures, all the three carnivorous fish species had significantly (p<0.05) higher tendency to concentrate both metals in their liver, followed by the kidney, gills, heart, gut, intestine, bones and skin. However, they exhibited significantly lower Al and Co concentrations in their muscles. The overall accumulation pattern of metals in the bodies of all three carnivorous fish species followed the order: Co>Al.

Endpoint:
bioaccumulation in aquatic species: aquatic plant
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
GLP compliance:
not specified
Test organisms (species):
other: Ceratophyllum demersum
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
Ceratophyllum demersum was tested for the bioaccumulation of metals (Al, Cu, Zn) over a 5 week period under laboratory conditions. Contrary to how many other experimental exposure studies on aquatic plants were done, as seen in the literature, the water was contaminated once off in the beginning of the experiments to simulate a “pollution event”. The 5 week exposure period was also longer than in most other studies in order to investigate variability over time. This macrophyte proved highly effective in the accumulation of these metals at all four exposure concentrations. The results showed that concentrations of the metals in the water varied in all treatments over time with no specific patterns emerging amongst the treatment groups. The metal concentrations in the plants were much higher compared to the metal concentrations in the water. The metal bioaccumulation in C. demersum was also variable between consecutive weeks per treatment and between consecutive treatments per week over a five week exposure period. This may be due to C. demersum being able to regulate Al, Cu, and Zn throughout the exposure period. The plant accumulated metals in the order: Zn>Al>Cu. The results show that metals are bioaccumulated quickly by C. demersum after the water is contaminated with metals, i.e. after the “pollution event”. However, over time, metals are continuously exchanged between the plants and the water, accounting for the fluctuations in metal concentrations observed over time. Therefore, the authors are of the opinion that should this species be used as a phytoremediator, the plants need to be removed from the contaminated water a week or two after the pollution event. It may be necessary to replace remediator plants until the metal levels are reduced to acceptable concentrations in the contaminated water. Further research is required on the use of C. demersum as a phytoremediator.
Executive summary:

Metal pollution is of major concern because metals can be bioaccumulated in aquatic organisms and have high toxicity. Metal concentrations can be increased along the food chain and could potentially threaten environmental and human health. As the coontail (Ceratophyllum demersum L.) is rootless, it is advantageous for use in laboratory bioassays as this would eliminate the complication of soil-root- continuum and shoot-root metal partitioning. It thus has the potential to be a suitable model for investi- gating metal stress in plants. The research objective was to determine the degree of Al, Cu and Zn bioac- cumulation in C. demersum L. after exposure to a metal cocktail in a simulated “pollution event” under laboratory conditions over a five week exposure period. Plants were divided into four experimental treatment groups, each with different exposure concentrations of Al (AlSO4), Cu (CuSO4) and Zn (ZnSO4) in mixture. A fifth uncontaminated group of plants served as the control. Aluminium, Cu and Zn concentrations were determined in water and plant samples by means of nitric acid digestion and ICP- MS analysis. This macrophyte proved highly effec- tive in the accumulation of these metals at all four exposure concentrations. The results showed that concentrations of the metals in the water varied in all treatments over time with no specific patterns emerging amongst the treatment groups. The metal bioaccumulation in C. demersum was also variable between consecutive weeks per treatment and be- tween consecutive treatments per week. This may be due to C. demersum being able to regulate Al, Cu, and Zn throughout the exposure period. The plant accumulated metals in the order: Zn>Al>Cu.

Endpoint:
bioaccumulation in aquatic species: aquatic plant
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
GLP compliance:
not specified
Test organisms (species):
other: plants, not specified
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
1. The pHs of the waters in the two rivers were close to neutral and did not stimulate the growth in aluminium concentrations.
2. The aluminium concentration in aquatic plants was relatively low and typical of environments subject to weak anthropopressure.
3. The aluminium concentrations in the two rivers covered by the study do not pose any danger to the environment of Western Pomerania or to the areas they flow through before feeding into the Baltic Sea.
4. There was no effect of the aluminium content in the water and sediments on the level of aluminium in aquatic plants.
Executive summary:

The study covered the aquatic environment of two small rivers in Western Pomerania, Poland, such as the Czerwona and the Grabowa. Its purpose was to determine aluminium bioaccumula- tion in the aquatic environment by testing water, bottom sediments and aquatic plants. Samples were taken in the summers of 2008-2011. pH, electrolytic conductivity and aluminium concen- tration were determined in water samples, while the sediment and plant samples were submitted to analyses of the aluminium content. The water pH oscillated between 6.04 and 8.95, while the electrolytic conductivity ranged from 440 to 1598 μS cm-1. The aluminium concentration in the river water was up to 0.138 mg Al dm-3 in the Czerwona and up to 0.425 mg Al dm-3 in the Grabowa. The maximum aluminium content in the bottom sediments was 47.01 mg Al kg-1 in the Czerwona River and 26.15 mg Al kg-1 in the Grabowa River. The maximum aluminium con- tent in the aquatic plants sampled from the Czerwona was 91.63 mg Al kg-1, and from the Gra- bowa – 1,077 mg Al kg-1. The bioconcentration factor (BCF) of aluminium for the Czerwona River ranged from 5.06 to 24,052, and for the Grabowa River – from 1.10 to 70,132. The concentration factor (CF) of aluminium in the bottom sediments oscillated between 66.72 and 23,492 in the Czerwona River and between 14.81 and 2,763 in the Grabowa. The aluminium content in the two rivers was relatively low in the water, sediments and aquatic plants, which is typical of environments without strong anthropopressure. The values fell within the limits set by environmental water quality standards. The low aluminium accumulation degrees in the biotic and abiotic components indicate that the environments of the two rivers have a low load of aluminium compounds.

Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
GLP compliance:
not specified
Test organisms (species):
other: Geophagus brasiliensis
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
The level of metal in water of the reservoir was lower than the maximum set forth in the legislation, except for that of Cd and Fe. In sediments, Cu, Cd, Cr, and Ni presented concentrations above the TEL. The Pb and Cr concentrations were above the limits set forth in the law for fish consumption by human beings. Al and Zn presented high concentrations in all tissues and on the superficial sediment. In the gills, the Fe presented a high concentration in relation to the other tissues. The liver presented higher affinity for bioconcentration of metals than the muscle and higher affinity for the bioconcentration of Cu, Co, Cd, Cr, Ag, and Ni than the G. brasiliensis gills. Regarding bioaccumulation, the liver has higher affinity than the muscle and also higher affinity for the bioaccumulation of Cu, Co, Cd, Cr, Ag, Pb, Ni, and As than the gills. Therefore, the liver is the tissue with the highest tendency to bioconcentrate and bioaccumulate metals in G. brasiliensis. The statistical analysis did not identify substantial differences in the levels of metal concentration between the body weight, size (length), and genre of the species and the three tissues under analysis.
Executive summary:

From the concentration in water and sediments, bioconcentration and bioaccumulation of copper (Cu), man- ganese (Mn), zinc (Zn), iron (Fe), cobalt (Co), cadmium (Cd), chrome (Cr), silver (Ag), lead (Pb), nickel (Ni), aluminum (Al), and arsenic (As) were determined in the gills, liver, and muscles of Geophagus brasiliensis in the Alagados Reservoir, Ponta Grossa, Paraná, Brazil. Metals were quantified through AAS, and a study was carried out on the existing relations between metal and body weight, size, and genre of this species. The level of metal in the water of the reservoir was lower than the maximum set forth in the legislation, except for that of Cd and Fe. In sediments, Cu, Cd, Cr, and Ni presented concentrations above the threshold effect level (TEL). Pb and Cr were above the limits for the G. brasiliensis. The tendency of metals present in the muscles of G. brasiliensis was Al> Cu>Zn>Fe>Co>Mn>Cr>Ag>Ni>Pb>Cd>As. In the gills, it was Al>Fe>Zn>Mn>Co>Ag>Cr>Ni>Cu>As> Pb>Cd, and the liver presented Al>Cu>Zn>Co>Fe>Mn> Pb > Ag > Ni > Cr > As > Cd. The bioconcentration and bioaccu- mulation of metal in the tissues follow the global tendency liver > gills > muscle. The statistical analysis did not point to significant differences in the metal concentration and body weight, size, and gender of the species in the three tissues under analysis.

Endpoint:
bioaccumulation in aquatic species, other
Remarks:
sela, zooplankton, fish
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Scientific research paper, following scientifically acceptable method and procedures which were outlined in the publication.
GLP compliance:
not specified
Test organisms (species):
other: zooplankton, fish and seals
Route of exposure:
aqueous
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
Aluminium concentrations were measured in livers of Baikal seal, zooplankton, and fish, constituting the food source for the seals. The aluminium concentration ranges were as follows: for Baikal seal the minimum-maximum values <1.0-5.7 mg/kg dry wt., for fish the average values ranged between 1.6-13.9 mg/kg wet wt. The dominant species of zooplankton contained 70.6 mg Al/kg wet wt. The results show that there is no biomagnification of aluminium at a lower trophic link (plankton- fish: BMF<0.2.).
Executive summary:

Concentrations of Al, Ba, Cd, Cu, Fe, Mn, Mo, Si, Sr, Zn, Ca, K, Mg, Na and P in the livers of Baikal seal, plankton, zoobenthos, and fish, constituting the food sources for the seals, were determined by ICP-MS and ICP-AES. The accumulation of elements in the liver of seals, affected by internal and external (environmental) factors, was assessed by multidimensional (ANOVA, FA) and correlation analyses. FA has enabled identification of abiotic and biotic factors responsible for the accumulation of elements in the livers of Baikal seals. Significant influence of sex and development stage of the seals analysed on hepatic concentrations of some elements was found. The observed differences in element concentrations between pups, males and females could be attributable to the reproductive cycle of this species. ANOVA showed differences in concentrations of Fe, Zn, Cu and Cd in seals from the three separate basins of the lake. BMFs suggest biomagnification of Fe and Zn in the fish-seal trophic link.

Endpoint:
bioaccumulation in aquatic species, other
Type of information:
other: US-EPA issue paper on metal bioaccumulation
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
no guideline required
Principles of method if other than guideline:
Scientific research paper, based on existing and/or field measurements, following scientifically acceptable methods and procedures
GLP compliance:
not specified
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
Organisms have eveolved in the presence of metals, and in many cases they have developed appropriate strategies of metal metabolisation (homeostasis) when concentrations exceed those normally encountered by the organism.
Executive summary:

Bioaccumulation in the aquatic environment

 

Biota have developed and evolved in the presence of metals and therefore have developed a capability to deal with accumulations of metal, at least to some degree. For elements that are not essential nutrients, this capability removes and sequesters potentially toxic species from sites of action. For essential elements, removal and sequestration processes that minimize toxicity are complemented by an ability to regulate concentrations for essentiality. As a result, concentrations of essential mineral nutrients in organisms tend to be highly regulated compared to non-essential elements.

The mechanisms of reducing metal accumulation and toxicity vary with the organism and include inhibiting uptake, detoxification, and storage and increasing elimination. In general, higher animals such as fish tend to show relatively more sophistication in this regard compared to aquatic invertebrates. The homeostatic mechanisms result in a negative correlation between BCF (or BAF) and exposure concentrations. At the lowest exposure concentrations the BCF values are highest and as concentrations increase BCF values fall. Depending on the organism, type of metal and exposure concentration, BCFs can range from less than 1 to over 106 in aquatic organisms, making representative single value BCF for a metal meaningless. While elevated BCF/BAF values have been measured and while they may provide for a simplified measure of bioaccumulation, linkages between BCF/BAF measures and detrimental impacts are generally lacking, making their use in a regulatory context problematic.

 

Biomagnification of metals in aquatic organisms is rare and is most evident for methyl mercury (which behaves more like an organic contaminant) and radiocesium.

Endpoint:
bioaccumulation in aquatic species, other
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline required
Principles of method if other than guideline:
Scientific research paper, following scientifically acceptable method and procedures which were outlined in the publication.
GLP compliance:
not specified
Test organisms (species):
other: Lymnaea stagnalis
Route of exposure:
aqueous
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach

 Type of tissue  H2O (µg Al/L)  Tissue concentration (µg/g dry wt)
 Whole soft tissue  234 -285  800 -1400
 Gut  78 -285  1500 -4100
 Digestive gland  234 -285  1600 -3000
 Kidney  234 -285  4100 -7500
Conclusions:
The accumulation of aluminium by the freshwater snail Lymnaea stagnalis at neutral pH was examined, when most aluminium would be predicted to be in an insoluble form as Al(OH)3. The concentrations of aluminium in various body organs during a 30-day exposure period and 20-day recovery period were measured to investigate differential distribution of the metal during uptake and excretion. Significant accumulations in the whole soft tissues of L. stagnalis were observed at all concentrations of added aluminium.
Executive summary:

This study examined the accumulation of aluminium (Al) by the freshwater snail Lymnaea stagnalis at neutral pH, when most Al would be predicted to be in an insoluble form (Al(OH)3). Snails were exposed to a range of Al concentrations (38–285 μg/L) for 30 days, followed by 20 days in clean water. Aluminium was measured using atomic absorption spectroscopy.

Significant accumulation of Al occurred in the whole soft tissues, gut, digestive gland and kidney at the latest by day 10. High concentration factors were observed, ranging from 4.5 × 103in the whole soft tissues to 6.3 × 104in the kidney, corresponding to actual concentrations of 800 to 7500 μg g−1, respectively. Proportionality between environmental (water) and tissue concentrations of Al was observed in the gut but not in the other tissues. Following transfer to clean water, rapid loss of Al from the whole soft tissues and gut was seen over the first 10 days. Loss of Al from the digestive gland was much less as a proportion of the total, with approximately 90% of the Al remaining in the tissue. In contrast, significant loss of Al from the kidney occurred between days 20 and 30, even in the continued presence of Al; little further loss occurred following transfer to clean water.

Aluminium is clearly available to the snail at neutral pH, the most likely route of entry being the gut. This could facilitate entry of the metal into the food chain. The possible roles of the digestive gland and kidney in the handling of Al are discussed.

Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Scientific research paper, following scientifically acceptable method and procedures which were outlined in the publication.
GLP compliance:
not specified
Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Route of exposure:
aqueous
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
The accumulation of dietary aluminium by rainbow trout Oncorhynchus mykiss was studied at high exposure concentrations (10 g Al/kg dry wt.) during 42 days. The exposure concentration was much higher than that found in invertebrate food species in the wild (1-4.9 mg/g dry wt.; Wren and Stephenson, 1991), and therefore represents an exposure situation unlikely to be exceeded in the environment. The study suggests that trout can accumulate aluminium across the gut, but bioavailability is low since only 1% or less of the total dose is retained by the fish. The absence of marked toxicity and the relatively limited dietary uptake of aluminium at the reported doses, suggest that transfer of aluminium through the food chain will be limited.
Executive summary:

A high oral concentration of 10 g Al/kg dry weight promoted toxicant accumulation in the muscle, gill, liver, kidney and mucus of trout. One mortality occurred and only a small proportion of the exposure dose was retained by the fish. The limited acute oral toxicity of Al implies that contamination levels found in food species are unlikely to be acutely toxic to wild trout.

Endpoint:
bioaccumulation in aquatic species: invertebrate
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Scientific research paper, following scientifically acceptable method and procedures which were outlined in the publication.
GLP compliance:
not specified
Test organisms (species):
Daphnia magna
Route of exposure:
aqueous
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
Water fleas (Daphnia magna) were exposed to total aluminium concentrations of 0.02, 0.32 and 1.02 mg/L for 24 h. Bioconcentration was related to pH with, the highest accumulation occurring at pH 6.5 and the lowest accumulation at pH 4.5.
Executive summary:

Aluminum may be either harmful or beneficial to Daphnia magna (Straus) depending on pH and on the Al concentration in the water. My results are based on laboratory experiments conducted at various concentrations of total Al (0.02–1.02 mg/L) in soft water (2.5 and 12.5 mg Ca/L) adjusted from pH 6.5 to 4.5. Maximum Al toxicity and maximum Al bioaccumulation were observed at pH 6.5 (at and above 0.32 mg total Al/L). At lower pHs, H+ was toxic to D. magna. Aluminum (1.02 mg/L) temporarily ameliorated H+ toxicity at pH 4.5. Calcium reduced H+ toxicity at pH 5.0 and Al toxicity at pH 6.5. Mortality in the presence of Al and also at low pH was associated with a net loss of Na and Cl from the daphnids. The Ca content of the daphnids was highly variable and showed no consistent pattern apart from a negative correlation with the Al content of the daphnids at pH 5.0 and 5.5. The 24-h bioconcentration ratio for Al was 10 000 at pH 6.5,4000 at pH 5.0, and negligible at pH 4.5. The rapid uptake of Al, particularly at circumneutral pHs, may be an additional source of Al for zooplanktivorous fish and other predators.

Endpoint:
bioaccumulation in aquatic species: invertebrate
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Scientific research paper, following scientifically acceptable method and procedures which were outlined in the publication.
GLP compliance:
not specified
Test organisms (species):
other aquatic crustacea: Asellus aquaticus, Nemoura sp, Isoperla grammatica, Plectrocnemia conspersa, Rhyacophila nubila.
Route of exposure:
aqueous
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
The accumulation of aluminium at low pH conditions in benthic invertebrates representing different functional feeding groups (predators and detritus feeders) was studied in this publication. Invertebrates of different taxa and feeding type were collected in the spring, when acidity and aluminium levels mostly increase, from seven streams in southern Sweden. Four of the streams typically had pH values of 4 - 4.5 and contained 0.40 - 0.70 mg inorganic A1/l. The other three streams showed pH values around 6 and aluminium concentrations of 0.05 mg inorganic A1/L. For most taxa that could be compared, the species from the most acidic streams (pH 4) contained more aluminium than those from less acidic streams (pH 6). At both pH levels there was a clear tendency that predators contained significantly lower amounts of aluminium than shredders, which does not support the hypothesis that aluminium can be accumulated along a food chain in an acidic environment.
Other experiments reported in this publication were related to caddisfly and mayfly nymphs moulting in waters of different hydrogen ion and aluminium ion concentrations. Data indicated that most aluminium is probably deposited on, or in, the exuviae and thus is shed before the emergence of the winged insects (Otto and Svensson, 1983; Frick and Hermann, 1990). This suggests that a transfer of aluminium into terrestrial environments via this route is generally not an important phenomenon.
Executive summary:

Acidified surface waters often show elevated aluminium (Al) levels, detrimental to fish and some invertebrates. Whether Al can accumulate in benthic invertebrates, with time and/or along the food chain, is not clear. To test this, benthic invertebrates, representing different functional feeding groups, were collected in spring from streams, with different acidity and Al concentrations. Weight-specific Al content was determined with an AAS. At localities with pH ≈ 4, high Al contents (≈ 1 mg inorg-Al g−1af dw) were found in shredders and/or deposit feeders (Asellus aquaticus, Nemoura sp., and limnephilids), while the predator Isoperla grammatica contained only ≈ 0.3 mg Al g−1, and the “filtering predator" Plectrocnemia conspersa almost no Al. Also at pH ≈ 6Nemourasp. and limnephilids showed significantly higher Al contents than did the predators Isoperla grammatica and Rhyacophila nubila, Al concentrations of the animals were often higher at pH 4 than at pH 6. Thus, no evidence of any food chain accumulation (or biomagnification) of Al could be validated. Accordingly, this study gives no support that the high concentrations of Al in fish and birds are due to their feeding on benthic invertebrates at low pH conditions. It was also found that animals that inhabit and/or consume benthic detritus as food contain highest Al levels.

Endpoint:
bioaccumulation in aquatic species: invertebrate
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Scientific research paper, following scientifically acceptable method and procedures which were outlined in the publication.
GLP compliance:
not specified
Test organisms (species):
other: Orconectes virilis
Route of exposure:
aqueous
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
Crayfish (Orconectes virilis) from a lake with an average total aluminium concentration of 36 µg/L were placed in caged tubes spiked with 40 µg/L total aluminium. The crayfish were transferred to a lake with background levels of 8 µg/L total aluminium. Half of the tubes were acidified to pH 5.3 and the others remained at pH 6.7. None of the crayfish accumulated aluminium. The same authors also carried out a laboratory experiment with crayfish obtained from the original lake. Crayfish were maintained in a solution of 500 µg/L for 14 days. No tissues showed an increase in aluminium concentration.
Endpoint:
bioaccumulation in aquatic species, other
Type of information:
other: review assessment, based on existing data
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
no guideline required
Principles of method if other than guideline:
Scientific research paper, based on existing and/or field measurements, following scientifically acceptable methods and procedures
GLP compliance:
not specified
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
It has been demonstrated that - unlike many organic substances - the BCF/BAF is not independent of exposure concentrations for many metals. Rarther it is inversely related to exposure concentrations (decreasing BCF/BAF with increasing exposure concentrations)
Executive summary:

The bioconcentration factor (BCF) and bioaccumulation factor (BAF) are used as the criteria for bioaccumulation in the context of identifying and classifying substances that are hazardous to the aquatic environment. The BCF/BAF criteria, while developed as surrogates for chronic toxicity and/or biomagnification of anthropogenic organic substances, are applied to all substances including metals. This work examines the theoretical and experimental basis for the use of BCF/BAF in the hazard assessment of several metals (Zn, Cd, Cu, Pb, Ni, and Ag). As well, BCF/BAFs for Hg (methyl and inorganic forms) and hexachlorobenzene (HCB) were evaluated.

The BCF/BAF data for Zn, Cd, Cu, Pb, Ni, and Ag were characterized by extreme variability in mean BCF/BAF values and a clear inverse relationship between BCF/BAF and aqueous exposure. The high variability persisted when even when data were limited to an exposure range where chronic toxicity would be expected. Mean BCF/BAF values for Hg were also variable, but the inverse relationship was equivocal, in contrast with HCB, which conformed to the BCF model. This study illustrates that the BCF/ BAF criteria, as currently applied, are inappropriate for the hazard identification and classification of metals. Furthermore, using BCF and BAF data leads to conclusions that are inconsistent with the toxicological data, as values are highest (indicating hazard) at low exposure concentrations and are lowest (indicating no hazard) at high exposure concentrations, where impacts are likely. Bioconcentration and bioaccumulation factors do not distinguish between essential mineral nutrient, normal background metal bioaccumulation, the adaptive capabilities of animals to vary uptake and elimination within the spectrum of exposure regimes, nor the specific ability to sequester, detoxify, and store internalized metal from metal uptake that results in adverse effect.

An alternative to BCF, the accumulation factor (ACF), for metals was assessed and, while providing an improvement, it did not provide a complete solution. A bioaccumulation criterion for the hazard identification of metals is required, and work directed at linking chronic toxicity and bioaccumulation may provide some solutions.

Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Scientific research paper, following scientifically acceptable method and procedures which were outlined in the publication.
GLP compliance:
not specified
Test organisms (species):
other: non-specified fish species
Route of exposure:
aqueous
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
This study is part of the evidence that documented the accumulation of waterborne aluminium exposure in fish (in/on the gills and surface mucus), while internal organs have been uncontaminated
Executive summary:

Results are presented from an experiment designed to investigate the deposition of Al species onto fish gills following the mixing of limed and acidic natural waters. The natural waters were labelled with 26Al and the distribution between high and low molecular weight forms was determined by ultrafiltration of water samples. In labelled acidic waters, the 26Al was present predominantly in low molecular weight forms, whereas in labelled limed waters the major fraction of 26Al was present in a high molecular weight form. In mixing experiments, 26Al was only detectable on fish gills when the 26Al was initially present in a low molecular weight form (i.e., in labelled acidic waters). Aluminium-26 was not detected on the gills of fish exposed to labelled limed waters. These results support the hypothesis that Al on fish gills arises from polymerization of low molecular weight species and that, within mixing zones, the high molecular weight species do not play a significant role in the precipitation of Al onto the gill surface.

Endpoint:
bioaccumulation in aquatic species: algae / cyanobacteria
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Scientific research paper, following scientifically acceptable method and procedures which were outlined in the publication.
GLP compliance:
not specified
Test organisms (species):
other: phytoplankton (not specified)
Route of exposure:
aqueous
Nominal and measured concentrations:
Al-concentrations ranged from undetectable (<10 µg/L) to a seasonal high of 104 µg/L. Concentrations of this element were high during the early part the year, and low (typically <20 µg/L) during most of the stratified period.
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach

Over the annual cycle, concentrations of Al in phytoplankton biomassranged from 1 to 15 mg/g dry weight (carbonate digestion) and 1 to 15 mg/g (total Al). The patterns for concentrations of carbonate and total digestion were broadly similar, suggesting that bound Al is always a substantial proportion of the total. The monthly sequence of Al concentrations did not fit a seasonal pattern in relation to stratification, but did relate to the peaks of diatom population that occurred in April and October. On both these dates the concentrations of bound and total Al were at annual minima of <1 and <2 mg/g, respectively. The fraction of Al occurring in bound form (carbonate/total Al) had an annual mean value of 43%. This bound Al varied considerably in relation to dominant algal population being low at times of high diatom population in April (31%) and October (9%) and high during the major bloom of colonial blue-green algae in July–September (71%).

Al-Log BAF (annual; total and acid digest): 5

Al-Log BAF (april-november ; stratification period; total and acid digest): 4.8

 Month Group  Total biovolume (%)  Main genera  Mean total Al (mg/g)  Bound element (%) 
 April  Diatoms  88

Asterionella, Cyclotella,

Aulacoseira, Stephanodiscus

 1.5  31
 June  Blue-green  95 Anabaena, Aphanizomenon  12.6  25
July   Blue-green  85 Anabaena, Aphanizomenon  3.3  62
 August  Blue-green 98  Anabaena, Gomphosphaeria  4.1  71
 September  Blue-green 97  Anabaena, Gomphosphaeri  3.0  71
 October  Diatoms  43  Aulacoseira, Stephanodiscus  2.0
 October  Blue-green  56  Anabaena, Microcystis  2.0
           
Conclusions:
Seasonal aluminium, silicon and transition metal (Mn, Fe, Ni and Cu) concentrations were measured in lake water and phytoplankton within an unpolluted lake, Rostherne, Mere, UK. Concentrations of aluminium in Epilimnion Lake water samples showed considerable seasonal variation. In the case of aluminium, concentrations ranged from undetectable (<10 µg/L) to a seasonal high of 104 µg/L. Concentrations of aluminium were high during the early part the year, and low (typically <20 µg/L) during most of the stratified period. Data show that phytoplankton biomass accumulates levels of aluminium, silicon and transition metals, irrespective of taxonomic composition. Over an annual cycle, concentrations of aluminium in phytoplankton biomass ranged from 1 to 15 mg/g dry wt.
Executive summary:

This study was carried out to monitor and relate seasonal Al, Si and transition metal (Mn, Fe, Ni and Cu) concentrations in lake water and phytoplankton within an unpolluted lake. Lake water concentrations of Al and Mn showed seasonal (high winter–low summer) variation. The clear annual correlation pattern had significant links among transition metals, but not Si–Al. Within phytoplankton biomass, separate analyses of acid (soluble) and carbonate (insoluble) constituents showed that most elements (Si, Ni, Cu and Fe) occurred in bound form, but insoluble Al and Mn concentrations were <50% total. Diatom abundance was characterised by high Si and low Al biomass concentration, with substantial amounts of Si also occurring during phases of blue-green dominance. The elemental correlation pattern of phytoplankton acid digests (soluble material) was different from carbonate digests, which had significant correlations among the three transition metals (Mn, Ni, and Cu)—but no relationships involving Si, Al and Fe. Data show that phytoplankton biomass accumulates high levels of Al, Si and transition metals, irrespective of taxonomic composition. The different correlation patterns seen for aquatic, soluble biomass and insoluble biomass elemental concentrations indicate that external availability, soluble uptake and insoluble deposition are distinct aspects of the pelagic ecosystem.

Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
other: review publication
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
no guideline followed
Principles of method if other than guideline:
Scientific review paper, discussing data on metal bioavailability and toxicity in low-alkalinity lakes
GLP compliance:
not specified
Test organisms (species):
other: non-specified fish species
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
This study is part of the evidence that documented the accumulation of waterborne aluminium exposure in fish (in/on the gills and surface mucus), while internal organs have been uncontaminated
Executive summary:

Fish in low-alkalinity lakes having pH of 6.0-6.5 or less often have higher body or tissue burdens of mercury, cadmium, and lead than do fish in nearby lakes with higher pH. The greater bioaccumulation of these metals in such waters seems to result partly from the greater aqueous abundances of biologically available forms (CH(3) Hg(+), Cd(2+), and Pb(2+)) at low pH. In addition, the low concentrations of aqueous calcium in low-alkalinity lakes increase the permeability of biological membranes to these metals, which in fish may cause greater uptake from both water and food. Fish exposed to aqueous inorganic aluminum in the laboratory and field accumulate the metal in and on the epithelial cells of the gills; however, there is little accumulation of aluminum in the blood or internal organs. In low-pH water, both sublethal and lethal toxicity of aluminum has been clearly demonstrated in both laboratory and field studies at environmental concentrations. In contrast, recently measured aqueous concentrations of total mercury, methylmercury, cadmium, and lead in low-alkalinity lakes are much lower than the aqueous concentrations known to cause acute or chronic toxicity in fish, although the vast majority of toxicological research has involved waters with much higher ionic strength than that in low-alkalinity lakes. Additional work with fish is needed to better assess (1) the toxicity of aqueous metals in low-alkalinity waters, and (2) the toxicological significance of dietary methylmercury and cadmium.

Endpoint:
bioaccumulation in aquatic species, other
Type of information:
other: review paper
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
no guideline required
Principles of method if other than guideline:
Scientific research paper, based on existing and/or field measurements, following scientifically acceptable methods and procedures
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
The accumulation review conducted by Suedel et al (1994) suggests that most inorganic metal compounds are not expected to biomagnify.
This review was conducted by:
(1) examining data from studies conducted in laboratory experiments to establish body burden ratios between trophic levels (trophic transfer coefficients; TCCs)
(2) comparing laboratory-derived TCCs with data obtained from field studies
(3) comparing biomagnification predictions described by published aquatic food-web models with data obtained in this review.
Executive summary:

Most metals examined showed potential for trophic transfer via uptake from food, but not in sufficient quantities to result in biomagnification. Those metals that show a propensity to biomagnify include arsenic, methyl mercury, and perhaps inorganic mercury. For these metals, evidence of biomagnification was inconsistent, since trophic transfer coefficient (TTC)values ranged from 0.1 to 100. The bioniagnification potentialofmetals in aquatic food webs appears to be a functionofthe propensity of metals to transform from inorganic to organic forms through food webs. Mercury and arsenic readily transform to organic forms in aquatic food chains, thus increasing the lipid solubility, modifying rates of transfer across membranes, and ultimately affecting accumulationofthese metals in aquatic organisms. Some organisms, such as mollusks, accumulated considerable quantities of metals for physiological requirements that were ordersofmagnitude higher than organisms at other trophic levels. In general, concentrationsofmost metals were often higher in tissuesofproducers and primary consumers (e.g., detritivores) than carnivorous fishes.

Endpoint:
bioaccumulation in aquatic species, other
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Scientific research paper, following scientifically acceptable method and procedures which were outlined in the publication.
GLP compliance:
not specified
Remarks:
This study was not conducted for REACH-purposes
Test organisms (species):
other: Lymnaea stagnalis
Route of exposure:
aqueous
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
This study investigated the suitability of gallium as a surrogate for aluminium in bioaccumulation tracing experiments. The freshwater snail, Lymnaena stagnalis was exposed to aluminium for up to 40 days. Aluminium concentrations were measured in the digestive gland and rest of soft tissues and showed similar bioaccumulation patterns as found by Elangovan (1997).
Executive summary:

Aluminum is a toxic metal whose complex aquatic chemistry, mechanisms of toxicity and trophic transfer are not fully understood. The only isotope of Al suitable for tracing experiments in organisms-(26)Al-is a rare, costly radioisotope with a low emission energy, making its use difficult. Gallium shares a similar chemistry with Al and was therefore investigated as a potential substitute for Al for use in aquatic organisms. The freshwater snail, Lymnaea stagnalis was exposed to either Al or Ga (0.0135 mM) under identical conditions for up to 40 days. Behavioural toxicity, metal accumulation in the tissues, and sub-cellular partitioning of the metals were determined. Al was more toxic than Ga and accumulated to significantly higher levels in the soft tissues (P < 0.05). The proportion of Al in the digestive gland (DG; detoxificatory organ) relative to other tissues was significantly lower than that of Ga (P < 0.05) from day 14 onwards. There were also differences in the proportions of Al and Ga associated with heat stable proteins (HSPs) in the digestive gland, with significantly more HSP present in the DGs of snails exposed to Al, but significantly less Al than Ga associated with the HSP per unit mass protein present. From this evidence, the authors concluded that Ga may be of limited use as a tracer for Al in animal systems.

Endpoint:
bioaccumulation in aquatic species, other
Remarks:
freshwater snail
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Scientific research paper, following scientifically acceptable method and procedures which were outlined in the publication.
GLP compliance:
not specified
Test organisms (species):
other: Lymnaea stagnalis
Route of exposure:
aqueous
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
Asilicon-specific intracellular mechanism for aluminium detoxification in aquatic snails (L. stagnalis) was identified, and assumed that this would be a widespread phenomenon, explaining how cells evade toxicity from a metal such as aluminium, which is both ubiquitous and toxic in ionic form.
Executive summary:

Silicon (Si) ameliorates aluminum (Al) toxicity to a range of organisms, but in almost all cases this is due to ex vivo Si-Al interactions forming inert hydroxyaluminosilicates (HAS). It was hypothesized that a Si-specific intracellular mechanism for Al detoxification in aquatic snails exists, involving regulation of orthosilicic acid [Si(OH)4]. However, the possibility of ex vivo formation and uptake of soluble HAS could not be ruled out The authorns now provided unequivocal evidence for Si-Al interaction in vivo, including their intracellular colocalization. In snails preloaded with Si(0H)4, behavioral toxicity in response to subsequent exposure to Al was abolished. Similarly, recovery from Al-induced toxicity was faster when Si(OH)4 was provided, together with rapid loss of Al from the major detoxificatory organ (digestive gland). Temporal separation of Al and Si exposure excluded the possibility of their interaction ex vivo. Elemental mapping using analytical transmission electron microscopy revealed nanometre-scale colocalization of Si and Al within excretory granules in the digestive gland, consistent with recruitment of Si(OH)4, followed by high-affinity Al binding to form particles similarto allophane, an amorphous HAS. Given the environmental abundance of both elements, it is anticipated that this is a widespread phenomenon, providing a cellular defense against the profoundly toxic Al(III) ion.

Endpoint:
bioaccumulation in aquatic species, other
Remarks:
algae, bryophytes and invertebrates
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Scientific research paper, following scientifically acceptable method and procedures which were outlined in the publication.
GLP compliance:
not specified
Test organisms (species):
other: algae, bryophytes and invertebrates
Route of exposure:
aqueous
Key result
Remarks on result:
other: no fixed BCF-value can be determined for Al; data are used in a weight of evidence approach
Conclusions:
Aluminium concentrations were determined in samples of filamentous algae, bryophytes and invertebrates from 24 stream sites in North Westland, South Island, New Zealand. Sites were variably contaminated by acid coalmine drainage and ranged in pH from 2.6 to 6.2. Aluminium concentration ranges were for algae n.d.- 5.46 mg/g dry wt., for bryophytes n.d.-6.51 mg/g dry wt., for herbivore-detritivores n.d.- 2.23 mg/g dry t., and for predators n.d.-3.66 mg/g dry wt. No significant differences were found between herbivore-detritivores and predatory insects with respect to body burdens of aluminium. Along with the finding that concentrations of metals in animals were generally lower than those in plants, this indicates that biomagnification of aluminium do not occur within stream food webs.
Executive summary:

Concentrations of Al and Fe were determined in samples of filamentous algae, bryophytes and invertebrates from 24 stream sites in North Westland, South Island, New Zealand. Sites were variably contaminated by acid coal mine drainage and ranged in pH from 2.6 to 6.2. Conductivity of stream water ranged from 16 to 944 μS25 /cm and maximum concentrations of total dissolved Al and total Fe measured in two successive years were 35.5 and 32.6 mg/L, respectively. Metal burdens of algae and bryophytes were not correlated with pH, conductivity or the concentrations of Al and Fe observed in stream water. Metal concentrations in invertebrates were significantly lower than those in plants (mg per g dry wt.), and were similar in herbivore–detritivores (mainly mayfly larvae) and carnivorous species. No evidence was found for the biomagnification of either metal within aquatic food webs. However, invertebrate species exposed to very high concentrations of Al and Fe varied considerably in body burdens, suggesting that groups of insects differ considerably in their physiological or morphological ability to exclude potentially toxic metals.

Endpoint:
bioaccumulation in aquatic species, other
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Remarks:
Summary of available data used for the endpoint assessment of the target substance
Adequacy of study:
weight of evidence
Justification for type of information:
Refer to analogue justification provided in IUCLID section 13.
Reason / purpose for cross-reference:
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Remarks on result:
other: No fixed BCF-value can be determined for Al; data are used in a weight of evidence approach

Description of key information

In general, metals do not biomagnify unless they are present as, or having the potential to be, in an organic form (e.g. methylmercury). Organometals tend to be lipid soluble, are not metabolized, and are efficiently assimilated upon dietborne exposure.The available evidence shows the absence of aluminium biomagnification across trophic levels both in the aquatic and terrestrial food chains. The existing information suggests not only that aluminium does not biomagnify, but rather that it tends to exhibit biodilution at higher trophic levels in the food chain. More detailed information can be found in the attached document (White paper on waiving for secondary poisoning for Al & Fe compounds final report 02-02-2010. pdf). BCFs for Aluminium can be found to range from quite low (~100) to quite high values (11,000 – see attached pdf on White paper for waiving secondary poisoning for iron and Aluminium. This variance can in large part be explained by the difference in exposure conditions for the various studies. The inverse relationship between water and BCF/BAF values limits the ability to describe hazard as a result of the size of the BCF, i.e., the most pristine ecosystems have the highest BCFs. A better approach is to directly assess the concentrations of Al at various trophic levels in the ecosystem.

 

Herrmann and Frick (1995) studied the accumulation of aluminium at low pH conditions in benthic invertebrates with time and representing different functional feeding groups (predators and detritus feeders). Invertebrates of different taxa and feeding type were collected in springtime, when acidity and A1 levels mostly increase from seven streams in southern Sweden. Four of the streams typically had pH values of 4 - 4.5 and contained 0.40 - 0.70 mg inorganic A1/L. The other three streams showed pH values around 6 and A1 concentrations of 0.05 mg inorganic A1/l. For most taxa that could be compared, the animals from the most acidic streams (pH 4) contained more A1 than those from the less acid streams (pH 6). At both pH levels there was a clear tendency that predators contained significantly less amounts of aluminium than shredders. The latter results do not support the hypothesis that aluminium can be accumulated along a food chain in an acidic environment.

Key value for chemical safety assessment

Additional information

More information can be found in the attached position paper (IUCLID section 13).