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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Reference
Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
Please see read-across statement section 13.
Reason / purpose for cross-reference:
read-across source
Conc. / dose:
3 mg/L
Temp.:
ca. 20 °C
pH:
8.3
Type:
BCF
Value:
23.11 dimensionless
Basis:
not specified
Time of plateau:
28 d
Calculation basis:
steady state
Remarks on result:
other: ± 12.82
Details on kinetic parameters:
A kinetic study was not performed to analyze the equilibrium concentrations of Cr in the organisms, but, generally, for most contaminants, greater than 80% of a steady state between sediment and organisms is approached in 28 days of exposure (ASTM 1997; Ingersoll et al. 2003).
Details on results:
Chromium concentrations in water and sediments among the control and the T1 and T2 tanks showed significant differences (p<0.001) and also between T1 and T2 (p<0.001). The Cr concentrations decreased in water and increased in sediment during the accumulation phase in T2.
The Cr concentration in C. demersum, L. udekemianus, Z. collastinensis, and C. decemmaculatus (µg/g dw) increased rapidly, reaching the highest values between 7 and 14 days of exposure, showing that accumulation capacity is higher in the aquatic plant and oligochaete than in the crabs and fish. It seems that the steady state is reached between 14 and 28 days by all of the species exposed in T2, whereas in T1, C. demersum and Z. collastinensis might not have attained equilibrium after 28 days of exposure.
No dead organisms were recovered from either treatments or control units.
The highest BCF obtained for C. demersum was 718.66 (± 272.91) in T2; for L. udekemianus, it was 172.55 ( ± 80.8); for Z. collastinensis, it was 67.72 (± 35.4); and for C. decemmaculatus, it was 23.11 (± 12.82) in T1 at 28 days.
Reported statistics:
Normality of data or log-transformed data was checked using the Kolmogorov-Smirnov goodness-of-fit test. Analysis of variance (ANOVA) followed by the Tukey test was used to compare mean values (a = 0.05). When data or transformed data were not normally distributed (e.g., data of elimination phase), we used the nonparametric Kruskal-Wallis test followed by a multiple-comparison test to check for significant differences between treatments (a = 0.05).
Validity criteria fulfilled:
not specified
Conclusions:
The highest BCF obtained for C. demersum was 718.66 (± 272.91) in T2; for L. udekemianus, it was 172.55 ( ± 80.8); for Z. collastinensis, it was 67.72 (± 35.4); and for C. decemmaculatus, it was 23.11 (± 12.82) in T1 at 28 days.
Executive summary:

The bioaccumulation and elimination capacity of chromium were examined in four freshwater species: the submersed aquatic plant Ceratophyllum demersum (Ceratophyllaceae), the oligochaete Limnodrilus udekemianus (Tubificidae), the crab Zilchiopsis collastinensis (Decapoda), and the fish Cnesterodon decemmaculatus (Poeciliidae). All of the species were exposed simultaneously to sediments spiked with Cr (K2Cr2O7) at different concentrations (3 and 6 mg Cr(VI)/L) for 28 days, followed by 7 days without Cr to evaluate the concentration of residual Cr. We found that Cr accumulated in the tissues of all four species. The highest bioconcentration factor obtained for each species is as follows: C. demersum, 718.66 (±272.91); L. udekemianus, 172.55(±80.8), Z. collastinensis, 67.72 (±35.4); C. decemmaculatus, 23.11 (±12.82), all at 28 days of exposure.

Description of key information

Spiked sediment, at 3 and 6 mg Cr(VI)/L for 28 days, followed by 7 days without Cr to evaluate the concentration of residual Cr. The highest bioconcentration factor obtained for each species is as follows:C. demersum, 718.66 (±272.91); L. udekemianus, 172.55(±80.8), Z. collastinensis, 67.72 (±35.4); C. decemmaculatus, 23.11 (±12.82), all at 28 days of exposure.

Key value for chemical safety assessment

BCF (aquatic species):
23.11 dimensionless

Additional information

The estimation methods given in the Technical Guidance Document for determining bioconcentration or bioaccumulation factors for fish, earthworms and uptake in the food chain are not applicable to chromium compounds. Measured values are available for a variety of systems.

A number of studies investigating bioaccumulation are available and are reproduced below.

Bioaccumulation in fish

The uptake and accumulation of chromium by fish appears to be lower than for other aquatic organisms. Bioconcentration factors (BCFs) of around 1 l/kg have been determined for chromium (VI) using rainbow trout over 22-30 days exposure, with a value of 2.8 l/kg being reported in trout muscle for a longer exposure of 180 days (USEPA, 1980; Fromm and Stokes, 1962; Calamari et al., 1982).

Mears & Eisler (1977) carried out a survey of total chromium levels in livers of marine fish (bluefish (Pomatomus saltatrix), tautog (Tautoga onitis) and tilefish (Lopholatilus chamaeleonticeps) collected off the coast.The total chromium concentrations found in the livers were found to decrease with fish body length in female bluefish and male tautog, but no significant correlations (at the p=0.05 level) were seen in the total chromium concentrations in liver of fish of different sizes in the male bluefish, female tautog or male and female tilefish samples. As this was a field study, it is likely that the majority of chromium measured was chromium (III). Giesy Jr. & Wiener (1977) analysed fresh water fish for levels of total chromium. The fish were taken from a lake where the average total chromium concentration of the water column was 0.35 µg/l. The mean whole body concentrations found in the fish (on a dry weight basis) were 0.16 mg/kg in bluegill (Lepomis macrochirus), 0.09 mg/kg in blueback herring (Alosa aestivalis), 0.28 mg/kg in brook silverside (Labidesthes sicculus), 0.19 mg/kg in golden shiner (Notemigonus crysoleucas) and 0.15 mg/kg in chain pickerel (Esox). Based on the measured concentrations of total chromium found in the water and fish, whole body BCFs in the range 260-800 l/kg on a dry body weight basis can be estimated (the mean dry weight/wet weight ratio of the fish was given as 0.22, so the fresh weight BCF values were 57-176 l/kg). Analysis of the stomach contents of chain pickerel indicated that this species was feeding mainly on bluegill. The authors concluded that, based on the measured concentrations in bluegill and chain pickerel, no bioaccumulation of total chromium was occurring through this food chain. As this was a field study, it is likely that much of the chromium present in the organisms in this study was as chromium (III).

BCFs of 109-126 l/kg were determined by Shuster Jr. & Pringle (1969) for chromium (III) (as chromic nitrate) in oyster (Crassostrea virginica) exposed to 0.05 and 0.10 mg Cr/l using a flow-through sea water system (salinity 31‰) over 20 weeks.

The bioaccumulation and elimination capacity of chromium were examined in four freshwater species by marchese et al, 2008: the submersed aquatic plant Ceratophyllum demersum (Ceratophyllaceae), the oligochaete Limnodrilus udekemianus (Tubificidae), the crab Zilchiopsis collastinensis (Decapoda), and the fish Cnesterodon decemmaculatus (Poeciliidae). All of the species were exposed simultaneously to sediments spiked with Cr (K2Cr2O7) at different concentrations (3 and 6 mg Cr(VI)/L)for 28 days, followed by 7 days without Cr to evaluate the concentration of residual Cr. We found that Cr accumulated in the tissues of all four species. The highest bioconcentration factor obtained for each species is as follows:C. demersum, 718.66 (±272.91); L. udekemianus, 172.55(±80.8), Z. collastinensis, 67.72 (±35.4); C. decemmaculatus, 23.11 (±12.82), all at 28 days of exposure.

The available data indicate that the bioconcentration factor for chromium (VI) in fish is relatively low at around 1 l/kg. Once

in the organism, reduction of chromium (VI) to chromium (III) appears to occur, resulting in an accumulation of total chromium in the organisms to a factor of approximately 100 times the original concentration in water. Uptake of chromium (III) directly from water is likely to be very low due to the limited water solubility and strong adsorption to sediment under most conditions found in the environment. The BCF value derived from Marchese et al, 2008 for Cr (VI) can be seen as worst case value.