Registration Dossier

Environmental fate & pathways

Bioaccumulation: aquatic / sediment

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Principles of method if other than guideline:
Method: other: largely compatible with OECD Guideline305
GLP compliance:
no
Specific details on test material used for the study:
The test material was Radiolabelled Benzisosthiazolone (1,2 Benzisothiazolin-3-one (BIT)) diluted where appropriate with non-labelled analytical grade BIT
Radiolabelling:
yes
Test organisms (species):
Lepomis macrochirus
Details on test organisms:
200 Bluegill Sunfish; four to six inches (10 to 15 cm) in length, were divided equally among five all-glass aquaria. Each aquarium contained 71 litres of water. One aquarium was used as a control. Throughout the test the fish were fed Purina Trout Chow ad libitum twice per week. Faecal material and feed not consumed were siphoned from these aquaria three times a week. The particulate filters were replaced three times a week
Route of exposure:
aqueous
Test type:
other: Each aquarium was a closed, continually-circulating system in which the water was removed, filtered for particulate matter and waste products, aerated to saturation, and reintroduced into the aquarium at the rate of 1000 ml per minute.
Water / sediment media type:
natural water
Total exposure / uptake duration:
56 d
Nominal and measured concentrations:
0.1 mg/l
Details on estimation of bioconcentration:
Bioconcentration was calculated as a function of water and tissue concentration.
Remarks on result:
not measured/tested
Key result
Conc. / dose:
> 0.01 - < 0.1 mg/L
Type:
BCF
Value:
ca. 6.62 dimensionless
Basis:
whole body w.w.
Time of plateau:
2 wk
Calculation basis:
steady state
Elimination:
no
Details on results:
BIT reached a maximum concentration in Bluegill Sunfish within three weeks of exposure and most (>90%) of the test material was detected in the polar extract.
The mean Steady State BCF from this data is 6.95 (5.91 – 7.79).
LogBCF = 0.84
Conclusions:
Where data were presented to allow a comparison, the study design appears compatible with OECD Test Guideline 305.
However, when compared to OECD305, there were several discrepancies which are discussed below;
The concentration of the test item in each tank was determined three times per week over a period of eight weeks.

The fish were fed ad libitum during the study (feeding was not adjusted to control body weight and lipid content). Two fish were sampled for analysis from each tank (on nine occasions), these samples were prepared and a composite sample was analysed, the weights of the individual or combined samples were not stated. These reporting inadequacies are not considered to impact the validity of the study since the results clearly demonstrate that BIT does not accumulate in Bluegill Sunfish at of 0.01 mg/l and 0.1 mg/l. The data which was not recorded would therefore not change the conclusion of the study.
The fish were descaled prior to analysis. This activity is not included in the OECD 305 guideline, and could be considered to have had a significant impact on the scientific integrity of the study, since the total residues reported do not include possible BIT residues adsorbed onto or incorporated into the scales. However, in the reported study, the descaling process is not considered to have negatively impacted the validity of the study.
A low Steady State BCF value calculated on the basis of the total BIT residues from the whole fish (minus scales), indicates low potential to bioconcentrate in any tissue of the test species, including flesh, lipid and viscera. The mean Steady State BCF (LogBCF = 0.84) is comparable to the EPIWIN estimated BCF value (LogBCF = 0.50). The calculated and estimated BCF values, together with the EPIWIN estimated LogKow value of 0.64, indicate that BIT does not bioconcentrate in fish tissue, therefore it is considered of low likelihood that BIT would preferentially be absorbed and stored in the scales.
BIT is highly water soluble, with no measurable surface activity, therefore the potential for adsorption is considered negligible.
Therefore the omission of possible residues from fish scales from the total residue is not considered to represent a significant data gap, hence the Study is considered valid. However, this omission, when considered alongside the reporting inadequacies typical in a Study undertaken before the introduction of GLP and more complete reporting regimes, lead to a reliability criteria of 2.
From the study data it can be concluded that BIT reaches a maximum concentration in Bluegill Sunfish within two to three weeks of exposure; the biological magnification is only 5.8 to 8.9 times the water concentration; most of the material is present in the polar extract; and tissue levels drop markedly within seven days of exposure termination. At environmental levels of 0.01 mg/l and 0.1 mg/l BIT does not appear to represent a bioconcentration hazard to fish.
Executive summary:

A study was conducted to determine the bioconcentration of the substance in fish according to a method similar to OECD Guideline 305. Based on the study results, a low steady-state BCF value calculated on the basis of the total residues of the test substance from the whole fish (minus scales), indicates low potential to bioconcentrate in any tissue of the test species, including flesh, lipid and viscera.  The mean steady state BCF (Log BCF = 0.84) is comparable to the EPIWIN estimated BCF (Log BCF = 0.50).  The calculated and estimated BCF values, together with the EPIWIN estimated Log Kow value of 0.64, indicate that the substance is unlikely to bioconcentrate in fish tissue, therefore it is considered of low likelihood that the test substance would preferentially be absorbed and stored in the scales. The substance is highly water soluble, with no measurable surface activity, therefore the potential for adsorption is considered negligible. From the study data it can be concluded that the substance reaches a maximum concentration in Bluegill sunfish within two to three weeks of exposure; the biological magnification is only 5.8 to 8.9 times the water concentration; most of the material is present in the polar extract; and tissue levels drop markedly within seven days of exposure termination.  At environmental levels of 0.01 and 0.1 mg/L, the substance does not appear to represent a bioconcentration hazard to fish (Fink, 1973).

Description of key information

Key value for chemical safety assessment

BCF (aquatic species):
6.62 dimensionless

Additional information

A study was conducted to determine the bioconcentration of the substance in fish according to a method similar to OECD Guideline 305. Based on the study results, a low steady-state BCF value calculated on the basis of the total residues of the test substance from the whole fish (minus scales), indicates low potential to bioconcentrate in any tissue of the test species, including flesh, lipid and viscera.  The mean steady state BCF (Log BCF = 0.84) is comparable to the EPIWIN estimated BCF (Log BCF = 0.50).  The calculated and estimated BCF values, together with the EPIWIN estimated Log Kow value of 0.64, indicate that the substance is unlikely to bioconcentrate in fish tissue, therefore it is considered of low likelihood that the test substance would preferentially be absorbed and stored in the scales. The substance is highly water soluble, with no measurable surface activity, therefore the potential for adsorption is considered negligible. From the study data it can be concluded that the substance reaches a maximum concentration in Bluegill sunfish within two to three weeks of exposure; the biological magnification is only 5.8 to 8.9 times the water concentration; most of the material is present in the polar extract; and tissue levels drop markedly within seven days of exposure termination.  At environmental levels of 0.01 and 0.1 mg/L, the substance does not appear to represent a bioconcentration hazard to fish (Fink, 1973).