Zinc hexafluorosilicate

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

bioaccumulation in aquatic species, other

Type of information:

other: evidence from degradation product

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test not corresponding to any standard but well described and considered relevant for BCF assessment.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Fishes were divided into 7 groups of 12 each (1 control). The experiments were conducted in a glass aquarium each containing 12 fish in 50 L of test solution.
The C. fusca of fish was exposed to their respective one tenth and one-thirtieth of 96 hr LC50 concentration of Zn.
The one-tenth of 96 hr LC50 of 9.75 mg/L and one-thirtieth of 96 hr LC50 of 3.60 mg/L were used for the experiments in the C. fusca fish, respectively.
The test fish was exposed to the above-mentioned sub-lethal concentrations separately for a period of 7, 14, and 21 days (bioaccumulation period). At the end of these periods, the remaining fish was kept in a container of tap water (depuration period, 10 days) for another period of 31 days.

GLP compliance:

not specified

Radiolabelling:

no

Details on sampling:

- Sampling intervals/frequency for test organisms: 7-14-21 and 31d
- depuration time: 31d
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods):
At the end of each exposure period, dissection to separate organs (kidney, muscle, liver, and gills) was performed. Two fishes were pooled to take samples from kidney, muscle, liver, and gills as the weight of 1 g for gills and muscles and 0.5 g for kidney and livers. The samples were digested in a mixture containing nitric acid (as HNO3; from Merck) and perchloric acid (as HClO4; from Merck). Organs were, then, accurately weighed into 50 mL Erlenmeyer flasks, then 4.5 mL nitric acid (65%) was added to each sample, and the samples were left overnight to be slowly digested (Ebrahimpour et al. 2011). Thereafter, 1.5 mL perchloric acid (72%) was added to each sample. Digestion was performed on a hot plate (sand bath) at 150 ◦C for about 6 h or until solutions were cleared and near to dry. After cooling, the solution was quantitatively transferred to 50 mL polyethylene bottles and made up to 25 mL with distilled water. Then the solution was filtered using 0.45μm nitrocellulose membrane filter (Ebrahimpour et al. 2011) The determination of Zn in the fish tissues was carried out using a GBS, Scientific Equipment flame furnace atomic absorption spectrometer. The detection limit for Zn was 0.005μg g−1. The mean recovery was 99% for Zn. The concentrations of Zn in fish tissues were presented in μgg−1 wet weight (ww).

Vehicle:

no

Test organisms (species):

other: Capoeta fusca

Details on test organisms:

During June 2012, C. fusca, belongs to the family Cyprinidae, was collected from qanats in Birjand, eastern Iran. Live fish was transported to the laboratory in polythene bags with qanatswater. Prior to the experiment, the fish was acclimatized for 7 days to laboratory conditions in precleaned glasses aquariums with tap water. The fish was not fed during the experiment period.

Route of exposure:

aqueous

Test type:

static

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

>= 7 - <= 21 d

Total depuration duration:

ca. 10 d

Hardness:

as CaCO3: 302 +/-2 (mg/l)

Test temperature:

22°C

pH:

9 +/-0.2

Dissolved oxygen:

8.9 +/- 0.1 (mg/l)

Details on test conditions:

Fishes were divided into 7 groups of 12 each. The first group served as the control group and the others as the experimental ones. The experiments were conducted in a glass aquarium each containing 12 fish in 50 L of test solution. The C. fusca of fish was exposed to their respective onetenth and one-thirtieth of 96 hr LC50 concentration of Zn. The one-tenth of 96 hr LC50 of 9.75 mg/L and one-thirtieth of 96 hr LC50 of 3.60 mg/L were used for the experiments in the C. fusca fish, respectively.

Nominal and measured concentrations:

3.6 and 9.75 mg/l

Type:

BCF

Value:

69.48 dimensionless

Basis:

organ w.w.

Remarks:

Kidney

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:3.6 µg/g Zn

Type:

BCF

Value:

29.69 dimensionless

Basis:

organ w.w.

Remarks:

Kidney

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:9.75 µg/g Zn

Type:

BCF

Value:

20.51 dimensionless

Basis:

organ w.w.

Remarks:

Liver

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:3.6 µg/g Zn

Type:

BCF

Value:

8.64 dimensionless

Basis:

organ w.w.

Remarks:

Liver

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:9.75 µg/g Zn

Type:

BCF

Value:

12.06 dimensionless

Basis:

organ w.w.

Remarks:

Gill

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:3.6 µg/g Zn

Type:

BCF

Value:

5.79 dimensionless

Basis:

organ w.w.

Remarks:

Gill

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:9.75 µg/g Zn

Type:

BCF

Value:

6.88 dimensionless

Basis:

organ w.w.

Remarks:

Muscle

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:3.6 µg/g Zn

Type:

BCF

Value:

2.92 dimensionless

Basis:

organ w.w.

Remarks:

Muscle

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:9.75 µg/g Zn

Elimination:

yes

Parameter:

other: depuration rate

Depuration time (DT):

10 d

Details on kinetic parameters:

- Uptake rate constant (k1):
Kidney: 0.137 (lower dose) and 0.058 (higher dose)
Liver: 0.040 (lower dose) and 0.0015 (higher dose)
Gill: 0.023 (lower dose) and 0.0014 (higher dose)
Muscle: 0.013 (lower dose) and 0.0016 (higher dose)

- Depuration (loss) rate constant (k2):
Kidney: 0.0021 (lower dose) and 0.00204 (higher dose)
Liver: 0.0015 (lower dose) and 0.00146 (higher dose)
Gill: 0.00139 (lower dose) and 0.00142 (higher dose)
Muscle: 0.0157 (lower dose) and 0.00106 (higher dose)

Reported statistics:

The Kolmogorov– Smirnov test was accomplished to analyze the normality of data distribution. The data related to content of the heavy metals in fish samples were analyzed with one-way ANOVA, followed by Tukey test (P < 0.05). All statistical calculations were performed with SPSS 19.

Validity criteria fulfilled:

yes

Conclusions:

Results demonstrating active regulation of zinc by the organism. Supports the general conclusion that bioconcentration is not a relevant parameter for the essential element zinc.

Reference 2

Endpoint:

bioaccumulation in sediment species, other

Type of information:

other: evidence from degradation product

Adequacy of study:

supporting study

Qualifier:

no guideline required

GLP compliance:

not specified

The most important exposure route of F for plants is uptake from the atmosphere.

Grass species have in comparison to other plant species a relatively high uptake rate. The equilibrium between the concentration in the atmosphere and in the grass is generally reached within 24 hours. In a period without rainfall the half-life of fluoride in grass is ca. 4 days in the summer and ca. 12 days in the winter (Slooff et al. 1988).

Consumption of fluoride containing plants may lead to elevated fluoride levels in both humans and animals. Fluoride concentrations in grass range from 1-10 mg/kg (dry weight) in areas with low fluoride emissions to 10-150 mg/kg (dry weight) in areas with high fluoride emissions. Fluoride concentrations in consumer crops range from 0.1-1.8 mg/kg. In other consumer products (tea, beer, wine, meat, eggs and milkproducts) fluoride concentrations of 0.05 (milk) to 6 mg/kg (wine) were measured (Slooff et al. 1988). Near an aluminium factory in the USA, the fluoride content in the foliage of cherry and peach

trees raised from 13 mg/kg to 65 and 76 mg/kg, respectively. The highest values, 196 and 186 mg/kg, respectively, were found 2 years after the factory began operating (Slooff et al. 1988).

Aquatic environment

In the RIVM Criteria Document on Fluorides (Slooff et al. 1988) it was concluded that the limited data available indicate that accumulation through food chains (biomagnification) is of little significance in the aquatic environment.

Fluorides accumulate in the skeletal tissues of terrestrial animals, both vertebrates and invertebrates, depending on their feeding habit. Data on a variety of invertebrates, collected from F-polluted sites, indicate that the lowest fluoride levels are found in cambial region feeders and herbivores, followed by omnivores, and were highest in predators, scavengers and pollinators. The relatively high levels in the latter three indicate possible biomagnification. For example accumulation factors (= level in organisms in polluted zone: level in organisms in control zone) of 1.5, 25, 21, and 54 were found for casebearer

Coleophora laricella, predatory spiders (arachnida), the honeybee Apis mellifera and bumblebees (Bombus sp.), respectively. Vertebrates store most of the fluoride retained in the body bones and, to a lesser content in the teeth.

This was demonstrated in herbivorous field voles Microtus agrestis and wood mice Apodemus sylvaticus and insectivorous common shrews Sorex araneus collected near an aluminium reduction plant. In moles Talpa europaea higher fluoride levels were found in consistency with fluoride levels in earthworms, their main food source. Higher fluoride levels were also found in foxes, ungulates and birds collected from polluted areas. Field voles and wood mice with gross changes in their teeth showed bone fluoride levels of 2500 to 15000 mg/kg (d.w.), which levels were 15- to 90-fold those in animals from unpolluted areas. Bone fluoride levels increased with age and were, as in invertebrates, dependent on feeding habit, with the lowest levels in herbivores and somewhat higher levels in omnivores

and carnivores (Janssen et al. 1989).

From the above-mentioned examples for the terrestrial environment it can be concluded that in vertebrates and invertebrates a similar food-dependent relationship was found for fluoride accumulation: the lowest levels in herbivores and (somewhat) higher levels in predators. The relatively high fluoride concentrations in predators indicate a moderate degree of biomagnification for fluoride in the terrestrial environment (Slooff et al. 1988).

Conclusions:

It was concluded that accumulation through food chains is of little significance in the aquatic environment.

Reference 3

Endpoint:

bioaccumulation in aquatic species, other

Type of information:

other: evidence from degradation product

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test not corresponding to any standard but well described and considered relevant for BCF assessment.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Healthy C. punctatus were collected from local freshwater bodies in and around Annamalai University, Annamalainagar. Fish were separately maintained at 27±1°C in 1,000 L tank with continuously aerated and dechlorinated tapwater at least one month prior to the experiments. Fish were fed. Semi-static system.
Zinc sulfate (ZnSO4 7H2O-Analar grade, Merck) was used in the present study.
Zinc accumulation was investigated in fish exposed to sub-acute doses of zinc over 45 days. Six replications (30 fish in each zinc concentration and control). No zinc was put into the aquarium containing the control fish.
The fish were dissected and different organs of gill, liver, kidney, intestine and muscle were taken from the experimental fish as well as control fish. The final acid digested extract was analysed for Zn concentration using Perkin Elmer Atomic Absorption Spectrophotometer-3100. The Zn concentration in tissue was recorded μg g-1 wet tissue.

GLP compliance:

not specified

Radiolabelling:

no

Details on sampling:

- Sampling intervals/frequency for test organisms: 15-30-45d
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods):
The fish were dissected and different organs of gill, liver, kidney, intestine and muscle were taken from the experimental fish as well as control fish separately and the tissues were washed in double distilled water and preserved in 10% formalin. Before analysis, formalin was removed using filter paper from each tissue. Five hundred mg from each tissue was placed in separate digestion flask and perchloricnitric acid mixture in the ratio of 1:2 (v/v) was added (FAO, 1975). The digestion flasks were gradually brought and kept at 130°C on hot plate until all materials dissolved and the digests were diluted with deionized water.

Vehicle:

no

Test organisms (species):

other: Channa punctatus

Details on test organisms:

Healthy C. punctatus (18−20 g in weight; 9−11 cm in length) were collected from local freshwater bodies in and around Annamalai University, Annamalainagar.

Route of exposure:

aqueous

Test type:

semi-static

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

45 d

Total depuration duration:

0

Hardness:

as CaCO3: 185-200 (mg/l)

Test temperature:

27 +/-1 °C

pH:

7.2 - 7.4

Dissolved oxygen:

8.9 +/- 0.1 (mg/l)

Details on test conditions:

Water: dechlorinated tap water
Alkalinity: as CaCO3: 170-175 mg/l
Photoperiod: 12/12
Acclimation: 1 month prior to exposure, fed hard boiled eggs and earthworm on alternate days
Exposure: worms only
Water replacement daily after feeding (60% tank)
The 96 h LC50 concentration of zinc was 48.68 mg L−1 for C. punctatus as calculated by using probit analysis method (Finney, 1971). Zinc accumulation was investigated in fish exposed to 1/3rd (13.24 mg L-1) and 1/6th (6.62. mg L-1) of 96 hr LC50 concentration of zinc over 45 days of exposure. The experiments were carried out in glass aquarium (100 L water capacity) with six replications (30 fish in each zinc concentration and control). No zinc was put into the aquarium containing the control fish. The water in the control and Zn containing aquarium was renewed everyday in order to minimize decrease in the Zn concentrations. At each interval of 15, 30 and 45 days of long-term exposure, six fish were sampled from
each group for determination of zinc in different organs.

Nominal and measured concentrations:

1/3rd (13.24 mg L-1) and 1/6th (6.62. mg L-1) of 96 hr LC50 concentration of zinc over 45 days of exposure

Details on estimation of bioconcentration:

Calculated from ratio concentration in organ and exposure concentration

Type:

BCF

Value:

4.98 dimensionless

Basis:

organ w.w.

Remarks:

gills

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:6.62 µg Zn/g

Type:

BCF

Value:

3.81 dimensionless

Basis:

organ w.w.

Remarks:

gills

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:13.24 µg Zn/g

Type:

BCF

Value:

7.51 dimensionless

Basis:

organ w.w.

Remarks:

Liver

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:6.62 µg Zn/g

Type:

BCF

Value:

5.08 dimensionless

Basis:

organ w.w.

Remarks:

Liver

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:13.24 µg/g Zn

Type:

BCF

Value:

5.84 dimensionless

Basis:

organ w.w.

Remarks:

intestine

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:6.62 µg Zn/g

Type:

BCF

Value:

3.18 dimensionless

Basis:

organ w.w.

Remarks:

intestine

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:13.24 µg Zn/g

Type:

BCF

Value:

6.94 dimensionless

Basis:

organ w.w.

Remarks:

kidney

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:6.62 µg Zn/g

Type:

BCF

Value:

4.7 dimensionless

Basis:

organ w.w.

Remarks:

Muscle

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:13.24 µg Zn/g

Type:

BCF

Value:

0.75 dimensionless

Basis:

organ w.w.

Remarks:

muscles

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:6.62 µg Zn/g

Type:

BCF

Value:

0.4 dimensionless

Basis:

organ w.w.

Remarks:

muscles

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:13.24 µg Zn/g

Reported statistics:

Data analyses were carried out using SPSS (version number-10) statistical package. Analysis of variance (ANOVA) was used to determine differences between various data sets. While the Dunnet test was used to compare experimental treatment groups against control.

Validity criteria fulfilled:

yes

Conclusions:

Results demonstrating active regulation of zinc by the organism. Supports the general conclusion that bioconcentration is not a relevant parameter for the essential element zinc.

Reference 4

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

other: evidence from degradation product

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test not corresponding to any standard but well described and considered relevant for BCF assessment.

Qualifier:

no guideline followed

Principles of method if other than guideline:

2 weeks acclimation. 15d contamination phase in flow through (closed circuit) system at environmentally relevant level. The 15-day metal exposure was followed by a 75-day complete decontamination.

GLP compliance:

not specified

Radiolabelling:

no

Vehicle:

no

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

14 d

Total depuration duration:

75 d

Test temperature:

22.4 +/-0.2

pH:

8.1

Dissolved oxygen:

8.3 mg/l

Nominal and measured concentrations:

1165.7 +/- 53.8 µg/l Zn

Type:

BCF

Value:

96.05 dimensionless

Basis:

organ w.w.

Remarks:

gills

Calculation basis:

steady state

Remarks on result:

other: Day 3 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

85.76 dimensionless

Basis:

organ w.w.

Remarks:

gills

Calculation basis:

steady state

Remarks on result:

other: Day 7 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

70.75 dimensionless

Basis:

organ w.w.

Remarks:

gills

Calculation basis:

steady state

Remarks on result:

other: Day 14 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

30.02 dimensionless

Basis:

organ w.w.

Remarks:

liver

Calculation basis:

steady state

Remarks on result:

other: Day 3 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

96.05 dimensionless

Basis:

organ w.w.

Remarks:

liver

Calculation basis:

steady state

Remarks on result:

other: Day 7 of exposure, significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

42.88 dimensionless

Basis:

organ w.w.

Remarks:

liver

Calculation basis:

steady state

Remarks on result:

other: Day 14 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

30.02 dimensionless

Basis:

organ w.w.

Remarks:

brain

Calculation basis:

steady state

Remarks on result:

other: Day 3 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

42.88 dimensionless

Basis:

organ w.w.

Remarks:

brain

Calculation basis:

steady state

Remarks on result:

other: Day 7 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

28.3 dimensionless

Basis:

organ w.w.

Remarks:

brain

Calculation basis:

steady state

Remarks on result:

other: Day 14 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Elimination:

yes

Parameter:

other: elimination

Depuration time (DT):

60 d

BCF data for muscles (w/w):

Day 03 of exposure, no significant difference with control: 14.58

Day 07 of exposure, no significant difference with control: 19.73

Day 14 of exposure, no significant difference with control: 22.30

Validity criteria fulfilled:

yes

Conclusions:

Results demonstrating active regulation of zinc by the organism. Supports the general conclusion that bioconcentration is not a relevant parameter for the essential element zinc.

Reference 5

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

other: evidence from degradation product

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test not corresponding to any standard but well described and considered relevant for BCF/BAF assessment.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Fish were fed with Daphnids fed beforehand with algae containing zinc or not, in a semi-static system. The aquaria were themselves containing zinc enriched water or non contaminated water.

GLP compliance:

no

Radiolabelling:

no

Vehicle:

no

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

Brachydanio rerio Hamilton-Buchanan were obtained as young fish (length approx. 25-30 ram) from a local trader and were acclimatized for 3 weeks feeding them with commercial fish food (Tetra Min). Ten fish were randomly distributed to each of twelve glass aquaria (251.). The sex of these young fish was not considered in the evaluation of the results because it could not be determined in each case

Route of exposure:

aqueous

Test type:

semi-static

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

40 d

Total depuration duration:

2 d

Hardness:

2.5 mmol/l

Test temperature:

19-22°C

pH:

7.8 +/- 0.3

Details on test conditions:

light regime 16:8

Nominal and measured concentrations:

250 µg/l Zn in water

Type:

BCF

Value:

0.002 dimensionless

Basis:

whole body d.w.

Calculation basis:

steady state

Remarks on result:

other: Day 40 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:250 µg Zn/l

Elimination:

yes

Parameter:

other: elimination

Depuration time (DT):

60 d

Details on results:

NO evidence of bioaccumulation of zinc from food (no difference between fish fed with polluted or unpolluted Daphnia)
Very little bioconcentration from water: concentration zinc in whole fish dry weight: from 330 to 390 µg Zn/g in 40 days

Validity criteria fulfilled:

yes

Conclusions:

Results demonstrating no biomagnification. Supports the general conclusion that bioconcentration is not a relevant parameter for the essential element zinc.

Reference 6

Endpoint:

bioaccumulation in aquatic species, other

Type of information:

other: evidence based on degradation product

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test not corresponding to any standard but well described and considered relevant for BCF assessment.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Fishes were divided into 7 groups of 12 each (1 control). The experiments were conducted in a glass aquarium each containing 12 fish in 50 L of test solution.
The C. fusca of fish was exposed to their respective one tenth and one-thirtieth of 96 hr LC50 concentration of Zn.
The one-tenth of 96 hr LC50 of 9.75 mg/L and one-thirtieth of 96 hr LC50 of 3.60 mg/L were used for the experiments in the C. fusca fish, respectively.
The test fish was exposed to the above-mentioned sub-lethal concentrations separately for a period of 7, 14, and 21 days (bioaccumulation period). At the end of these periods, the remaining fish was kept in a container of tap water (depuration period, 10 days) for another period of 31 days.

GLP compliance:

not specified

Radiolabelling:

no

Details on sampling:

- Sampling intervals/frequency for test organisms: 7-14-21 and 31d
- depuration time: 31d
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods):
At the end of each exposure period, dissection to separate organs (kidney, muscle, liver, and gills) was performed. Two fishes were pooled to take samples from kidney, muscle, liver, and gills as the weight of 1 g for gills and muscles and 0.5 g for kidney and livers. The samples were digested in a mixture containing nitric acid (as HNO3; from Merck) and perchloric acid (as HClO4; from Merck). Organs were, then, accurately weighed into 50 mL Erlenmeyer flasks, then 4.5 mL nitric acid (65%) was added to each sample, and the samples were left overnight to be slowly digested (Ebrahimpour et al. 2011). Thereafter, 1.5 mL perchloric acid (72%) was added to each sample. Digestion was performed on a hot plate (sand bath) at 150 ◦C for about 6 h or until solutions were cleared and near to dry. After cooling, the solution was quantitatively transferred to 50 mL polyethylene bottles and made up to 25 mL with distilled water. Then the solution was filtered using 0.45μm nitrocellulose membrane filter (Ebrahimpour et al. 2011) The determination of Zn in the fish tissues was carried out using a GBS, Scientific Equipment flame furnace atomic absorption spectrometer. The detection limit for Zn was 0.005μg g−1. The mean recovery was 99% for Zn. The concentrations of Zn in fish tissues were presented in μgg−1 wet weight (ww).

Vehicle:

no

Test organisms (species):

other: Capoeta fusca

Details on test organisms:

During June 2012, C. fusca, belongs to the family Cyprinidae, was collected from qanats in Birjand, eastern Iran. Live fish was transported to the laboratory in polythene bags with qanatswater. Prior to the experiment, the fish was acclimatized for 7 days to laboratory conditions in precleaned glasses aquariums with tap water. The fish was not fed during the experiment period.

Route of exposure:

aqueous

Test type:

static

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

>= 7 - <= 21 d

Total depuration duration:

ca. 10 d

Hardness:

as CaCO3: 302 +/-2 (mg/l)

Test temperature:

22°C

pH:

9 +/-0.2

Dissolved oxygen:

8.9 +/- 0.1 (mg/l)

Details on test conditions:

Fishes were divided into 7 groups of 12 each. The first group served as the control group and the others as the experimental ones. The experiments were conducted in a glass aquarium each containing 12 fish in 50 L of test solution. The C. fusca of fish was exposed to their respective onetenth and one-thirtieth of 96 hr LC50 concentration of Zn. The one-tenth of 96 hr LC50 of 9.75 mg/L and one-thirtieth of 96 hr LC50 of 3.60 mg/L were used for the experiments in the C. fusca fish, respectively.

Nominal and measured concentrations:

3.6 and 9.75 mg/l

Type:

BCF

Value:

69.48 dimensionless

Basis:

organ w.w.

Remarks:

Kidney

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:3.6 µg/g Zn

Type:

BCF

Value:

29.69 dimensionless

Basis:

organ w.w.

Remarks:

Kidney

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:9.75 µg/g Zn

Type:

BCF

Value:

20.51 dimensionless

Basis:

organ w.w.

Remarks:

Liver

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:3.6 µg/g Zn

Type:

BCF

Value:

8.64 dimensionless

Basis:

organ w.w.

Remarks:

Liver

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:9.75 µg/g Zn

Type:

BCF

Value:

12.06 dimensionless

Basis:

organ w.w.

Remarks:

Gill

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:3.6 µg/g Zn

Type:

BCF

Value:

5.79 dimensionless

Basis:

organ w.w.

Remarks:

Gill

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:9.75 µg/g Zn

Type:

BCF

Value:

6.88 dimensionless

Basis:

organ w.w.

Remarks:

Muscle

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:3.6 µg/g Zn

Type:

BCF

Value:

2.92 dimensionless

Basis:

organ w.w.

Remarks:

Muscle

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:9.75 µg/g Zn

Elimination:

yes

Parameter:

other: depuration rate

Depuration time (DT):

10 d

Details on kinetic parameters:

- Uptake rate constant (k1):
Kidney: 0.137 (lower dose) and 0.058 (higher dose)
Liver: 0.040 (lower dose) and 0.0015 (higher dose)
Gill: 0.023 (lower dose) and 0.0014 (higher dose)
Muscle: 0.013 (lower dose) and 0.0016 (higher dose)

- Depuration (loss) rate constant (k2):
Kidney: 0.0021 (lower dose) and 0.00204 (higher dose)
Liver: 0.0015 (lower dose) and 0.00146 (higher dose)
Gill: 0.00139 (lower dose) and 0.00142 (higher dose)
Muscle: 0.0157 (lower dose) and 0.00106 (higher dose)

Reported statistics:

The Kolmogorov– Smirnov test was accomplished to analyze the normality of data distribution. The data related to content of the heavy metals in fish samples were analyzed with one-way ANOVA, followed by Tukey test (P < 0.05). All statistical calculations were performed with SPSS 19.

Validity criteria fulfilled:

yes

Conclusions:

Results demonstrating active regulation of zinc by the organism. Supports the general conclusion that bioconcentration is not a relevant parameter for the essential element zinc.

Reference 7

Endpoint:

bioaccumulation in sediment species, other

Type of information:

other: evidence based on degradation product

Adequacy of study:

supporting study

Qualifier:

no guideline required

GLP compliance:

not specified

The most important exposure route of F for plants is uptake from the atmosphere.

Grass species have in comparison to other plant species a relatively high uptake rate. The equilibrium between the concentration in the atmosphere and in the grass is generally reached within 24 hours. In a period without rainfall the half-life of fluoride in grass is ca. 4 days in the summer and ca. 12 days in the winter (Slooff et al. 1988).

Consumption of fluoride containing plants may lead to elevated fluoride levels in both humans and animals. Fluoride concentrations in grass range from 1-10 mg/kg (dry weight) in areas with low fluoride emissions to 10-150 mg/kg (dry weight) in areas with high fluoride emissions. Fluoride concentrations in consumer crops range from 0.1-1.8 mg/kg. In other consumer products (tea, beer, wine, meat, eggs and milkproducts) fluoride concentrations of 0.05 (milk) to 6 mg/kg (wine) were measured (Slooff et al. 1988). Near an aluminium factory in the USA, the fluoride content in the foliage of cherry and peach

trees raised from 13 mg/kg to 65 and 76 mg/kg, respectively. The highest values, 196 and 186 mg/kg, respectively, were found 2 years after the factory began operating (Slooff et al. 1988).

Aquatic environment

In the RIVM Criteria Document on Fluorides (Slooff et al. 1988) it was concluded that the limited data available indicate that accumulation through food chains (biomagnification) is of little significance in the aquatic environment.

Fluorides accumulate in the skeletal tissues of terrestrial animals, both vertebrates and invertebrates, depending on their feeding habit. Data on a variety of invertebrates, collected from F-polluted sites, indicate that the lowest fluoride levels are found in cambial region feeders and herbivores, followed by omnivores, and were highest in predators, scavengers and pollinators. The relatively high levels in the latter three indicate possible biomagnification. For example accumulation factors (= level in organisms in polluted zone: level in organisms in control zone) of 1.5, 25, 21, and 54 were found for casebearer

Coleophora laricella, predatory spiders (arachnida), the honeybee Apis mellifera and bumblebees (Bombus sp.), respectively. Vertebrates store most of the fluoride retained in the body bones and, to a lesser content in the teeth.

This was demonstrated in herbivorous field voles Microtus agrestis and wood mice Apodemus sylvaticus and insectivorous common shrews Sorex araneus collected near an aluminium reduction plant. In moles Talpa europaea higher fluoride levels were found in consistency with fluoride levels in earthworms, their main food source. Higher fluoride levels were also found in foxes, ungulates and birds collected from polluted areas. Field voles and wood mice with gross changes in their teeth showed bone fluoride levels of 2500 to 15000 mg/kg (d.w.), which levels were 15- to 90-fold those in animals from unpolluted areas. Bone fluoride levels increased with age and were, as in invertebrates, dependent on feeding habit, with the lowest levels in herbivores and somewhat higher levels in omnivores

and carnivores (Janssen et al. 1989).

From the above-mentioned examples for the terrestrial environment it can be concluded that in vertebrates and invertebrates a similar food-dependent relationship was found for fluoride accumulation: the lowest levels in herbivores and (somewhat) higher levels in predators. The relatively high fluoride concentrations in predators indicate a moderate degree of biomagnification for fluoride in the terrestrial environment (Slooff et al. 1988).

Conclusions:

It was concluded that accumulation through food chains is of little significance in the aquatic environment.

Reference 8

Endpoint:

bioaccumulation in aquatic species, other

Type of information:

other: evidence based on degradation product

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test not corresponding to any standard but well described and considered relevant for BCF assessment.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Healthy C. punctatus were collected from local freshwater bodies in and around Annamalai University, Annamalainagar. Fish were separately maintained at 27±1°C in 1,000 L tank with continuously aerated and dechlorinated tapwater at least one month prior to the experiments. Fish were fed. Semi-static system.
Zinc sulfate (ZnSO4 7H2O-Analar grade, Merck) was used in the present study.
Zinc accumulation was investigated in fish exposed to sub-acute doses of zinc over 45 days. Six replications (30 fish in each zinc concentration and control). No zinc was put into the aquarium containing the control fish.
The fish were dissected and different organs of gill, liver, kidney, intestine and muscle were taken from the experimental fish as well as control fish. The final acid digested extract was analysed for Zn concentration using Perkin Elmer Atomic Absorption Spectrophotometer-3100. The Zn concentration in tissue was recorded μg g-1 wet tissue.

GLP compliance:

not specified

Radiolabelling:

no

Details on sampling:

- Sampling intervals/frequency for test organisms: 15-30-45d
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods):
The fish were dissected and different organs of gill, liver, kidney, intestine and muscle were taken from the experimental fish as well as control fish separately and the tissues were washed in double distilled water and preserved in 10% formalin. Before analysis, formalin was removed using filter paper from each tissue. Five hundred mg from each tissue was placed in separate digestion flask and perchloricnitric acid mixture in the ratio of 1:2 (v/v) was added (FAO, 1975). The digestion flasks were gradually brought and kept at 130°C on hot plate until all materials dissolved and the digests were diluted with deionized water.

Vehicle:

no

Test organisms (species):

other: Channa punctatus

Details on test organisms:

Healthy C. punctatus (18−20 g in weight; 9−11 cm in length) were collected from local freshwater bodies in and around Annamalai University, Annamalainagar.

Route of exposure:

aqueous

Test type:

semi-static

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

45 d

Total depuration duration:

0

Hardness:

as CaCO3: 185-200 (mg/l)

Test temperature:

27 +/-1 °C

pH:

7.2 - 7.4

Dissolved oxygen:

8.9 +/- 0.1 (mg/l)

Details on test conditions:

Water: dechlorinated tap water
Alkalinity: as CaCO3: 170-175 mg/l
Photoperiod: 12/12
Acclimation: 1 month prior to exposure, fed hard boiled eggs and earthworm on alternate days
Exposure: worms only
Water replacement daily after feeding (60% tank)
The 96 h LC50 concentration of zinc was 48.68 mg L−1 for C. punctatus as calculated by using probit analysis method (Finney, 1971). Zinc accumulation was investigated in fish exposed to 1/3rd (13.24 mg L-1) and 1/6th (6.62. mg L-1) of 96 hr LC50 concentration of zinc over 45 days of exposure. The experiments were carried out in glass aquarium (100 L water capacity) with six replications (30 fish in each zinc concentration and control). No zinc was put into the aquarium containing the control fish. The water in the control and Zn containing aquarium was renewed everyday in order to minimize decrease in the Zn concentrations. At each interval of 15, 30 and 45 days of long-term exposure, six fish were sampled from
each group for determination of zinc in different organs.

Nominal and measured concentrations:

1/3rd (13.24 mg L-1) and 1/6th (6.62. mg L-1) of 96 hr LC50 concentration of zinc over 45 days of exposure

Details on estimation of bioconcentration:

Calculated from ratio concentration in organ and exposure concentration

Type:

BCF

Value:

4.98 dimensionless

Basis:

organ w.w.

Remarks:

gills

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:6.62 µg Zn/g

Type:

BCF

Value:

3.81 dimensionless

Basis:

organ w.w.

Remarks:

gills

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:13.24 µg Zn/g

Type:

BCF

Value:

7.51 dimensionless

Basis:

organ w.w.

Remarks:

Liver

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:6.62 µg Zn/g

Type:

BCF

Value:

5.08 dimensionless

Basis:

organ w.w.

Remarks:

Liver

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:13.24 µg/g Zn

Type:

BCF

Value:

5.84 dimensionless

Basis:

organ w.w.

Remarks:

intestine

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:6.62 µg Zn/g

Type:

BCF

Value:

3.18 dimensionless

Basis:

organ w.w.

Remarks:

intestine

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:13.24 µg Zn/g

Type:

BCF

Value:

6.94 dimensionless

Basis:

organ w.w.

Remarks:

kidney

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:6.62 µg Zn/g

Type:

BCF

Value:

4.7 dimensionless

Basis:

organ w.w.

Remarks:

Muscle

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:13.24 µg Zn/g

Type:

BCF

Value:

0.75 dimensionless

Basis:

organ w.w.

Remarks:

muscles

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:6.62 µg Zn/g

Type:

BCF

Value:

0.4 dimensionless

Basis:

organ w.w.

Remarks:

muscles

Calculation basis:

steady state

Remarks on result:

other: End of exposure time

Remarks:

Conc.in environment / dose:13.24 µg Zn/g

Reported statistics:

Data analyses were carried out using SPSS (version number-10) statistical package. Analysis of variance (ANOVA) was used to determine differences between various data sets. While the Dunnet test was used to compare experimental treatment groups against control.

Validity criteria fulfilled:

yes

Conclusions:

Results demonstrating active regulation of zinc by the organism. Supports the general conclusion that bioconcentration is not a relevant parameter for the essential element zinc.

Reference 9

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

other: evidence based on degradation product

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test not corresponding to any standard but well described and considered relevant for BCF assessment.

Qualifier:

no guideline followed

Principles of method if other than guideline:

2 weeks acclimation. 15d contamination phase in flow through (closed circuit) system at environmentally relevant level. The 15-day metal exposure was followed by a 75-day complete decontamination.

GLP compliance:

not specified

Radiolabelling:

no

Vehicle:

no

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

14 d

Total depuration duration:

75 d

Test temperature:

22.4 +/-0.2

pH:

8.1

Dissolved oxygen:

8.3 mg/l

Nominal and measured concentrations:

1165.7 +/- 53.8 µg/l Zn

Type:

BCF

Value:

96.05 dimensionless

Basis:

organ w.w.

Remarks:

gills

Calculation basis:

steady state

Remarks on result:

other: Day 3 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

85.76 dimensionless

Basis:

organ w.w.

Remarks:

gills

Calculation basis:

steady state

Remarks on result:

other: Day 7 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

70.75 dimensionless

Basis:

organ w.w.

Remarks:

gills

Calculation basis:

steady state

Remarks on result:

other: Day 14 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

30.02 dimensionless

Basis:

organ w.w.

Remarks:

liver

Calculation basis:

steady state

Remarks on result:

other: Day 3 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

96.05 dimensionless

Basis:

organ w.w.

Remarks:

liver

Calculation basis:

steady state

Remarks on result:

other: Day 7 of exposure, significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

42.88 dimensionless

Basis:

organ w.w.

Remarks:

liver

Calculation basis:

steady state

Remarks on result:

other: Day 14 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

30.02 dimensionless

Basis:

organ w.w.

Remarks:

brain

Calculation basis:

steady state

Remarks on result:

other: Day 3 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

42.88 dimensionless

Basis:

organ w.w.

Remarks:

brain

Calculation basis:

steady state

Remarks on result:

other: Day 7 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Type:

BCF

Value:

28.3 dimensionless

Basis:

organ w.w.

Remarks:

brain

Calculation basis:

steady state

Remarks on result:

other: Day 14 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:1.166 µg Zn/l

Elimination:

yes

Parameter:

other: elimination

Depuration time (DT):

60 d

BCF data for muscles (w/w):

Day 03 of exposure, no significant difference with control: 14.58

Day 07 of exposure, no significant difference with control: 19.73

Day 14 of exposure, no significant difference with control: 22.30

Validity criteria fulfilled:

yes

Conclusions:

Results demonstrating active regulation of zinc by the organism. Supports the general conclusion that bioconcentration is not a relevant parameter for the essential element zinc.

Reference 10

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

other: evidence based on degradation product

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test not corresponding to any standard but well described and considered relevant for BCF/BAF assessment.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Fish were fed with Daphnids fed beforehand with algae containing zinc or not, in a semi-static system. The aquaria were themselves containing zinc enriched water or non contaminated water.

GLP compliance:

no

Radiolabelling:

no

Vehicle:

no

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

Brachydanio rerio Hamilton-Buchanan were obtained as young fish (length approx. 25-30 ram) from a local trader and were acclimatized for 3 weeks feeding them with commercial fish food (Tetra Min). Ten fish were randomly distributed to each of twelve glass aquaria (251.). The sex of these young fish was not considered in the evaluation of the results because it could not be determined in each case

Route of exposure:

aqueous

Test type:

semi-static

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

40 d

Total depuration duration:

2 d

Hardness:

2.5 mmol/l

Test temperature:

19-22°C

pH:

7.8 +/- 0.3

Details on test conditions:

light regime 16:8

Nominal and measured concentrations:

250 µg/l Zn in water

Type:

BCF

Value:

0.002 dimensionless

Basis:

whole body d.w.

Calculation basis:

steady state

Remarks on result:

other: Day 40 of exposure, no significant difference with control

Remarks:

Conc.in environment / dose:250 µg Zn/l

Elimination:

yes

Parameter:

other: elimination

Depuration time (DT):

60 d

Details on results:

NO evidence of bioaccumulation of zinc from food (no difference between fish fed with polluted or unpolluted Daphnia)
Very little bioconcentration from water: concentration zinc in whole fish dry weight: from 330 to 390 µg Zn/g in 40 days

Validity criteria fulfilled:

yes

Conclusions:

Results demonstrating no biomagnification. Supports the general conclusion that bioconcentration is not a relevant parameter for the essential element zinc.

Description of key information

Zinc is an essential element which is actively regulated by organisms, so bioconcentration/bioaccumulation is not considered relevant for all inorganic zinc substances. As a rule, the ranges of BCF values observed have no relation to toxicity. They are the result of these active regulation mechanisms that keep the internal zinc concentration of the organisms within an optimal range.

 

Fluoride:

It was concluded that accumulation through food chains is of little significance in the aquatic environment.

Additional information

Bioaccumulation is not considered relevant for essential elements because of the general presence of homeostatic control mechanisms.

McGeer et al (2003) extensively reviewed the evidence on bioconcentration and bioaccumulation of zinc as a function of exposure concentration in a number of taxonomic groups (algae, molluscs, arthropods, annelids, salmonid fish, cyprinid fish, and other fish). The data clearly illustrated that internal zinc content is well regulated. All eight species taxonomic groups investigated exhibited very slight increases in whole body concentration over a dramatic increase in exposure concentration. In fact, most species did not show significant increases in zinc accumulation when exposure levels increased, even when exposure concentrations reached those that would be predicted to cause chronic effects. This suggests that adverse effects related to Zn exposure are independent of whole body accumulation. Due to the general lack of increased whole body and tissue concentrations at higher exposure levels, the zinc BCF data showed an inverse relationship to exposure concentrations. In all cases, the relationship of BCF to exposure was significant and negative. The slopes of the BCF/BAF – exposure relations were: algae: -1.0, insects: -0.79, arthropods: -0.73, molluscs: -0.83, salmonids: -0.92, Centrarchids: -0.80, Killifish: -0.84, other fish: -0.87. Overall, species mean slope was -0.85 +/- 0.03 (McGeer et al 2003).

The physiological basis for the inverse relationship of BCF to zinc exposure concentration arises from Zn uptake and control mechanisms. At low environmental zinc levels, organisms are able to sequester and retain Zn in tissues for essential functions. When Zn exposure is more elevated, aquatic organisms are able to control uptake. There is clear evidence that many species actively regulate their body Zn concentrations, including crustaceae, oligochaetes, mussels, gastropods, fish, amphipods, chironomids by different mechanisms (McGeer et al 2003).