Reaction products of sodium glucoheptonate with zinc sulfate and sodium hydroxide

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1974

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Guideline:

other: American Public Health Association, American Water Works Association and Water Pollution Control Federation: Standard methods for the examination of water and wastewater. 13th ed. Public Health Association, Washington, D. C. (1971).

Version / remarks:

96-h acute bioassay using juvenile rainbow trout

Deviations:

not specified

GLP compliance:

not specified

Specific details on test material used for the study:

Reagent-grade zinc sulphate

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

Well water (hardness: 330 mg/liter as CaCO3) was used for the hard water experiments and dechlorinated tap water (hardness = 25 mg/liter as CaCO3) was used for the soft water experiments.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

The eggs, in plastic hatching trays, were incubated in the 265-liter tanks. Water temperatures averaged 12.5 C until hatching was complete six weeks later.

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

25 mg/L as CaCO3 (soft water), 330 mg/L as CaCO3 (hard water)

Test temperature:

15°C (juveniles), 11°C (eyed eggs)

Details on test conditions:

TEST SYSTEM
- Test vessel: The test aquaria were 265-liter fiberglass tanks with acrylic plastic covers.
- Aeration: All tanks were aerated throughout the experiments
- Type of flow-through (e.g. peristaltic or proportional diluter): modified proportional diluter
- Renewal rate of test solution (frequency/flow rate): 2L every 3 min
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates):
- No. of vessels per control (replicates):

TEST MEDIUM / WATER PARAMETERS
- Alkalinity: hard water: 238 +- 13.85, soft water: 25 +- 4.65
- Intervals of water quality measurement: Weekly water-quality determinations were performed according to the methods of the American Public Health Association et al. (1976) and analysis of variance tests (P = 0.05) revealed no difference in water quaility between test aquaria.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : LC50

TEST CONCENTRATIONS
- Spacing factor for test concentrations:
- Test concentrations:

Duration:

96 h

Dose descriptor:

LC50

Remarks:

hard water

Effect conc.:

7 210 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

430 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Remarks:

soft water, life stage: eyed egg

Effect conc.:

2 720 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element

Basis for effect:

mortality (fish)

Conclusions:

The 96-hour LC50 values for juvenile rainbow trout in hard and soft water at 15°C were 7210 and 430 µg/L, respectively. Obviously, the acute toxicity of zinc to rainbow trout decreases as water hardness increases. The acute bloassay with eyed eggs resulted in a LC50 value of 2720 µg zinc/L, which indicates that the eyed egg is one of the more resistant stages in the rainbow trout!s life cycle.

Executive summary:

The 96-hour LC50 values for juvenile rainbow trout in hard and soft water at 15°C were 7210 and 430 µg/L, respectively. Obviously, the acute toxicity of zinc to rainbow trout decreases as water hardness increases. The acute bloassay with eyed eggs resulted in a LC50 value of 2720 µg zinc/L, which indicates that the eyed egg is one of the more resistant stages in the rainbow trout!s life cycle.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
Please refer to read-across statement attached under section 13 of this IUCLID file.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The toxicity of glucoheptonate complexes is driven by the supplied metal cation that can affect mineral balance of the organism, while no toxicity is attributed to the organic part of the molecule - glucoheptonate moiety - up to considerable amounts. The stability constant of zinc glucoheptonate is low, the chelate is a weak complex at normal environmental pH range (4-9) (Alekseev et al., 1998; please refer to the read-across statement). Thus, it is expected to dissociate in aquatic environments. The released equimolar amount of zinc from zinc glucoheptonate is assumed to determine its toxicity to fish. In this regard, the toxicity of zinc originated from another zinc compound could provide additional information on toxicity of zinc glucoheptonate. Therefore, data on zinc sulphate is presented here as source of data for the target substance zinc glucoheptonate to address the toxicity of the metal cation.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The source substance zinc sulphate is reagent grade.
Information on purity of the registered substance is provided in the target record under "Test material" as confidential. The calculation of a hazard value for zinc glucoheptonate is based on 75 % content of zinc glucoheptonate in the registered product. Another component is Na2SO4.
Sodium is a macroelement occurring in surface waters and in living organisms in considerable amounts. Sulfur species are also found in living organisms. Thus, these cations and anions are considered not to impact the toxicity of zinc glucoheptonate.

3. ANALOGUE APPROACH JUSTIFICATION
As announced in the hypothesis for the read-across, zinc glucoheptonate is expected to dissociate in aquatic environments (at normal pH range 4-9). Zinc sulphate is a salt that fully dissociates in water, too. However, the amount of zinc released from zinc glucoheptonate and from zinc sulphate is different because the molecular masses of these compound are different . Also the proportion of zinc to glucoheptonate or to sulphate anions will be different. As a result, more zinc will be released from the salt zinc sulphate than from zinc glucoheptonate. Thus, data on zinc sulphate represent worst case for zinc glucoheptonate.

4. DATA MATRIX
please refer to the data matrix attached in section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

96 h

Dose descriptor:

LC50

Remarks:

soft water (25 mg CaCO3/L)

Effect conc.:

2.71 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Remarks:

hard water (330 mg CaCO3/L)

Effect conc.:

45.51 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Remarks:

life stage: eyed eggs, soft water (25 mg CaCO3/L)

Effect conc.:

17.17 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element

Basis for effect:

mortality (fish)

Sublethal observations / clinical signs:

MW Zn in ZnGHA = 2 x 65.4 = 130.8 g/mol

MW ZnGHA = 619.2 g/mol

EC (ZnGHA) in target = EC (Zn) in source / 130.8 x 619.2

LC50

LC (Zn) in source = 430 µg/L

LC (ZnGHA) in target = 430 / 130.8 x 619.2 = 2.04 mg/L

Purity: 75%

2.04 / 0.75 = 2.71 mg/L

LC50

LC (Zn) in source = 7210 µg/L

LC (ZnGHA) in target = 7210 / 130.8 x 619.2 = 34.13 mg/L

Purity: 75%

34.13 / 0.75 = 45.51 mg/L

LC50

LC (Zn) in source = 2720 µg/L

LC (ZnGHA) in target = 2720 / 130.8 x 619.2 = 12.88 mg/L

Purity: 75%

12.88 / 0.75 = 17.17 mg/L

Conclusions:

The 96-hour LC50 values for juvenile rainbow trout in hard and soft water at 15°C were 45.51 and 2.71 mg/L, respectively. The acute bloassay with eyed eggs resulted in a LC50 value of 17.17 mg ZnGHA/L, which indicates that the eyed egg is one of the more resistant stages in the rainbow trout!s life cycle.

Executive summary:

The 96-hour LC50 values for juvenile rainbow trout in hard and soft water at 15°C were 45.51 and 2.71 mg/L, respectively. The acute bloassay with eyed eggs resulted in a LC50 value of 17.17 mg ZnGHA/L, which indicates that the eyed egg is one of the more resistant stages in the rainbow trout!s life cycle.

Description of key information

There is no data available for the target substance zinc glucoheptonate (ZnGHA) on acute toxicity towards fish. However, there is data available for different zinc compounds. Since the ecotoxicity of zinc glucoheptonate is driven by zinc ion, this data is used within a frame of a weight-of-evidence approach to assess the toxicity of zinc glucoheptonate. The effect levels of of the different zinc compounds are converted to ZnGHA under consideration of the molecular weight and the purity.

Effect-concentrations of zinc on Cottus bairdi, Micropterus salmoides, Lepomis macrochirus, Ictalurus punctatus, Salmo gairdnerii Richards, Oncorhynchus tschawytscha and Pimephales promelas were found in literature. The values were converted to the target substance ZnGHA (table 1). Except for L. macrochirus (Pickering and Henderson, 1966 (reviewed by Reed et al., 1980)) and the swim-up alevins of O. tschawytscha, all LC50 (96 h,186 h, 14 d) values were above 1 mg ZnGHA/L (table 1). 

The toxicity of zinc to the mottled sculpin (Cottus bairdi), the second most sensitive fish species for which toxicity data were available was tested. The median 96-h lethal zinc concentration (LC50) was 439 µg Zn/L (hardness of 154 mg/L as CaCO3) for feral mottled sculpin (Cottus bairdi), decreasing to a median incipient lethal level of 266 µg Zn/L after 13 d. The statistically significant no-observed-effect concentration and lowest-observed- effect concentration were 172 and 379 µg Zn/L, respectively (Brinkman et al., 2005).

The 96-hour LC50 values for juvenile rainbow trout in hard and soft water at 15°C were 7.21 and 0.43 mg Zn/L (2.71 and 45.51 mg ZnGHA/L), respectively. Obviously, the acute toxicity of zinc to rainbow trout decreases as water hardness increases (Sinley et al., 1974).

The acute toxicity of Zn to Pimephales promelas, at three pH values (6.3, 7.3, and 8.3) in very hard reconstituted water (hardness 300-320 mg/L as CaC03) was tested. In contrast to other species, for P. promelas there was no linear decrease in zinc toxicity with decreasing pH. Toxicity of zinc to P. promelas was greatest at the intermediate pH (7.3) (LC50 = 330 µg Zn/L; 2.08 mg ZnGHA/L) and was least at the low pH (6.3) (LC50 = 780 µg/L; 4.92 mg ZnGHA/L). At the pH of 8.3 the LC50 it was 500 µg/L (3.16 mg ZnGHA/L) (Schubauer-Berigan et al., 1993).

Bluegill fry, channel catfish fingerlings, and largemouth bass fingerlings were subjected to varying concentrations of soluble zinc in waters relatively high in alkalinity (199 - 335 mg/L) and the salts of calcium and magnesium. The LC50 (14 d) value for Largemouth bass (Micropterus salmoides) was 8 mg Zn/L (50.5 mg ZnGHA/L), for Bluegill (Lepomis macrochirus) it was 11 mg Zn/L (69.43 mg ZnGHA/L), and for the Channel catfish (Ictalurus punctatus) it was 8.2 mg Zn/L (51.76 mg ZnGHA/L) (Reed et al., 1980).

Lloyd et al. (1961) studies the impact of water hardness on the median period of survival ofSalmo gairdnerii Richards. It was demonstrated that the hardness of water has a significant impact on zinc toxicity. While in soft water (15 - 20 mg/L as CaCO3) the zinc concentration giving a median period of survival was 0.56 mg Zn/L (3.53 mg ZnGHA/L) in a total exposure time of 7 days, the zinc concentration giving a median period of survival in hard water (320 mg/L as CaCO3) was 3.5 mg Zn/L (22.09 mg ZnGHA/L) in a total exposure time of 3 days.

Continuous-flow toxicity tests were conducted to determine the relative tolerances of newly hatched alevins, swim-up alevins, parr, and smolts of chinook salmon (Oncorhynchutss tshawytscha) and steelhead (Salmo gairdneri) to zinc. Newly hatched alevins were much more tolerant to zinc than were later juvenile forms. However, the later progression from swim-up alevin, through parr, to smolt was accompanied by a slight increase in metal tolerance. The 96-h LC50 values for all four life stages of Chinook samon (Oncorhynchus tshawytscha) ranged from 97 to 701 µg Zn/L (0.61 – 4.42 mg ZnGHA/L). Steelhead were consistently more sensitive to these metals than were chinook salmon (Chapman, 1978).

For rainbow trouts (O. mykiss) the eyed egg was found to be one of the more resistant stages in the life cycle. The acute bioassay with eyed eggs resulted in a LC50 value of 2720 µg Zn/L (17.17 mg ZnGHA/L) (Sinley et al., 1974).

Conclusion

The regarded studies indicate that the LC50-values of ZnGHA on fish are clearly above the cut-off value for classification of 1 mg/L. In addition, it was shown, that water hardness significantly decreases zinc toxicity (Lloyd, 1961, Sinley et al., 1974), whereas a decrease of pH does not show a clear effect, as demonstrated for other species (Schubauer-Berigan et al., 1993). Regarding life-stage, eyed eggs of O. mykiss were found to be one of the more resistant stages in the life cycle (Sinley et al., 1974). In the case of O. tschawytscha, newly hatched alevins were much more tolerant to zinc than were later juvenile forms. However, the later progression from swim-up alevin, through parr, to smolt was accompanied by a slight increase in metal tolerance (Chapman, 1978).

Table 1: Lethal concentration (LC)-values from studies performed with elemental zinc (Zn²⁺) converted to ZnGHA under consideration of the molecular weight ande the purity

Species	Duration of exposure	Dose descriptor	Basis for effect	elemental Zn in source substance [mg/L]	Zn GHA (75 %) [mg/L]	Impact	Reference
Cottus bairdi	96 h	LC50	mortality	0.439	2.77		Brinkman et al., 2005
C. bairdi	96 h	NOEC	mortality	0.172	1.09		Brinkman et al., 2005
C. bairdi	96 h	LOEC	mortality	0.379	2.39		Brinkman et al., 2005
O. mykiss	96 h	LC50	mortality	0.43	2.71	soft water (25 mg CaCO3/L)	Sinley et al. 1974
O. mykiss	96 h	LC50	mortality	7.21	45.51	hard water (330 mg CaCO3/L)	Sinley et al. 1974
O. mykiss	96 h	LC50	mortality	2.72	17.17	soft water; life stage: eyed egg	Sinley et al. 1974
Pimephales promelas	96 h	LC50	mortality	0.78	4.92	pH 6-6.5	Schubauer-Berigan et al. 1993
P. promelas	96 h	LC50	mortality	0.33	2.08	pH 7-7.5	Schubauer-Berigan et al. 1993
P. promelas	96 h	LC50	mortality	0.5	3.16	pH 8-8.5	Schubauer-Berigan et al. 1993
Micropterus salmoides	638 min	median lethal time (time after which 50 % mortality occured)	mortality	30	189.36		Reed et al., 1980
M. salmoides	14 d	LC50	mortality	8	50.5		Reed et al., 1980
Lepomis macrochirus	14 d	LC50	mortality	11	69.43		Reed et al., 1980
Ictalurus punctatus	14 d	LC50	mortality	8.2	51.76		Reed et al., 1980
L. macrochirus	96 h	LC50	mortality	5.46	0.03	alkalinity 18 mg/L, 25°C	Pickering and Henderson (1966) (reviewed by Reed et al. (1980))
L. macrochirus	96 h	LC50	mortality	40.9	0.26	alkalinity 300 mg/L, pH 8,1 25°C	Pickering and Henderson (1966) (reviewed by Reed et al. (1980))
L. macrochirus	96 h	LC50	mortality	11.5	0.07	alkalinity 36 mg/L, pH7 - 7.8, 7°C	Pickering and Henderson (1966) (reviewed by Reed et al. (1980))
Salmo gairdnerii Richards	3 d	median period of survival	mortality	3.5	22.09	hard water (320 mg/L as CaCO3)	Lloyd, 61
S. gairdnerii Richards	7 d	median period of survival	mortality	0.56	3.53	soft water (15-20 mg/L as CaCO3)	Lloyd, 61
Oncorhynchus tschawytscha	96 h	LC50	mortality	>0.661	>4.17	Life stage: newly hatched alevins	Chapman, 1978
O. tschawytscha	96 h	LC50	mortality	0.097	0.61	Life stage: swim-up alevins	Chapman, 1978
O. tschawytscha	96 h	LC50	mortality	0.463	2.92	Life stage: 5-8 months old parrs	Chapman, 1978
O. tschawytscha	96 h	LC50	mortality	0.701	4.42	Life stage: smolts	Chapman, 1978
O. tschawytscha	186 h	LC50	mortality	>0.661	>4.17	Life stage: newly hatched alevins	Chapman, 1978
O. tschawytscha	186 h	LC50	mortality	0.097	0.61	Life stage: swim-up alevins	Chapman, 1978
O. tschawytscha	186 h	LC50	mortality	0.395	2.49	Life stage: 5-8 months old parrs	Chapman, 1978
O. tschawytscha	186 h	LC50	mortality	0.364	2.3	Life stage: smolts	Chapman, 1978

 

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

2.71 mg/L