Lithium hexafluorophosphate(1-)

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adult fish: sub(lethal) effects

Type of information:

other: Information on major hydrolysis product of the registered substance (released rapidly on contact with water/moisture).

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Detailed report of experimental work, published in a peer-reviewed journal

Justification for type of information:

Part of weight-of-evidence approach adapting the information requirements of Annex IX 9.1.6 under REACH in accordance with Annex XI Section 1.2. Lithium hexafluorophosphate is reactive and unstable in water and air. Reaction in contact with water proceeds rapidly, with release of hydrogen fluoride (forming hydrofluoric acid). The reaction can be summarised as: LiPF6 + 4H2O → 5HF + LiF + H3PO4. The release of HF occurs within 4 seconds in water (Unpublished stability and degradation report, 2011). Subsequently, the lithium fluoride hydrolysis product will dissociate, releasing F- ions. Hence the long-term toxicity of LiPF6 to aquatic organisms is determined by the toxicities of its hydrolysis products F-, Li+ and PO4(3-). Sufficient data concerning these toxicities are available to allow determination of the long-term environmental toxicity of LiPF6 without the performance of new tests.

Principles of method if other than guideline:

Twelve groups of rainbow trout were fed a basal diet. Each groups diet was supplement with varying concentration of dibasic sodium phosphate.
Groups monitored for effects on growth, feed intake, concentration of inorganic phosphate in plasma over 53 days

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
PO4(3-) is a hydrolysis product of the reaction of LiPF6 with water

Analytical monitoring:

not specified

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Test type:

flow-through

Water media type:

freshwater

Total exposure duration:

53 d

Hardness:

Ca concentration ranged from 40-50 mg/L

Test temperature:

16.5-17.5C

Nominal and measured concentrations:

Fish were fed pelleted diet containing 1 - 12 g phosphorus/kg dry matter (prepared by diet supplementation with dibasic sodium phosphate)

Duration:

53 d

Dose descriptor:

LOEC

Effect conc.:

2 other: g/kg

Nominal / measured:

nominal

Conc. based on:

other: g phosphorus in dry feed

Basis for effect:

weight

Details on results:

Pelleted feed intake and bodyweights increased with increasing levels of phosphate administration. Bodyweight increases showed a plateau around 3-4 g P/kg dry matter in feed. No adverse effects were reported.

Conclusions:

Direct administration to fish of phosphate in food pellets over a prolonged period caused increased growth without reported adverse effects.

Reference 2

Endpoint:

fish early-life stage toxicity

Type of information:

other: Information on major hydrolysis product of the registered substance (released rapidly on contact with water/moisture).

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Justification for type of information:

Part of weight-of-evidence approach adapting the information requirements of Annex IX 9.1.6 under REACH in accordance with Annex XI Section 1.2. Lithium hexafluorophosphate is reactive and unstable in water and air. Reaction in contact with water proceeds rapidly, with release of hydrogen fluoride (forming hydrofluoric acid). The reaction can be summarised as: LiPF6 + 4H2O → 5HF + LiF + H3PO4. The release of HF occurs within 4 seconds in water (Unpublished stability and degradation report, 2011). Subsequently, the lithium fluoride hydrolysis product will dissociate, releasing F- ions. Hence the long-term toxicity of LiPF6 to aquatic organisms is determined by the toxicities of its hydrolysis products F-, Li+ and PO4(3-). Sufficient data concerning these toxicities are available to allow determination of the long-term environmental toxicity of LiPF6 without the performance of new tests.

Qualifier:

according to guideline

Guideline:

other: EPA 540/86 Fish early life stage test

Principles of method if other than guideline:

Fish embryos <24h old were exposed under flow-through conditions for 22 days. Hatching, mortality, growth were monitored.

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Li+ is a hydrolysis product of the reaction of LiPF6 with water

Analytical monitoring:

no

Details on test solutions:

Prepared in limed/flocculated,filtered and UV-irradiated lake water

Test organisms (species):

Pimephales promelas

Details on test organisms:

Embyros <24h old

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

22 d

Remarks on exposure duration:

22 days from the mean hatch time for controls

Hardness:

56-70 mg CaCO3/l

Test temperature:

24.4-25C

pH:

7.2-7.5

Dissolved oxygen:

>84% saturation

Nominal and measured concentrations:

1.2, 1.9, 3.2, 5.4, 9.0, 15.0 mg LiCl/l (nominal)

Details on test conditions:

Intermittent flow diluter feeding glass aquaria

Reference substance (positive control):

no

Duration:

22 d

Dose descriptor:

LC50

Effect conc.:

1.4 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Li+ concentration

Basis for effect:

mortality

Duration:

22 d

Dose descriptor:

EC50

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Li+ concentration

Basis for effect:

growth rate

Duration:

22 d

Dose descriptor:

LOEC

Effect conc.:

0.31 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Li+ concentration

Basis for effect:

length

Remarks:

(most sensitive growth parameter)

Duration:

22 d

Dose descriptor:

NOEC

Effect conc.:

0.2 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Li+ concentration

Basis for effect:

length

Remarks:

(most sensitive growth parameter)

Conclusions:

NOEC in this fish early life stage study was 0.2 mg Li+/l.

Reference 3

Endpoint:

long-term toxicity to fish, other

Remarks:

Prolonged fish toxicity test

Type of information:

other: Information on major hydrolysis product of the registered substance (released rapidly on contact with water/moisture).

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well described report of experimental studies, published in a peer-reviewed journal

Justification for type of information:

Part of weight-of-evidence approach adapting the information requirements of Annex IX 9.1.6 under REACH in accordance with Annex XI Section 1.2. Lithium hexafluorophosphate is reactive and unstable in water and air. Reaction in contact with water proceeds rapidly, with release of hydrogen fluoride (forming hydrofluoric acid). The reaction can be summarised as: LiPF6 + 4H2O → 5HF + LiF + H3PO4. The release of HF occurs within 4 seconds in water (Unpublished stability and degradation report, 2011). Subsequently, the lithium fluoride hydrolysis product will dissociate, releasing F- ions. Hence the long-term toxicity of LiPF6 to aquatic organisms is determined by the toxicities of its hydrolysis products F-, Li+ and PO4(3-). Sufficient data concerning these toxicities are available to allow determination of the long-term environmental toxicity of LiPF6 without the performance of new tests.

Qualifier:

according to guideline

Guideline:

other: EPA/600/4-91/002 Short term methods for estimating chronic toxicity of effluents and receiving waters to freshwater organisms

Principles of method if other than guideline:

Test of lithium toxicity to fathead minnow larvae (7-day exposure)

GLP compliance:

not specified

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Li+ is a product of the hydrolysis reaction of LiPF6 with water

Analytical monitoring:

yes

Details on sampling:

In experiment 1, samples from the lowest 4 of 5 test concentrations were analysed.

Details on test solutions:

Prepared in river water (Li< 0.04 mg/l, Na 17.4 mg/l) or in Dilute Mineral Water (Li <0.04 mg/l, Na 2.8 mg/l)

Test organisms (species):

Pimephales promelas

Details on test organisms:

Larval stage

Test type:

semi-static

Water media type:

freshwater

Total exposure duration:

7 d

Test temperature:

25C

Nominal and measured concentrations:

Experiment 1: 0.26, 0.98, 1.90, 3.0 mg Li+/l (measured) plus 4.0 mg/l (nominal).
Experiment 2: 0.5, 1.0, 2.0, 4.0 mg Li+/l (nominal)

Details on test conditions:

Daily test solution renewal

Duration:

7 d

Dose descriptor:

IC50

Effect conc.:

0.57 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: Li+ concentration

Basis for effect:

growth rate

Remarks on result:

other: In Dilute Mineral Water

Duration:

7 d

Dose descriptor:

other: IC25

Effect conc.:

0.38 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: Li+ concentration

Basis for effect:

growth rate

Remarks on result:

other: In Dilute Mineral Water

Duration:

7 d

Dose descriptor:

IC50

Effect conc.:

2.47 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: Li+ concentration

Basis for effect:

growth rate

Remarks on result:

other: In river water

Duration:

7 d

Dose descriptor:

other: IC25

Effect conc.:

1.99

Nominal / measured:

meas. (not specified)

Conc. based on:

other: Li+ concentration

Basis for effect:

growth rate

Remarks on result:

other: In river water

Details on results:

An effect of sodium concentration was suggested by the observed lower toxicity of lithium in Dilute Mineral Water compared to river water. This was confirmed in a subsequent experiment using Dilute Mineral Water with added sodium: with 40 mg Na/l, exposure to Li+ at 4 mg/l caused no evident toxicity while with 10 mg Na/l the same Li+ concentration proved 100% lethal.

The authors concluded that in natural waters the presence of sodium is sufficient to prevent lithium toxicity, noting that high lithium tolerance limits for three species of Utah river fish were reported by workers who used reconstituted river water (49 mg Na/l) in their tests.

Conclusions:

Although an IC25 value for larval growth as low as 0.38 ng Li+/l was reported, the study results indicate this will have little relevance for risk assessment in natural waters (where the presence of sodium will limit Li+ toxicity).

Reference 4

Endpoint:

fish life cycle toxicity

Type of information:

other: Information on major hydrolysis product of the registered substance (released rapidly on contact with water/moisture).

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Detailed report of experimental work undertaken for US Government Department

Justification for type of information:

Part of weight-of-evidence approach adapting the information requirements of Annex IX 9.1.6 under REACH in accordance with Annex XI Section 1.2. Lithium hexafluorophosphate is reactive and unstable in water and air. Reaction in contact with water proceeds rapidly, with release of hydrogen fluoride (forming hydrofluoric acid). The reaction can be summarised as: LiPF6 + 4H2O → 5HF + LiF + H3PO4. The release of HF occurs within 4 seconds in water (Unpublished stability and degradation report, 2011). Subsequently, the lithium fluoride hydrolysis product will dissociate, releasing F- ions. Hence the long-term toxicity of LiPF6 to aquatic organisms is determined by the toxicities of its hydrolysis products F-, Li+ and PO4(3-). Sufficient data concerning these toxicities are available to allow determination of the long-term environmental toxicity of LiPF6 without the performance of new tests.

Principles of method if other than guideline:

Investigation of lithium effects on early life stages of the rainbow trout life cycle

GLP compliance:

no

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Li+ is a hydrolysis product of the reaction of LiPF6 with water

Analytical monitoring:

yes

Details on test solutions:

All test concentrations were sampled for Li+ analysis

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Test type:

flow-through

Water media type:

freshwater

Remarks on exposure duration:

31-32 days for egg hatching tests. 30 days (tests 1-2) or 10 days (test 3) for juvenile survival tests .

Post exposure observation period:

In egg hatching tests: 31-32 days after egg exposure

Hardness:

64 - 70 mg CaCO3/l

Test temperature:

Egg hatching tests: 9.9-12.5C. Juvenile survival tests: 9.8-10.6C.

Nominal and measured concentrations:

Hatching tests:
- nominal 1-1000 mg Li+/l, mean measured 1.01-1071 mg Li+/l (test 1: Li from Li2CO3)
- nominal 0.25-70 mg Li+/l, mean measured 0.21-70.8 mg Li+/l (tests 2 and 3: Li+ from Li2CO3).
In juvenile survival tests:
- nominal 0.06-1.0 mg Li+/l, mean measured 0.05-1.35 mg Li+/l (test 1: Li from Li2CO3)
- nominal 0.25-4.0 mg Li+/l, mean measured 0.23-4.01 mg Li+/l (tests 2 and 3: Li+ from Li2CO3).

Details on test conditions:

Control groups water contained <0.02 mg Li+/l

Duration:

30 d

Dose descriptor:

LOEC

Effect conc.:

0.6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: Li+ concentration

Basis for effect:

other: juvenile survival

Remarks on result:

other: Juvenile survival proved to be the most sensitive endpoint among all of the life cycle stages investigated

Details on results:

Conclusions from 3 separate experiments for each endpoint.
Egg integrity (protective membrane maintenance): lowest LOEC 4.3 mg Li+/l (NOEC circa 1 mg Li+/l)
Egg fertilisation rate: lowest LOEC 70 mg Li+/l
Completion of embryogenesis: LOEC <10 mgLi+/l (NOEC circa 1 mg Li+/l)
Egg hatching: lowest LOEC 3.6 mg Li+/l (NOEC circa 1 mg Li+/l)
Fry survival: lowest LOEC 2.4 mg Li+/l
Juvenile survival: lowest LOEC 0.6 mg Li+/l (NOEC may be <1 mg Li+/l).

Li+ generated from lithium carbonate could be tested to higher concentrations and (comparing equivalent nominal Li+ concentrations) appeared generally slightly more toxic than Li+ generated from lithium fluoride. However this difference may reflect lower/slower solubilisation of Li+ from LiF.

Conclusions:

The lowest determined LOEC value in this study was 0.6 mg Li+/l (for juvenile survival).

Reference 5

Endpoint:

adult fish: sub(lethal) effects

Type of information:

other: Information on major hydrolysis product of the registered substance (released rapidly on contact with water/moisture).

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test result reviewed/assessed in an authoritative expert review document

Justification for type of information:

Part of weight-of-evidence approach adapting the information requirements of Annex IX 9.1.6 under REACH in accordance with Annex XI Section 1.2. Lithium hexafluorophosphate is reactive and unstable in water and air. Reaction in contact with water proceeds rapidly, with release of hydrogen fluoride (forming hydrofluoric acid). The reaction can be summarised as: LiPF6 + 4H2O → 5HF + LiF + H3PO4. The release of HF occurs within 4 seconds in water (Unpublished stability and degradation report, 2011). Subsequently, the lithium fluoride hydrolysis product will dissociate, releasing F- ions. Hence the long-term toxicity of LiPF6 to aquatic organisms is determined by the toxicities of its hydrolysis products F-, Li+ and PO4(3-). Sufficient data concerning these toxicities are available to allow determination of the long-term environmental toxicity of LiPF6 without the performance of new tests.

Principles of method if other than guideline:

21-day test of toxicity to fish

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
F- is a product of the rapid reaction of LIPF6 with water

Analytical monitoring:

yes

Test type:

semi-static

Water media type:

freshwater

Total exposure duration:

21 d

Hardness:

12 mg CaCO3/l

Details on test conditions:

Test solutions renewed daily

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

4 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: fluoride concentration

Basis for effect:

adult mortality

Remarks on result:

other: Slooff et al, 1988

Details on results:

The reported LC5 value of 4 mg/l is considered in the EU RAR document to correspond to a mortality NOEC

Conclusions:

A 21-day NOEC of 4 mg F-/l is reported for adult mortality

Reference 6

Endpoint:

long-term toxicity to fish, other

Remarks:

prolonged fish toxicity studies

Type of information:

other: Information on major hydrolysis product of the registered substance (released rapidly on contact with water/moisture).

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Detailed review of published information, subjected to academic review

Justification for type of information:

Part of weight-of-evidence approach adapting the information requirements of Annex IX 9.1.6 under REACH in accordance with Annex XI Section 1.2. Lithium hexafluorophosphate is reactive and unstable in water and air. Reaction in contact with water proceeds rapidly, with release of hydrogen fluoride (forming hydrofluoric acid). The reaction can be summarised as: LiPF6 + 4H2O → 5HF + LiF + H3PO4. The release of HF occurs within 4 seconds in water (Unpublished stability and degradation report, 2011). Subsequently, the lithium fluoride hydrolysis product will dissociate, releasing F- ions. Hence the long-term toxicity of LiPF6 to aquatic organisms is determined by the toxicities of its hydrolysis products F-, Li+ and PO4(3-). Sufficient data concerning these toxicities are available to allow determination of the long-term environmental toxicity of LiPF6 without the performance of new tests.

Principles of method if other than guideline:

Statistical analysis of published data on acute and longer term toxicity of fluoride to fish

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
F- is a product of the rapid reaction of LiPF6 with water

Test organisms (species):

other: Rainbow trout (O. mykiss) and 6 other fish species

Remarks on exposure duration:

Acute toxicity data: <4 days. Longer term toxicity data: >4 days

Dose descriptor:

LC50

Effect conc.:

2.3 mg/L

Conc. based on:

other: fluoride concentration

Basis for effect:

mortality

Remarks on result:

other: Lowest reported value for studies of >4 days duration

Details on results:

O. mykiss was the fish species most sensitive to fluoride toxicity in acute toxicity. In longer term tests, a wide range of LC50 values have been reported for O. mykiss, giving higher and lower LC50 values than those reported for other fish species. The lowest reported LC50 value for longer term exposure was 2.3 mg F-/l (for O. mykiss) and the calculated 95th percentile longer term LC50 value (across all fish species considered) was 2.62 mg F-/l.

Conclusions:

The lowest fish NOEC in studies of duration >4 days cited in this review was 2.3 mg F-/l.

Reference 7

Endpoint:

long-term toxicity to fish, other

Remarks:

prolonged fish toxicity information

Type of information:

other: Information on major hydrolysis product of the registered substance (released rapidly on contact with water/moisture).

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Results cited in authoritative review by an international expert group, but lacking experimental detail

Justification for type of information:

Part of weight-of-evidence approach adapting the information requirements of Annex IX 9.1.6 under REACH in accordance with Annex XI Section 1.2. Lithium hexafluorophosphate is reactive and unstable in water and air. Reaction in contact with water proceeds rapidly, with release of hydrogen fluoride (forming hydrofluoric acid). The reaction can be summarised as: LiPF6 + 4H2O → 5HF + LiF + H3PO4. The release of HF occurs within 4 seconds in water (Unpublished stability and degradation report, 2011). Subsequently, the lithium fluoride hydrolysis product will dissociate, releasing F- ions. Hence the long-term toxicity of LiPF6 to aquatic organisms is determined by the toxicities of its hydrolysis products F-, Li+ and PO4(3-). Sufficient data concerning these toxicities are available to allow determination of the long-term environmental toxicity of LiPF6 without the performance of new tests.

Principles of method if other than guideline:

Review of fish toxicity data in 3 different published papers

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
F- is a product of the rapid reaction of LiPF6 with water

Analytical monitoring:

not specified

Test organisms (species):

other: Rainbow trout (Neuhold and Sigler, 1960). Rainbow and brown trout (Camargo, 1966). Mullet (Hemens et al, 1975).

Details on test organisms:

Rainbow and brown trout: freshwater species. Mullet: marine species

Test type:

other: Semi-static (Neuhold and Sigler). Not specified (Camargo, Hemens et al)

Remarks on exposure duration:

20 days (Neuhold and Sigler). Safe level calculated for infinite exposure (Camargo). 68-113 days (Hemens et al)

Hardness:

Soft water, <3 mg CaCOs/l (Neuhold and Sigler). Unspecified (Camargo, Hemens et al)

Test temperature:

13C (Neuhold and Sigler). Unspecified (Camargo, Hemens et al)

Duration:

20 d

Dose descriptor:

LC50

Effect conc.:

>= 2.7 - <= 4.7 mg/L

Nominal / measured:

not specified

Conc. based on:

other: fluoride concentration

Basis for effect:

adult mortality

Remarks on result:

other: Rainbow trout (Neuhold and Sigler, 1960)

Dose descriptor:

NOEC

Effect conc.:

5.1 mg/L

Conc. based on:

other: fluoride concentration

Basis for effect:

other: calculated safe concentration for long-term exposure

Remarks on result:

other: Rainbow trout (Camargo, 1966)

Dose descriptor:

NOEC

Effect conc.:

7.5

Conc. based on:

other: fluoride concentration

Basis for effect:

other: calculated safe concentration for long-term exposure

Remarks on result:

other: Brown trout (Camagro, 1966)

Duration:

113 d

Dose descriptor:

NOEC

Effect conc.:

5.5 mg/L

Nominal / measured:

not specified

Conc. based on:

other: fluoride concentration

Basis for effect:

adult mortality

Remarks on result:

other: Mullet (Hemens et al, 1975). 68 day NOEC 5.9 mgF-/l

Duration:

113 d

Dose descriptor:

other: Effect concentration

Effect conc.:

5.5 mg/L

Nominal / measured:

not specified

Conc. based on:

other: fluoride concentration

Basis for effect:

growth rate

Remarks:

: reduced growth of smaller (16/18 mm) test fish

Remarks on result:

other: Mullet (Hemens et al, 1975)

Description of key information

Given the hydrolytic instability of LiPF6, long-term toxicity to aquatic organisms is best defined in terms of the toxicity of its F-, Li+ and PO4(3 -) hydrolysis products as a weight-of-evidence approach.  Review of the known toxicities of these leads to a clear conclusion that the fluoride released from LiPF6 is the “toxic marker” for long-term toxicity to fish: from the lowest reported fluoride long-term fish NOEC of 2.3 mg F-/l a long-term NOEC value of 3.1 mg LiPF6/l is calculated (based on the expected complete F- release).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

3.1 mg/L

Additional information

HF

In the aquatic environment, HF will principally be present in the form of fluoride ion. For this reason, test data obtained using soluble inorganic fluorides can be used to evaluate HF toxicity and LC50 or NOEC values expressed in terms of mg F-/l are appropriate for assessment of HF toxicity to aquatic organisms (HF: EU Risk Assessment Report, 2001).

 

Fluoride

A number of long-term toxicity tests with freshwater fish have been reviewed (WHO EHC 227, 2002): in a 20-day semistatic test using soft water (CaCO3 <3 mg/l), long-term LC50 values of 2.7 – 4.7 mg/l were recorded, but other workers calculated that 5.1 and 7.5 mg F-/l represent safe concentrations for rainbow and brown trout respectively. A long-term NOEC for rainbow trout (21-day semistatic test LC5 value) of 4 mg F-/l in very soft water (CaCO3 12 mg/l) is cited in the HF: EU Risk Assessment Report (2001), and a test of mullet (marine fish) exposed to fluoride at 5.9 or 5.5 mg/l for 68 or 113 days had no effect on survival, although growth of smaller fish was reduced (WHO EHC 227, 2002).  In a detailed study of public domain information of fluoride toxicity to various fish species, Fleiss (2011) showed that among LC50 values from studies longer than 4 days, rainbow trout gave both the lowest and highest values: the lowest reported LC50 value was 2.3 mg/l. The lower 95^thpercentile value calculated from all longer term LC50s considered was 2.62 mgF-/l.

 

Lithium

After three separate experiments on rainbow trout, looking at egg integrity, fertilisation, embryogenesis, hatching and then sac-fry and juvenile survival, Emery, Klopfer and Skalski (1981) reported “lowest rejected concentration tested” (LOEC) values of 3.3 mg Li+/l following LiF exposure and 0.6 mg Li+/l after Li2CO3 exposure. 

 

Kzos, Beauchamp and Stewart (2003) measured growth inhibition of fathead minnow larvae exposed to lithium for 7 days in low sodium (ca. 2.8 mg/l) water or natural stream water (ca. 17 mg Na/l) and found lithium toxicity to be inversely related to sodium level: with added sodium at 40 mg/l, exposure to Li+ at 4 mg/l caused no evident toxicity while but with 10 mg Na/l the same Li+ concentration proved 100% lethal. In the low sodium water an IC50 value for growth of 0.57 mg/l was reported. These workers concluded that in natural waters the presence of sodium is sufficient to prevent lithium toxicity, noting that high lithium tolerance limits for three species ofriver fish were reported by workers who used reconstituted river water (49 mg Na/l) in their tests.

 

A fish early life stage study using the fathead minnow (conducted according to US EPA and ASTM guidelines and under GLP) and lithium chloride is available (Long, Brown and Woodburn, 1998). Effects on embryos and larvae were assessed over a 26-day period (including 22-23 days post hatching) in treated river water (hardness 56-70 mg/l as CaCO3). EC50 and NOEC values calculated in terms of Li+ ion concentration were 1.0 and 0.2 mg/l respectively.

 

Phosphate

A study of phosphorus supplementation in rainbow trout over 53 days found no evidence that addition of Na2HPO4 into low-phosphorus basal diet at levels giving up to 10.96 g P/kg dry weight (equivalent to 33.6 g PO4/kg or 50.2 g Na2HPO4/kg) adversely affected growth or survival; indeed, weight gain was increased with phosphate supplementation up to a level of approximately 5 g P/kg in diet (equivalent to 8g PO4/kg) (Rodehutscord, 1996). 

 

Key value for assessment

The NOEC value reported for lithium in a fish early life stage test (0.2 mg/l) corresponds to an LiPF6 concentration of 4.4 mg/l. Given the range of long-term fish NOEC and LC50 values reported for fluoride (variable mainly due to variations in water hardness), it is reasonable to consider the lowest long-term LC50 value of 2.3 mg F-/l (below the long-term fish NOEC cited in the HF: EU Risk Assessment Report, 2001 and below the level occurring naturally in surface waters of areas where fluoride-containing rock formations exist) as an indicative threshold value for fluoride toxicity: this corresponds to an LiPF6 concentration of 3.1 mg/l. Due to its low toxicity, the contribution of phosphate to LiPF6 toxicity is considered insignificant. It is therefore concluded that the fluoride released from LiPF6 in water is the “toxic marker” for long-term toxicity to fish and a long-term NOEC value of 3.1 mg/l for LiPF6 is taken for use in assessment.