Potassium salts of [hexane-1,6-diylbis[nitrilobis(methylene)]]tetrakisphosphonic acid (4-7 K:1)

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:

key study

Study period:

from 9 July 1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: US EPA 1979

Deviations:

not applicable

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

no

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all

- Sampling method: concentrations were determined on days 0, 2, 4, 7, 9, and 11.

- Sample storage conditions before analysis: not reported

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: direct weights of the test substance, corrected for active acid, were added directly to the test vessels.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM

- Common name: rainbow trout

- Source: fishery called Creek hatchery in Lewiston, Montana, USA.

- Length at study initiation (length definition, mean, range and SD): initial mean standard length 34.3 mm

- Weight at study initiation (mean and range, SD): initial mean weight of 0.57g

- Method of breeding: not reported


- Feeding during test

- Food type: commercial fish food Rangen's

- Amount: 3% body weight

- Frequency: daily


ACCLIMATION

- Acclimation period: 14 days

- Acclimation conditions (same as test or not): similar conditions to test: holding tanks on 16 h daylight period.

- Type and amount of food: commercial fish food Rangen's, 3% body weight

- Feeding frequency: daily

- Health during acclimation (any mortality observed): not reported

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

14 d

Hardness:

255 ppm as CacO3 in the dilution water

pH:

control: 8.1-8.6
low concentration: 7.6-8.4 (new solution) 8.3-8.6 (old solution)
high concentration: 5.8-6.6 (new solution) 8.4-8.5 (old solution)

The pH increased during the Friday to Monday water renewal periods. It is thought by the authors of the report that this is due to the aeration put in place on day 6.

Dissolved oxygen:

control: 8.2-10 mg/l
low concentration: 8.8-9.5 (new solution), 8.5-8.9 (old solution)
high concentration: 9.2-10.5 (new solution), 9.0-9.2 (old solution)

Nominal and measured concentrations:

Nominal concentrations: 0, 75, 140, 240, 420, 750 mg active acid/l
Measured concentrations: 0, 74, 137, 232, 408 and 703 mg active acid/l

Details on test conditions:

TEST SYSTEM

- Type (delete if not applicable): open

- Material, size, headspace, fill volume: 40 L glass aquaria, filled to 30 L of test solution

- Aeration: aeration took place on days 6, 8, 10, 12, 13 and 14 by gently bubbling compressed air, when DO levels were approaching 40%.

- Renewal rate of test solution (frequency/flow rate): 72%, i.e. 22.5 L, were replaced on each Monday, Wednesday and Friday

- No. of organisms per vessel: 20

- No. of vessels per concentration (replicates): 1

- No. of vessels per control (replicates): 1


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: well water

- Metals: all <0.01 ppm, except Iron 0.012 ppm and Nickel 0.0157 ppm

- Pesticides:
- Alkalinity: 368 ppm as CacO3

- Conductivity: 50 uhmos/cm

- Culture medium different from test medium: no

- Intervals of water quality measurement: water quality parameters were measured on each renewal date (Mon, Wed, Fri) in low, medium and high concentrations.


OTHER TEST CONDITIONS

- Adjustment of pH: none reported

- Photoperiod: 16 h daylight

- Light intensity: not reported


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : behaviour and mortality were observed daily.


TEST CONCENTRATIONS

- Spacing factor for test concentrations: 1.7 to 1.9

- Justification for using less concentrations than requested by guideline: n/a

- Range finding study: none reported

Reference substance (positive control):

yes

Remarks:

Antimycin A

Key result

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

440 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Remarks:

active acid

Basis for effect:

mortality (fish)

Remarks on result:

other: (350-560)

Duration:

72 h

Dose descriptor:

LC50

Effect conc.:

440 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Remarks:

active acid

Basis for effect:

mortality (fish)

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

74 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Remarks:

active acid

Basis for effect:

behaviour

Remarks:

loss of equilibrium

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

232 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Remarks:

active acid

Basis for effect:

mortality (fish)

Details on results:

- Observations on body length and weight: weight measurements of surviving fish at the end of the study (in percentages of the control group mean weight): 74 mg/l 90%; 137 mg/l 90%; 232 mg/l 76% and 408 mg/l 74%.

- Other biological observations: although only 5% mortality was observed at 232 mg/l, all test fish at this concentrations exhibited loss of equilibrium within 30 minutes after beginning the test. All surviving test fish at this concentrations recovered from the apparent initial toxicant shock, and the same behavioural response was noted immediately following each solution change at 232 and 408 mg/l. The loss of equilibrium following solution changes was thought to be due to a pH effect, as initial pH levels decreased with increasing toxicant concentration.

- Mortality of control: <5%

Results with reference substance (positive control):

- Results with reference substance valid? yes

Reported statistics and error estimates:

Litchfiled and Wilcoxon methods

Sublethal observations / clinical signs:

Table 1. Summary of mortalities during the 14 day exposure.

Nominal concentration (mg/l)	Days of exposure
	1	3	14
Control	0	0	0
74	0	0	0
137	0	0	0
232	5	5	5
408	40	40	40
703	95	100	100

Table 2. Mean measured total phosphorous and Dequest 2051 concentrations.

Nominal concentration (mg/l)	Mean
	P	Dequest 2051
Control	--	--
75	19.3	74
140	35.5	137
240	60.2	232
420	106	408
750	183	703

Validity criteria fulfilled:

yes

Remarks:

however, the pH and DO were low at the high concentration

Conclusions:

A 72h and 14d LC50 value of 440 mg active acid/L have been determined for the effects of the test substance on the mortality of the freshwater fish Oncorhynchus mykiss (reported as Salmo gairdneri) based on arithmetic mean measured concentrations. A NOEC value of 232 mg active acid/L based on mortalities has also been reported in the same study.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: US EPA 1979

Deviations:

not applicable

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

no range finding test and no analytical monitoring

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: an appropriate amount of test substance was added to each vessel and dispersed

- Controls: sea water only

Test organisms (species):

Cyprinodon variegatus

Details on test organisms:

TEST ORGANISM

- Common name: sheepshead minnow

- Source: stocked ponds at Bionomics Marine Research Laboratory

- Length at study initiation (length definition, mean, range and SD): 15-20 mm

- Method of breeding: not reported

- Feeding during test: not fed


ACCLIMATION

- Acclimation period: min. 7 days

- Acclimation conditions (same as test or not): not reported

- Type and amount of food: not reported

- Health during acclimation (any mortality observed): <1% mortality

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

20 ± 1⁰C

pH:

control: 8.3 to 8.2; exposure concentrations: 6.1 to 7.1

Dissolved oxygen:

≥60%

Salinity:

25‰

Nominal and measured concentrations:

Nominal concentrations: Control, 1000, 1800, 3200, 5600 and 10 000 µl/l (ppm)

Details on test conditions:

TEST SYSTEM

- Test vessel: jars

- Type (delete if not applicable): open

- Material, size, fill volume: glass, 19 L which contained 15L of seawater

- Aeration: no

- No. of organisms per vessel: 10

- No. of vessels per concentration (replicates): 1

- No. of vessels per control (replicates): 1


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: natural, filtered (5 micrometers) sea water

- Intervals of water quality measurement: 24 hours


OTHER TEST CONDITIONS

- Adjustment of pH: none

- Photoperiod: not reported

- Light intensity: not reported


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortalities were recorded every 24 hours


TEST CONCENTRATIONS

- Spacing factor for test concentrations: 1.8 to 2

- Range finding study: not reported to have been conducted

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 3 200 - < 5 600 other: µl/l (ppm)

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 820 - < 1 430 other: µl/l (ppm)

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

active acid

Basis for effect:

mortality (fish)

Details on results:

- Mortality of control: 0%

Reported statistics and error estimates:

LC50s were calculated by linear regression

Sublethal observations / clinical signs:

Table 1. Summary of findings.

Nominal concentration (u/l; ppm)	Mortality (%)
	24 h	48 h	96 h
Control	0	0	0
1000	0	0	0
1800	0	0	0
3200	0	0	0
5600	100	100	100
10 000	100	100	100

Result expressed as nominal concentration. Properties of the test substance and evidence from other studies (where concentrations were 

measured) indicate that nominal and measured concentrations are likely to be in good agreement.

A 96 h LC50 value between 3200 and 5600 µl/l (ppm) of test substance has been determined. This is equivalent to 820-2430 µl/l (ppm) in terms of HMDTMP active acid. The specific gravity of the test substance is 1.23 therefore the results in terms of mg/l are:

HMDTMP-xK = 96 h LC50 >3900 and <6900 mg/l, where the middle point is 5400 mg/l

HMDMTP acid = 96 h LC50 >1000 and >3000 mg/l, where the middle point is 2000 mg/l

Validity criteria fulfilled:

yes

Conclusions:

a 96 h LC50 value of >3900 <6900 mg/l of test substance, corresponding to >1000 and <3000 mg/l active acid, has been determined for the effects of the test substance on the mortality of the marine fish species Cyprinodon variegatus based on nominal concentrations.

Description of key information

14 d LC₅₀ 440 mg active acid/L, O. mykiss, reliability 2 (ABC 1979, read-across from HMDTMP acid)

96 h LC₅₀ >1000 and <3000 mg active acid/l, C. variegatus, reliability 2 (EG&G 1976)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

440 mg/L

Marine water fish

Marine water fish

Effect concentration:

2 000 mg/L

Additional information

72-hour and 14-day LC₅₀ values of 440 mg active acid/L have been determined for the effects of HMDTMP-H on the mortality of the freshwater fish Oncorhynchus mykiss (reported as Salmo gairdneri) based on arithmetic mean measured concentrations. A NOEC value of 232 mg active acid/L based on mortalities has also been reported in the same study (ABC 1979).

A 96 hour LC₅₀ value between >3900 and <6900 mg/L of test substance, corresponding to >1000 and <3000 mg/L active acid, has been determined for the effects of the registered substance, HMDMTP(4 -7K), on the mortality of the marine fish species Cyprinodon variegatus based on nominal concentrations (EG&G 1976). The mid point of the range is 2000 mg active acid/L, which is used as the key marine water value and the 14 -day LC₅₀ value of 440 mg active acid/L has been selected as the key freshwater value.

A supporting study also indicates low short-term toxicity of the substance to fish, where a 96 hour LC₅₀ value of >2400 mg active acid/L with the freshwater catfish Ictalurus punctatus (Monsanto 1976) has been reported.

The acid, sodium and potassium salts in the HMDTMP category are freely soluble in water. The HMDTMP anion can be considered fully dissociated from its sodium or potassium cations when in dilute solution. Under any given conditions, the degree of ionisation of the HMDTMP species is determined by the pH of the solution. At a specific pH, the degree of ionisation is the same regardless of whether the starting material was HMDTMP-H, HMDTMP.4Na, HMDTMP.7K or another salt of HMDTMP.

Therefore, when a salt of HMDTMP is introduced into test media or the environment, the following is present (separately):

1. HMDTMP is present as HMDTMP-H or one of its ionised forms. The degree of ionisation depends upon the pH of the media and not whether HMDTMP (4-7K) salt, HMDTMP (4-7Na) salt, HMDTMP-H (acid form), or another salt was used for dosing.

2. Disassociated potassium or sodium cations. The amount of potassium or sodium present depends on which salt was added.

3. It should also be noted that divalent and trivalent cations would preferentially replace the sodium or potassium ions. These would include calcium (Ca²⁺), magnesium (Mg²⁺) and iron (Fe³⁺). These cations are more strongly bound by HMDTMP than potassium and sodium. This could result in HMDTMP-dication (e.g. HMDTMP-Ca, HMDTMP-Mg) and HMDTMP-trication (e.g. HMDTMP-Fe) complexes being present in solution.