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Long-term toxicity to aquatic invertebrates

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Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to Guideline study. Pre dates OECD Guideline
Qualifier:
equivalent or similar to guideline
Guideline:
other: ASTM Subcommittee on Safety to Aquatic Organisms : Proposed standard practise for conduction renewal life-cycle toxicity tests with Daphnia magna draft nr2 1982
GLP compliance:
not specified
Analytical monitoring:
yes
Vehicle:
no
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnid
- Source: Brood stock
- Age at study initiation (mean and range, SD): < 24h
- Method of breeding: The brood stock was cultured and maintained in aerated (90-105% saturation) 2.91 - liter animal jars. A 2.0-liter open-ended tube with 1.0 mm nylon bolting cloth affixed to the bottom was contained within each jar to facilitate harvesting first instars. Th screened end of the tube was held approximately 1.5 cm off the bottom by two Pyrex triangles placed one on top of the other. Each tube contained 25 adult daphnids. When the tube was lifted, the adults remained on the screen while the first instars passed into the beaker for harvesting. Each brood stock animal jar contained the appropriate amount of food and water made up to a 2.0 liter volume. The brood stock food, water and glass receptacles were changed 3 time per week. The brood stock was kept in an environmental chamber set at 20 +-1°C and a photoperiod of 16h light : 8h dark. Twenty-four hours before testing, mutiparous females were isolated. The neonates produced by these adults were removed and used for testing within 24h.
- Feeding during test
- Food type: S. capricornutum
- Amount: 1.25 mg/L dry weight
- Frequency: 3 days per week
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
21 d
Hardness:
170 mg/l (as CaCO3)
Test temperature:
19.5 - 20.5 °C
Dissolved oxygen:
7.3 - 8.0 mg/L
Nominal and measured concentrations:
The nominal concentrations were 7. 14. 28. 56 and 105 mg/L as boron
Measured concentrations : 6.4, 13.6, 29.4, 59.3 mg/L as boron
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 600ml Pyrex beakers. Each beaker contained a 1.0 mm mesh stainless steel platform and 5 glass tubes (2.5 x 12.5 cm) with 363 µm nylon mesh bottoms. The tubes were placed on the platform to allow water circulation. Each test beaker contained 500 ml of the appropriate amounts of test material, food and water.
- Aeration: gently aerated to achieve 90 to 105 % saturation.
- Renewal rate of test solution (frequency/flow rate): 3 days per week
- No. of organisms per vessel: 5 (1 per tube)
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Lake Huron water was used to culture daphnids and as the test dilution water. This water was carbon-filtered, UV-irradiated and adjusted to a hardness of approximately 170 mg/L as (CaCO3) with CaCl2. The water was then autoclaved at 120°C and 124.1 kPa for 35 min.
- Alkalinity:58 +- 5 mg/L as CaCO3
- Conductivity: 290 +- 21 µmhos/cm


OTHER TEST CONDITIONS
- Photoperiod: 16 h light: 8 h dark


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : 3 days per week the young produced by each adult were counted and discarded and adult survival was recorded.
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
29.4 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
mortality
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
6.4 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
reproduction
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
6.4 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
growth
Remarks:
mean size
Duration:
21 d
Dose descriptor:
LC10
Effect conc.:
41.1 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
mortality
Remarks on result:
other: confidence limits: 8.9 - 189.3 mg/L
Duration:
21 d
Dose descriptor:
EC10
Effect conc.:
6.6 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
reproduction
Remarks on result:
other: confidence limits: 0.6 - 72 mg/L
Duration:
21 d
Dose descriptor:
EC10
Effect conc.:
29.2 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
growth
Remarks on result:
other: confidence limits: 17.3 - 49.3 mg/L
Details on results:
NOEC and LC10/EC10 values are provided for the endpoints reported, i.e. mortality, reproduction and growth. Preference is given to the use of EC10/LC10 values for PNEC derivation
Reported statistics and error estimates:
The LC10/EC10 values have been recalculated with the log-logistic model using Toxicity Relationship Analysis Program, Version 1.21A. Finney's method of probit analysis or the moving average method was used to calculate the LC50 values. Data were analyzed for NOEC and LOEC using a two tailed Dunnett's t test (alpha = 0.05). Mean comparisons between test and control concentrations were performed on the following endpoints : mean number of broods per daphnid, mean total young per daphnid and mean length.
Duration Endpoint Effect conc. Nominal/Measured Conc. based on Basis for effect Remarks (e.g. 95% CL)
21 d LC50 52.2 mg/L measured element mortality
21 d LOEC 59.3 mg/L measured element mortality
21 d LOEC 13.6 mg/L measured element reproduction
 21 d LOEC   13.6 mg/L  measured element   growth (mean size)  
Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study with acceptable restrictions. Peer-reviewed technical publication. Study meets guidelines except that temperature was elevated to 24 °C to accelerate growth and test duration was shorter (14d) than current methods.
Principles of method if other than guideline:
Two replicate 14-day static renewal chronic toxicity tests were conducted with Daphnia magna Straus
GLP compliance:
not specified
Analytical monitoring:
yes
Vehicle:
no
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Strain/clone: Straus
- Source: Laboratory reared
- Feeding during test
- Food type: Selenastrum capricornutum
- Amount: 2.5 mg dry wt./L of water
- Frequency: 3 days / week
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
14 d
Hardness:
170 mg/L as CaCO3
Test temperature:
23 to 25.2°C
pH:
7.3 - 8.2
Dissolved oxygen:
> 90% saturation (range 8.3 to 8.8 mg/L)
Nominal and measured concentrations:
all analyzed concentrations were within a range of 98.5 and 111.4 % of nominal.
Measured: 7.4, 13.8, 28.1, 57.4, 107.4 mg/L in Test I; 7.8, 14.3, 28.9, 60.0, 113.2 mg/L in Test II
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 600 mL glass beaker, each containing five glass tubes (2.5 x 12.5 cm) with 363 µm mesh bottoms. The tubes were supported about 1.0 cm off of the bottom of the beaker with a 1.0 mm mesh stainless steel platform. During the studies, each beaker contained the appropriate amount of food, dilution water and test material made up to a 500 mL volume.
- Aeration: gentle
- Renewal rate of test solution (frequency/flow rate): 3 times / week
- No. of organisms per vessel: One neonate daphnid in each uniquely labeled tube.
- No. of vessels per concentration (replicates): 4x5 = 20



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Lake Huron water. This water was obtained from the Midland Water Treatment Plant prior to final chlorination and was adjusted to a hardness of about 170 mg/L (as CaCO3) prior to autoclaving. The water was autoclaved at 121 °C and 124 kPa for 35 minutes.
- Culture medium different from test medium: No
- Intervals of water quality measurement: pH, D.O., and temperature were also measured and recorded on each renewal day.


OTHER TEST CONDITIONS
- Photoperiod: 16 hr light/8 hr dark
- Light intensity: +- 1700 - 2400 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The reproductive endpoint was obtained by hand counting the neonates on a Monday, Wednesday, and Friday basis. Growth was calculated by determining the dry weight of the surviving adult organisms at the tests end. Survival data were collected every Monday, Wednesday, and Friday
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
13.8 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
mortality
Remarks on result:
other: Test I
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
13.8 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
reproduction
Remarks on result:
other: Test I
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
13.8 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
growth
Remarks on result:
other: Test I
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
14.3 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
mortality
Remarks on result:
other: Test II
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
14.3 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
reproduction
Remarks on result:
other: Test II
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
14.3 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
growth
Remarks on result:
other: Test II
Duration:
14 d
Dose descriptor:
LC10
Effect conc.:
24 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
mortality
Remarks on result:
other: Test I; confidence limits: 17.2 - 33.8 mg/L
Duration:
14 d
Dose descriptor:
EC10
Effect conc.:
16.6 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
reproduction
Remarks on result:
other: Test I; confidence limits: 13.7 - 18.9 mg/L
Duration:
14 d
Dose descriptor:
EC10
Effect conc.:
20.6 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
growth
Remarks on result:
other: Test I; confidence limits: 0.2 - 2002 mg/L
Duration:
14 d
Dose descriptor:
LC10
Effect conc.:
25.8 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
mortality
Remarks on result:
other: Test II; confidence limits: 24.6 - 26.3 mg/L
Duration:
14 d
Dose descriptor:
EC10
Effect conc.:
16.6 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
reproduction
Remarks on result:
other: Test II; confidence limits: 15.5 - 17.2 mg/L
Duration:
14 d
Dose descriptor:
EC10
Effect conc.:
13.2 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
growth
Remarks on result:
other: Test II; confidence limits: 13.0 - 13.7 mg/L
Details on results:
NOEC and LC10/EC10 values are provided for the endpoints reported, i.e. mortality, reproduction and growth. Preference is given to the use of EC10/LC10 values for PNEC derivation
Reported statistics and error estimates:
Data derived from the studies were analyzed by a one-tailed Dunnett's test (alpha = 0.05). The Dunnett's procedure used simultaneously tested for heterogeneity of variances using Bartlett's test. If the variances were heterogeneous the Wilcoxon signed rank test was used to compare the means (Hollander and Wolfe 1973). Mean comparisons between test and control concentrations were performed on the following endpoints: percent survival, mean total young/adult, mean brood size/adult and mean dry weight/adult.

The LC10/EC10 values have been recalculated with the log-logistic model using Toxicity Relationship Analysis Program, Version 1.21A.
Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 211 (Daphnia magna Reproduction Test)
Qualifier:
according to guideline
Guideline:
other: EU New Draft Guideline "Prolonged toxicity study with Daphnia magna (inhibition of reproduction)"
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
The samples of approximately 50 ml were received in polyethylene bottles from the Department of Environmental Toxicology of the TNO Nutrition and Food Research Institute on 5 August and 20 October 1999. Upon receipt they were identified with the unique codes. They were analysed on 11 August and 22 November 1999.
Vehicle:
no
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Source: fresh-water crustacean Daphnia magna, cultrued in the laboratory under standard conditions. Daphnia magna has been cultured at TNO in the dilution water used for the present test
- Feeding during test
- Food type: cells of the unicellular alga Chlorella sp. and some 'yeast' was added as extra food
- Frequency: daily

Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
21 d
Hardness:
212 mg/L (as CaCO3)
Test temperature:
19.3 - 20.9 °C
pH:
7.2 - 8.0
Dissolved oxygen:
> 7.4 mg/L
Nominal and measured concentrations:
Nominal concentration : 1.8, 3.2, 5.6, 10, 18, 32 and 56 mg B/L.
Measured concentrations: 0.57, 2.59, 3.92, 6.55, 10.78, 19.49, 34.17 and 59.14 mg/L
The actual measured boron concentrations were between 98% and 102% of the nominal values in the newly prepared test solutions and between 105 and 108% in the spent solutions
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 100 ml all-glass beakers, each containing 50 ml of exposure medium.
- Aeration: no aeration
- Renewal rate of test solution (frequency/flow rate): every Monday, Wednesday and Friday
- No. of organisms per vessel: 1


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: DSWL-E prepared from ground water
- Total organic carbon: 1.6 mg/L
- Chlorine: 3.5 mmol/L
- Ca/mg ratio: 2 : 1
- Culture medium different from test medium: No
- Intervals of water quality measurement: pH values and oxygen concentrations were measured weekly in one of the newly prepared control test vessels and in one vessel of each test substance concentration. The pH and oxygen concentration were also measured in the same spent solutions, just before replacement and in any test vessel with a dead animal. The pH of the exposure media was not adjusted to that of the dilution water. The temperature was measured in one of the control vessels and the highest concentration tested just before and just after replacement of the test media.


OTHER TEST CONDITIONS
- Photoperiod: 16 light - 8 dark with transition periods of 30 min


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The dead animals were recorded daily, and removed if applicable, and any young born were counted and removed at each replacement time and at the end of the test. The condition (swimming behaviour, colour or any other visually observable morphological or behavioural criterion) and the size of the original test animals were qualitatively compared with those of the control animals at the same time.


RANGE-FINDING STUDY
- Appropriate concentrations for the toxicity tests were determined in a preliminary range finding test.
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
10.8 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
element
Basis for effect:
reproduction
Duration:
21 d
Dose descriptor:
EC10
Effect conc.:
17.7 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
element
Basis for effect:
reproduction
Remarks on result:
other: confidence limits: 15.5 - 20.2 mg/L
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
34.2 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
element
Basis for effect:
mortality
Details on results:
NOEC and LC10 values have been calculated for the endpoint reproduction. Preference is given to the use of the EC10 (17.7 mg/L) compared to the NOEC (10.8 mg/L ) value for reporduction. For the endpoint mortality, both the NOEC (34.2 mg/L) and LC10 (44.5 mg/L) values could be calculated. However the LC10 for the endpoint mortality was not reliable because of the large confidence interval between 0 mg/L - infinity.
Reported statistics and error estimates:
Statistical significance for mortality was determined with a binomial test at a 95 % and 99 % significance level. Statistical significance for reproduction was dermined using the two-tailed Dunnett-test at a 95 % and 99 % significance level using the mean number of young per female as observed values. In both cases, the obersvations at each concentrion were compared with those of the control. In the case of significance at the 99% level only that significance is given.

The LC10/EC10 values have been recalculated with the log-logistic model using Toxicity Relationship Analysis Program, Version 1.21A

If the reproduction of Daphnia magna is inhibited at sublethal concentrations the (cumulative) reproduction can often be described by: Ri(c) = R(0)/[1 + (c/EC50)^b] + ei in which Ri is the (cumulative) reproduction in the ith test vessel. R depends on the concentration of the test compound c. EC50 is the concentration at which the reproduction is reduced to 50% of the reproduction in the unstressed control. b is a slope parameter ( the larger b, the steeper the slope of the relation between concentration and reproduction). In each experiment a certain error, ei, will occur. These errors are assumed to be independent and normal distributed with expectation 0 and variance σ². Given these assumptions about the relation between concentration and reproduction and about the error in the observations the maximum likelihood estimations of the parameters of the function are calculated. Estimation of the LC50 and its confidence interval : At a given time, the mortality probability of an individual is assumed to be logistically related to the logarithm of the concentration, i.e. pi = (ei+p0)/(1+ei), where ei = (ci/α)^(1/β) and pi is the mortality probability in the ith concentration p0 is the mortality probability in concentration α is the LC50 β is a parameter inversely proportional to the maximum gradient of the dose response function ci is the ith concentration The parameters p0, α and β are estimated from the counts by means of the maximum likelihood method; i.e. the parameter values to be selected maximize the probablity of the counts as a function of the three parameters. Since the distribution of α will not be symmetrical the variance-covariance matrix is not estimated for the parameters p0, α and β themselves, but for p0, γ = ln α and β. The variance-covariance matrix is estimated by the inverse of the information matrix. The 95% confidence interval of the LC50 is now given as. α.exp(+-2[var(γ)]^(1/2))= α.exp(+-2[var(ln(α))]^(1/2))

Duration Endpoint Effect conc. Nominal/Measured Conc. based on Basis for effect Remarks (e.g. 95% CL)
21 d EC50 22 mg/L nominal element reproduction
21 d LOEC 18 mg/L nominal element reproduction
21 d LC50 34 mg/L nominal element mortality
21 d LOEC 56 mg/L nominal element mortality
 21 d LOEC  32 mg/L nominal  element  condition  
Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study, pre OECD guidline
Qualifier:
no guideline followed
Principles of method if other than guideline:
A chronic semi-static procedure was followed in conducting the 21 day chronic toxicity test.
GLP compliance:
not specified
Analytical monitoring:
yes
Details on sampling:
Water samples were collected for analytical verfification of boron from one test chamber in the control and in each of the test concentrations. One set of water samples was collected from the "old" test solutions and one set was collected also from the "new" test solutions at the time of water renewal.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Source: obtained from a stock culture
- Feeding during test : The daily diet ocnsisted of 0.15 ml of a 5:1 mixture of Ralston Purina Trout Chow and dehydrated alfalfa, both certified pesticide-free, in deionized water. The diet was supplemented with 1 ml of an alga suspension containing approximately 20 million cells of the green alga, Selenastrum capricornutum Printz, per ml of AAP medium (U.S. EPA 1971)


METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES:
On the day preceding test initiation, reproductively mature adults were isolated. The young produced by these adults were removed and used in a test within 24h.
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
21 d
Hardness:
166 (range 135 - 217) mg/L as CaCO3
Test temperature:
19.2 (range 18-21) °C
pH:
7.1 - 8.7
Dissolved oxygen:
> 9 mg/l ( > 90% saturation)
Nominal and measured concentrations:
The measured boron concentrations in the test waters exceeded 95% of the corresponding nominal values.
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 250 ml glass beakers containing 200 ml of the test solution
- Aeration:
- Renewal rate of test solution (frequency/flow rate): 3 times per week
- No. of organisms per vessel: 7 contained one daphnid and 3 contained 5 daphnid
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 20 ( 6 containing five daphnids and 14 containing one daphnid)


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Carbon filtered, well water which has been described previously (Maki and Bishop 1979)


OTHER TEST CONDITIONS
- Photoperiod: 16h light : 8h dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Adult survival and number of young were recorded daily for each test chamber. Prior to renewal the young produced by adults in the three beakers containing five organisms were discared. Surviving adults in these test chambers were enumerated and retained. Surviving adults and juveniles in the remaining seven beakers were enumerated after which juveniles and dead adults were discarded.
Duration:
21 d
Dose descriptor:
EC10
Effect conc.:
18.2 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
reproduction
Remarks on result:
other: analytical confirmation; confidence limits: 2.8 - 120.1 mg/L
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
27 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
growth
Remarks on result:
other: analytical confirmation
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
6 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
reproduction
Remarks on result:
other: analytical confirmation
Duration:
21 d
Dose descriptor:
EC10
Effect conc.:
52.9 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
growth
Remarks on result:
other: analytical confirmation; confidence limits: 49.6 - 56.3 mg/L
Details on results:
NOEC and EC10 values are provided for the endpoints reported, i.e. reproduction and growth. Preference is given to the use of EC10 values for PNEC derivation
Reported statistics and error estimates:
The LC10/EC10 values have been recalculated with the log-logistic model using Toxicity Relationship Analysis Program, Version 1.21A. T-tests were used to analyze differences in mean brood sizes and in daphnid length. Length of the adults surviving 21 days of exposure were determined from the apex of the helmet to the base of the spine. All statistical procedures followed ZAR (1974)

Description of key information

Daphnia magna,21 day freshwater: EC10, 17.7 mg/l (reproduction), NOEC 10.8 mg/l (reproduction),

NOEC 34.2 mg/L (mortality), LC10 44.5 mg/L (mortality)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
17.7 mg/L

Additional information

NOEC and LC10 values have been calculated for the endpoint reproduction. Preference is given to the use of the EC10 (17.7 mg/L) compared to the NOEC (10.8 mg/L ) value for reporduction. For the endpoint mortality, both the NOEC (34.2 mg/L) and LC10 (44.5 mg/L) values could be calculated. However the LC10 for the endpoint mortality was not reliable because of the large confidence interval between 0 mg/L - infinity.