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Endpoint:
additional ecotoxicological information
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Reliable and relevant with restrictions (Partially fulfills ecotoxicity reliability and relevancy criteria as identified in the attached document, “Criteria for Determining the Reliability and Relevance of Ecotoxicological Data”; attached in the overall endpoint summary for Section 6). Study meets generally accepted scientific standards and is well documented. Study design follows an OECD guideline (211) with acceptable and documented deviations. Exposure concentrations were measured using common acceptable analytical techniques. An acceptable control test was incorporated. Information regarding exposure to nickel in the diet (algae) is detailed and satisfactory. Relevant endpoints (growth, survival, and reproduction) are assessed. Study is considered a K2 study, as opposed to a K1 study, because D. magna were exposed to some nickel present in the water in addition to the dietary nickel exposure, and because the form of nickel added to water in which Daphnia’s diet were grown (green alga) was not detailed.
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2009

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: OECD Guideline 211 (Daphnia magna Reproduction Test)
Deviations:
yes
Remarks:
Two deviations in M4 medium preparation: (1) total Zn concentration was increased to 26 µg/L; and (2) the strong metal chelator EDTA in the medium was omitted and replaced with 4 mg/L of natural dissolved organic carbon (DOC).
Principles of method if other than guideline:
The green alga (Pseudokirchneriella subcapitata) was exposed to a control and 5 nickel concentrations for 64 h. The algae were harvested and their nickel contents and nutritional quality were measured. They were then used as food in a 21-day dietary exposure experiment with Daphnia magna, during which survival and reproduction were monitored daily. Daphnia growth was measured as length at the end of the experiment and, at the same time, their nickel body burden was measured.
GLP compliance:
no
Type of study / information:
Dietary nickel exposure for an aquatic invertebrate species. Impacts on the relevant endpoints of growth, survival and reproduction measured.

Test material

Reference
Name:
Unnamed
Type:
Constituent

Results and discussion

Any other information on results incl. tables

Endpoint: Mortality. NOEC >= 837 ug/g dry weight (measured mean concentration; 21 day exposure to nickel as element via diet). Details: Mortality was ≤ 10% in all treatments including daphnia exposed to the highest dietary nickel concentration (internal nickel burden of algal diet) of (mean +/- sd) 837 +/- 33 ug nickel/g dry wt.

Endpoint: Growth. LOEC = 85.6 ug/g dry weight (measured mean concentration; 21 day exposure to nickel as element via diet). Details: Length (linear distance between top of head and base of apical spine) at day 21 was significantly (p<0.05) reduced in daphnids fed algal diets containing (mean +/- sd) 85.6 +/- 6.7 µg nickel/g dry wt, compared to daphnids fed a control diet.

Endpoint: Growth. NOEC = 68.5 ug/g dry weight (measured mean concentration; 21 day exposure to nickel as element via diet). Details: Length (linear distance between top of head and base of apical spine) at day 21 in daphnids fed algal diets containing (mean +/- sd) 68.5 +/- 12.5 µg nickel/g dry wt was not significantly (p>0.05) different to daphnids fed a control diet.

Endpoint: Reproduction. LOEC = 85.6 ug/g dry weight (measured mean concentration; 21 day exposure to nickel as element via diet). Details: Total reproduction (number of juveniles produced per daphnid) at day 21 was significantly (p<0.05) reduced in daphnids fed algal diets containing (mean +/- sd) 85.6 +/- 6.7 µg nickel/g dry wt, compared to daphnids fed a control diet.

Endpoint: Reproduction. NOEC = 68.5 ug/g dry weight (measured mean concentration; 21 day exposure to nickel as element via diet). Details: Total reproduction (number of juveniles produced per daphnid) at day 21 in daphnids fed algal diets containing (mean +/- sd) 68.5 +/- 12.5 µg nickel/g dry wt was not significantly (p>0.05) different to daphnids fed a control diet.

 

- Mortality of parent animals: Mortality was ≤ 10% in all treatments.

- See table 1 for data related to the number of offspring produced, length, time to first brood, and first/second/third/fourth/fifth brood size.

Table 1: Experimental conditions (pH, dissolved Ni) and results of the chronic D. magna exposure to 6 different dietary Ni levels.a

 

Nickel concentration in exposures of algal diets

Control

225 µg/L

449 µg/L

898 µg/L

1800 µg/L

3590 µg/L

Measured Ni concentration (µg/L)

7.5

230.5

462.9

900.4

1699

3484

Internal Ni burden of algal diet

<4.0

33.7 +/- 3.6

68.5 +/- 12.5

85.6 +/- 6.7

391 +/- 23

837 +/- 33

Average pH during exposure

7.82

7.68

7.65

7.76

7.55

7.50

Dissolved Ni week 1 (µg/L)

< DLb

4.2

7.3

8.7

26.3

111.3

Dissolved Ni week 2 (µg/L)

< DL

4.7

12.8

15.4

62.5

177.7

Dissolved Ni week 3 (µg/L)

< DL

5.1

16.8

15.9

105.5

132.8

D. magna Ni body burden at day 21 (µg/g)

< DLc

< DL

< DL

54.0

49.6

72.5

Survival (%)

90

100

100

100

100

90

Length at day 21 (mm)

3.75 +/-0.17

3.73 +/-0.18

3.64 +/-0.12

3.36 +/-0.11*

3.44 +/-0.19*

3.37 +/-0.12*

Total reproduction (# juveniles/daphnid)

99.8 +/-14.1

103.5 +/-27.3

100.6 +/-8.8

66.5 +/-9.5*

69.5 +/-14.3*

64.1 +/-10.3*

Time to first brood (days)

8.9 +/-0.3

8.1 +/-0.6*

7.8 +/-0.6*

8.2 +/-0.4*

8.1 +/-0.3*

8.2 +/-0.4*

First brood size (# juveniles)

13.8 +/-2.7

10.9 +/-2.6*

9.2 +/-2.7*

9.6 +/-2.6*

9.5 +/-4.4*

8.7 +/-1.6*

Second brood size (# juveniles)

18.7 +/-4.2

16.1 +/-5.2

17.4 +/-3.6

12.5 +/-4.9*

13.9 +/-3.4*

12.1 +/-3.2*

Third brood size (# juveniles)

25.8 +/-5.2

25.4 +/-3.5

22.2 +/-5.1

16.4 +/-3.9*

15.9 +/-5.6*

14.8 +/-1.9*

Fourth brood size (# juveniles)

21.6 +/-6.4

26.8 +/-6.1

25.9 +/-4.2

13.2 +/-3.6*

17.4 +/-4.9

14.9 +/-3.2*

Fifth brood size (# juveniles)

19.8 +/-7.7

24.2 +/-10.3

25.7 +/-4.2

14.8 +/-6.2*

16.0 +/-1.8*

12.3 +/-3.5*

Intrinsic rate of natural increase (rm)

0.36 +/-0.01

0.37 +/-0.02

0.37 +/-0.02

0.34 +/-0.02

0.35 +/-0.03

0.34 +/-0.01

 * Significant differences between the control exposure and elevated dietary nickel exposures (Mann-Whitney-U test; p<0.05).

aData on toxicological endpoints are presented as mean ± standard deviation (n= 9 for control and highest Ni exposure, n = 10 for other treatments).

bBelow detection limit of 5 µg/L.

cDetection limit for D. magna nickel burdens- 4.0 µg nickel/g dry wt.

 

Other information:

Mortality was ≤ 10% in all treatments and there were no significant differences (p>0.05) relative to the control.

The 21-day length and total reproduction were significantly reduced (p < 0.05) in the daphnids fed with algal diets containing 85.6 µg nickel/g dry wt or more.

 

Waterborne dissolved nickel in the control remained below the detection limit of 5 ug/L. Higher levels of dietary exposure resulted in the introduction of increasing amounts of dissolved nickel in the test media, up to a maximum of 178 µg/L (in the 3590 µg/L nominal nickel in algae exposure solution). The authors suggest that although daphnids were exposed to nickel in solution in addition to the diet, that the main contributor to the reproductive effects observed in daphnids was from the dietary nickel exposure.

 

At the individual level, a significant (p < 0.05) reduction of the first brood size (compared to the control) occurred for daphnids exposed to all dietary nickel concentrations (as low as 225 µg/L nominal nickel in algae exposure solution, or at an internal nickel burden of 33.7 +/- 3.6 ug/g d.w. in algal diet). For the second, third, fourth and fifth broods, only daphnids exposed to concentrations ≥ 85.6 µg nickel/g dry wt in diet exhibited significantly (p < 0.05) reduced brood sizes. The rate of maturation, indicated by time to first brood, was significantly reduced at all dietary nickel exposures compared to the control (as low as 225 µg/L nominal nickel in algae exposure solution).

 

Note that D. magna nickel body burdens remained below the detection limit in the control and in the two lowest dietary exposure levels (225 and 449 µg/L nominal nickel in algae exposure solution).

Daphnids exposed to dietary nickel concentrations of 85.6 µg/g dry wt in the diet and higher exhibited increased body burdens between 49.6 and 72.5 µg/g dry wt.

The pH of the exposure media never deviated by more than 0.5 pH units from the target of pH 8.0.

 

Applicant's summary and conclusion

Conclusions:
The authors concluded that D. magna exposed during 21 days to dietary Ni concentrations between 85.6 and 837.3 µg/g dry wt of algal food (accumulating a total nickel body burden ranging from 49.6 to 72.5 µg/g dry wt) experienced significant inhibition of reproduction and growth by 33.1 and 9.6% compared to the control treatment, respectively.
Executive summary:

Study rated by an independent reviewer.