Sodium selenite

Additional ecotoxological information

Administrative data

Endpoint:

additional ecotoxicological information

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test:
The effects of dietary Se on Sea Urchin (Lytechinus variegatus) growth were studied experimentally.
- Short description of test conditions:
Semipurified formulated feeds containing 0.6, 1.1, or 2.4 mg selenium/kg feed (as sodium selenite) for 12 wk (n = 16 individuals per feed treatment, 15.59 ± 0.18 SE g initial wet weight, 31.29 ± 0.12 SE mm diameter; 32 ± 2 ppt salinity and 22 ± 1 C).
- Parameters analysed / observed:
diameter, body weight

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Sodium selenite

EC Number:

233-267-9

EC Name:

Sodium selenite

Cas Number:

10102-18-8

Molecular formula:

H2O3Se.2Na

IUPAC Name:

disodium selenite

Specific details on test material used for the study:

Source: Zeigler Bros, Inc., Gardners, Pennsylvania, USA

Results and discussion

Any other information on results incl. tables

Survival was 100% in all treatments over the 12-wk study period.

At week 12, test diameters inL.variegatusfed 1.1 mg selenium/kg feed were significantly larger (P <0.05) than those in sea urchins fed 2.4 mg selenium/kg feed but not those fed 0.6 mg selenium/kg feed. Mean wet and dry weights increased significantly (P <0.05) in sea urchins fed selenium feeds during the 12-wk study. At week 12, sea urchins fed 0.6 and 1.1 mg selenium/kg feed had signifi- cantly higher (P <0.05) wet and dry weights than those fed 2.4 mg selenium/kg feed (P=0.0024, P=0.0007, respectively), resulting in higher SGR (Table 4).

Sea urchins fed 2.4 mg selenium/kg feed had conspicuous signs of pathology. Four sea urchins fed 2.4 mg selenium/kg feed had gas-filled membrane distensions (resembling those found in mammalian enterocolitis), green lanterns instead of white, and/or red coelomic fluid upon dissection at 12 wk.

Applicant's summary and conclusion

Conclusions:

High levels of dietary selenium (2.4 mg Se/kg feed) significantly decreased weight gain, test diameter, test wet weight, and dry ovary production compared to sea urchins fed the 0.6 and/or the 1.1 mg selenium/kg feed, suggesting that high levels of dietary selenium negatively affect sea urchin physiology. Observable pathologies in sea urchins fed high levels of dietary selenium included red coelomic fluid and pigmented organs, consistent with an inflammatory response. Additionally, selenium accumulated in the gut, gonad, and test at levels generally proportional to selenium in the feed. A selenium requirement is suggested but not established in this 12-wk study. These data suggest toxicity for high levels of dietary selenium in L. variegatus, resulting in a variety of growth inhibitions and pathologies.