Calcium oxide

Long-term toxicity to fish

Administrative data

Endpoint:

fish, juvenile growth test

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Meets generally accepted scientific standards with acceptable restrictions.

Data source

Reference

Reference Type:

publication

Title:

The Chronic Effects of Dietary Lead in Freshwater Juvenile Rainbow Trout (Oncorhynchus mykiss) Fed Elevated Calcium Diets

Author:

Alves LC & Wood CM

Year:

2006

Bibliographic source:

Aquatic Toxicology 78: 217-232

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The study examined the impact of elevated Ca2+ on the responses to chronic dietary Pb exposure in juvenile rainbow trout. Only the data for those samples without the addition of lead are reported.
Trout were fed reference (0.3 µg Pb/g, ~20 mg Ca2+/g) diets in the presence of background (~20 mg Ca2+/g) or (~60 mg Ca2+/g) of added Ca2+ (as CaCO3) for 42 days.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Calcium carbonate

EC Number:

207-439-9

EC Name:

Calcium carbonate

Cas Number:

471-34-1

Molecular formula:

CH2O3.Ca

IUPAC Name:

calcium carbonate

Test solutions

Details on test solutions:

Six replicated nominal dietary Pb and/or Ca2+ treatments:
(A) 0 μg Pb/g + 20 mg Ca2+ /g
(B) 0 μg Pb/g + 60 mg Ca2+ /g

Test organisms

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: Humber Springs Trout Hatchery (Orangeville, Ont)
- Age at study initiation (mean and range, SD): 20-23 g
- Weight at study initiation (mean and range, SD): mean weight of 25.8 ± 0.5 g
- Feeding during test: Yes
- Food type: Commercial salmon fry pellets
- Amount: 1.5% body mass/day
- Frequency: Once daily

ACCLIMATION
- Acclimation period: 3 weeks

Study design

Test type:

flow-through

Water media type:

freshwater

Total exposure duration:

42 d

Test conditions

Hardness:

140 mg/L as CaCO3

Test temperature:

11-13 °C

pH:

7.4-7.7

Nominal and measured concentrations:

Nominal: 20 and 60 mg Ca2+/g dry weight
Measured: 19.2 and 61.0 mg Ca2+/g dry weight

Details on test conditions:

TEST SYSTEM
- Test vessel: 200 L polypropylene flow-through aerated tanks that were divided into 2x100 L sections
- Renewal rate of test solution (frequency/flow rate): 1 L/min of dechlorinated Hamilton water, pumped only once through the tanks.
- No. of organisms per vessel: 25 fish per section
- No. of vessels per control (replicates): 2 (Tanks 1 and 5)


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dechlorinated Hamilton water


OTHER TEST CONDITIONS
- Photoperiod: 12 h light and 12 h dark


EFFECT PARAMETERS MEASURED: Fish from each tank were bulk-weighed on days 0, 8, 15, 22, 29 and 36. Specific growth rates (SGR) expressed as a % per day were determined using linear regression of the natural logarithm of mean bulk weight versus time data. The food conversion efficiency (FCE, %) was also calculated.
On day 0, two randomly selected fish per tank were sacrificed. On days 14, 28 and 42, four randomly selected fish per tank section were also sacrificed. Blood samples were taken immediately. Vertebral bone, brain, gill baskets, anterior, mid and posterior intestine, anterior and posterior kidney, liver, muscle, spleen, stomach and remaining carcass were dissected out.
Blood samples were also taken on days 0, 7, 21 and 35.

Results and discussion

Details on results:

Growth and survival: Enhanced Ca2+ diets (60 mg Ca2+/g) had no effects on survival, despite a tendency for SGR to be lower in fish fed these diets. The mean fish weight (g) remained constant across all groups during the course of the experiment. FCE was significantly lower in the 0 µg Pb/g + 60 mg Ca2+/g compared to the 0 µg Pb/g + 20 mg Ca2+/g treatments.

Pb accumulation in tissues: Pb concentrations in the control treatment of all tissues were low (<0.05 µg/g tissue wet weight) but were significantly elevated on days 14 and 28 and occasionally on day 42, when compared to day 0.

Ion regulation and Na+, K+-ATPase activity: There were no significant differences observed in plasma Cl- and K+ in all treatments when compared to the controls over the duration of the experiment.

Applicant's summary and conclusion

Conclusions:

Enhanced Ca2+ diets (60 mg Ca2+) had no effects on survival. Mean fish weights remained constant across all treatments.