Determination of Acute and Sub-Chronic Toxicity of Emerging
Contaminants in Early Life Stages of Rainbow Trout (Oncorhynchus
mykis)
Schultz, D.1*, Tang, S.1, Beitel, S.1, Sarauer, B.1, Hanson, S.1, Wiseman, S.B.1, Jones, P.D.1, Giesy, J.P.1, Janz, D.1, Hecker, M.1
1
University of Saskatchewan, Saskatoon, Saskatchewan, Canada
Methods and Procedures
Background
 Some of the ECs of concern that are frequently
found in MWWE include hexabromocyclododecane (HBCD), silver (AG) nanoparticles, shortchain chlorinated paraffins (SCCP), 17αethynylestradiol (EE2), and Prozac™ (FLX)
 Many rural Canadian municipalities discharge
MWWE with little to no treatment, resulting in
elevated exposures to these ECs in receiving
waterbodies
Objectives
 Fish will be exposed under continuous flowthrough conditions, and subsamples will be
collected at critical development stages
(hatching, swim-up, sexual differentiation
Preliminary Results
 Endpoints will include hatching success,
time to hatch, survival, time to swim-up,
time and success of sexual differentiation,
and morphological and histological defects,
as well as endpoint specific rates of
development.
 Fish will be reared according
Environment Canada guidelines (1).
 It appears that high doses of AgNP (30 nM) have
the potential to increase incubation time and
decrease hatching success in O. mykiss
Figure 3: Exposure system setup. The three replicates of each test
concentration will be supplied by the same reservoir under continuous
flow-through conditions. Each replicate will contain two egg chambers,
whose purpose is to contain the fry once hatched and allow for easier egg
inspection.
to
Hatching Data
a
b
MWWE
30
c
AgNP
90
Prozac
40
 There seems to be no relationship between
MWWE, Prozac, or EE2 on incubation times or
hatching success in O. mykiss
 Future research will aim to further characterize
the effects of these emerging chemicals to other
native species, in order to aid in the development
of more appropriate environmental risk
assessment strategies for receptors of concern.
*
Mortality (%)
To investigate the sub-chronic effects of ECs on
early life stages of Rainbow Trout by
 Characterizing effects of ECs on fertilization
success, embryonic development, and hatchability
of Oncorhynchus mykis
25
75
20
60
15
10
30
45
20
30
10
5
15
0
CTR
10
0
50
0
CTR
0.1
0.3
Treatment
 Identifying the potential impact of ECs on fry
survival, transition to exogenous feeding, and
sexual differentiation
1
3
10
30
CTR
0.5
Treatment Concentration (nM)
1.95
7.81
31.25
125
Treatment Concentration (nM)
Prozac
AgNP
550
MWWE
*
460
440
420
600
*
500
480
Degree Days to Hatch
 Comparing sensitivity of Oncorhynchus mykiss to
selected ECs relative to standard laboratory fish
species
 Toxic effects on native Canadian fish species
will differ to those of model laboratory species
Mortality (%)
 Because rainbow trout are native to North America
and introduced extensively elsewhere, as well as
their high trophic level, they may be at particular
risk to ECs
 Responses to chronic exposures of O. mykiss to
selected ECs will differ from acute effects of the
same chemicals
Figure 2: Adult Rainbow Trout (O. mykiss)
550
Degree Days to Hatch
 There is a lack of data regarding the chronic
toxicity of ECs to aquatic wildlife, particularly to
early life stages of native fish species living in
environments of concern
 Exposure to MWWE will lead to adverse effects
on early life stages of O. mykiss
 Chronic exposures of O. mykiss to selected ECs
will have life stage specific toxic effects
 For each chemical, the lowest doses were
selected based on environmental relevance
and increased incrementally thereafter
Degree Days to Hatch
 ECs are continuously released via points sources
(e.g. MWWE) and diffuse sources (e.g. runoff),
and thus, are ubiquitous in the aquatic environment
Experimental Design
 O. mykiss gametes will purchased from
TroutLodge, WA, USA and fertilized and
immediately transferred to exposure
solutions (EE2, FLX, MWWE, Ag
nanoparticle) and sediments (HBCD, SCCP)
Mortality (%)
 Emerging contaminants (ECs) have recently gained
notoriety due to their potential toxicity to wildlife
and humans
Hypothesis
450
400
350
450
400
350
300
400
500
300
CTR
0.1
0.3
1
3
10
30
CTR
0.5
1.95
Treatment Concentration (nM)
7.81
31.25
125
500
Treatment Concentration (nM)
References
380
CTR
10
50
1. Environment Canada. 1998. Biological Test
Method: Toxicity Tests Using Early Life Stages of
Salmonid Fish (Rainbow Trout). Report EPS
1/RM/28. 2nd Ed. Technical Report, Ottawa,
Ontario.
Treatment Concentration (%)
b
EE2
60
650
50
600
Degree Days to Hatch
d
Mortality (%)
a
EE2
40
30
20
10
CTR
1
3
10
30
Treatment Concentration (nM)
450
400
100
300
300
CTR
1
3
10
30
100
300
Treatment Concentration (nM)
d
Figure 1: Early developmental stages of O. mykiss including early
eyed- egg (a), alevin (b), fry (c), and juvenile (d).
Created by Peter Downing – Educational Media Access and Production © 2011
500
350
0
c
550
Figure 1: Degree days to hatch and mortality (%) in municipal wastewater effluent (A), silver nanoparticles (B), Prozac™
(C), and 17β-ethynylestradiol (D). All concentrations are reported in nanoMoles. Error bars represent ± one standard
deviation from the mean of three replicates (two replicates in controls). Significance indicated by: *p<0.05.
Acknowledgments