1. Pesticides in the Chesapeake Bay Watershed
Vicki Blazer, Kelly Smalling, Michelle Hladick and Patrick Phillips
U. S. Geological Survey

2. Adult Fish Kills in the Potomac
Multiple bacterial pathogens, but no consistent findings
Aeromonas hydrophila and other motile Aeromonads
Aeromonas salmonicida
Flavobacterium columnare
Multiple, often heavy parasite infestations
Leeches, trematodes, myxozoans, cestodes
Opportunistic fungal infections
Skin papillomas
Largemouth Bass Virus
High prevalence of intersex, vitellogenin in male fishes
Impaired Ecosystem
Immunosuppression

3. Mortalities of YOY Smallmouth Bass Susquehanna
Occurring since 2005, late spring/early summer
Also coinfections
Aeromonas hydrophila and other motile Aeromonads
Flavobacterium columnare
Largemouth Bass Virus
Trematodes
Cestodes
Myxozoan parasites

4. Correlations with Landuse and Chemicals PA Drainages
Study done in late summer
Discrete water samples at time of fish sampling
11 sites in the Susquehanna, 5 out of basin
Chemical
Contaminants or Landuse
Intersex Prevalence
rho p
Intersex Severity
rho p
Agricultural landuse
0.7044
0.0129
WWTP/sewage facilities
0.0936

5. Spawning Study Potomac Intersex and Land-use
Conducted in the spring, 5 sites in the Potomac, 1 out of basin
Landuse
Characteristics
Intersex Prevalence
Intersex Severity r2 p
Human population
0.42
0.08
# WWTP
0.34
0.13
WWTP flow
0.63
0.02
Percent agriculture
0.50
0.05
# Animal feeding operations
0.56
0.03
Total animal numbers
0.48
0.06
Animal density
0.58
Poultry Houses

6. Intersex and Chemical Correlations
Discrete water samples collected in spring at Potomac sites
No estrogens were present at levels above the detection limit
Chemical
Contaminants
Intersex Prevalence
Intersex Severity
rho p
Atrazine
0.88
0.009
Deethylatrazine
0.68
0.090
Acetochlor
0.79
0.036
Metolachlor
0.81
0.028

7. Chesapeake Bay Endocrine Disruption Study Agricultural Integrator Sites
4 - 6 sites where monthly to biweekly water samples, plus storm events, are collected and analyzed for hormones, pesticides, phytoestrogens and total estrogenicity from Nov to present
Sediment samples in spring and fall
Tissue samples for contaminant analyses
Adult fish are collected in the spring prespawn ( ) and at some sites in the summer and fall
YOY (1-3 months of age) are collected in early summer ( )

8. Location of Integrator Sites
Pine Creek
Chillisquaque Creek
West Branch Mahantango
Location of
Integrator
Sites
Antietam Creek
South Branch Potomac

9. Integrator Site Water Samples
Analyzed for 130 pesticides or degradates (GC)
13 including neonics (LC) – not included
Detected 30 at least once
Most only occasionally detected
Atrazine, simazine, metolachlor – most common; fipronil, metalaxyl next most common

10. Pesticides Detected Herbicides Insecticide Fungicide Atrazine Simazine
Metolachlor
Fipronil
Metalaxyl
Pine (43a)
19b (1c)
1 (0)
12 (1)
0 (0)
WB Mahantango (47)
41 (17)
34 (9)
2 (0)
2 (0)
Chillisquaque (36)
14 (3)
32 (9)
7 (0)
Antietam (42)
36 (3)
39 (5)
11 (0)
0 (0)
SB Potomac (41)
18 (0)
3 (0)
10 (1)
aTotal number of water samples from 11/2014 through 7/2017
bTotal detects
cDetects above the 100 ng/L assessment threshold

11. Chillisquaque Atrazine Concentrations (ng/L)
37,971
Jan Feb March April
May June July Aug Sept Oct Nov Dec

12. Adults - recrudescence
Key Exposure Periods
Nest/eggs – sediment/water
Water food, sediment
Water, maternal, sediment
Final maturation,
sperm quality
YOY – sexual differentiation
and organ development
Adults - recrudescence
April – May June – July August – Dec - March

13. Water Versus YOY Tissue
Bifenthrin (4) and pendamethalin (6) only occasionally detected
Bifenthrin detected only once on 10/29/15 at Chilli
Pendamethalin not detected at all in water samples in 2015

14. YOY Whole Body Pesticides (ng/g; ppb) Chillisquaque
Date
8/14/14
Bifenthrin
Metolachlor
p,p’DDD
p,p’-DDE
Pendimethalin 1
6.3
7.3 2
0.7
1.0
3.4
11.6 3
0.3
0.5
2.4
4.4 4
0.6
1.1
5.2 5
0.9
3.7
9.4 6
20.1 7
3.5
7.6 8
14.5 9
1.6
1.4
1.5
14.1

15. Recent USGS Study Midwestern Streams
Citation – Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams by Lisa Nowell and 10 coauthors in Science of the Total Environment: In press
100 streams weekly water samples during May-August 2013
Compared streams in agricultural and urban settings
94 pesticides and 89 degradates were detected
Median of 25 compounds detected per sample and 54 detected per site

16. Midwest Stream Study
Used aquatic life benchmarks and the Pesticide Toxicity Index as a screening level assessment for potential effects on fish, benthic invertebrates and aquatic plants
Pesticide toxicity index utilizes these benchmarks to assess potential toxicity of pesticide mixtures – calculating toxic units and concentration additions for pesticides with the same modes of action
Aquatic life benchmarks (fish) based on a few species exposed in the laboratory to individual pesticides
Life cycle/partial life cycle/early life stage assessments – assess survival, growth of adult and young, maturation, eggs spawned, hatchability, embryo survival and visible abnormalities

17. Conclusions
Few compounds were predicted to be major contributors to toxicity
Atrazine, metolachlor, fipronil, acetochlor, imidacloprid, carbendazim, organophosphate insecticides
Aquatic invertebrates = 53% of the streams predicted to have chronic toxicity, 12% acutely toxic
Aquatic plants 75% had acute but reversible effects with 9% having chronic longterm effects on plant communities
Potential effects on fish were unlikely

18. Adverse Effects Monitoring
Myxozoan
Trematode
metacercariae
Flavobacterium
columnare
Fish Immune
System
Adverse Effects Monitoring
Snail
host
Benthic
Worm host
Actinopsore
Fish infective
stage
Cestode
pleurocercoid
Intermediate host
Amphipod, copepod

19. Underlying Infectionsa a a a a a

20. Trematode Example Atrazine Bifenthrin – immunomodulation
Increase algal/periphyton Increased snail populations
Atrazine
Immunomodulation Increased trematode cercariae
Bifenthrin – immunomodulation
Reduces aquatic insect larvae which consume cercariae
Estrogens (estrone) - immunomodulation, increase snail populations
Increased Trematode Infections

21. Acknowledgements
USGS – Chesapeake Bay Environments and Environmental Health programs
WV Division of Natural Resources
MD Department of Natural Resources
PA Fish and Boat Commission
PA Department of Environmental Protection
West Virginia University
Penn State University