March 26, 2015
MN Landscape Arboretum
Toxic Substances Hydrology Program
Environmental Health Mission Area
U.S. Geological Survey
Dana W. Kolpin and Michelle L. Hladik
Widespread occurrence of
Neonicotinoid insecticides in
streams across the U.S.
Neonicotinoids in the News• Implicated in Colony Collapse Disorder (CCD) in honeybees
- worker bees abruptly disappear
• Risk to other pollinators (bumble bees, butterflies)
What are neonicotinoids?- Neurotoxic insecticides developed to replace OPs and
carbamates. Structurally similar to nicotine.
- active against a broad spectrum of insects
- potent at low doses
- provide long term control
- active systemically (taken up throughout entire plant)
- Strongly bind to insect nAChRs (nearly irreversible).
- block nerve receptors in open position
- constant neuromuscular stimulation leads to death
- Highly water soluble with long aqueous and soil half-lives.
clothianidin thiamethoxamimidacloprid
S
N
HN
N
HN
NO2
Cl
NCl
N
N
HNNO2
S
N
HN
N
N
NO2
Cl
O
Many products Few ingredients
Home use- pets: topical
- lawn and garden: foliar spray, granular, tree injection
Agricultural use- row crops: foliar spray, seed treatment
- pasture: granular
Most widely used class of insecticides worldwide.
- Use of treated seeds has tripled in last decade.
- nearly all corn and 1/3 of soybeans
- Almost all clothianidin use is as seed treatments.
Rapid increase in the agricultural
use of Neonics
Environmental Fate
http://sitn.hms.harvard.edu/wp-content/uploads/2014/12/CB-FIgure-1.jpg
Nationwide sampling (2012-2014)
Results of nationwide study
Neonic Detection
1 or more: 53%
2 or more: 26%
3 or more: 11%
5 or more: 3%
Sand Run Gulch near Parma, ID
Neonic Land Use S. rhoClothianidin row crops +0.47 (0.003)
Thiamethoxam row crops +0.47 (0.003)
Imidacloprid urban +0.47 (0.003)
Hladik and Kolpin, in prep
(3%)
(16%)
Midwest in heart of heavy neonic use
2013 Midwest Neonics Study
Hladik et al., 2014
(59-86% rowcrops)
(21-36% rowcrops)
Most Commonly Detected Neonics
Neonics detected at
all 9 sites (and in
multiple samples).
Multiple neonics
detected in 43 of 79
samples (28 of 29
during May-June).
Levels can exceed
chronic toxicity for
imidacloprid.
Imidacloprid chronic
exposure toxicity level
(35 ng/L)
To
tal N
eo
nic
oti
no
id C
on
ce
ntr
ati
on
(n
g/L
)
0
100
200
300
400
500
Monthly Sites
Old Mans Creek
Mar Apr May Jun Jul Aug Sep Oct
Temporal Results - 2013
- Classic “spring flush” phenomena as herbicides (atrazine)
- likely association with seed treatments
Transport driven by use and precip
Streams during elevated
flow conditions: IA, 2014
Flow Cloth Thia Imid
Site Date (cfs) (ng/L) (ng/L) (ng/L)
Omaha 6/19/13 40,700 18 11 4.4
6/18/14 73,300 25 18 11
Fulton 6/24/13 973 74 40 4.8
6/19/14 2,720 98 40 11
Old Mans 6/26/13 1,240 84 26 23
7/01/14 5,560 68 20 25
Wapello 7/01/13 50,000 62 30 15
7/03/14 107,000 53 20 19
Big Sioux 6/20/14 64,300 77 38 20
Garber 6/20/14 25,000 132 73 26
Comparison of 2013 to 2014
a
b
c
Streams in an important ecosystem:
Chesapeake Bay (2014)
Antietam Creek near Sharpsburg, MD
2014
Apr May Jun
To
tal N
eo
nic
otino
id C
once
ntr
atio
n (
ng
L-1
)
0
10
20
30
40
Dis
cha
rge
(m
3 s
-1)
1
10
100
Clothianidin
Thiamethoxam Chronic Toxicity
a
Big Pipe Creek at Bruceville, MD
2014
Apr May Jun
To
tal N
eo
nico
tino
id C
onc
ent
ratio
n (n
g L
-1)
0
50
100
150
Dis
cha
rge
(m
3 s
-1)
0.1
1
10
100Clothianidin
Thiamethoxam
Chronic Toxicity
Chillisquaque Creek at Chillisquaque, PA
2014
Apr May Jun
To
tal N
eo
nico
tino
id C
onc
ent
ratio
n (n
g L
-1)
0
50
100
150
200
Dis
cha
rge
(m
3 s
-1)
0.1
1
10
100
Clothianidin
Imidacloprid
Thiamethoxam
Chronic Toxicity
b
c
Antietam Creek near Sharpsburg, MD
2014
Apr May Jun
To
tal N
eo
nic
otino
id C
once
ntr
atio
n (
ng
L-1
)
0
10
20
30
40
Dis
cha
rge
(m
3 s
-1)
1
10
100
Clothianidin
Thiamethoxam Chronic Toxicity
a
Big Pipe Creek at Bruceville, MD
2014
Apr May Jun
To
tal N
eo
nic
otino
id C
once
ntr
atio
n (
ng
L-1
)
0
50
100
150
Dis
cha
rge
(m
3 s
-1)
0.1
1
10
100Clothianidin
Thiamethoxam
Chronic Toxicity
Chillisquaque Creek at Chillisquaque, PA
2014
Apr May Jun
To
tal N
eo
nic
otino
id C
once
ntr
atio
n (
ng
L-1
)
0
50
100
150
200
Dis
cha
rge
(m
3 s
-1)
0.1
1
10
100
Clothianidin
Imidacloprid
Thiamethoxam
Chronic Toxicity
b
cAntietam Creek near Sharpsburg, MD
2014
Apr May Jun
To
tal N
eo
nic
otino
id C
once
ntr
atio
n (
ng
L-1
)
0
10
20
30
40
Dis
cha
rge
(m
3 s
-1)
1
10
100
Clothianidin
Thiamethoxam Chronic Toxicity
a
Big Pipe Creek at Bruceville, MD
2014
Apr May Jun
To
tal N
eo
nic
otino
id C
once
ntr
atio
n (
ng
L-1
)
0
50
100
150
Dis
cha
rge
(m
3 s
-1)
0.1
1
10
100Clothianidin
Thiamethoxam
Chronic Toxicity
Chillisquaque Creek at Chillisquaque, PA
2014
Apr May Jun
To
tal N
eo
nic
otino
id C
once
ntr
atio
n (
ng
L-1
)
0
50
100
150
200
Dis
cha
rge
(m
3 s
-1)
0.1
1
10
100
Clothianidin
Imidacloprid
Thiamethoxam
Chronic Toxicity
b
c
21% Ag: 11 ng/L Cloth+Thia 32% Ag: 64 ng/L Cloth+Thia 41% Ag: 93 ng/L Cloth+Thia
- clothianidin: 59%
- thiamethoxam: 29%
- imidacloprid: 6%
Chronic toxicity levels
exceeded in 2 samples (12%)
Transport driven by use and
precipitation
a
b
c
Temporal patterns in urban streams: GASope Creek near Marietta, GA
2012
Oct Jan Apr Jul Oct Jan Apr Jul Oct
Imid
acl
orp
id C
onc
ent
ratio
n (n
g L
-1)
0
20
40
60
80
100
Dis
cha
rge
(m
3 s
-1)
0.01
0.1
1
10
100
Imidacloprid
2013 2011
Chronic Toxicity
Chattahoochee River near Whitesburg, GA
2011
Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
To
tal N
eo
nico
tino
id C
onc
ent
ratio
n (n
g L
-1)
0
20
40
60
80
100
120
140
Dis
cha
rge
(m
3 s
-1)
1
10
100
1000Imidacloprid
Dinotefuran
Acetamiprid
2012
Chronic Toxicity
a
b
: 39% urban
: 18% urban
9% pasture67 samples collected
on a fixed schedule
- imidacloprid: 87%
- dinotefuran: 10%
- acetamiprid: 7%
(90%)
(79%)(32%)
(5%)
No relation to stream flow
Clothianidin
Imidacloprid
December 2012 June 2013
Instream transport:
Fourmile Creek
(Ankeny, IA)
Dec, 2012
99% effluent
June, 2013
11% effluent
- Conservative instream
transport of neonics
along 4.8 km reach.
- Imidacloprid levels in
effluent higher compared
to clothianidin.
De Perre et al., 2015
Southern Illinois University
Hladik et al., 2014
U.S. Geological Survey
Planting of treated seeds
promotes neonic transportOld Mans Creek near Iowa City, IA
Dis
ch
arg
e (
m3/s
ec
)
0.01
0.1
1
10
100
Clo
thia
nid
in (
ng
/L)
0
100
200
300
ND
Mar Apr May Jun Jul Aug Sep Oct
Seed Treatment Paradox
Logic
Touted as a better management practice
over broadcast application
- dual action control
- provides a barrier around seed
- systemic agent absorbed by new roots
- proactive (preventing infestation will increase yields)
- targeted application (less chemical use compared
to broadcasting)
Seed Treatment ParadoxDoes seed treatment translate to decreased
insecticide use (clothianidin vs chlorpyrifos)?
Individual field scale?
- for 100 acre field, clothianidin use would be 7%
that of chlorpyrifos
Statewide scale with ubiquitous seed treatment?
- 2013 clothianidin use is 99% that of the 2001
chlorpyrifos use
- Similar use but on substantially more crop acres
Millions of acres of prophylactic neonic use in Iowa
Yes
No
Seed Treatment Paradox
Reality1. At statewide level, does not translate to less use.
2. EPA study found no increase in soybean yields
through use of treated seeds.
3. Can unintentionally reduce crop yields - slugs unaffected by neonic exposure via treated seeds
- slugs transmitted toxins to predaceous beetles
- decreased predaceous beetle population
- increased slug population
- reduced soybean yields (Douglas et al., 2015)
4. Contributes to widespread neonics in streams- unknown environmental impact
- Neonics frequently detected in streams across U.S.- Can exceed chronic and even acute levels
- Contributions from both urban and Ag use
- Transport in Ag settings driven by use and precip.- Current use patterns creating a “spring flush” of
neonics in Midwestern streams
- Seed treatments are increasing overall neonic use
across the U.S. translating to increased neonic
detections in U.S. streams.
- More research needed to understand potential
environmental effects from exposures via neonic
levels in streams.
Summary
Questions?
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