Citation Rankings
Highly Cited Researchers
Highly Cited Researchers 481 Scientists Citation Rankings - 2025
Discover the world’s highly cited researchers through the AD Scientific Index 2025 Citation Rankings.
These rankings evaluate scientists based on their total and recent citation counts, capturing the breadth and real-time currency of academic recognition. Citation data reveals how widely a scholar’s work is referenced, applied, and extended across diverse disciplines. The rankings are routinely updated to reflect ongoing citation growth, while eliminating distortions from excessive co-authorship and institutional inflation. Premium tools provide access to detailed citation dynamics, unethical citation behavior detection, and field-normalized benchmarking.
* Total Citation Counts Rankings
Ranking Based On Selection: 1
Toxicology
bioinformatics
Computational Toxicology
Systems Biology
Endocrine Disruptio
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
35,078
11,446
0.326
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* Total Citation Counts Rankings
Ranking Based On Selection: 2
risk analysis
air pollution
benefit cost analysi
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
34,351
16,913
0.492
* Total Citation Counts Rankings
Ranking Based On Selection: 3
environmental toxicology
drug discovery
nuclear receptor
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
27,996
7,134
0.255
* Total Citation Counts Rankings
Ranking Based On Selection: 4
Nanotechnology
Materials Chemistry
Water Reserac
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
27,954
15,098
0.540
* Total Citation Counts Rankings
Ranking Based On Selection: 5
Lung diseases
iron homeostasis
fibers
particles
air pollutio
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
25,739
8,006
0.311
* Total Citation Counts Rankings
Ranking Based On Selection: 6
Environmental Soil Chemistry
Synchrotron Techniques
Bioavailability
Nanoparticles in the Environment
Plant Uptak
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
22,457
9,763
0.435
* Total Citation Counts Rankings
Ranking Based On Selection: 7
Environment
landscape ecology
remote sensing
GI
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
21,627
5,941
0.275
* Total Citation Counts Rankings
Ranking Based On Selection: 8
Chemistry
Cheminformatics
Nuclear Magnetic Resonance
Drug Discover
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
20,292
10,762
0.530
* Total Citation Counts Rankings
Ranking Based On Selection: 9
Computational chemistry
cheminformatics
toxicolog
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
17,848
8,673
0.486
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* Total Citation Counts Rankings
Ranking Based On Selection: 10
toxicology
genomic
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
16,968
8,013
0.472
* Total Citation Counts Rankings
Ranking Based On Selection: 11
biolog
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
16,086
5,556
0.345
* Total Citation Counts Rankings
Ranking Based On Selection: 12
freshwater ecology
biogeochemistry
acidificatio
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
15,706
3,853
0.245
* Total Citation Counts Rankings
Ranking Based On Selection: 13
read-across
chemical risk assessment
skin sensitisation
QSAR
machine learnin
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
15,000
7,538
0.503
* Total Citation Counts Rankings
Ranking Based On Selection: 14
toxicology
pharmacokinetics
thyroid
PFAS
dioxin
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
14,978
3,758
0.251
* Total Citation Counts Rankings
Ranking Based On Selection: 15
Xenobiotic compounds in environmental medi
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
14,602
9,803
0.671
* Total Citation Counts Rankings
Ranking Based On Selection: 16
developmental biolog
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
14,543
5,134
0.353
* Total Citation Counts Rankings
Ranking Based On Selection: 17
environmental microbiology
microbial ecology
regenerative system desig
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
13,936
3,744
0.269
* Total Citation Counts Rankings
Ranking Based On Selection: 18
wetland and sea level ris
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
13,934
4,303
0.309
* Total Citation Counts Rankings
Ranking Based On Selection: 19
Global Land Cover
Remote Sensing
Global mangrove monitorin
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
13,586
6,858
0.505
* Total Citation Counts Rankings
Ranking Based On Selection: 20
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
12,910
9,412
0.729
* Total Citation Counts Rankings
Ranking Based On Selection: 21
biostatistics
dose-response
pharmacokinetics
high throughput screening
quantitative risk assessmen
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
12,668
5,358
0.423
* Total Citation Counts Rankings
Ranking Based On Selection: 22
Atmospheric Chemistr
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
12,146
3,741
0.308
* Total Citation Counts Rankings
Ranking Based On Selection: 23
environmental geochemistry
contaminant transport
groundwater
remediation
arseni
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
11,933
4,910
0.411
* Total Citation Counts Rankings
Ranking Based On Selection: 24
soils
roots
biochar
contaminated soil remediation
nanomaterial
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
11,735
4,721
0.402
* Total Citation Counts Rankings
Ranking Based On Selection: 25
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
11,301
3,049
0.270
* Total Citation Counts Rankings
Rankings
19,011
8,784
1
Ranking Based On Selection: 1
Richard Judson
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
35,078
11,446
0.326
Toxicology
bioinformatics
Computational Toxicology
Systems Biology
Endocrine Disruptio
* Total Citation Counts Rankings
Rankings
19,640
9,054
2
Ranking Based On Selection: 2
Bryan Hubbell
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
34,351
16,913
0.492
risk analysis
air pollution
benefit cost analysi
* Total Citation Counts Rankings
Rankings
26,871
12,224
3
Ranking Based On Selection: 3
Keith A Houck
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
27,996
7,134
0.255
* Total Citation Counts Rankings
Rankings
26,928
12,249
4
Ranking Based On Selection: 4
Mallikarjuna Nadagouda
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
27,954
15,098
0.540
Nanotechnology
Materials Chemistry
Water Reserac
* Total Citation Counts Rankings
Rankings
30,475
13,749
5
Ranking Based On Selection: 5
Andrew Ghio
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
25,739
8,006
0.311
Lung diseases
iron homeostasis
fibers
particles
air pollutio
* Total Citation Counts Rankings
Rankings
36,999
16,448
6
Ranking Based On Selection: 6
Kirk G Scheckel
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
22,457
9,763
0.435
Environmental Soil Chemistry
Synchrotron Techniques
Bioavailability
Nanoparticles in the Environment
Plant Uptak
* Total Citation Counts Rankings
Rankings
39,054
17,253
7
Ranking Based On Selection: 7
James Wickham
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
21,627
5,941
0.275
Environment
landscape ecology
remote sensing
GI
* Total Citation Counts Rankings
Rankings
42,732
18,660
8
Ranking Based On Selection: 8
Antony John Williams
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
20,292
10,762
0.530
Chemistry
Cheminformatics
Nuclear Magnetic Resonance
Drug Discover
* Total Citation Counts Rankings
Rankings
50,888
21,879
9
Ranking Based On Selection: 9
Ann M Richard
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
17,848
8,673
0.486
Computational chemistry
cheminformatics
toxicolog
* Total Citation Counts Rankings
Rankings
54,388
23,185
10
Ranking Based On Selection: 10
Russell S Thomas
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
16,968
8,013
0.472
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* Total Citation Counts Rankings
Rankings
58,423
24,756
11
Ranking Based On Selection: 11
James Lazorchak
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
16,086
5,556
0.345
* Total Citation Counts Rankings
Rankings
60,398
25,482
12
Ranking Based On Selection: 12
John L Stoddard
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
15,706
3,853
0.245
freshwater ecology
biogeochemistry
acidificatio
* Total Citation Counts Rankings
Rankings
64,075
26,861
13
Ranking Based On Selection: 13
Grace Patlewicz
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
15,000
7,538
0.503
read-across
chemical risk assessment
skin sensitisation
QSAR
machine learnin
* Total Citation Counts Rankings
Rankings
64,209
26,914
14
Ranking Based On Selection: 14
Michael Devito
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
14,978
3,758
0.251
* Total Citation Counts Rankings
Rankings
66,401
27,740
15
Ranking Based On Selection: 15
Mark Strynar
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
14,602
9,803
0.671
* Total Citation Counts Rankings
Rankings
66,761
27,877
16
Ranking Based On Selection: 16
Thomas B Knudsen
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
14,543
5,134
0.353
* Total Citation Counts Rankings
Rankings
70,567
29,252
17
Ranking Based On Selection: 17
Jay Garland
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
13,936
3,744
0.269
environmental microbiology
microbial ecology
regenerative system desig
* Total Citation Counts Rankings
Rankings
70,576
29,257
18
Ranking Based On Selection: 18
Roxanne Johnson
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
13,934
4,303
0.309
* Total Citation Counts Rankings
Rankings
72,801
30,047
19
Ranking Based On Selection: 19
Chandra Giri
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
13,586
6,858
0.505
* Total Citation Counts Rankings
Rankings
77,564
31,738
20
Ranking Based On Selection: 20
Jia Xing
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
12,910
9,412
0.729
* Total Citation Counts Rankings
Rankings
79,352
32,391
21
Ranking Based On Selection: 21
R Woodrow Setzer
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
12,668
5,358
0.423
biostatistics
dose-response
pharmacokinetics
high throughput screening
quantitative risk assessmen
* Total Citation Counts Rankings
Rankings
83,583
33,913
22
Ranking Based On Selection: 22
John H Offenberg
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
12,146
3,741
0.308
* Total Citation Counts Rankings
Rankings
85,409
34,576
23
Ranking Based On Selection: 23
Richard Wilkin
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
11,933
4,910
0.411
environmental geochemistry
contaminant transport
groundwater
remediation
arseni
* Total Citation Counts Rankings
Rankings
87,154
35,213
24
Ranking Based On Selection: 24
Mark G Johnson
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
11,735
4,721
0.402
soils
roots
biochar
contaminated soil remediation
nanomaterial
* Total Citation Counts Rankings
Rankings
91,196
36,663
25
Ranking Based On Selection: 25
Brian Gullett
US Environmental Protection Agency
Washington, United States
Citation Metrics
Total
Last 6 Years
Last 6 Years / Total
11,301
3,049
0.270