- Environmental Chemistry 27
- Environment, general 26
- Environmental Health 20
- Atmospheric Protection/Air Quality Control/Air Pollution 19
- Ecotoxicology 19
- Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution 17
- Soil Science & Conservation 11
- Biotechnology 10
- Pollution, general 10
- Environmental Engineering/Biotechnology 9
- Monitoring/Environmental Analysis 9
- Analytical Chemistry 8
- Microbiology 7
- Engineering, general 6
- Biochemistry, general 5
- Chemistry/Food Science, general 4
- Earth Sciences, general 4
- Environmental Physics 4
- Industrial Chemistry/Chemical Engineering 4
- Industrial and Production Engineering 4