clean and dirty water samples in hands

analysis analyzing background biochemist biochemistry biologist biology biotechnology blue chemical chemist chemistry clean clear contageous contaminated contamination cut cutout detail dirty ecologic ecology environment exam examine experiment filtered filtering finger fingers fluid girl hand hands health healthcare hold holding human indoor industry isolated job lab laboratorian laboratory liquid macro medical medicine microbiology nature out people plastic polluted pollution purity research researching sample science scientist septic studio technician test testing toxic tube unclean unhealthy waste water wellbeing woman work worker working