Photo de l'écologiste masqué, costume de protection avec éprouvette, pouce en l'air, au bord de la rivière - Photo & image de stock

Chemist with bulb and raised finger sits on river bank

Photo of biologist in mask, protective suit with test tube, finger down, on river bank

Ecologist with test-tube and mask, protective suit, finger down, sits on river bank

Chemist looks at flask with water sitting on river bank

Ecologist looks at flask with water sitting on river bank

Photo of chemist takes water for examination in pond

Ecologist with bulb and raised finger down on nature

Photo biologist takes water for examination in pond

Ecologist with bulb writes in folder on banks of river, blurred background

Chemist on river bank with test tube and water in hands

Ecologist in respirator with test-tube on blurred background

Biologist with bulb and folder on river bank, blurred background

Ecologist in blue gloves with test tube in hands takes sample of water near lake shore

Laboratory assistant with bulb in hand on river bank in summer

Photo of hand in blue glove with test tube on blurred gray background

Ecologist in safety glasses and respirator holds flask with water in hands on street