THE EFFECT OF CHROMIUM ON THE GROWTH OF CHLORELLA PYRENOIDOSA ALGAL CULTURES

Different forms of chromium can be found in soil, water and even in the air. Around 60% of the chromium in the air is a result of human activities, the rest occurs naturally (by way of volcanic eruptions, fires). Gaseous chromium cannot be found in the atmosphere, chromium binds to the solid particles or to the atmospheric aerosol drops. Most of the forms of Cr (VI) occur in the environment as a result of industrial activity, having chromite as main source, also known as iron and chromium chromate. The ideal composition is FeCr2O4. The chromium in the water originates from dust from the air and cliff erosion. The chromium in freshwater varies in the range 0.1-800 mg/l. In polluted areas the values can be even higher. In natural waters Cr(III) and Cr(VI) is stable.