Effects of Detergents on River Nile Water Microflora

Generally, the number of genera and species of microflora were found to be decreased in River Nile water-treated with different doses of detergents. While the counts of the micro-floral populations (bacteria, fungi, algae) were inhibited by detergent treatments, only those of algae, in some cases, were promoted either slightly or markedly. From the results obtained it could be stated that algae are more sensitive to detergents under investigation that bacteria and fungi while they could not tolerate the high levels used (5 or 10g/L). This may be due to the rise in water pH which was observed to be significantly reduced to 4.2 and 2.7, respectively.
Gram positive cocci were highly sensitive to all doses of all detergents used while Gram positive bacilli were inhibited by the low doses and completely suppressed in response to all mixture doses and to high doses of the other detergents. No stimulatory effect on bacteria by any detergent was observed. With regard to fungi, it was found that some species were more sensitive to detergents than the others. Some species were inhibited by some detergents and promoted by the others. Penicillium chrysogenum was the most tolerant species and could be regarded as detergent tolerant fungus and may be used as a biological indicator for water pollution by detergents.
It was also observed that some algal species were very sensitive to all detergents used while others were tolerant to the same detergents and sensitive to others. It was also observed that a third group of algae were resistant to high doses of different detergents. These could be considered as detergent-tolerant species and regarded as biological indicators of pollution.