Fungal contamination of commercial drinking water in Lagos, Nigeria

Water deemed fit for consumption ought to conform to minimum standards that pose no significant health risk to the consumers. Bottled and Sachet water constitutes the major source of drinking water in Lagos State Nigeria. We conducted a study to investigate the presence of fungi in the commercially available water brands in the study area.

A study collected eleven commercial water brands, including eight bottled and three sachet brands, from retail outlets. Samples with production dates ranging from 24 h to 3 weeks were filtered using membranes inoculated into SDA and incubated at 27 °C and at 37 °C. Pure fungal cultures were identified using microscopic and macroscopic features, using mycology atlas.

All brands of water (bottled and sachet) analyzed grew at least one fungal isolate thus giving an absolute (100%) rate of contamination in this study. Overall, the predominant fungal pathogen was Aspergillus fumigatus sensu lato (s.l) and Aspergillus niger (n = 6, 30%), followed by Aspergillus terreus (n = 2, 10%). Other isolated fungal species were Aspergillus terreus, A. flavus, Candida albicans, Cladosporium spp. and Penicillium spp. Each of the brands was contaminated with at least one fungal pathogen and at most two.

The study reveals a high level of fungal contamination in retailed water, particularly in areas with at-risk populations. These fungi can cause allergic reactions or diseases in humans. The study suggests Nigeria's food and drug regulatory bodies should include routine screening for fungi in commercial water production like their bacteria counterparts.