The textile industry contributes significantly to the economy in many countries. However, there are concerns that textile wastewater contains toxic substances whose compositions vary among textile industries, necessitating the characterization of every textile industry's wastewater for effective treatment. This study, therefore, evaluated the levels of heavy metals and microorganisms in the wastewater released by a textile industry in Ikorodu, Lagos, Nigeria. Samples of the wastewater were treated and subjected to atomic absorption spectroscopy (AAS) and microbiological examinations using standard protocols, and the results were compared with the Federal Environmental Protection Agency's acceptable limits for wastewater. The average daily oral ingestion (ADOI), average daily dermal ingestion (ADDI), and hazard quotient (HQ) of the heavy metals were also evaluated. The AAS revealed permissible levels of lead, cadmium, nickel, copper, manganese, arsenic, calcium, magnesium, iron, and chromium, but zinc was above the permissible limits (> 1.00 mg/L). The ADOI and ADD1 of the heavy metals were within the permissible limits, except for the ADDI of lead, nickel, and arsenic. The HQ of nickel (oral), manganese (oral), cadmium (dermal), and chromium (dermal) were above the recommended limits (≥1). The microbiological examination revealed non-permissible levels of total bacteria (Bacillus subtilis, Pseudomonas aerginosa, and Lactobacillus spp.) and fecal coliform (Escherichia coli). These results suggest that the wastewater could pose some health and environmental risks and needs to be treated.
Key words: hazard quotient, heavy metals, microorganisms, textile, wastewater
|
