Abstract
The number of eateries is growing around the world because they provide jobs and food to urban people who do not have time to cook. However, there are concerns that eatery wastewater may contain hazardous compounds and microorganisms. In view of the above, this study determined the chemical characteristics, heavy metal concentrations, and microbiological loads of wastewater collected from three eateries in Lekki, Lagos, Nigeria. The human exposure to heavy metals via oral and dermal contact, as well as the hazard quotient of daily exposure to these heavy metals, was also calculated. The chemical characterization revealed that nitrate, ammonia, and phosphate levels in all of the wastewater samples were above the limits of the Federal Environmental Protection Agency, while sulphate levels were normal. Copper, lead, cadmium, nickel, and chromium levels were within the permissible levels, but zinc was above the limits in the three eateries. The average daily oral and dermal exposure to heavy metals was normal, while the hazard quotient of daily dermal exposure to zinc and chromium in the three eateries was abnormal (> 1). In all of the eateries, bacterial and fungal levels were above permitted limits, but no coliforms were found. The results imply that the wastewater from the three eateries are hazardous and could pose environmental and health hazards. It is recommended that eatery owners treat wastewater before releasing it into the environment.
Highlights
Studies have linked increasing heavy metal exposure and microbial infection to the rising prevalence of diseases worldwide (Wu et al, 2019; Yahaya et al, 2020a)
Nitrates, ammonia, and phosphate were above the limits
The results obtained under the current study are consistent with those of Ezigbo and Ezigbo (2020) and Gurd et al (2020), who detected some chemical characteristics of water beyond recommended levels in fast-food wastewater
Summary
Studies have linked increasing heavy metal exposure and microbial infection to the rising prevalence of diseases worldwide (Wu et al, 2019; Yahaya et al, 2020a). More than 200 diseases are caused by pathogenic bacteria and chemicals found in food alone, ranging from diarrhea to cancer (WHO, 2020). Biogeochemical cycles, soil fertility, decomposition of dead plants and animals, biodegradation of organic chemicals, and health promotion all require microorganisms (Felicita and Marija, 2017; Macro, 2020). Some bacteria, fungi, protozoa, and viruses can cause diseases (Steffan et al, 2018). Heavy metal has no precise definition; it is broadly described as any element having a high molecular weight and a density five times that of water (Yahaya et al, 2020b). At certain concentrations, Yahaya et al, 2022
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