Determination of the Toxicological Risk of Urban Waste from the City of Uvira Dumped into the North-Western Coast in Lake Tanganyika (Democratic Republic of Congo)

Lumami Kapepula Vercus,Patricia Luis Alconero,Nsimanda Ipey Camille,Lukusa Mbaya Alain,Théophile Ndikumana,Musibono Dieu-Donné,Bart Van Der Bruggen,Njoyim Estella Buleng Tamungang

doi:10.4236/jep.2021.1210041

Abstract

This study focuses on determining the toxicological risks of urban waste from the city of Uvira, discharged into Lake Tanganyika, on the surrounding population. Volatile organic compounds were measured in a variety of solid waste matrices, including inorganic micropollutants in wastewater and fish. The concentrations of Hg and Pb in the lake were found to be 1.21 and 1.42 μg/L respectively and between 0.83 to 18.36 μg/L of Hg and 8.25 to 670 μg/L of Pb, at the collector outlet. The presence of trace metallic elements, such as Cr, Co, Ni, Cu, Zn, As, Sb, Hg and Pb, were detected at high concentrations compared to the WHO standard. An ecotoxicology experiment herein on wastewater samples showed lethal pollutant concentrations of the order of 0.0055 mL/mL which killed at least 50% of fish (LC50), confirming the toxicity of the wastewater. These potentially harmful effluents also contain volatile organic compounds originating in high concentration from the pharmaceutical discharges of the general Uvira hospital, in particular: toluene, ethylbenzene, m-xylene/p-xylene, o-xylene and chloroform in higher concentrations compared to the norm. Other components such as benzene, bromodichloroethane and 1,1-dichloroethane were found to be present, but at a concentration below 0.05 ppb. A variety of trace organics can be suspected to be present as well.

Highlights

The hydrosphere is among the ecosystems most threatened by the impact of anthropogenic effects over the past century [1] [2] [3]
This study focuses on determining the toxicological risks of urban waste from the city of Uvira, discharged into Lake Tanganyika, on the surrounding population
It is worthy of note that the water from Lake Tanganyika was used as a reference and the wastewater samples from the collector diluted by 10 to 90% were considered as indicators of the toxicological level

Summary

Introduction

The hydrosphere is among the ecosystems most threatened by the impact of anthropogenic effects over the past century [1] [2] [3]. Living things can be exposed to a large number of xenobiotics, synthetic or natural (toxins), from microorganisms, plants or animals, which can disrupt the normal metabolic processes of a person or animal and are harmful to the body. These can be toxic products, such as environmental pollutants Micropollutants are linked to diffuse emissions of particles and domestic practices [5]. Among the most commonly encountered organic micropollutants are 1,4-dichlorobenzene, 1,1-dichloroethane, toluene, xylenes, ethylenediaminetetraacetic acid EDTA and acetone [6]. It is interesting to note that the low concentration of trace organic compounds in wastewater and their low biodegradability make their treatment difficult in intensive purification processes [7]

Objectives

Methods

Results

Conclusion