Leseprobe
Abstract
Poor solid waste management systems from urban municipal dumpsites into surface and subsurface water sources can be harmful to the urban population who use these water sources. Gradual accumulations of contaminants in the water sources can result in high loads of pollutants that are potentially toxic to the users. In Mizan Aman town river Gechab, Cosakol, Shonga, petrous, and nimbus Rivers are drain through the town and inter into water supply dam. This study was conducted from December 2020 to April 2021, per day Solid waste generated 66% was degradable and 34% non-degradable solid waste .Water samples were collected from wells and the surface water during both at dry and rainy seasons. Electrical conductivity, total hardness, TDS, fluoride, Zinc, manganese, dissolved nitrate iron, phosphate all were determined using flame atomic absorption spectrometry. Faecal coliforms, total coliforms were determined by the membrane filtration method. The Physic-chemical parameters and biological parameters are measured from streams, wells and at water tap which shows other than the pH, temperature, Electrical conductivity, total hardness, TDS, iron, fluoride odor, and taste, all other concentration values are exceeded the Ethiopia minister of water and irrigation for drinking water and WHO guideline at wet season this was due to runoff at rain season and causes the water body was to polluted. It has been observed that the major sources of pollutants into the water bodies were organic waste as well as coliform bacteria derived from these waste dumps. The elevated levels of bacteria make the water bodies unsafe for both primary and secondary contacts.
Correlation was also done to show that the disposal site and its distance between water body's the result show that water body at upstream of the dumping site was not polluted when compared with downstream dumping site stream and wells this shows waste from dumping site was directly enter into streams and well during rain season by runoff
Keywords
Solid waste, water quality, Dumpsite, water pollution and water pollution
1. Introduction
Development in the twentieth century shifted rural inhabitants to cities and towns, resulting in a slew of environmental issues. Environmental challenges are being handled on a global, regional, and local scale. Solid waste management from home, commercial, and agricultural sources is one of the most pressing environmental issues today. Solid waste management is a problem that authorities in fast-growing cities, particularly in developing countries, are grappling with. According to the World Health Organization, solid waste disposal takes precedence over water quality in Africa ( Aljaradin, M., & Persson, K. M. (2015)
Based on a projected population of 82861 and an average daily waste generation of 0.34 kg per person, Mizan Aman generates annually about 10,142,186.4 kg of solid waste. The high population and its associated increase in urbanization and economic activities within the Mizan Aman town have made the impact on surface and sub-surface water quality at dry and wet season is very obvious. (E. S., & Studies, R. (1857).Open solid waste dumping is a frequent practice because it is fairly affordable for municipal solid garbage.” Open dumping, composting, and landfilling are the most popular waste disposal methods in Ethiopia. Open dumping is decided on the basis of geography rather than geological or hydrogeological concerns (Adebayo Bello, I., & bin Ismail, M. N. (2016)
It is a common site seeing water bodies flowing through most of these solid waste dump sites. Five prominent water bodies which are found flowing through the town and solid waste dump sites have been studied in order to ascertain the effects of the dump sites on water quality of streams and wells. It is a known fact that virtually all water pollutants are hazardous to humans as well as lesser species. For example Very high amounts of fluoride greater than 10mg/. can lead to skeletal fluorosis, Nitrate greater than 5.5mg/l can cause methemoglobinemia or “BlueBaby Syndrome “affects human health headaches, dizziness, flushing of your face and neck, upset stomach or throwing, low blood pressure, and irregular heart rhythms. Phosphorous one of the crucial nutrients for algal growth and can contribute meaningfully to the eutrophication of lakes and reservoirs (WHO (2018))These known effects therefore support the need to assess the effects of these dumpsites on the water quality of these water resources which are widely in use by the communities leaving around them.
2. Material and Method
Mizan-Aman town is located in the Southern Nations, Nationalities, and People's Region. The town was one of the zonal cities or capital cities of the zone. It is located at a distance of 561 and 836 kilometers southwest of Addis Ababa and Hawassa respectively. The town is also found at a distance of 50 and 230 km from Tepi and Jimma respectively. Astronomically, the town is suited 06059'80'' north latitude and 350 35' 60'', east longitude. The city is divided into two sub-city Mizan and Aman sub-city. The total area covers 2925 hectares of land with an average elevation of 1345-1460 meters above sea level
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Figure 1 Map showing the study area
2.1. Geology and hydrology
The local geology of the area is composed dominantly of basaltic rock types. This rock is characterized by affinity (fine-grained) with tight joints &sub vertical random fracturing at places. Boreholes, which have penetrated to a depth of 302m during the previous investigation program (Zone, M. (2019) have also revealed that the underground is made of the tertiary trap series volcanic s i.e. (Basalts, rhyolites, ignimbrites).
State of an aquifer in the geological environments like Mizan Aman, where tertiary volcanic rocks characterize the area, groundwater could be expected within secondary porosity i.e. existence of sufficient fracture &weathering. Where fracture zones intercept watercourses, it is believed that deep groundwater recharge could be enhanced. However, though the area has several streams &receives sufficient rainfall, fracturing in the area is poor. The approach previously attempted to locate borehole sites by inferring structural zones & following the saline principle as (Zone, M. (2019)
2.2. Collection of Water Samples
Sampling of water from the study area was done over a period of six months (December 2020 - April, 2021).Wet season samples were obtained in March, April and May while dry season samples were collected in December, January and February. The locations of the sampling sites were established using a Garmin 45 Ground Positioning System (GPS). The geographical locations, site elevations and types of samples collected from both streams and well sampling site are presented on Table 1 and 2 respectively. At each sampling point, two sets of water samples were collected into separate pre-cleaned 1 L polyethylene bottles. 2.0 mL of concentrated HNO3 was added to one
Table 1 GPS date sample site from Streams
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Table 2 GPS data from sample site of wells
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The negative sign indicate the upstream of solid waste dumping site and positive sign indicate downstream of solid waste dumping site At each sampling point, two (dry and wet season) sets of water samples were collected into separate pre-cleaned 1 L polyethylene bottles. 2.0 mL of concentrated HNO3 was added to one of the bottles. The acidified sample was used for eelmental analysis. The non-acidified sample was analyzed for biological characteristics.
Collected samples were stored in a cooler containing ice cubes, and later transported to the laboratory at the Department of Chemistry, Mizan Tepi University , for analysis. At the laboratory, samples were stored in refrigerators at 4oC until analysis.
2.3. Chemicals, Reagents, and Standards
HNO3 (Merck, Germany); H2O2 (30%, Merck, Germany), were used for mineralization of the samples. Standard stock metal solutions were prepared from Cd stock standard solution (1000 mg/L in 2.0% HNO3, Trace CERT, Fluke, Switzerland), (NO3) stock standard solution (1000 mg/L in 2.0% HNO3, Trace CERT, Fluke, Switzerland), Mn stock standard solution (1000 mg/L in 2.0% HNO3, Trace CERT, Fluke, Switzerland), P,F,Mn and stock standard solution (1000 mg/L in 2.0% HNO3, Trace CERT, Fluke, Switzerland),TDS and Zn stock standard solution (999 mg/L in 1.4% HNO3, Techno lab AB, Sweden) respectively. For all dilutions, demineralized redistilled water was utilized. Calibration curves were developed by using celebrants prepared by appropriate dilution of the 1.0 gJ.1
2.4. TDS, Fe, F, P, Zn, (NO3) and Mn Measurements by using flame atomic absorption spectrometry
Determination of metals in the acidified filtered (0.45 |im Millipore filter) water samples were carried out in accordance with standard methods. The concentrations of TDS, Fe, F, P, Zn, (NO3) and Mn in the samples were respectively estimated by comparison with either the respective calibration curve or by the standard addition technique.
2.5. Physical and Chemical Measurements
Temperature and pH were measured in-situ and recorded at the sampling sites. Nitrates, phosphates and physical parameters such as turbidity and suspended solids were also determined using standard methods
2.6. Determination of Biological Characteristics
Total coliforms and Faecal coliforms were determined by membrane filtration method exhausting M-Endo-Agar at 37oC and on MFC Agar at 44oC ± 0.5oC for 48 hours, respectively. All species of helminthic eggs in water samples were quantified using the concentration method. The identities of the specific helminthic eggs were recognized using the World Health Organization (WHO 2018) bench aid for the diagnosis of intestinal parasites
3. Results and Discussion
3.1.Solid waste generation rate and its composition
The amount of solid waste generated per day from the household, institutional and commercial is 44.06kg/day,202.1kg/day, and 154kg/day respectively and the total amount becomes 400.16 kg/day the percentage of solid wastes generated per day from all sours from (figure 2) below are 31%,16%,,11%,,10%,,9%,,7%,,6%,,5%,,5%, and 5%, for food waste, fruits, wood, paper, ashes, plastic, glass, metal, and bottles, respectively. The collected data shows that the maximum
proportion of refuse caused by food waste second highest was fruit waste and the third-highest was ashes. The per capita waste generation rate is important to predict future waste groups and to evaluate the waste generation trends (Jung, H. Y. E. (2016)).
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Figure 2 Total solid waste composition
The total value of degradable solid waste generated from the municipality was considerably higher than the value for non-degradable solid waste materials. From (fig.3) below the total value of degradable waste generation was 66% while the value for the non-degradable solid waste was 34% .this shows waste from Mizan Aman municipal was polluting the environments.
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Figure 3 Degradable and Non-Degradable solid waste
3.2. Physical Parameters
The physical parameters of water quality can be broken down into many topics and one need to take into consideration the nature of the physical parameters of the ecosystem surrounding a water source to be able to understand the physical appearance of water. Physical parameters which usually determine water quality are considered below
3.3. Temperature of water
Temperature affects sediment and microbial growth among other characteristics of water and it is also a known fact that the rate at which chemical reactions occur increase with increasing temperature and the rate of biochemical reactions usually double for every 10oC rise in temperature. Physically, less oxygen can dissolve in warm water than in cold water. This is because increased temperature decreases the solubility of gases in water. Increased temperature increases respiration leading to increased oxygen consumption and increased decomposition of organic matter. It is for these reasons that the temperatures of the water samples were determined for the river systems and wells. The mean of streams at dry seasonal water temperature ranged from 21.24°C to 22.53 °C in the wet season, 19.11 °C to 20.53oC at for wells the mean at dry seasonal water temperature ranged from 21.39°C to 22.53°C in the wet season, 18.45°C to 19.96°C Since water temperature affects the concentration of biological, physical, and chemical constituents of water, the relatively high temperatures recorded would speed up the decomposition of organic matter in the water. Hence, population of bacteria and phytoplankton would double in warm weather in a very short time.
Table 3 Temperature measured from streams during the dry and rainy seasons
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Table 4 Temperature values for the four wells measured during dry and rainy seasons
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3.4. pH of Water
pH is important in water quality assessment as it influences many biological and chemical processes within a water body. The pH values recorded were slightly alkaline with little variations among the study sites. The mean pH in stream water ranged from 7.25 to 7.38 during the dry season and 7.112 to 7.32 during the rainy season and was slightly alkaline and the mean of pH in wells during the dry season is from 7.23 to 7.6 and 7.5 to 7.9 in rain seasons did not show an extensive variation. The mean pH during the study was within the guidelines and in an adequate range. It is a known fact that variations in pH affect chemical and biological processes in water and low pH increases the availability of metals and other toxins for intake by aquatic life
Table 5 pH measured from the stream during the dry and rainy season
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Table 6 pH measured from wells during the dry and rainy seasons
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3.5.Chemical Parameters
Chemical characteristics of water can affect aesthetic qualities such as how water looks, smells, and tastes. This can also affect its toxicity and whether or not the water is safe to use. Since the chemical quality of water is important to the health of humans as well as the plants and animals that live in and around streams, it is necessary to assess the chemical attributes of water. It is in light of these facts that the following chemical parameters have been determined for the water systems
1.1.Electrical Conductivity of Water
The electrical conductivity (EC) for wet and dry seasons as compared at streams and wells in Figures 5 and 6 indicate that at downstream of the dumping site the electrical conductivity during the rainy season increasing downward because of dumping site runoff directly inter into the streams and well . All sampling points other than S1 had relatively high electrical conductivity as compared to the Ethiopia ministry of water and irrigation (EMWI) and WHO guidelines.
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Figure 4EC measured from the stream during dry and rainy seasons
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Figure 5EC measured from wells during dry and rainy seasons
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