Environmental and Public Health Aspects of Solid Waste Management at the Lemna Dumpsite in Calabar, Cross River State, Nigeria

This study is aimed at investigating the level of environmental pollution and the potential impacts of municipal solid wastes on public health. The health risk assessment was determined through a survey of the present facilities used for solid waste management in the metropolis. Waste bins, types of depots, modes of transportation of wastes to disposal sites and methods of disposal were amongst the facilities investigated. The microbiological and physicochemical analysis of decomposing solid waste, leachate, soil, air at dumpsite, stream and Ikot Effanga Mkpa river waters were carried out using standard microbiological procedures. The prevalent bacteria besides fungi isolated from decomposing solid waste, soil, leachate, stream and river water samples were Escherichia coli 55 (13.31%) and 48 (14.33%) Chromobacterium spp 36 (18.18%), Staphylococcus spp 37 (17.70%), Salmonella spp 45(16.85%) and Klebsiella spp (17.06%) respectively. Statistical analysis of the bacterial and fungal counts showed significant difference (p<0.05) between the sources of sampling, months of sampling and seasons of sampling. Decomposing solid wastes followed by soil and leachate had the highest counts at 5% level of probability. The high bacterial Original Research Article Bassey et al.; IJTDH, 10(3): 1-13, 2015; Article no.IJTDH.20023 2 counts coupled with these findings are indicative of the possible high risk of microbial infections and a potential destruction of biodiversity from the toxic chemicals of the wastes. The results of the physicochemical analysis showed that virtually, most of the parameters determined are above the WHO permissible limits for drinking water. It is recommended that a fit for purpose strategy be developed for waste management with control measures that are health and eco-friendly.


INTRODUCTION
Municipal Solid Wastes (MSW) constitutes environmental and public health hazards all over the world. Hence, the management of solid waste is a vital tool for the enhancement of social services whose budget and provisions are made in line with population projection. Solid waste management in its entire ramification is a planned system of effectively controlling the production, storage, collection, transportation, processing, and disposal or utilization of waste in a sanitary aesthetically economical manner that is in accordance with the best principles of public health. This of course includes all administrative, financial, legal planning functions as well as the physical aspects of waste handling [1].
Solid wastes that constitutes nuisance to the environment consist of household waste, construction and demolition debris of residence and street wastes generated from residential and commercial complexes. Garbage has often originated enormously from the rapid urbanization, changes in the life style and food habits, resulting in increase in the amount and types of solid waste [2]. Unfortunately, the ability to manage such enormous waste is beyond the resources of most administrations in developing countries [3][4][5][6].
Sanitation geared towards environmental friendliness is the essence of municipal solid waste management and disposal of waste. The main aim of waste treatment and safe disposal is to exclude pathogens, germs, vectors and diseases such as rats, cockroaches, mosquitoes, particulate matter, hazardous chemicals e.g. petrol, spirits, spirits, syringes from hospitals, radioactive substances, drugs and heavy metals. Therefore, it is of utmost importance that each stage of solid waste management be technically planned in a manner to avoid environmental and public health hazards listed above [7]. PAI Associate International [8], reports that little or no attention has been given to ensuring that households in Nigeria play their part effectively in the organization of solid wastes storage, collection and disposal. It also reports that only a few cities like Jos in Nigeria have bye-law that is rigorously enforced as they specify dustbins for households [8].
However, in the developed countries of the world, greater concern is on the development of an ecologically sound and health-promoting ways of managing the millions tons of urban wastes that are generated daily. In the western world, each household produces approximately one ton of solid waste per year. The vast waste produced from Agriculture, industries, mining and commerce are not included.
Waste management and disposal techniques in Nigeria needs urgent attention. A number of solid waste management companies and authorities in Nigeria still do not adopt the sanitary landfill/controlled tipping method that allows the waste to be dumped in accordance with best principles of public health and the environment. Here the wastes are compacted and covered in trenches at the end of each day. If waste is dumped in an uncontrolled manner, it often consumes much space and may be a breeding ground for rodents, insects; and leachates may also contaminate underground water as they seep down.
In most part of the world, there are regulations that govern where a landfill (Sanitary landfill) can be placed and how it can operate the whose process begins with a proposal for the site followed by an environmental impact assessment of the site to determine that the area of land is necessary for the proposal landfill, the composition of the underlying soil and bedrock, the historical or archaeological value of the proposed site and the potential effects of the landfill and possible contamination on local wildlife. This is often preceded by a permit from the local, state and federal government authorities to kick start the operation. The choice for sanitary landfill by most developed countries on proper environmental impact assessment is based on the fact that it is environmental friendly and does not contaminated both the underground water and the environment. It is on record that most Nigerian cities including Calabar uses open dump system of waste disposal [8]. For instance, Lemna dumpsite in Calabar metropolis is an on open dump with no control of rodents, flied and other pollutants, thus posing environmental and public health consequences such as underground water and soil contamination by toxic metals, aesthetic nuisance, air pollution, surface water contamination, noxious odours and often times, a suitable breeding ground for mosquitoes, flies, rodents, snakes and pathogenic microorganisms.
The study was undertaken at Lemna dumpsite to assess the level of environmental pollution and the potential impacts on public health in relation to solid waste management in Calabar Metropolis, the capital of Cross River State, Nigeria. Calabar metropolis whose current population is about 371,022,000 is situated between latitude 4º57'N and longitude 8º20E (Fig. 1).

Health Risk Assessment of Solid Waste Management in Calabar
In order to assess the health risk of solid waste management in Calabar metropolis, a survey was undertaken to find out the existing facilities used for the management of solid waste. The facilities include; waste bins available at residential areas, markets, industrial and office places; types of depots if present; mode transportation of waste to the disposal dumpsite (if landfill).

Soil Sample Collection
A garden rake was used to remove the waste to expose the soil beneath the waste dump from where the soil samples were collected. The soil samples were taken at 15cm and 30cm depth with the use of a hand-driven auger and then taken to the laboratory in labeled sterile Petridishes seated with masking tape and foil in icecold boxes at approximately 4°C for both microbiological and physicochemical analysis.

Decomposing Solid Waste Sample Collection
A previously sterilized large wooden spatula rinsed with sterile, distilled water was used to collect the decomposing solid waste samples into sterile Petri dishes, sealed with masking tape and foil, and properly labeled as DSW 1 , DSW 2 , DSW 3 , and DSW4 to indicate the sampled points at the Ikot Effanga Mkpa dumpsite. The samples are transported to the laboratory in ice-cold boxes for microbiological and physicochemical analysis or store at 4ºC until they were needed for analysis.

Leachate Sample Collection
PVC pipes were bought and cut into four parts, each of 1.0-1.5 length. The base end of each pipe was permanently sealed with a pipe cover and an adhesive while the top ends were just fitted with pipe covers. The pipes (both 1m and 0.5m length) were perforated evenly at considerable distances from their base ends to allow for water percolation and collection. The whole pipe lengths were then buried into an already dug ground in each sampling point with small allowances at the top for access to top ends (which were only temporarily sealed). The dug out soil and wastes were replaced back to the ground and made to properly cover the pipes. This was left for a period of three to four (3)(4) weeks before sampling for the percolated leachates. Sterile enema pumps were used for the leachate collection into sterile bottles and labeled properly as L 1 , L 2 , L 3 and L 4 respectively. The samples were then taken to the laboratory for microbiological and physicochemical analysis or stored in the refrigerator maintained at 4 0 C until required for analysis.

Water Sample Collection from Ikot-Effanga Mkpa Stream and River
Water samples were collected from Ikot-Effanga Mkpa stream and River into which run-off from the dumpsite flows and labeled as SW 1 ,SW 2 ,SW 3 ,SW 4 and RW 1 ,RW 2 ,RW 3 ,RW 4 respectively. For both stream and river, the locations sampled consisted of two upstream and two downstream points. The waters samples were collected using standard procedures and precautions into previously sterilized containers and transported to the laboratory in an Ice-cold boxes for microbiological and physicochemical analysis or stored at 4ºC in a refrigerator until needed for analysis.

Bacteriological Analysis of Soil, Decomposing Solid Waste and Water Samples
One gram (1 g) of the soil was dissolved in 9ml sterile distilled water. The solution was then used to make ten-fold serial dilutions in the range of 10 -1 -10 -9 [9,2]. One milliliter (1 ml) of the sample dilution from 10 -4 -10 -7 was then seeded into sterile Petri dishes and total bacterial count was determined by pour plate technique using tryptone soya Agar that can support the growth of aerobes and anaerobes [10]. Tryptone soya agar supplemented with 1% (w/v) of cysteine hydrochloride (BDH chemicals, U.K.) used for the isolation of anaerobes while tryptone soya was used for the isolation of aerobes. All aerobic cultures were incubated at ambient temperature that fluctuates between 25-28°C, for 48 hours, while anaerobic cultures were incubated in a Baird and Tatlock anaerobic jar at 30°C for 48 to 72 hours. The visible growth (colonies) between 30 and 300 were multiplied by the reciprocal of the dilution pactors and recorded as colony forming units per gram (cfu/g) of the waste [9], [1]. Same treatment was given to decomposing solid waste (DSW), Ikot Effanga Mkpa stream and river water samples. Each of the dilution (10 ) was cultured in triplicate to determine the mean counts. The colonies growth from the tryptone soya agar were picked using a sterile wire loop and streaked on nutrient agar and incubated at 37°C for 24hours. This was repeacted several times to obtain pure culture of bacterial isolates. The district colonies were then subcultured into nutrient agar slants and stored in the 4°C regrigerator until required for characterization.

Total Fungal Counts
Same procedure adopted for bacterial was used for fungal counts for both the decomposing solid waste and soil samples. The only difference was the media used which was sabouraud dextrose agar supplemented with 100µg of streptomycin and 15µg of nystatin to inhibit bacterial growth. The plates were incubated for 3-5 days at room temperature. The characteristic colonies were sub-cultured on malt extract agar (oxoid), acidified to pH of 4.8 to suppress the growth of bacteria and obtain pure cultures of fungal isolates. The isolates were identified using standard identification procedures [11].

Microbiological Analysis of Air at Dumpsite
Settle plates method described by [10] was used for the analysis. Nutrient agar plates in triplicate were exposed at the dumpsite (10 m, 20 m, 30 m and 100 m) away from the dumpsite for an hour between 10AM and 12PM. The plates were then covered after 1 hour and transported to the laboratory for incubation at 25-28°C for 24 hours. The bacterial colonies that appeared on the plate were counted. The counts on plate placed at 10 m and 100 m away from the dumpsite were compared to give an insight on the level of air pollution.

Microbiological Analysis of Leachates
Leachates from such dumpsites are often turbid, therefore, serial ten-fold dilutions were made in the range of 10 -1 -10 -9 . One mililitre was dissolved in 9 mililitre of sterile distilled water to give 10 -1 dilution, followed by 10 -2 upto 10 -9 . Same analysis given to soil and decomposing solid waste was adopted for the leachate and the counts obtained expressed as colony forming units per mililitre of leachate (cfu/ml). Same purification procedures were used as that of soil and decomposing solid waste isolates.

Plate 1. (A) Perforated PVC pipes used for sampling of leachates from the dumpsite (B) Perforated PVC pipe buried at Lemna Dumpsite (C) Control PVC pipe buried 500m away from
Lemna dumpsite (D) Buried perforated PVC pipe filled with leachates after three (3) weeks

Characterization and Identification of Purified Microbial Isolates
Pure cultures of the isolates were inoculated onto nutrient agar to obtain purer isolates. MacConkey agar was used for the isolation of coli-aerogeneslike enteric microorganisms [9] Xylose Lysine Deoxychocolate (XLD) agar was used for the presumptive identification of both Salmonella and Shigella and are incubated at 37°C for 24 hours [9]. On the MacConkey agar, Escherichia coli colonies appeared red and non-mucoid; Aerobacter aerogenes colonies appeared pink and mucoid; Enterococcus faecalis appeared red, minute and round; Staphylococcus colonies appeared pale-pink and opaque, while Pseudomonas colonies appeared brown with fluorescent growth [12]. On XLD agar, Shigella formed red colonies as they can ferment xylose, lactose or sucrose [12] Salmonella also formed red colonies. Proteus strains formed red colonies with black centres [13]. The purified isolates were characterized using Bergey's manual of determinative bacteriology [12].

Physicochemical Analysis of Soil and Decomposing Solid Waste
Moisture content of the soil was determined by determining the differences in weight before and after drying the soil in an oven at 120°C to constant weight. The soil samples were then and dried, ground with wooden roller and sieved through a 2mm mesh. pH was determined using pretreated soil samples mixed with distilled water in the ratio of 1:2 (w/v) using the Jenway pH meter models 5 [14]. The method described by [15] used for the determination of organic carbon and available phosphorus. Ammonium (NH + 4 ) was determined by measuring the NH 3 liberated action of (MgO) with NH + 4 in the soil extract. Nitrite was determined spectrophotometrically by the diazotization method as nitrate after reduction in a cadmium reduction system [14]. Total Hydrocarbon (THC) measured followed extract with redistilled n-hexane before determining the total hydrocarbon content colorimetrically at 430nm using a DR/3000 HACH spertrophotomer (Loveland Colorado). Particle size was done by the Bouyoucos hydrometer method [16] as modified by [17]. Total nitrogen was done using the Micro-Kjeldahl digestion method [14].
All the decomposing solid waste samples were air-dried as was the case with soil, followed by grinding with a wooden roller and sieved with a 2 mm mesh. Total organic carbon, electrical conductivity, available phosphorus, pH total hydrocarbon, potassium, calcium, sodium and magnesium were determined using the same procedures for analyzing soil samples.

Physicochemical Analysis of Ikot-Effanga Mkpa Stream/River Water
The pH, dissolved oxygen (DO 2 ) conductivity and water temperatures were determined at the site of sampling (Lemna dumpsite). Water temperature and dissolved (DO 2 ) were measured using JEWWAY 970 DO 2 meter with sensitivity of ±0.1%. Salinity was measured using the Argentometric method. Turbidity (NTU) BOD 5 , nitrite, (NO ) were determined using same procedures described for the leachates analysis.

Physiocochemical Analysis of Leachates
Turbidity was determined spectrophotometrically using standards according to HACH. Biochemical oxygen demand (BOD 5 ) was determined as the difference between the initial oxygen concentration in sample and concentration after 5 days incubation in DO at 20°C [18]. Nitrite and nitrate were measured spectrophotometrically by turbidometry using barium chloride [18]. Total hydrocarbon was determined as described in soil analysis. Chloride was determined titrimetrically using silver nitrate and potassium dichromate as indicator [14]. Temperature was determined using the Celsius thermometer.

Physicochemical Analysis for Heavy Metals in Leacthate and Water
Using appropriate salts of the metal (Cr, Cd, Zn, Ni, Pb, Co, Mn, Cu, and Fe) the concentration of each metal in leachate were measured from the sample after due calibration runs using atomic absorption spectrophotometer (AAS Model 2380) [19].

Statistical Analysis
Statistical analysis using factorial experiment (ANOVA) was used to determine the association between the months of January to March, June to August on the one hand, and sources of samples on the other with respect to mean bacterial and fungal counts obtained.

RESULTS
The operational factors of solid wastes with much concern on public health are presented in Table 1. The results obtained shows the various sources of solid waste generated in Calabar metropolis, with emphasis on whether the households that generate the waste possessed dustbins or not and whether the waste generated were sorted out or not before they were transported to the disposal site. The survey also indicate that the mode of collection, transportation, disposal method and treatment of the solid waste generated do not conform to the safe principles of public health, except that the wastes transported to the dumpsite in trucks were covered with tarpaulin to reduce aerial contamination. In soil samples, location B had the highest bacterial counts of 8.7±2.16x10 6 cfu/g for January, 16.6±1.25x10 cfu/g for February and 16.3+2.16x10 cfu/g for March (P<0.05). However, location D which was used as the control location for the three months of sampling had the lowest bacterial counts of 5.4±1.63x10 6 cfu/g for January, 9.7±1.69x10 6 cfu/g for February and 9.8±1. However, Ikot Effanga Mkpa river downstream sample C had the highest bacterial counts of 9.4±1.69x10 6 cfu/ml for January, 6.7±1.69x10 6 cfu/ml for February and 9.5±0.82x10 6 cfu/ml for March, while upstream sample D had the lowest counts of 4.7+2.16x10 cfu/ml for January, 5.4+3.68x10 cfu/ml for February and 5.5±1.69x10 6 cfu/ml for March (p<0.05). Table 3 shows the mean total bacterial counts of Lemna dumpsite decomposing solid waste, leachate, Ikot Effanga Mkpa stream and river samples during the wet season of June-August, 2011. The results obtained showed that soil sample C had the highest bacterial counts of 8.3±1.69x10 6 cfu/g in August, 6.3±3.74x10 6 cfu/g in June and 6.3±2.4x10 6 cfu/ml in July (P<0.05) while sample D had the lowest bacterial counts of 3.7±2.05x10 6 cfu/ml in June, 5.7±2.16x10 6 cfu/g in August and 6.3±1.24x10 6 cfu/ml in July (p<0.05). For leachate samples, location B consistently had the highest bacterial counts of 6.2±2.05x10 6 cfu/ml in June, 6.4±3.

DISCUSSION
The Lemna solid waste dumpsite is an unlined, uncontrolled, unplanned and open dump located by Parliamentary Extension Road in Calabar metropolis. This dumpsite is used by Calabar Municipal Council for waste disposal and so holds a lot of household wastes that are received on daily basis. The level of pollution, seepage into the underground water, contamination of the nearby stream/river and the potential impacts on public health in relation to solid waste management at the dumpsite was effectively studied by sampling soil at the dumpsite, leachate, air, nearby stream and river water during the dry and wet seasons.
The study revealed that the composition, storage and disposal of solid waste in Calabar metropolis potentially have environmental and public health implications. Health risk assessment of solid waste management in the metropolis shows that, only about 70% households have appropriate containers as dustbins. It is revealed that government do not provide dustbin to about 30% of the the populace, hence the high increase of indiscriminate dumping of municipal solid wastes in the metropolis. Moreover, central depots where each household can deposit wastes for collection by garbage trucks and tippers are not evenly located along most streets and, in most cases, located very far away from most available space (Eja et al., 2003), a situation that is attributed to the high cost of purchasing the dustbins. This situation is not different in most Nigerian cities including Abuja till date, as reported by Aliyu [20]. Solid wastes are not sorted out (separated) into biodegradable and non-biodegradable wastes as is the practice in developed countries. In view of this, bottles and tins are also separated at the point of collection in order to facilitate proper handling by authorities [21] while some of the separated wastes could be recycled. Industrial waste which normally contains toxic chemicals and sometimes radio-active substances including electronic wastes, are dumped together with domestic, market and commercial wastes which poses very serious health consequences. It was observed in this study that wastes conveyed in trucks and tippers to disposal sites were covered with tarpaulin which has helped partly to reduce aerial spread of particulate substances and odour. But because the disposal site is an open dump, aerial pollution seems to be very high as wastes are being discharged from trucks/tippers at distances within a few meters from the dumpsite. This implies that residents living near the dumpsite are at risk of contracting air borne infections from bacteria, fungi or toxic chemical substances. This is quite possible during the dry windy period of the year (January to March) which was when this study was carried out, with mean bacterial counts ranging from 36.5±0.06 to 45.2±0.08 within 10 meters from the dumpsite of study. Fungal counts also ranged from 14.0±1.25 to 18.0±2.87 within 10 meters from the dumpsite. However, the further away from the dumpsite, the lesser the level of aerial contamination by particulate substances.
These findings indicate that the air environment around the waste dumpsite is usually contaminated by particulate substances.
Although the physicochemical parameters in air were not measured, dust, oxides of nitrogen, sulfur dioxide, carbon monoxide, hydrocarbons, radioactive substances and a trace of toxic elements have been reported to be associated with air pollution caused by solid waste incineration [16].
The bacterial and fungal counts from decomposing solid waste, soil at dumpsite, leachate, Ikot-Effanga Mkpa stream and river water samples were generally high during the three months of sampling from January to March, 2011 (Tables 2 and 3 [8] reported that as long as solid waste disposal is essentially of the simple dumping type, its effects on land pollution need to be stressed strongly. Some of the most common contaminants contributing to land pollution around urban centers are household refuse especially food remnants, packing materials such as papers, cartons, boxes, plastics, tyre residuals, cans and ash resulting from burning; also organic industrial residuals such as those from cannery operations like pulp, pits and culls, etc [10] often contribute immensely to urban land pollution. From the environmental point of view, the pollution from open dumping of waste could result in the production of not only unsightliness but also in the production of bad odours resulting from the decomposition of solid wastes. From public health point of view, such improper waste disposal techniques can become a serious health hazard through creating a suitable environment from which diseases can be transmitted. A report by PAI Associate International opines that such communicable diseases may be fly borne. They include typhoid, dysentery, cholera, onchocerciasis, sandfly fever and conjunctivitis, others may be rodent-borne zoonosis, e.g. echinostomiasis, haemorrhagic septicaemia, while some may be mosquito-borne diseases such as filariasis, dengue, malaria and yellow fever [23]. Advocated the use aqueous of Editan (Lasianthera africana), Ikongetidot (Veronia amygdalina) and Atama (Heinsia crinata) that have demonstrated effective spectrum of activity against most isolated pathogenic bacteria an alternative regimen. Soilborne fungal diseases associated with infected buried waste may also be related to open dumping system of waste disposal [8,24].

CONCLUSION
From that tremendous useful information obtained in this comprehensive study, it is pertinent to conclude that the open waste dump at the Ikot-effanga mkpa dumpsite constitute a source of microbial and toxic chemical contamination of the dumpsite, the underground water, Ikot effanga mkpa stream and river through run-off inputs. This poses serious health risk and destruction of biodiversity in both terrestrial and aquatic ecosystems of the area. The situation could be aggravated by the poor storage systems in homes and establishments thus constituting good channels for disease transmission by flies, mosquitoes and rats. Further assessments could be need during the rainy season to have a comparative idea of the level effanga mkpa solid waste dumpsite is of great public health concern as it contains microbial pathogens capable of initiating various infectious diseases in Calabar metropolis. The dumpsite has to a greater extend influenced the pollution of the air, the soil, and surface water bodies within the vicinity.

CONSENT
It is not applicable.

ETHICAL APPROVAL
It is not applicable.