ABSTRACT
This study is therefore set to evaluate the effect of the effluent discharged from the ceiling industry into the immediate ecosystem; .Ekwuru river. The physicochemical characteristics of the effluent, at the discharge points at Ekwuru river were analyzed. Two suspected groups of pollutants of concern namely Polycyclic aromatic hydrocarbons (PAHs) and Heavy metals were investigated in the samples using Gas chromatograpy and Atomic absorption spectrophotometer. A reference site 20km from the ceiling industry was used as control since there was no record of such investigation prior to the establishment of ceiling industry .The results showed that the PAHs in effluent is 0.0739mg/ml, while the upstream of the river had 0.00533mg/ml, downstream of the river with 0.0094mg/ml. point of discharge of the effluent into the river with
0.0574mg/ml. pond water with 0.0060.The effluent showed the heavy metals (Cd ,As, Pb, Hg, Zn, Ni) with the ceiling effluent having significantly (p >0.05) higher values of most heavy metals than the pond water sample(control). The contaminated fish from the river had for 1km away from point of discharge of the effluent into the river 0.1102µg/kg, downstream
0.1004µg/kg, up-stream 0.0979µg/kg, pond fish 0.0429µg/kg.
Heavy metals and PAHs in water samples of River Ekwuru followed in the order, effluent discharge point >downstream > up-stream. The result of the antioxidant in fish showed significant (p >0.05) elevations in SOD 4.61 ± 0.001 to 8.89±0.01,GPX 7.96 ± 0.00 to 7.96 ±
0.00 to 73.01 ±0.02, CAT 0.35±0.02 to 0.57 ±0.01, TP 15.16±0.02 to 22.48± 0.02, while there is non significant (p<0.05) decrease in MDA 0.05±0.00 to 0.34 ± 0.10.The result of the physicochemical parameters in the water showed significant (p>0.05) elevations in PHOS 1.03±
0.02  to  7.35±  0.01, COD34.67±0.01  to  85.53±  0.22  OD1  3.60±  0.10 to  11.60±0.10,   OD2 2.10±0.10 to 6.60±0.20  BOD 30.00±0.00 to 100.00± 0.00, TEM 27.33±0.58 to 29.00 ± 0.00, pH7.10±0.10 to 11.27±0.02.the elevation is as a result of the pollutant in the water. The hazard risk in the PAHs were above one in the point of discharge of the effluent, while at the up-stream and down-stream of Ekwuru river were below one. Consumption of fish from Ekwuru river can cause non-carcinogenic and carcinogenic effect on average  consumption of 25kg per capita per day for a life time of 70 years in most of the sample locations.
CHAPTER ONE
INTRODUCTION
Water pollution results from dispersing of unwanted effluent in a water system thereby changing the water quality. The industrial sector is the major sources of pollution, but in addition to that is the Ceiling Sheet Effluent (CSE) which also affects the environment adversely (Feredonu, et al.,
2010). Over the years, considering the numerical growth and urbanization, industrial and agricultural land use, this has tremendously increased in the discharge of polycyclic aromatic hydrocarbons, pesticides, fuels, lubricants to the receiving water bodies and has caused undesirable effects on different component of aquatic environment (Saad et al., 1984), compared with the organic compounds that are readily degraded upon introduction into the environment (Ho et al., 2012)
Ceiling sheet industries are mega project, which require not only huge capital investment, but also various natural resources such as fossil fuels and water, thus creating an immeasurable impact on the environment and generating tremendous stress in the ecosystem (Emenike et al.,
2017). The combustion of fossil fuel is the mixture of hydrocarbons which include: straight chain, branched, cyclic hydrocarbons, polycyclic aromatic hydrocarbons, (PAHs) and inorganic substances. In large concentration, ceiling sheet effluents are toxic to many organisms including humans, soil organisms and aquatic life (Afkar et al., 2010). This can affect the health of the organism due to chronic exposure to high concentrations. Risk assessment is the process of estimating the potential impact of a chemical, physical, microbiological or psychological hazard on a specified human population or ecological system under a specific set of conditions and for a certain time frame (Paustenbach, 1989). PAHs are by-product of combustion and are naturally occurring chemicals in the environment. Forest fires and volcanoes are major natural sources of PAHs. Industrial emissions, waste site incineration, and burning of fossil fuel are anthropogenic source. Heavy metals have variously been used to denote: metals with density greater than 5, and metals which are toxic to man and other life forms when found in the environment. The eight most common pollutant heavy metals listed by the Environmental Protection Agency (EPA) are mercury, cadmium, lead, arsenic, chromium, copper, nickel and zinc (Arthar and Vohora, 2001). Aquatic pollution by PAHs and heavy metals is very prominent in industrialized areas and they
are leached to the water bodies, thus causing toxic effect to aquatic organisms by accumulating in their bodies hence this study.
1.1 Risk Assessments
Risk assessment is the process of estimating the potential impact of a chemical, physical, microbiological or psychological hazard on a specified human population or ecological system under a specific set of conditions and for a certain time frame. (Paustenbach 2015). The scope of environmental health risk assessment (EHRA) can cover health impacts of chemical pollutants and contaminants in air, water, soil and food. risk assessment is intended to provide complete information to risk managers specifically policymakers, and regulators, so that the best possible decisions are made.(Paustenbach 1989).
Risk Assessment is the central component of risk analysis and provides a scientific basis for risk management decisions on measures that may be needed to protect human health. It evaluates the possible danger in the consumption of organic chemicals by animals and human. Risk is characterized by assessing the Hazard Quotient (HQ), the Health Risk Index (HRI) and the lifetime cancer risk (LCR). The HQ is a simple ratio of single exposure and effect values and may be used to express hazard or a relative safety (Gerba, 2010)
1.1.2 Steps in risk assessment
To conduct risk assessments, the national academy of science risk assessment paradigm has proven to be a useful tool (National Research Council, 1983). This paradigm divides the risk assessment process into four distinct steps: hazard identification, dose-response assessment, exposure assessment and risk characterization (Cirone and Duncan, 2000).
The purpose of hazard identification is to evaluate the weight of evidence for adverse effects in humans based on assessment of all available data on toxicity and mode of action. It is designed to address primarily two questions: (1) whether an agent may pose a health hazard to human beings, and (2) under what circumstances an identified hazard may be expressed. Hazard identification is based on analyses of a variety of data that may range from observations in humans to analysis of structure-activity relationships. The result of the hazard identification exercise is a scientific judgment as to whether the chemical evaluated can, under given exposure conditions, cause an adverse health effect in humans. Generally, toxicity is observed in one or more target organ(s). Often, multiple end-points are observed following exposure to a given
chemical. The critical effect, which is usually the first significant adverse effect that occurs with increasing dose, is determined (Paustenbach, 2002).
Dose-response assessment is the process of characterizing the relationship between the dose of an agent administered or received and the incidence of an adverse health effect. For most types of toxic effects (i.e. organ-specific, neurological/ behavioral, immunological, non-genotoxic carcinogenesis, reproductive or developmental), it is generally considered that there is a dose or concentration below which adverse effects will not occur (i.e. a threshold). For other types of toxic effects, it is assumed that there is some probability of harm at any level of exposure (i.e. that no threshold exists). At the present time, the latter assumption is generally applied primarily for mutagenesis and genotoxic carcinogenesis.
The third step in the process of risk assessment is the exposure assessment, which has the aim of determining the nature and extent of contact with chemical substances experienced or anticipated under different conditions. Multiple approaches can be used to conduct exposure assessments. Generally, approaches include indirect and direct techniques, covering measurement of environmental concentrations and personal exposures, as well as biomarkers (Kakkar and Jaffery, 2005). Questionnaires and models are also often used. Exposure assessment requires the determination of the emissions, pathways and rates of movement of a substance and its transformation or degradation, in order to estimate the concentrations to which human populations or environmental spheres (water, soil and air) may be exposed. Depending on the purpose of an exposure assessment, the numerical output may be an estimate of either the intensity, rate, duration or frequency of contact exposure or dose (resulting amount that actually crosses the boundary). Three main exposure routes are determined in exposure assessment: dermal, oral and respiratory. For risk assessments based on dose-response relationships, the output usually includes an estimate of dose. It is important to note that the internal dose, not the external exposure level, determines the toxicological outcome of a given exposure. The general equation of selected exposure route is as follows:
ADD =
-1
In this equation C is concentration in the media (mg kg
-1
-1
), IR is ingestion rate (kg day
), EF is
exposure frequency (days year
), ED is exposure duration (years), BW is body weight (kg), AT
is average time (days).
Risk characterization is the final step in risk assessment. It is designed to support risk managers by providing, in plain language, the essential scientific evidence and rationale about risk that they need for decision-making. In risk characterization, estimates of the risk to human health under relevant exposure scenarios are provided. Thus, a risk characterization is an evaluation and integration of the available scientific evidence used to estimate the nature, importance, and often the magnitude of human and environmental risk, including attendant uncertainty, that can reasonably be estimated to result from exposure to a particular environmental agent under specific circumstances.
1.2 Ceiling sheet
Ceiling sheet industry makes use of polyvinyl chloride in the production of ceiling sheets. Polyvinyl chloride abbreviated PVC is the world’s third-most widely produced synthetic plastic polymer, after polyethylene and polypropylene. Of all synthetic thermoplastics, polyvinyl chloride (PVC) is probably one of the polymers in modern use with the oldest pedigree. Regnault in France first produced vinyl chloride monomer in 1835 and Baumann first recorded its sunlight. The earliest patents for PVC production were taken out in the USA in 1912 and pilot plants producing PVC began in Germany and the USA in the early 1930’s. Early PVC processing technology was based on established rubber molding processes and the products that could be manufactured were limited to those using heavily plasticized polymer. The main problem was the inability to convert the polymer into usable products without severe thermal degradation because of the tendency of the polymer to dehydrochlorinate at elevated temperatures. It was not until the discovery of suitable stabilizers that processing technology advanced to the point where the full potential of the polymer could be realized. Nowadays, by choosing suitable stabilisers and plasticisers, the polymer can be converted into a wide variety of different products as diverse as plastisols, which provide the seals in some closures, through coated fabrics used in architectural applications, films and sheets for use in packaging applications and extruded pipes and sections for use in building applications.
1.2.1 Production methods
There are three commercial processes for the production of PVC:
1. Suspension polymerization
2. Emulsion polymerization
3. Bulk or mass polymerization
Suspension polymerization Liquid vinyl chloride is insoluble in water and disperses to fine droplets when mechanically agitated. The droplets remain in suspension as long as the agitation continues.
Polymerization is carried out in pressurized vessels under the influence of heat and initiators and/or catalysts, which are soluble in the water. A typical initiator is an organic peroxide. The reaction is exothermic and the heat evolved is carried to the sides of the reaction vessel by the water. Suspension agents known as protective colloids are added to the reactor to prevent the monomer droplets coalescing and the polymer particles from agglomerating.(European Commission Regulation (EU, 2011)
1.3 History of Emenite company
Emenite Limited, located at Emene Enugu East, Enugu State a member of the Belgian Etex Group started operation in 1963 under the name Turners Asbestos Cement Company Nigeria Limited. The company was incorporated in 1961 with registration and shareholdings of both Turners and Newall Limited and Government of Eastern Nigeria owning 80% and 20% respectively. Indigenization decree of 1973 changed the shareholding of the company. Turner & Newall Limited and Government of Eastern Nigeria then owned 60% percent and 40% percent respectively with the company’s name changed to Turners Building Product (Emene) Ltd. Turners and Newall Ltd divested its interest in the company and transferred 51% of its shareholding to Eterdutremer Societe Anonyme of Belgium (now Etex Group S.A) and the balance of 49% to the then Anambra and Imo State, now Anambra, Enugu, Imo, Abia and Ebonyi states As a result of the new shareholding arrangement, the company changed its name to Emenite Limited as is presently known. The materials for the production of all these products are polyvinyl chloride. cement.(Okafor, 2016).
This material content is developed to serve as a GUIDE for students to conduct academic research
RISK ASSESSMENT OF CEILING SHEET COMPANY EFFULENT ON EKWURU RIVER IN EMENE ENUGU STATE, USING CATFISH (CLARIAS GERIPINUS)
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