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Achudume AC* and Odoh S
Institute of Ecology and Environmental Studies, OAU, Ile-Ife, Nigeria
Received Date: November 23, 2011; Accepted Date: December 13, 2011; Published Date: December 15, 2011
Citation: Achudume AC, Odoh S (2011) Seasonal Variations in Physico-Chemical Parameters of the Topcamp Stream and Heavy Metals Accumulation in Freshwater Crustacean. J Ecosys Ecograph 1:106. doi:10.4172/2157-7625.1000106
Copyright: © 2011 Achudume AC, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Physico-chemical data may be collected systematically as basis for planning and wherever possible, for determining priorities of intervention with suitable control measures and to assess the efficacy of measurement put into operation. Heavy metals data and other parameters were studied in a natural stream, Topcamp stream. Samples were collected from point source and zones of dilution in two different seasons. Fresh water crustacean as bioindicator of pollution were used for identification of major contaminants. Results of the present survey indicate that the water temperature and pH were thoroughly mixed from Associated Match Industry with the clear waters of the upper Topcamp stream. Heavy metal contents at various seasons show arsenate, Cr, Cu, Fe, Mn and Zn present at concentrations near or below detection limits in water samples. Iron was present at abnormally high levels above the limit established for Nigeria both in rainy and wet seasons, whereas, Mn, and Fe, predominate in dry season closely followed by Zn2 +. The concentrations of As, Cr, and Zn in crab Sudanenautes africanus africanus were minimal and more consistent with the level of metals in surface water. Overall, the physico-chemical parameters like pH, Electrical Conductivity, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and Heavy Metals under investigation were within the permissible limits. Environmental awareness programmes can be organized to encourage conservation and management activities of Topcamp stream.
Heavy metals; Crustacean; Physico-chemicals; BOD; COD; Environmental awareness
The volume and characteristics of waste water (effluent) depend upon the type of manufacturing process adopted and the extend of reuse of water employed in the plant [1]. Obviously, an optimum industrial production depends on different types of water sources [2].
In recent past, there has been an increase awareness of drastic environmental problems caused by widespread environmental contamination along Topcamp stream especially the area most impacted between Associated Match Industry and Fan Milk in Southwest, Nigeria (Figure 1). Topcamp stream is an important reservoir of Eleyele dam and one of the most significant water resources where important birds and aquatic animals prevail.
Figure 1: Detailed Map of Study Area showing Sampling Stations.
The native fauna composed of 12 species including some endemic fresh water tilapia, claris, crabs, small settlements and limited agricultural areas due to its topography and soil characteristics [3].
There is growing concern that the quality of this water is in serious jeopardy. An expanded and reliable data base is required to more illustrate the consequences of environmental degradation and to identify opportunities to correct and avoid the degradation. The present study was to determine the relationship between physico-chemical parameters and bioindicator from the point source downstream to identify major contaminants and guide future sampling. In addition, several samples were collected from zone of mixing in order to increase the likelihood of detecting and better assess dilution and assimilation. In addition to chemical analyses, several fresh water crabs, Sudanenautes africanus africanus, were acutely bioassay. Finally, to increase the awareness of the public about the possible long-term effects of health hazard of hidden toxicity.
The study was conducted on the effluents released from the Associated Match Industry, SW, Nigeria. The industry was established in last decade and is engaged in the manufacturing of matchsticks. The industry has only one main effluent channel. The volume of highly colored effluent moves through some settlements, agricultural lands and nearby forests and ultimately joins the Eleyele river about 10 Km north of the industry. It is located between longitudinal 7° 24 25” and 7° 24 55” and latitudinal 3° 52 00” and 3° 52 40” (Figure 1).
For the study of seasonal variations on physico-chemical characteristics of matchsticks industrial effluent, ten sampling stations were selected. Four sampling stations are along the effluent stream (Ps0, Ps1, Ps2, Ps3,) from the match industry. One station was at the confluence of the effluent stream and an adjacent natural stream (Topcamp stream, C1), three stations along the Topcamp stream (Bc0, Bc1, Bc2) before the confluence, and two stations after the confluence (Ac1, Ac2) (Figure 1). The interval between two adjacent sampling stations was 20 m apart and 1.0, 2.0 and3.0 km distances from the origin of effluent. The stations were selected on the basis of extent of dilution. A portable Global Position System (GPS) set was used to measure the grid coordinates (longitude and latitude) of sampling stations. The field survey was 12 months period for both dry (October-April) and wet (May-September) seasons. Samples were collected from the sampling stations between 10 am to 2 pm in sterilized plastic carboy, brought to the laboratory and analyzed for measurement of various physicochemical parameters.
Temperature of the effluents and ambient temperature was measured in situ using portable digital multi-stem thermometer (Hanna Instrument Co., Italy) with external sensing probe. The pH of the effluent samples was measured using digital portable pH meter (Hanna Instrument Co., Italy). The pH meter was allowed to stabilize before taking the final reading. The electrical conductivity (EC) of effluent was measured in situ using portable conductivity meter at 25oC (Hanna Instrument Co., Italy).
Several samples [5] of surface water were collected in 1 L, and cleaned, distilled water-rinsed plastic containers. Samples intended for monitoring effluent sites were collected near those sites; mixing point samples were collected 1 m from the bank. Dissolved and suspended solids were determined by standard gravimetric procedures. Chloride, biological oxygen demand (5-day BOD), and chemical oxygen (COD) were determined by standard colorimetric titration procedures [4]. Strongly acidic or alkaline samples were neutralized to pH 7-8 for BOD determinations.
For elemental analysis, the effluent samples were acidified to a final concentration of 2% with nitric acid. Two samples were divided in half; one portion of each was spiked with known concentrations of the 10 analytes in question in order to determine percent recovery. Blanks, unspiked samples and spiked samples were analyzed according to APHA [5]. The instrument was standardized frequently with matrix-matched standards (Inorganic Ventures, Lakewood, NJ). Standardization was verified with appropriate external standards (Spex Industries, Inc., Edison, NJ). Analyte recovery in spiked samples ranged from 92 to 100%.
Twenty identified crab specimens were collected along the Topcamp stream flow, which are consumed by local people. Each crab was excised and 2 g of the muscle tissue was digested in acid mixture. Concentrations of metals (As, Cr, Cu, Fe, Mo, Zn) in all the samples were measured by atomic absorption spectrophotometer at Obafemi Awolowo University Central Laboratory. Calibration was made with standard solutions. The precision and accuracy of determination was checked by repeated analyses of the sub-samples of the standards and by recovery tests.
Statistical analyses of physico-chemical parameters and metals contents determined in water and crab samples were evaluated statistically using analysis of variance (ANOVA) technique.
Figures 2 to 6 list the physical and biological characteristics effluent samples from Associated Match Industry upstream from Topcamp at various sampling stations in two seasons. The temperature and pH in the water are moderate and other parameters were consistent with slow moving water. Figure 2A and B present the mean concentrations of physico-chemical parameters of Topcamp stream for dry and rainy season showing water temperature, turbidity, color and suspended solids at various stations in a progression from point source (Ps0) downstream to the confluence point (C1) to station BC2 where thorough mixing of the waters from Associated Match Industry with clear waters of the upper Topcamp stream occurred. Figure 3A and B present mean concentrations of chemical parameters showing pH, acidity and alkalinity at different seasons. Figure 4A and B present mean concentrations of nutrient compounds and oxygen effluent samples in dry and rainy seasons indicating Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and Demand Oxygen (DO) in saturation.
Figure 2a: Mean concentration of Physical parameters of Topcamp stream in dry season.
Figure 2b: Mean concentration of physical parameters of Topcamp stream in rainy reason.
Figure 3a: Mean concentration of chemical parameters of Topcamp stream in dry season.
Figure 3b: Mean concentration of chemical parameters of Topcamp stream in rainy season.
Figure 4a: Mean concentration of nutrient compound and oxygen parameter of water/effluent samples in dry season.
Figure 4b: Mean concentration of nutrient compound and oxygen parameter of water/effluent samples in rainy season.
Figure 5A and B present mean concentrations of major ions showing calcium, magnesium, potassium, sodium, chloride and sulphate. Figure 6A and B present mean concentrations of heavy metal contents of Topcamp stream at various seasons showing arsenate, Cr, Cu, Fe, Mn and Zn present at concentrations near or below detection limits in water samples. Iron was present at abnormally high levels above the limit established for Nigeria both in rainy and wet seasons, closely followed by Mn in dry season, whereas, Mn2+, Fe2+, predominate in dry season closely followed by Zn2+. The concentrations of the elements were higher in rainy than dry season notably Fe. The source of the reference sample is immediately upstream from Associated Match Industry. This site is characterized by cloudy brownish water.
Figure 5a: Mean concentration of major ions (mgl-1) of Topcamp stream in dry season.
Figure 5b: Mean concentration of major ions (mgl-1) of Topcamp stream in rainy season.
Figure 6a: Mean Concentration of Heavy metal content of Topcamp stream (mgl-1) in dry season.
Figure 6b: Mean Concentration of Heavy metal content of Topcamp stream(mgl-1) in rainy season.
Figure 7A and B present mean concentrations of heavy metals in crab specimens (ugg-1) from Top camp Stream in both dry and rainy seasons showing the concentrations (mg/l) of elements in crab, Sudanenautes africanus africanus in up and downstream in the vicinity of Associated Match. The concentrations of Ca2+ > Fe2+ > Mn2+ > Cu2+ were present in similar order in both seasons respectively. The concentrations of As2+, Cr2+ and and Zn2+ were minimal and more consistent with the level of metals in surface water. Ca2+ and Fe2+, predominate in crab samples except at the confluence (C1).
Figure 7a: Mean concentration of heavy metals in crab specimens (ugg-1) of Top camp Stream in dry season.
Figure 7b: Mean concentration of heavy metals in crab specimen (ugg-1) of Topcamp Stream in rainy season.
The ecographic representations of the parameters in this study are independent and are characterized by remarkable differences between the two seasons. Figure 2A and B graphically present color and total solid of the effluent in two seasons, this specify that the industry should make all efforts to minimally remove color and the solid materials as much as possible before discharge of the effluent into the water body. However, acidity and alkalinity are appropriate for inland water (Figure 3A and B). Nitrate, (Figure 4A), Potassium (Figure 5A and B) and iron concentrations (Figure 6A) were among the highest reported in the present study. The remarkably high manganese (Figure 6B) concentrations and dissolved oxygen (Figure 4A) in both season seemed to confirm some discharges from the source point. The down stream from the Associated Match well represents a mixing of the stream while the dissolve oxygen percent saturation in dry season reflects precipitation as the highly contaminated backflow effluent from the source point. The reactive nature of the effluent is further evidence of seasonal variation. The close relationship between COD and BOD (Figure 4) indicate the presence of biodegradable substances all year round. In general, these differences may be due to variations in manufacturing processes, production capacity and efficiency of treatment plants as well as sites of effluent collection.
The concentration levels of most elements found in this study do not constitute a risk factor for human health and appear to be below the permissible limits set by the UNEP [6]. However, higher concentrations of Fe and K in the effluent suggest these metals predominate in the stream both in rainy and dry seasons, low pH may suggest that the effluent are the source of these elements possibly from the industrial processes. The presence of Cu, Mn and Mg may be due to their richness in the surrounding niche.
The common crab Sudanenautes africanus africanus is one of the few species found in all the seasons. The routes of the metal absorption in the decapods crustaceans are from the digestive tract and the heavy metals also cross the permeable gill membranes [7]. Heavy metals such as Fe, Cu, Mn and Zn are essential since they play an important role in biological system such as in normal growth and development in crustaceans, whereas, metals such as Cd and As are non-essential [8], can be toxic even in traces. The essential metals can produce toxic effects when they accumulate and their levels are excessively elevated as in Fe, Mn, Cu, and Ca. The absence of or low level amounts of cadmium and arsenate revealed that the crabs are not continuously exposed to heavy metals, probably as a result of which they do not accumulate in the muscle or other tissues.
Going by the criteria adopted by European Union, US Environmental Protection Agency (EPA), the United Nations Food and Agricultural Organization (UNFAO) and the Inland Waters Directorate of Canada (IWD), the quality of Topcamp stream is considered as medium and does not need any special treatment for irrigation. Several other authors have reported the suitability of water for irrigation from different parts of the world [9-11] and guidelines of drinking water quality in health criteria and supporting information [12]. In the present study, physicochemical parameters like pH, Na, As, Cu, Cr, Zn, EC, BOD, and COD were well within the permissible levels for streams recommended by WHO [12]. Although no significant metal concentration was found in water, some metals residues like Mn (Figure 6A and B) and Fe and Ca (Figure 7A and B) were found at higher concentrations in the crabs. These findings indicate that while the Associated Match Industry is contributing adversely to organic pollution in the stream, there are probably many other non identified sources contributing too and unless these sources are identified the dynamics of pollution in Topcamp may not fully be understood.
In conclusion, the results revealed that there are very minimum or below detectable elements before the confluence. It also showed that the main source of metals contamination in the stream is from Associated Match Industry. Metal accumulation levels in crab samples vary with seasons and sampling stations. It is widely accepted that metal contaminants are compounds that adversely affect water and food quality of the aquatic ecosystems. Thus, the need for remedial intervention be encouraged to sustain the current level of pollutants and/or improve the quality of the stream water which could be improved to meet both International limitation standards for drinking water by corrective measures requiring only physical treatment and disinfections.
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