Heavy metals in the aquatic environment have to date originated fundamentally from naturally occurring geochemical resources. Nonetheless, this has been enhanced by anthropogenic activities resulting in pollution. Consequently, relationships and partitioning of heavy metals in the dissolved phase, suspended particulate matter (SPM), sediments and shrimp (Macrobrachium felicinum) were investigated in five selected sites along Taylor creek, southern Nigeria. The degree of relationships between the various metals was dissimilar in each of the investigated matrices. In the matrices studied, not several significant relationships (P<0.05) were obtained. Only Ni-Cd (r=0.95), Mn-Cd (r=0.63), Mn-Ni (r=0.64) were associated in the sediments and in SPM, Zn-Ni (r=0.72), which suggests that the sources were not common for both matrices. In the dissolved phase, no strong relationships (P<0.05) between the heavy metals were obvious. The best relationships were observed for Ni-Zn (r=0.72) and Cd-Pb (r=0.65). Partitioning coefficients (Kd) of heavy metals between dissolved phase and SPM were generally low, which is typical for fresh water ecosystems and fairly stable over the creek all through the seasons. Furthermore, the bio-concentration factors (BCFs) of Macrobrachium felicinum were low unlike those of other natural waters. Thus, the physical state of the aquatic ecosystem points to the fact that the heavy metals bio-accumulated by Macrobrachium felicinum give cause for concern when viewed in perspective to community health issues, as the communities along the creek depend directly on shrimps as a protein source.

Key words: Heavy metals, Macro brachium felicinum, Partitioning, sediments, SPM, Taylor creek

Multivariate statistical techniques were applied for evaluation of temporal/ spatial variations and interpretation of a large complex water-quality data set of Shiroud River that discharges to southern part of Caspian Sea, Iran. Totally 16 parameters of water quality were monitored during 12 months at 8 sites in mountainous, flat and estuary areas. Factor analysis (FA) results showed that the first factor explained 25.76% of the total variance [comprise of electrical conductivity (EC), total dissolved solids (TDS), total hardness, calcium ion and water temperature levels]. The second factor called water quality indicator factor explained 13.99% [comprise of silicate, dissolved oxygen (DO) and pH levels], and the third factor called phosphate pollutant factor explained 10.72% (comprise of orthophosphate and total phosphorus (TP)). Additional factors were affected by part of nutrient, flow rate and general water quality, each of them recorded variance less than 10%. Discriminate analysis (DA) gave the best results for both spatial and temporal analysis. It has provided an important data reduction as it uses only four parameters (mean river depth, DO, NH4 +, and EC). Thus, DA allowed a reduction in the dimensionality of the large data set, explaining a few indicator parameters responsible for large variations in water quality. The present study shows the usefulness of multivariate statistical techniques for analysis and interpretation of complex data sets, and identifies probable source components in order to explain the pollution of Shiroud River.

The objective for the development of digital map of Dhaka Sylhet National Highway (N2) is to facilitate the highway transportation organizations. The Dhaka Sylhet National Highway (N2) is 284.9 km. On the basis of International Roughness Index (IRI), it’s 90.8% is good, 7.4% is Fair. The percent of poor section is 1.2 and has a bad section of 0.56%. The Dhaka Sylhet National Highway (N2) has four different pavement widths. Road-length of 272.3 km has a pavement width of 7.5 m. Pavement width 14 m has a road length of 10.4 km. Pavement width 10.2 m and Pavement width 10.3 m each has a road length of 1.1 km. In our study, three major bridges of N2 were suggested to easy traffic movement and safe handling of future traffic.

Key words: International Roughness Index, National highways, Pavement width, GIS

The removal of chromate ions in trace concentration from tannery wastewater effluent using Ion exchange technique was carried out by varying parameters such as Chromate concentration and contact time. A maximum of 99% removal efficiency in the batch Ion exchange process was achieved over an equilibrium contact time of 20min. The equilibrium uptake of chromate was constant at average 9.8mg/L for initial chromate concentration of 10mg/L irrespective of the high concentration of chloride and sulphate ions in the wastewater. This inferred that the interference of these co-ions have no significant effect on the chromate uptake by the ions exchange resins used in this study. While, in the column experiments high effectiveness in the removal of chromate ions in trace concentration was observed. A removal efficiency of 98% of chromate removal was achieved even in the presence of high concentration of competing Ions. Obviously, this has shown the selectively of the resin towards the chromate uptake. The ion-exchange technique was found to be appealing for the removal of trace concentration of chromate when in the background there is high concentration of chloride and sulphate co-ions present in the tannery wastewater.

A new, local agro-industrial waste was valorized by chemical treatment and tested for its ability to remove cationic dye from aqueous solution. Tendu (Diospyros melanoxylon) leaves refuse, a solid waste from bidi industry which caused disposal problem, was studied as a biosorbent. Raw tendu waste (TLR), along with sulfuric acid carbonized tendu waste (TLR-CM) and tendu waste treated with dilute sulfuric acid (TLR-2N) were utilized as sorbent for uptake of crystal violet from aqueous solutions. Adsorption studies were carried out at various dye concentrations and contact times. It followed the pseudo-second-order kinetics and followed the Langmuir adsorption isotherm. Interestingly, milder acid treatment of the tendu waste enhanced biosorption, whereas drastic acid carbonization of tendu waste resulted in reduced adsorption of dye. The maximum adsorption capacities for crystal violet for TLR-2N, TLR and TLR-CM are 67.57, 42.92 and 22.47 mg/g respectively. Commercial activated carbon had maximum adsorption capacity for crystal violet of 151.52 mg/g. Thus a renewable solid waste with mild acid treatment can offer a cost effective alternative to activated carbon.

Key words: Biosorption, Diospyros melanoxylon, Solid tendu waste, Dye, Crystal violet

* Corresponding author Email: gnagda@gmail.com

Among the environmental problems in Nigeria is the lack of proper management of municipal solid wastes (MSW), which is capable of releasing hazardous chemicals via leachate to the surrounding environment. In this study, the potential toxic effects of raw leachate obtained from Aba-Eku landfill (AERL) on Clarias gariepinus; and the microorganisms that may be present in the leachate were investigated. Physico-chemical analysis showed that the leachate contained toxic constituents. The 96 h LC50 obtained was 36.6%. Haematocrit %, erythrocyte number, haemoglobin concentration, leukocyte and lymphocyte number increased with increasing leachate concentration. Histopathological lesions were marked in the gills, kidney and liver of exposed fishes and were concentration dependent. A total of 112 bacterial isolates belonging to 17 genera were recorded from samples of AERL. Potential pathogens and toxin producing microorganism were identified. These  observations are of prime health concern because there is no known containment or treatment system for the leachate generated from the study site. Our findings would be of assistance in the assessment of hazardous effects of chemicals from waste landfills discharged into the aquatic environment and in making policy on environmental waste management.
Key words: Fish , Haematology, Histopathology, Leachate, Microorganism, Physico-chemical parameters

* Corresponding author Email: adekunle.bakare@mail.ui.edu.ng

A study was performed in Hybrid Up flow Anaerobic Sludge Blanket (HUASB) and Anaerobic Filter (AF) reactors to compare the start-up time and optimum HRT required for the treatment of poultry slaughterhouse wastewater under similar loading conditions. Initially, the reactors were started at an OLR of 0.77 Kg COD/m3.d and HRT of 36 h. Loading rates were increased by reducing HRT 24, 16, 12, 10 and 8h which corresponds the OLR of 1.15, 1.74, 2.27, 2.74, 3.43 Kg COD/ m3.d. HUASB reactor showed TCOD and SCOD removal efficiencies of 80% and 86%, respectively at an optimum HRT of 10 h whereas AF reactor showed 70% (TCOD) and 79% (SCOD) at optimum HRT of 12 h. Reducing HRT beyond 10h in HUASB reactor shown sludge wash out and lower COD removal efficiencies of less than 80% and beyond 12 h in AF marked decreased efficiencies as low as 66%. HUASB and AF reactors took 120, 147 respectively, for complete start-up. The granules of 2-2.5  mm sizes were observed in HUASB and less than 1 mm were observed in AF with settling velocities ranging between 0.5-0.83 m/min and 0.5-0.65m/min, respectively. From Residence Time Distribution studies, dispersion numbers (<0.2) showed both the reactors attained plug flow regime. The present study revealed that the HUASB reactor has very good removal efficiency and less start-up time compared to that of AF reactor for the treatment of poultry slaughterhouse wastewater.

Key words: Poultry Slaughterhouse wastewater, HUASB, AF, Granules, Settling velocity, Residence Time distribution

Active carbons were produced from bagasse, millet and sorghum straws by chemical activation with H3PO4. Carbon precursors with particle size of 1180 μm were used, in order to overcome difficulties caused by low density and high ash content. The influence of preparation conditions (temperature, residence time, and acid impregnation ratio) on the yield of the active carbons was examined. The impregnation ration which was controlled by varying the proportion of H3PO4 used for the activation had a strong influence on the yields of the carbons. The pyrolysis temperature was varied in the range 100-450 °C, but equilibrium yields of the active carbons were highest at 450C with optimum impregnation ratio of 13.6. The potential of the active carbons as efficient and economical means of removing mixture of aromatic hydrocarbon contaminants from water was indicated by the complete removal of objectionable odor from contaminated water samples containing 35.1348 mg/cm3 benzene and 34.8534 mg/cm3 Toluene, which are known carcinogens. Spectrophotometric determinations of the two solutes in the remediate water samples indicated slow but steady adsorption of the benzene/toluene mixture on the active carbons.

Key words: Binary mixture, Benzene, Toluene, Water, Active carbon, Agricultural waste