Nigerian Industrial Standard Research Articles

Physico-chemical and bacteriological quality assessment of some selected sachet water brands produced in Gwale local government Area, Kano Nigeria

The proliferation of sachet water products has been fuelled by the rising demand for clean, safe drinking water in areas where access to potable water sources remains a challenge. Unfortunately, some of the sachet water producers fail to adhere to the standards set by regulatory agencies, resulting in potential health risk for the unsuspecting consumers. Therefore, critical investigation of the various parameters of these water products is needed to determine whether they meet the safety standards established by regulatory agencies. Thirty (30) different brands of sachet water (15 NAFDAC registered and 15 non-NAFDAC registered) were randomly collected (n=3) from producers in Gwale Local Government Area, Kano Nigeria to assess their physico-chemical and bacteriological quality. The parameters were determined using standard methods. The mean results of the temperature, pH, turbidity, conductivity, chloride and total hardness of the NAFDAC registered samples were found to be in the range of 25.9-29.7 oC, 6.8-7.2, 0.1-1.2 NTU, 11.0-41.8µs/cm,15.0-25.1 mg/L and 2.0-17.6 mg/L respectively, while for the non-NAFDAC registered samples, the mean range were found to be 25.8-30.8 oC, 6.6-8.7, 0.5-2.2 NTU, 13.6-46.8 µs/cm, 17.0 23.0mg/L and 15.8-25.3 mg/L for the same parameters respectively. These results are in compliance with the standards set by the National Agency for Food Drug Administration and Control (NAFDAC), Nigerian Industrial Standard (NIS) and World Health Organization (WHO) except pH values of 8.7 found in some non-NAFDAC registered samples which were a bit higher than the recommended limits. Some non- NAFDAC registered samples were found to contain aerobic mesophilic bacteria, though below the limit set by the aforementioned regulatory agencies. Statistically, there is significant difference (p>2.326) between the NAFDAC registered and the non-NAFDAC registered samples in aerobic mesophilic bacterial count but there is no significant difference in terms of coliform count between the two groups (p< 2.326). This finding highlights the need for regular microbiological monitoring so as to ensure public health safety.

Effect of solvothermal-treated polyethylene on the mechanical properties of sandcrete blocks and concrete

In building construction, seepage and dampness in walls present serious problems since they can cause structural failures and damage in both residential and commercial contexts. Finding more affordable options is necessary as mitigating these problems frequently requires expensive fixes. This study aims to evaluate the effects of solvothermal-treated polyethylene added at concentrations ranging from 0 to 1.0% on the mechanical properties of concrete and sandcrete blocks. In addition to assessing the workability, split tensile strength, and compressive strength of concrete samples at different levels of the polyethylene (PE) inclusion, the study looked into the water absorption capacity, density, and compressive strength of sandcrete blocks. The blocks’ compressive strength and water absorption capacity reduced as the amount of polyethylene additives rose, although there was a slight increase in the density. These changes remain well within the Nigerian Industrial Standards’ specified limits. Hardened concrete shows a drop in density, compressive strength, and split tensile strength with increasing polyethylene content, while fresh concrete's workability decreases as the percentage increases. 0.4% incorporation of the treated polyethylene achieved the target strength of 20 N/mm2 while Sandcrete blocks with up to 1% of the solvothermal treated polyethylene had compressive strengths more than the 2.5 N/mm2 minimum required for non-load-bearing walls. About 61% reduction in water absorption was achieved in 48 h by the blocks, presenting a promising and cost-effective solution for seepage-related issues in building construction.

ASSESSMENT OF HEAVY METAL CONTAMINATION AND HEALTH RISK ASSOCIATED WITH SELECTED BOREHOLE WATER PROXIMAL TO A DUMPSITE IN GIWO, BAUCHI STATE

Water quality is a critical concern for human well-being and ecological stability, particularly as groundwater serves as a vital source of freshwater globally, sustaining various societal sectors. Human activities have increasingly polluted groundwater with contaminants, notably heavy metals, presenting potential health hazards to communities reliant on these water sources. This study investigates heavy metal contamination in borehole water samples from four distinct locations within Giwo, Bauchi State, Nigeria, and evaluates the associated long-term health risks of consuming this water. Analysis of the water samples identified iron to have the highest concentration (1.140 mg/L) while lead recorded the lowest concentration (0.0003 mg/L), the concentrations of zinc and copper across all the four locations were within the Nigerian Standard for Drinking Water Quality (NSDWQ) established by the Nigerian Industrial Standard (NIS) of 3.0 mg/L and 1.0 mg/L. The Average Daily Intake (ADI) from water consumption for, zinc, iron, copper, cadmium, and manganese were consistently below their corresponding Reference Doses (RfDs) of 0.3 mg/kg/day, 0.7 mg/kg/day, 0.04 mg/kg/day, 0.0005 mg/kg/day, and 0.14 mg/kg/day, respectively for all water samples analyzed while the remaining heavy metals exhibited ADIs exceeding their established RfDs. Hazard Quotient (HQ) values for most metals were below the threshold of 1, suggesting a relatively low risk of adverse health effects. However, prolonged consumption of this water may heighten cumulative health risks associated with specific heavy metals, warranting continuous monitoring and remedial actions.

PHYSICOCHEMICAL ANALYSIS AND WATER QUALITY ASSESSMENT OF SELECTED LOCATION IN MAIDUGURI METROPOLIS USING WEIGHTED ARITHMETIC WATER QUALITY INDEX

Access to safe drinking water is crucial for human health and well-being, however many people around the world including Nigeria face challenges in accessing clean water source. The quality of water is an important public issue and water in Maiduguri is no exception. This study focuses on evaluating the physicochemical parameters of borehole water in Maiduguri. Water samples were collected from three locations namely Polo, Moduganari and Old Maiduguri which were analyzed following standard procedure. The results showed that Temperature, pH, Total Dissolved Solids (TDS), Calcium, Chloride and Manganese levels were within safe limits of 25 oC, 6.5-8.5, 500 mg/l, 200-300 mg/l, 250 mg/l and 0.2 mg/l set by World Health Organization (WHO) and Nigerian Industrial Standard (NIS). However, Old Maiduguri and Moduganari had elevated levels of nitrate 35.95 mg/l and 39.95 mg/l compared to Polo with 22.6 mg/l. Dissolved oxygen levels were quite below the standards of 6.5mg/l in all three locations, while turbidity was within the acceptable limits of 5 NTU. According to the Weighted Arithmetic Index (WAI) Method, the water quality in Polo and Moduganari was classified as poor, with Water Quality Index (WQI) values of 59.67 and 51.56, respectively. On the other hand, the water quality in Old Maiduguri was classified as very poor, with a WQI value of 88.03. These results highlight the varying degrees of water quality across the study locations, emphasizing the need for interventions to improve water quality, particularly in Old Maiduguri, to ensure the well-being of the local population.

EFFECT OF MIX RATIO AND CURING ON COMPRESSIVE STRENGTH OF SANDCRETE HOLLOW BLOCKS

ABSTRACT The standards of the materials used in a building’s construction greatly influence its strength and durability. In Nigeria, hollow sandcrete block is the most common material used in buildings. This study evaluates the effect of the water-cement ratio and then the aggregate-cement ratio (mix ratio) on the compressive strength and density of hollow sandcrete blocks of size 9" (225 X 225 X 245mm). Six water–cement ratios (0.35, 0.40, 0.45, 0.50, 0.55 and 0.60) and five mix ratios (1:6, 1:7, 1:8, 1:9 and 1:10) were used and the compressive strength and density of the blocks were determined. The results were checked for compliance with the Nigerian Industrial Standard (NIS) (2004) and BS 2028 (1983). The results revealed that 0.45 is the optimum water-cement ratio with the highest compressive strength value of 3.34 N/mm2. Furthermore, the 28-days compressive strengths of the 1:6, 1:7, 1:8, 1:9 and 1:10 were found to be 2.88 N/mm2, 2.85N/mm2, 2.71N/mm2, 2.49N/mm2 and 2.46 N/mm2 respectively. The study samples have a density range of 1527kg/mm3 to 1815kg/mm3 meeting the minimum requirement of 1500kg/mm3 by BS 2028 (1983). For commercial purposes mix ratios of 1:8 and below should be used because they meet the minimum requirement of 2.5N/mm2 compressive strength specified by NIS (2004).

Physico-Chemical Quality Of Drinking Water From Various Sources In Abia State, Nigeria

The majority of Nigerians lack access to a safe drinking water source, making sustainable and equitable access to safe drinking water a challenge. The current study was designed to evaluate the physicochemical quality of drinking water from various sources in 24 randomly selected communities throughout Abia State, Nigeria. These communities were selected from 8 Local Government Areas within the 3 senatorial zones of Abia State. Using sterile universal containers, water samples were collected from the major drinking water sources in the selected communities. On-site evaluation of the pH, electrical conductivity (EC), total dissolved solids (TDS) and temperature of the water samples was carried out using a HI9813-6 pH/EC/TDS/Temperature meter. The pH values of the water samples from all sampled communities ranged between 4.1 and 5.9, and the acidic pH levels of the water samples were not within the Nigerian Industrial Standard's (NIS) approved range of 6.5 - 8.5. Furthermore, the water sources in the selected communities were found to have ambient temperatures ranging from 25.8 - 31.8oC. The average electrical conductivity (0.04 µS/cm) and total dissolved solids (36.4 mg/L) of water samples from all senatorial zones studied were both within acceptable limits of 1000 µS/cm and 500 mg/L respectively. Although the other parameters (temperature, EC and TDS) evaluated in this study were within acceptable limits for drinking water physicochemical quality, this study emphasizes the importance of effective water treatment, safe distribution to households, and continuous monitoring and quality assessment of drinking water sources in Nigeria.

Hydrogeochemical evaluation and geospatial distribution modeling of the major ion chemistry of groundwater and their suitability for drinking and irrigation in Lagelu, Southwestern Nigeria

Shallow groundwater is an essential resource for domestic, agricultural, and small-scale industrial uses in Lagelu in Oyo State, Southwestern Nigeria. A total of 20 representative groundwater samples were collected from different hand-dug wells and analyzed for the major cations, anions, and heavy metals to establish their suitability for drinking and irrigation. Geospatial variation maps of the major cations and anions were produced using the inverse distance weighted algorithm. The results of the respective concentrations of pH, TDS, EC, HCO3−, NO3−, SO42−, Cl−, PO42−, Ca2+, Mg2+, Na+, K+, Zn2+, Cu+, Pb2+, and As+ except Fe2+ are within the recommended range set by the World Health Organization (WHO) and Nigerian Industrial Standards for Drinking Water Quality (NSDWQ). Based on the hydrogeochemical facies, the groundwater belongs to Na+–K+–Cl−–SO42−, and Ca2+–Mg2+–Cl−–SO42− water types. Gibb’s diagram shows that the interaction of rocks and water dominate the processes that control the ionic compositions of the groundwater due to rock weathering and dissolution. The correlation matrix that specifies the ion concentration relationship showed that TDS, K+, and Fe2+ strongly correlate positively with EC, Na+, and Ca2+, respectively. CO32−, Na+, and Cu moderately correlate positively with Cl−, Mg2+, and pH, respectively. The indices used to determine groundwater suitability for irrigation classified over 90% of the samples as suitable for irrigation.

Morphometric and Heavy Metals Accumulation in the Muscles of Five Demersal Seafoods Sampled in Nigerian Coastal Waters

This study examined the morphometric and heavy metals accumulated in the muscles of five demersal sea-foods: Parapenaeopsis atlantica, Penaeus monodon, Penaeus notialis, Portunus validus and Cynoglossus browni from Nigerian coastal waters. 506 deep frozen samples (at -200C) each of the five demersal species were taken upon arrival from thirty-one (31) industrial fishing trawler vessels owned by a private fishing company in Lagos, Nigeria. Samples were thawed and morphometric characteristics such as weight, total length, standard length, body depth and carapace length/head length were measured. The heavy metals [Lead (Pb), Iron (Fe), Zinc (Zn), Arsenic (As), Mercury (Hg) and Cadmium (Cd)] were analyzed using 210 Atomic Absorption Spectrophotometer (AAS). The morphometric characteristics revealed that P. atlantica and P. notialis showed no significant difference in mean values only for their carapace lengths while both species showed statistically different observations for other variables. The order of the heavy metals mean concentration was Zn>Fe>Pb. As and Cd had relatively very low values of <0.01mg/kg while Hg was not detected in all samples. The findings of this study revealed high and increasing values of Zinc in all five demersal species under consideration exceeding maximum limits for FAO/WHO and NIS (Nigerian Industrial Standard). The zinc value of the species appears to be contained in this order; P. notialis > C. browni > P. monodon > P. validus >P. atlantica. However, Iron value for P. atlantica is above the limit of FAO/WHO. Consumption of the species invariably leads to a rise in the Zinc contents in diets and in humans which may cause gastrointestinal disorders, kidney and liver abnormal functioning especially in infants and children while other heavy metals contained in the species do not pose a threat to human health.

Quality Assessment of Sandcrete Blocks Produced Along-Oke Fomo Area, Ilorin, Kwara State

In this study, the quality of sandcrete blocks produced along Oke-fomo, a rapidly developing area of Ilorin, Kwara State, Nigeria was investigated. Seven commercial block industries were randomly selected from where five sandcrete block samples of 450 x 225 x 225mm were sourced. Fine aggregate samples were also obtained from each of these industries and transported to the materials laboratory of Ministry of works, Ilorin. The tests carried out include sieve analysis and compressive strength. The dimension of the blocks was also checked. The mix ratio, curing techniques/duration and batching method were obtained through interaction with the block manufacturers. The results obtained showed that the aggregates are suitable for block making having satisfied the overall grading requirement specified in BS EN 12620 (2002). The mix ratio adopted by the industries ranges from 1:12 to 1:14 which is against the standard 1:6 specified in NIS 87:2004. The compressive strength of the sandcrete blocks was found to be below the Nigerian Industrial Standard (NIS) 87:2004 specification with an overall highest compressive strength of 0.98N/mm2 when compared with the NIS 2.5 and 3.5N/mm2 for non-load and load bearing walls respectively. The study concluded that block producer should adhere strictly to the laid down standard especially in mix ratio and curing duration. However, it was recommended that formal training should be periodically organized for block industries and the public should also be sensitized about the danger in using substandard sandcrete blocks. This will to a large extent improve the production of quality sandcrete blocks and promote the market for the standardized ones while averting consequences associated with weak sandcrete blocks such as collapse of walls.

Physicochemical and Microbiological Assessment of Some Sachet Water Produced in Irele, Ondo State, Nigeria

This study presents the result obtained from the quality assessment of some sachet water produced in Irele, Ondo State, Nigeria. Eight different brands of sachet water certified by the National Agency for Food and Drug Administration and Control (NAFDAC) representing the western, northern, eastern, central and southern part of Irele were obtained, their physicochemical characteristics and microbiological parameters were investigated using standard analytical procedures to determine the level of agreement with World Health Organization (WHO) and Nigerian Industrial Standard (NIS) requirements for drinking water. The results from the Physico-chemical characteristics temperature, electrical conductivity, pH, total dissolved solids, total hardness, total alkalinity, nitrate and chloride were in the range of 6.2 - 27.0 oC , 77.2-142.3 μS/cm, 7.40 -7.60, 47.7 - 99.5 mg/L, 11.3 - 51.3 mg/L, 13.20 - 70.0 mg/L, 0.8 to 2.5 mg/L and 0.01 - 0.02 mg/L respectively. The concentrations of iron, copper and manganese were in the range of 0.01 - 0.02 mg/L, 0.13 - 0.18 mg/L and 0.01- 0.6 mg/L. The concentrations of cadmium, mercury, lead, and arsenic were not detected in the sachet water studied except in sample H were their concentrations were 0.003, 0.001, 0.01, and 0.01mg/L, respectively. The microbial quality of the studied sachet water was within the WHO recommended standard. All the studied parameters have their values within the recommended limit set by WHO except for sample H with a manganese concentration above the set standard. There is a need for NAFDAC and other water monitoring agencies to focus on promoting the safety of drinking water, particularly sachet water. The Sources of water, production processes, and environment should be inspected regularly by monitory agencies to certify that there is no deviation from recommended standards.

Evaluation of the compressive strength of commercial sandcrete blocks produced in two metropolises of Delta State, Nigeria

The mechanical properties of sandcrete block greatly influenced the durability of structures built from it. This study was carried out to assess the compressive strength of sandcrete blocks produced in two major developmental and rapidly urbanizing zones of Delta State, Nigeria. 150 and 225 mm sandcrete blocks were sampled from 18 blocks moulding factories in Ndokwa East and Ughelli North Local Government Areas of Delta State, Nigeria. Five sandcrete block was sampled from each block moulding factory, at the rate of 9 factories per Local Government Area. The compressive strength of the sampled blocks was determined in accordance with the ASTM International standards. The results of compressive strength test showed that the compressive strengths of the blocks, regardless of the block size ranged from 0.61 to 16.19 MPa. Analysis of the results revealed that apart from the customized blocks, the compressive strengths of all the other blocks fell below the Nigerian Industrial Standard (NIS) recommendations of 2.5 MPa for non-load bearing walls. The general poor quality of the sandcrete blocks is attributed particularly to the poor mix ratios adopted by the block producers which fell short of NIS recommendations. Thus, this study recommended that standard regulatory agencies should closely monitor all the block making factories in the state, to ensure that sandcrete blocks produced or brought into the state met NIS recommendations

Sewage Water Treatment Analysis Using Activated Charcoal in Packed Column

The research study analyzed sewage water from Eagle Island Nkpolu-Oroworukwo community, Port Harcourt and its treatment with activated charcoal for its re-application. The water sample collected was analyzed experimentally for both untreated and treated samples to determine pH, Total Dissolved Solid (TDS), Total Suspended Solid (TSS), Total Solid, Total Hardness, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Phosphate (PO4), and Nitrate (NO3). Also, water quality index (WQI) and status of water was also investigated to know the quality of untreated and treated water sample by analyzing ten parameters based on the recommended standards of the World Health Organization (WHO), Nigerian Industrial Standards (NIS) and Federal Environmental Protection Agency (FEPA) for water quality. The water quality index values for the untreated and treated samples are 108.213 and 40.024 respectively. The values of the water quality index showed that the untreated sewage water belongs to grade E, hence its unsuitability while that of the treated water sample showed a good quality water as it belongs to grade B that falls between the range of 25 – 50. Thus, water quality index is applied as a tool for comparing water quality of different sources and locations and sewage water treatment with activated charcoal in a packed column is an effective tool for sewage water treatment.

Development of eco-friendly fired clay bricks incorporated with granite and eggshell wastes

In this study, we explored the effective reuse of granite powder (GP) and eggshell powder (ESP) wastes for the production of clay bricks as an alternative waste disposal method while improving the properties of the fired clay bricks (FCBs). Furthermore, the utilization of wastes is aimed at reducing environmental pollution and degradation due to exceedingly waste disposal and landfill construction. The study investigated the influence of granite waste, eggshell powder, and firing temperature on the physical-mechanical properties of the FCBs. Four batches of bricks were produced with varying compositions of clay, GP, ESP, and were fired to three different temperatures of 900, 1000, and 1100 °C at a ramp rate of 10 °C/min. Microstructural, chemical, and mineralogical characterization were carried out by FTIR, SEM/EDS, XRF and XRD respectively. The results obtained showed that the FCBs incorporated with 20% of GP and 10% of ESP produced the highest compressive strength of 3.12 MPa, bulk density of 1.76 g/cm3 and water absorption of 12.2% at 900 °C which is regarded as energy-saving process for the manufacture of FCBs. The compressive strength of 3.12 MPa exceeded the minimum compressive strength of 1.65 MPa standard as recommended by the Nigerian Building and Road Research Institute (NBRRI), Nigerian Building Code and Nigerian Industrial Standards for building purposes. Therefore, the reuse of granite and eggshell powder from waste for the manufacture of FCBs is feasible and an effective alternative waste disposal solution for sustainable development while alleviating environmental pollution and degradation.

Statistical Explanatory Assessment of Groundwater Quality in Gwale LGA, Kano State, Northwest Nigeria

Groundwater is one of the significant sources of drinking water in the world. To protect groundwater quality for domestic consumption, it is important to undertake a periodic investigation of its quality to improve the healthy living of the ever-increasing population. In this paper, we have analyzed physical and chemical (physicochemical) concentration levels in groundwater samples collected from twenty-eight sampling locations during the raining season in Gwale, Northwest Nigeria. About fifteen physicochemical parameters such as electric conductivity (EC), turbidity (Turb), pH, temperature (Temp), nitrate (NO3), phosphate (PO4), total dissolved solid (TDS), chloride (Cl), sulphate (SO4), calcium (Ca), magnesium (mg), sodium (Na), total hardness (TH), iron (Fe) and alkalinity (Alk) were analyzed. The concentrations levels of groundwater parameters in each sampling location were compared with the permissible limits of drinking water qualities specified by the Nigerian Industrial Standard (NIS) to determine the suitability of drinking water in the study area. Karl Pearson’s coefficient of correlation was applied to the groundwater dataset to identify the influence of each physicochemical parameter to the groundwater contamination. Also, hierarchical cluster analysis was used to classify the groundwater samples based on contamination density as well as to identify the sources of water contamination. The results from correlation analysis revealed that EC, TDS, Ca, TH, Mg, SO4, Na and Cl were influenced the water contamination in many of the study locations based on the conventional significance levels (1% and 5%). From the results of cluster analysis, three statistically significant groups (cluster 1, cluster 2 and cluster 3) were formed which were defined as lower contaminated areas, moderately contaminated areas and higher contaminated areas, respectively. The contamination levels identified in the three clusters were attributed to anthropogenic and industrial activities in the raining season. Therefore, groundwater from cluster 3 (Salanta, Hauren makaranta, Dandago, Mandawari and Magashi) are found unsuitable for drinking. This study is useful in monitoring groundwater quality and could be applied in any other location.

The Application of Response Surface Methodology in Understanding the Compressive Strength and Water Absorption Capacity of Sandcrete Blocks

It becomes pertinent to improve the performance of sandcrete blocks with the use of eco-friendly material because it is the conventional walling unit system in Nigeria. This study evaluates the presence of calcined clay as a locally sourced material in producing hollow sandcrete blocks, using the Box and Behnken Design of Response Surface Methodology as experimental design. The design considers three independent variables, which are; percentage calcined clay, binder to aggregate ratio, and curing days. Calcined clay was used as a partial replacement for cement, and varied between 0% and 40%. The binder-aggregate ratio was varied between 0.125 and 0.25, while the curing days was varied between 28 and 90. The result of the X-ray fluorescence (XRF) analysis before and after calcination shows that visual observation of color change and the samples have similar pozzolanic content. The density of the sandcrete blocks produced ranged from 2146.46 kg/m3to 2209.60 kg/m3. Previous studies have shown that an increase in the percentage of cement replacement with pozzolana causes a reduction in density. However, experimental results obtained show that the density was not impaired by the replacement of cement with calcined clay. Besides, the water absorption results were far less than the maximum value of 12% specified by the Nigerian Industrial Standard (NIS). The compressive strength also exceeds the minimum amount set by the NIS. From the RSM analysis, a prediction model and an optimal condition of 16% calcined clay, binder to aggregate ratio of 0.20, and curing days of 61 were achieved for compressive strength. Keywords sandcrete blocks; calcined clay; binder to aggregate ratio; curing days; compressive strength.

Physicochemical and Microbiological Assessment of Drinking Water in Kari Estate Bauchi Nigeria

Some sources of drinking water in Kari Estate in Bauchi Metropolis were analyzed for physicochemical contents and coliform contamination. A total of five samples were collected from different sources as follows: 2 sachets water, 2 wells, and tap water. The physicochemical analysis included the determinations of temperature, pH, electrical conductivity, total dissolved solids, turbidity, colour, suspended solids, odour, taste, total hardness, iron, nitrate, nitirite, manganese, ammonia, fluoride and cyanide. The two wells had total coliforms of 6 and 10 and faecal coliforms of 4 and 5 respectively. Tap water had total and faecal coliforms of 7 and 3 respectively. E. coli were identified in the samples from wells while Bacillus sp. were found in the tap water. Although the physicochemical contents of the samples were normal range, coliform counts of the wells and tap water were above those set by the Nigerian Industrial Standards (NIS) and the World Health Organization (WHO) standards. Presence coliforms above the standards indicates contamination and that the water may be unsafe for drinking. The presence of E. coli suggests that improvement in monitoring and water hygiene practices should be employed to improve the drinking water quality.

Assessment of Influence and Threshold Ratios of Titanium Dioxide and Calcium Carbonate as Pigments on the Physico-Mechanical Properties of Emulsion Paint

Titanium dioxide (TiO2) also known as Titanium White, is an inorganic, synthetic pigment used in paint to protect the substrate from harmful effects of ultraviolet light when lead pigments are regarded as toxic. However, its use is being limited since it causes flu-like symptoms, respiratory problem and skin irritation. Calcium carbonate (CaCO3) is a chemical commonly used as an extender pigment in cement to provide bulkiness at relatively low cost. Because of the problem associated with TiO2, it is of importance to regulate and optimize the use of TiO2 relative to CaCO3 and their influence on the physico-mechanical properties of emulsion paints. Nine paint specimens were formulated using 0 – 80 grams per litre of TiO2 and 120 – 200 grams of CaCO3, respectively at 10 gram interval. The following tests were performed on them: specific gravity, viscosity, pH, surface drying time, hard drying time, wash-ability/adhesion and opacity tests, in accordance to Nigerian Industrial Standard (NIS) 278: 1990. The result shows that all samples met specifications of 10 poise maximum, 5%, 7.5-9.0, 20 minutes, 2 hours, and 201 minimum, for viscosity, specific gravity, pH, surface drying time, hard drying time and wash-ability/adhesion properties, respectively. However, six sample specimens only met the requirement of NIS 278:1990 of 2coats for good opacity. In conclusion, TiO2 has no negative effect on the other physio-mechanical properties except the opacity of the paint and so specimens 7, 8 and 9, and ratio 30:170 is considered the threshold values for the paint production.

A Study on Suitability of Foamed Sandcrete Solid Block with Fly-Ash as Partial Replacement of Sand

In this study, the properties of foamed sandcrete solid block (FSSB) with varying percentage of sand replacement with fly-ash were investigated. These properties include workability, wet and dry density, stability, water absorption capacity and compressive strength. 150mm cube specimens were used for the determination of both the compressive strength and the dry density of the FSSB. The plastic density was investigated using a container of known volume, and its workability determined using the slump test. The fly-ash content was varied from 0 to 50% at interval of 10%. The specimens without the fly-ash served as the control. At the designed density of 1500kg/m3, the results for the control specimens at 28 day curing age was 3.74N/mm2. As for 50% sand replacement with fly-ash, the compressive strength were 2.37 N/mm, and 3.31 N/mm2 at 7-days 28-days curing age respectively, both satisfied the minimum compressive strength of 1.8N/mm2 and 2.5N/mm2 at the curing age of 7-days and 28-days respectively for conventional sandcrete block for building wall unit as allowed by Nigerian Industrial Standard (N.I.S). The result also shows an appreciable decrease in density of FSSB with 1411.8kg/m3, as compared to dense sandcrete solid block with average of 1950kg/m3, which will significantly reduce the overall dead load of the building structure. FSSB with 50% sand replacement with fly-ash also showed a much improved water absorption capacity of 9.81% as control specimen of 11.73%. Fly-ash can be used to reduce the quantity of sand used in FSSB production; thus ridding our environment of potentially harmful wastes, as well as reduce the consumption of non-renewable resources. Keywords— Foamed Sandcrete, Compressive Strength, fly-ash, dry density, stability, cement

Assessment of Physico-Chemical Parameters and Their Pollution Implications on the Major Dams in Ekiti State

The study was aimed at assessing the Physico-chemical parameters namely, temperature, electrical conductivity (EC), pH, turbidity, total alkalinity (TA), total hardness (TH), total dissolved solids (TDS), dissolved oxygen (DO2); total solids (TS), total suspended solids (TSS) colour, potassium, Zinc, Copper, total Iron, BOD, COD etc. in three dams in Ekiti State, South-West Nigeria. The seasonal variations in the physicochemical parameters of water of the dams were studied from November, 2017 to October, 2018. Water samples were collected from the dams on monthly basis and analyzed for 26 water physico-chemical parameters by using standard methods. The standards for the drinking water recommended by the Indian Council of Medical Research (ICMR), World Health Organization (WHO), Nigerian Industrial Standard (NIS), National Environmental Standards and Regulations Enforcement Agency (NESREA) and Bureau of Indian standards (BIS) were used in this study. The comparison of the physico-chemical parameters values with the standard values of WHO guidelines and other international standards revealed the high level of BOD, COD, turbidity, DO2, pH, colour, K, Fe, Mn, Cu, Zn, Pb and Cd in the water content. There were significant differences (p > 0.05) between the seasons (dry and wet) values of some of the physicochemical parameters in Egbe dam, Ureje dam and Ero dam. pH, DO2, TSS, EC, TDS and TS had higher values in the rainy season while Temperature, BOD, COD, NO3, Alkalinity, NO2 and PO4 had higher values during the dry season in the dams with few exemptions. The accumulation of these parameters in high values may render the dams’ water unsuitable for drinking. In this study, it was observed that most of the physico-chemical parameters except metals were higher in Ureje dam than Egbe dam and Ero dam. This might be due to population increase, indiscriminate dumping of refuse around the dam, urbanization, domestic effluents and other attendant problems of the State capital where the dam is located and thus indicate that Ureje dam was more contaminated than Egbe and Ero dams in terms of anthropogenic contamination. Conclusively, the water from Egbe, Ureje and Ero dams may support fish production but is not fit for domestic and drinking purpose without adequate treatment.

COMPARATIVE STUDY OF CORNCOB ASH-BASED LATERITIC INTERLOCKING AND SANDCRETE HOLLOW BLOCKS

The high cost of conventional walling materials, increase in emission of CO2 due to cement production and improper disposal of corncob lead to persistent bottlenecks in low-cost and sustainable housing delivery, environmental pollution, and agricultural wastage respectively. This study investigates the use of corncob ash (CCA) as cement additive in producing lateritic interlocking blocks (LIB) and compares its physical characteristics and production cost with Sandcrete hollow block (SHB). Portland limestone cement (PLC) was replaced by CCA in varying percentages 5, 10 and 15%. The density, compressive strength and water absorption of the blocks were determined and compared with the Nigerian standard requirements and specifications. The experimental results showed optimal strength at 3% PLC and 10% CCA with a compressive strength of 4.13MPa, water absorption of 6.60% and density of 1869.47Kgm-3 at 28 days curing for LIB. For 450mm × 225mm × 225mm SHB, compressive strength, water absorption and density at 28 days curing were 3.86MPa, 4.69%, and 1849.95Kgm-3 respectively. All the blocks produced satisfied the recommendations of both the Nigerian Building and Road Research Institute and the Nigerian Industrial Standards. The cost per square meter of SHB and LIB was 4.62 USD and 2.35 USD respectively. The experimental results indicated that LIBs have better strength and are cheaper than SHBs. Recycling of CCA as a supplement material seems to be a feasible solution not only to the problem of adopting indigenous waste material in the production of LIB but also to the environmental problem.