Background: Water pollution from abattoir effluents may create substantial environmental and public health hazards. Available literature is scanty on the quality of groundwater located near abattoirs in tropical developing countries like Nigeria. This study, therefore, accessed the impact of abattoir activities on the quality of groundwater in Omu-Aran Nigeria.Methods: A total of eighteen water samples were taken from five privately own wells and one control well located at varying distances and elevations to the abattoir. The physicochemical characteristics of the water were determined using the standard methods. Data were analyzed using descriptive statistics and ANOVA. Results:The mean values of parameters in the water samples collected from the studied wells ranged from 5.80 ± 0.20 to 7.23 ± 0.55 mg/L, 12.0 ± 1.0 to 26.0 ± 2.0 mg/L, 0.06 ± 0.02 to 0.16 ± 0.02 mg/L and 208.0 ± 24.25 to 254.67 ± 12.22 cfu/mL for dissolved oxygen, biological oxygen demand, lead and total coliforms, respectively. There was a significant difference in the quality of water from the studied and control wells in the parameters except that of total coliform. The quality of the groundwater improved with increasing distance from the abattoir. Conclusions:Findings revealed that abattoirs have the potential to impact the quality of groundwater. Therefore, careful consideration is required when choosing a location for siting new abattoirs. For existing ones, particularly those close to residential areas, effective pollution control measures should be put in place to protect groundwater. which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Waste effluents from abattoirs have been documented to have harmful effects on the soil media. There is little information about the level of contamination by abattoir effluents on the soil media in Omu-Aran. This study therefore assessed soil samples for possible contamination of physicochemical parameters and heavy metals from different points and some meters away from the mini abattoir in Omu-Aran, Kwara State, Nigeria. Soil samples which are 18 in number were collected from the soil around wells which are owned by individuals and a well designated as Control situated at distances which vary and different elevations to the abattoir. The physicochemical parameters of the soil samples were obtained by applying the standard methods. The analysis of data was achieved using descriptive statistics and ANOVA. The mean values of parameters in the soil samples collected around the studied wells ranged from 31.00±2.00–110.03±8.72 mg/L and 7.21±0.02–7.83±0.02 for electrical conductivity and pH respectively. Chloride, nitrate and phosphate had values of 6.37±0.13–9.13±0.21 mg/L, 3.67±0.07–4.50±0.31 mg/L and 3.86±0.07–5.41±0.30 mg/L respectively. However, average values for heavy metals (Ni, Cr and Pb) though slightly higher than the control site, were above permissible limits. Activities within Omu-Aran Abattoir impacts negatively on the surrounding arable soils; therefore, pollution control procedures which are sustainable should be implemented for abattoirs situated in residential areas.

This research was conducted to determine growth stage-specific crop coefficient (Kc) and Consumptive Use (CU), for Capsicum chinense (Ata rodo) grown under irrigation in Omu-Aran, North central Nigeria. Daily CU and growth stagespecific crop coefficient Kc for Capsicum chinense was measured using a developed and calibrated hydraulic weighing lysimeter over 2 consecutive dry seasons (2015/16 and 2016/17). The values of CU and growth stage-specific Kc obtained were compared to that estimated using CROPWAT 8.0 and with existing Food and Agricultural Organization (FAO) Kc values for bell pepper. The Kc values determined over the growing seasons varied from 0.32 to 0.7, 1.02 to 1.45 and 0.76 to 0.9 representing Kc initial, Kc mid-season and Kc late season (Kc ini , Kc mid and Kc end), respectively. These Kc varied significantly (P < 0.05) from FAO established Kc values. The observed Kc was validated using relevant statistical methods. The seasonal CU of Capsicum chinense was 580.01 ± 54 mm, while the reference evapotranspiration increased from 3.26 mm day −1 in October to 4.19 mm day −1 in February. The crop factor increased from 0.7 in October to attain its peak of 1.45 in January, but decreased to 0.9 during crop senescence in February. Likewise, the daily crop water need was 2.28 mm day −1 in October but reached its peak of 5.82 mm day −1 in January and thereafter decreased to 3.77 mm day −1 in February. Mean monthly water need of Capsicum chinense pepper was 68.36 mm month −1 in October. The water need of crop rose to its peak of 166.32 mm month −1 in December, and thereafter declined to 113.13 mm month −1 in February It is inferred that the application of growth stage-specific Kc will assist in irrigation management and would serve as useful guide for precise water applications for areas around Omu-Aran as it differs from region to region.

Treatment performance of horizontal flow (HF) and vertical flow (VF) constructed wetland planted with Rhynchospora corymbosa were compared. The average porosity of the CW beds were 0.55, hydraulic retention time (HRT) of 3 days, hydraulic loading rate (HLR) and Organic Loading rate were 0.058 m/day and 3.96 (gÁBOD/m 2 Áday), respectively with a volumetric flow rate of 0.14 m 3 / day. The pollutant concentration of graywater before and after its introduction to the CWs was measured using standard sampling and analyses methods. The mean removal efficiencies (RE) for HF and VF CWs were BOD, 35% and 35.4%; COD, 61.9% and 56.7%; TN, 87% and 92%; TP, 95% and 65%; TSS, 86% and 59.6%; pH, 8.8% and 12.8%, respectively. The graywater was highly contaminated in terms of nutrient and organic load. The mean values of the parameters tested for different CWs were significantly different (P 0.05). This comparative study favored HF over VF Constructed wetland with HF found to be a viable alternative for graywater treatment for organics, nutrients and suspended solids removal. The result provided insight into the performance of CWs planted with R. corymbosa.

Batch-fed horizontal sub-surface flow constructed wetlands (HssFCW) were developed to compare the potential of Canna indica and Oryza sativa L. in removing heavy metals and nutrients from piggery effluent. Piggery effluent samples were characterized for nutrients (N and P) and metals (Mg, Al, Ca and Fe) before and after introducing them to the HssFCW with hydraulic retention time (HRT) of 3 days and operational flowrate of 0.014 m 3 /day. Three sets of constructed wetlands (CWs) were monitored during the dry season for 3 months. The bioconcentration factor (BCF) and translocation factor (TF) for the plants were evaluated. The results were all significantly different at p 0.05. O. sativa L removes more nutrients and metals than C. indica. The BCF for O. sativa L. was higher than for C. indica, while the TF for C. indica was higher for O. sativa L., indicating a higher metal translocation potential. Use of C. indica, a non-food crop, poses no health risks in HssFCWs whereas the grains of O. sativa L. are consumed directly by humans, presenting potential risks when used in HssFCWs. Compared to an annual O. sativa L., the perennial C. indica can be grown continuously in CWs for the phytoremediation of piggery effluent. NOVELTY STATEMENTNo known work about the phytoremediation potential of the two studied macrophytes in the agro-ecological zone is known. The study also provides insight into the bioconcentration of metals in the edible part of Oryza sativa L. FARO 44 (SIPI 692033). The characterization of piggery effluent revealed that its compositions were above the allowable limit for reuse and recycling despite the adoption of low-water use intensive method. The study showed that Oryza sativa L accumulates more metals in the above-ground tissues than in its root and provide insight into its use as a phytoremediation plant in the study area. The footprint of pollutants and metals in Oryza sativa L makes a perennial C. indica more suitable than O. sativa L. in piggery effluent phytoremediation.