Health Risks Associated with Consumption of Vegetables Grown using Domestic Wastewater in Minna, Niger State, Nigeria

Most vegetables consumed in the cities of developing countries are grown using wastewater discharged through township drainage network. This paper, therefore, investigates the risk involved in the consumption of such vegetables. The human daily intake rate (DIR) and Health Risk Index (HRI) of heavy metals were calculated using established formulae and the values of DIR ranged from 0.10 mg/kg/day to 0.71 mg/kg/day in wastewater plots in dry season for adults and 0.10 mg/kg/day to 0.14 mg/kg/day for children. Health risk index (HRI) values ranges from 0.40 mg/kg/day to 0.75 mg/kg/day in wastewater plots for adults in dry season and 0.20 mg/kg/day to 0.95 mg/kg/day for children. In wet season wastewater plots, the HRI ranges from 0.40 mg/kg/day to 0.95 mg/kg/day for children. The values of Hazard index (HI) ranged between 1.00 mg/kg/day and 1.21 mg/kg/day for all the seasons. Statistical analysis showed that there is a significant difference between the wet and dry season values for all the parameters assessed. Finally, uptake of heavy metals from the soil by all the vegetable crops under investigation was established. Therefore proper monitoring needs to be carried out to regulate consumption of vegetables produced from the experimental sites as continuous application of the industrial wastewater may lead to further accumulation of these heavy metals

Assessment of Heavy Metals Uptake by Vegetables Cultivated on Soil Receiving Industrial Wastewater in Minna, Nigeria

Consumption of vegetable crops grown on soil irrigated with industrial wastewater has been the order of the day in most urban towns and cities of Nigeria, despite reports of its serious health impact. This study assessed the possibility of uptake of heavy metals by crops grown on soil receiving industrial wastewater during rainy and dry seasons. The crops investigated are Spinach, Cayenne Pepper, Jute mallow, roselle and lady’s fingers okra. The initial composition of the wastewater was analyzed to contain 0.89 mg/l of chromium, 0.74 mg/l of cadmium, 1.04 mg/l of copper and 2.81 mg/l of iron. Control water used for this experiment contain no trace of any of these heavy metals. The experimental soil was also analyzed and contained 0.10 mg/kg of chromium, 0.06 mg/kg of iron before irrigation in dry season. After irrigation at the wastewater plots, the heavy metal concentrations in soil had increased to 6.24 mg/kg of chromium and 7.50 mg/kg of iron. In wet season, the concentrations of heavy metals in the soil were 0.00 mg/kg of chromium and 2.32 mg/kg of iron before irrigation. After irrigation in wet season, the concentrations increased to 6.01 mg/kg of iron. Mean difference of heavy metal concentrations were significantly high in vegetables in dry season, with values ranging from 0.03 mg/kg to 211mg/kg in wastewater plots, 0.20 mg/kg to 215 mg/kg in wet seasons wastewater plots, 0.00 mg/kg to 157 mg/kg in dry season. It is however recommended that consumption of vegetables irrigated with domestic/industrial wastewater be strongly discouraged because of its serious health implications.&nbsp

EFFECT OF TREATED SEWAGE SLUDGE ON THE QUALITY OF OKRA FRUIT

Treated sewage sludge (Defective) has been identified to increase heavy metals in the soil which are in turn transferred to plants. In view of this, the study is aimed at assessing the effects of treated sewage sludge on the quality parameters of okra fruits. The randomized block design was employed in raising okra plants with three treatments (0t/ha, 10t/ha, and 20t/ha sewage sludge amendment) over a land area of 56.3m2. Soil analysis was used to determine the level of nitrogen, phosphorus, and potassium in the soil. After 2months, the okra fruits were harvested by cutting the pods off, slicing, oven drying, milling, and labeled correctly prior to laboratory analysis. The heavy metal content in the okra fruit were analysed using atomic absorption spectrometer. The parameters analyzed were Cd, Pb, Cu, Fe, and Zn. The concentration of the selected heavy metals was subjected to descriptive statistics and one-way analysis of variance (ANOVA). The transfer factor was also determined. Most soils in the okra field was sand. Study found out that the soil was deficient in phosphorus and potassium. Bioaccumulation of heavy metals were not found in the okra fruit since Cu, Zn and Fe have transfer factors of less than 1. In addition, transfer factor order in okra fruit were Zn>Cu>Fe>Cd>Pb. The study revealed that the application of sewage sludge at 10t/ha and 20t/ha resulted in high uptake of Zn and Fe whereas cadmium and lead were not detected. The study concluded that consumption of the okra fruit grown on 10t/ha and 20t/ha were very safe since Cu, Fe, and Zn in the okra fruit were less than desirable limit as recommended by FAO and WHO. There is need to determine hazard quotient, the health risk index, morbidity status the enrichment factor and degree of contamination in okra fruit. Effect of sewage sludge at different application rates between 25t/ha and 60t/ha be seriously investigated so as to determine the optimal level of heavy metal in the okra frui

Modelling Crop Evapotranspiration and Water Use Efficiency of Maize Using Artificial Neural Network and Linear Regression Models in Biochar and Inorganic Fertilizer-Amended Soil under Varying Water Applications

The deficit irrigation strategy is a well-known approach to optimize crop water use through the estimation of crop water use efficiency (CWUE). However, studies that comprehensively reported the prediction of crop evapotranspiration (ETc) and CWUE under deficit irrigation for improved water resources planning are scarce. The objective of the study is to predict seasonal ETc and CWUE of maize using multiple linear regression (MLR) and artificial neural network (ANN) models under two scenarios, i.e., (1) when only climatic parameters are considered and (2) when combining crop parameter(s) with climatic data in amended soil. Three consecutive field experimentations were carried out with biochar applied at rates of 0, 3, 6, 10 and 20 t/ha, while inorganic fertilizer was applied at rates of 0 and 300 Kg/ha, under three water regimes: 100% Full Irrigation Treatment (FIT), 80% and 60% FIT. Seasonal ETc was determined using the soil water balance method, while growth data were monitored weekly. The CWUE under each treatment was also estimated and modelled. The MLR and ANN models were developed, and their evaluations showed that the ANN model was satisfactory for the predictions of both ETc and CWUE under all soil water conditions and scenarios. However, the MLR model without crop data was poor in predicting CWUE under extreme soil water conditions (60% FIT). The coefficient of determination (R2) increased from 0.03 to 0.67, while root mean-square error (RMSE) decreased from 4.07 to 1.98 mm after the inclusion of crop data. The model evaluation suggests that using a simple model such as MLR, crop water productivity could be accurately predicted under different soil and water management conditions

ASSESSMENT OF HEAVY METALS UPTAKE BY VEGETABLES CULTIVATED ON SOIL RECEIVING INDUSTRIAL WASTEWATER IN MINNA, NIGERIA

Consumption of vegetable crops grown on soil irrigated with industrial wastewater has been the order of the day in most urban towns and cities of Nigeria, despite reports of its serious health impact. This study assessed the possibility of uptake of heavy metals by crops grown on soil receiving industrial wastewater during rainy and dry seasons. The crops investigated are Spinach, Cayenne Pepper, Jute mallow, roselle and lady’s fingers okra. The initial composition of the wastewater was analyzed to contain 0.89 mg/l of chromium, 0.74 mg/l of cadmium, 1.04 mg/l of copper and 2.81 mg/l of iron. Control water used for this experiment contain no trace of any of these heavy metals. The experimental soil was also analyzed and contained 0.10 mg/kg of chromium, 0.06 mg/kg of iron before irrigation in dry season. After irrigation at the wastewater plots, the heavy metal concentrations in soil had increased to 6.24 mg/kg of chromium and 7.50 mg/kg of iron. In wet season, the concentrations of heavy metals in the soil were 0.00 mg/kg of chromium and 2.32 mg/kg of iron before irrigation. After irrigation in wet season, the concentrations increased to 6.01 mg/kg of iron. Mean difference of heavy metal concentrations were significantly high in vegetables in dry season, with values ranging from 0.03 mg/kg to 211mg/kg in wastewater plots, 0.20 mg/kg to 215 mg/kg in wet seasons wastewater plots, 0.00 mg/kg to 157 mg/kg in dry season. It is however recommended that consumption of vegetables irrigated with domestic/industrial wastewater be strongly discouraged because of its serious health implications

EFFECT OF DIFFERENT RISER HEIGHTS ON SPRINKLER IRRIGATION PERFORMANCE UNDER CONSTANT OPERATING PRESSURE

The study assessed the effect of different riser heights on the sprinkler irrigation performance to cater for the cultivation of taller crops and reduce water losses. A layout of 144 m2 was designed according to the length of mainline and lateral lines, and 36 catch cans were positioned in a grid of 2 m apart. The water caught in Cans were subjected to One-way ANOVA using the Tukey method in Minitab 17 Environment. The risers 4m, 3m and 2m, were significantly different because the means without any letter in common and concluded that some of the riser height have the different mean value of water caught in the catch cans. The results showed that as the riser height increased the mean application rate decreased. Also, the Coefficient of Uniformity (%) for riser height 2 m and 3 m were rated excellent. The Distribution of Uniformity (%) for 2 m and 3 m were rated excellent and fair. The study concluded that riser heights 2 m and 3 m had the optimum CU and DU at 1.6 bar (operating pressure) reduce water losses. The study suggested that sprinkler irrigation should be carried out in Gidan Kwano campus between 5:06 pm and 11:35 am. Also, wind direction should be established before the installation of sprinkler irrigation