COMPARATIVE STUDY

Vegetables are consumed in both the developing and developed countries of the world due to their high nutritive values, however they also contain some high levels of toxic substances including metals.This study assessed the comparative concentrations of selected heavy metals:cadmium (Cd), lead (Pb), nickel (Ni), zinc (Zn), and copper (Cu) in four commonly consumed leafy vegetables: fluted pumpkin (Telfairia occidentalis), bitter leaf (Vernonia amygdalina), water leaf (Talinum triangulare), and scent leaf (Ocimum gratissimum) cultivated in polluted (Oluku) and unpolluted (Iyowa) sites in Benin City, Edo State, Nigeria. Samples were analysed using Atomic Absorption Spectrophotometry (AAS), and results were compared with FAO/WHO permissible limits. The concentrations of all heavy metals were below recommended safety thresholds, with the general trend of accumulation being polluted site > unpolluted site. Statistical analysis (p < 0.05) revealed significant variations for some metals, particularly Zn, Cd, and Cu, across the two locations. Bitter leaf and scent leaf exhibited higher tendencies for metal accumulation compared to other vegetables. Although all concentrations were within safe limits, continuous cultivation near polluted areas may lead to long-term contamination risks. The findings highlight the influence of anthropogenic activities such as waste disposal and vehicular emissions on metal uptake in vegetables and underscore the need for regular environmental monitoring, improved waste management, and public awareness to ensure food safety

This study was carried out to comparatively study different snail production systems using crops as cover. The systems evaluated were open and screened paddocks in comparison with the conventional paddock. In the open and screened paddocks, four different crops (Pueraria phaseoloides, Centrosema mole, Calapogonium mucunoides and Manihot esculenta) were cultivated to simulate the natural environment of the snails. The snails were allowed to live on the crops as applicable in the wild for the first 6 weeks after which concentrate was introduced for another six weeks while conventional feeding materials like pawpaw leaves, fruits and water leaf were utilized in the conventional paddock. A total number of three hundred and twenty (320) apparently healthy Archachatina marginata with liveweight between 50 to 60 g were used in the study which was laid out in a 2 X 4 factorial in Randomized Complete Block Design with four replicates. Data collected on growth, reproduction, environmental temperature and relative humidity were subjected to Analysis of Variance (ANOVA) using GenStat version 12.0 statistical software. Significant level was taken at P < 0.05. There was a significant difference (P < 0.05) in the weight of the snails among the four cover treatments when compared on the basis of the production systems. The snails in the Mucuna, Centro, Puero and Cassava screened paddock recorded 10.75, 5.90, 5.63 and 4.43 g weight gain respectively while the snails reared under the open paddock in Mucuna, Puero, Centro and Cassava had weight gain of 4.28, 3.7, 2.9 and -2.8 g respectively. The snails in the conventional paddock had an average weight gain of 6.5 g. The snails reared under Cassava in the screened paddock laid the highest average number of eggs (10). Snails from the Mucuna pen in the screened paddock had bigger average size of eggs (20 mm) while the Snails from the Centro pens in the screened paddock had the highest average egg weight (1.30 g). The incubation period ranged between 26.5 to 32 days. Eggs laid by snail in the Centrosema pen in the screened paddock recorded 100 % hatching. The average temperature recorded at 0, 6 and 12 weeks for Open paddock were 39.43, 37.98 and 45.05 oC; for screened paddock were 36.19, 36,67 and 42.76 oC and conventional paddock were; 39.75, 39.10 and 45.05 oC respectively. The relative humidity recorded in the open paddock at 0, 6 and 12 weeks were 77.31, 63 and 65.11 %; screened paddock were 77.31, 66.63 and 71.56 % and Conventional paddock were 78.75, 68.75 and 67.50 % respectively. It was concluded that rearing snails under a screened paddock did not only help to regulate the temperature and relative humidity of the snails immediate environment but also protected the snails from intruders, predators and escape which are the major factors responsible for successful snail farming

This study investigated the comparative drying performance and product quality of fluted pumpkin (Telfairia occidentalis) leaves processed using traditional open sun drying (OSD) and an improved parabolic-shaped solar dryer (PSSD). Freshly harvested fluted pumpkin leaves were divided into two batches and dried under both methods to a target moisture content of 10% (wet basis). Key performance indicators measured included drying time, drying rate, and final moisture content, while sensory attributes such as colour, odour, texture, and overall acceptability were assessed using a 9-point Hedonic Scale. Results revealed that the PSSD achieved significantly faster drying (4.55 h) and higher drying (21.78 g/hr) compared to OSD (6.05 h and 16.22 g/hr, respectively), with the statistically significant (p = 0.027). Sensory evaluation further indicated that leaves dried with the PSSD were preferred (overall acceptability = 7.9) to those dried under open sunlight (5.9), with superior colour retention and aroma preservation (p < 0.001). The enhanced efficiency and product quality observed in parabolic solar drying demonstrate its potential as a sustainable, energy-efficient alternative for preserving perishable leafy vegetables in Nigeria. Adoption of this technology can substantially reduce postharvest losses, improve marketability, and promote year-round availability of nutrient-rich vegetables like fluted pumpkin.

This study investigated the comparative drying performance and product quality of fluted pumpkin (Telfairia occidentalis) leaves processed using traditional open sun drying (OSD) and an improved parabolic-shaped solar dryer (PSSD). Freshly harvested fluted pumpkin leaves were divided into two batches and dried under both methods to a target moisture content of 10% (wet basis). Key performance indicators measured included drying time, drying rate, and final moisture content, while sensory attributes such as colour, odour, texture, and overall acceptability were assessed using a 9-point Hedonic Scale. Results revealed that the PSSD achieved significantly faster drying (4.55 h) and higher drying rate (21.78 g/hr) compared to OSD (6.05 h and 16.22 g/hr, respectively), with the difference statistically significant (p = 0.027). Sensory evaluation further indicated that leaves dried with the PSSD were preferred (overall acceptability = 7.9) to those dried under open sunlight (5.9), with superior colour retention and aroma preservation (p <0.001). The enhanced efficiency and product quality observed in parabolic solar drying demonstrate its potential as a sustainable, energy-efficient alternative for preserving perishable leafy vegetables in Nigeria. Adoption of this technology can substantially reduce postharvest losses, improve marketability, and promote year-round availability of nutrient-rich vegetables like fluted pumpkin.

This study aims to conduct a comparative analysis of the key architectural and construction features of green buildings and Benin traditional buildings, with a focus on their adaptability and resilience to local climate conditions and environmental factors. The research will first examine the general characteristics of green buildings and Benin traditional buildings, including their underlying design principles, material selection, and construction techniques. This will involve a review of the existing literature on the subject, as well as an assessment of the environmental performance and sustainability aspects of each building type. The study will further look into the adaptability and resilience of these building features, such as energy efficiency, water conservation, and waste management, compare to the traditional building practices and techniques employed in Benin. The role of cultural influences, traditional knowledge, and innovative sustainable solutions in enhancing the adaptability and resilience of these buildings will also be explored. Furthermore, the research will investigate the potential for integrating green building strategies with Benin traditional building practices to create more climate-responsive and environmental-friendly structures. This will involve identifying the challenges and opportunities in bridging the gap between modern green building approaches and traditional construction methods. The findings of this study contribute to a better understanding of the comparative advantages and limitations of green buildings and Benin traditional buildings in addressing local environmental conditions and climate change adaptation. The insights gained can inform policymakers, architects, and construction professional in developing more sustainable and resilient building practices that combine the best of both approaches.