Heavy metals, such as cadmium (Cd), lead (Pb) and zinc (Zn), are important environmental pollutants, particularly in urban areas with high anthropogenic pressure. The uptake and accumulation of Cd, Pb and Zn in vegetables (Amaranthus hybridus L.) grown in the valley bottom soils of some cities in southwestern Nigeria were investigated. The concentration of heavy metals in vegetable leaves ranged from 0.4 to 2.0 for Pb (CV, 33), 0.38 to 1.20 for Cd (CV, 25) and 8.2 to 30.4 for Zn (CV, 33). In the vegetable stems, the concentration ranged from 0.8 to 2.6 for Pb (CV = 33), 0.6 to 2.5for Cd (CV, 22) and 11.4 to 18.9 for Zn (CV, 35). Concentration of metals in vegetable roots ranged from 2.2 to 5.1 for Pb (CV, 33), 1.4 to 4.9 for Cd (CV, 22) and 10.2 to 29.0 for Zn (CV, 35). Transfer factors (TF) were in the range of 0.22 and 3.00, with Cd having the highest TF of 3.00. Estimated intake vegetables in µg day −1 ranged from 72 to 82 for Cd, 69 to 120 for Pb and 105 to 200 for Zn. The intakes were above the recommended minimum risks levels. Potential risks, particularly for Cd and Pb intake, exceed the daily requirement for consumers of the leafy vegetable at all the sites. The apparent influence of anthropogenic inputs from the cities to these valleys was reflected by the higher concentrations than the reference location. Food quality assurance systems in vegetables grown in urban valley bottoms need to comply with the world standard on heavy metal concentration.

This study was conducted to evaluate the wetland water quality (WWQ) over a period of 3 years and establish relationships between these qualities using Ramsar site Uchali Wetland, Pakistan (32 °33′N, 72 °01′E). WWQ data obtained were subjected to summary statistics, generalized linear model (glm), correlation, covariance and cluster analysis. The glm of the monthly mean water indices showed that the mean returned for pH (2.57) was not significant while means for others were significant (p < 0.05). The correlation analysis of the WWQ indices indicated that 56% of the pairing indices were inversely correlated while 44% were directly correlated and three piles of clusters of WWQ indices were distinct. The wetland water is not very safe for drinking but safe for other non-domestic uses since it contains fewer microbes and the water health model as arrived at in this study provides a management protocol for wetland water.

Speargrass posed a major constraint to crop producion in some agroecologies in Nigeria.  Hence, the study was conducted to investigate the influence of seasons, rainfall and temperature patterns on speargrass components growth with the view to improve its management. This study was conducted between 2014 and 2016 at Eruwa (7˚32’0˚N, 3˚ 25’0 ˚E, 187m altitude) in Derived savanna (DS) and Kishi (08˚.98’N, 003˚.94’E; 364m altitude) in the southern Guinea savanna (SGS)–northern fringe agroecologies of Nigeria. Twelve months of the year starting from July were randomly assigned to plots in an abandoned speargrass infested farmland, replicated three times and arranged in Randomized Complete Block Design. Monthly temperature, rainfall and speargrass samples (shoot and rhizome) were measured. Results showed that rainfall amount varied across the months in both locations. The highest rainfall was recorded in September (264.20 mm) and hottest month was May, 2016 (28.5oC) in Derived savanna between 2014 and 2016 (Table 1). Kishi had 186 mm rainfall in the wettest months and the hottest months had 28.0 oC within the specified period of the study (Table 2).  Total speargrass total dry weight (STDW) increased with rise in rainfall in both locations. Meanwhile, there were variations in the components (Shoot and rhizome) weight. However, there was decline in speargrass dry matter during the dry months (January to April) in the locations. This might have reflected the effects of moisture deficit.  Notwisthanding, Rhizome:shoot varied  at both locations. Derived savanna (Eruwa) had rhizome:shoot >1.00 in five months throughout the study (5/24), while southern Guinea savanna (Kishi) had rhizome:shoot >1.00 in eleven months (11/24). Speargrass control might be more challenging especially in SGS than DS in the months with higher Rhizome:shoot ratio > 1.00. Derived savanna had more months (19/24 months) with lower rhizome:shoot ratio (< 1.00) than SGS (13/24 months). This might have resulted from more rainy months and better distribution of rainfall in Derived savanna for speargrass shoot growth and the resultant decrease in rhizome:shoot (< 1.00). This is a clue for better translocation of herbicides for season-long speargrass control.

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