In this study, eleven soil samples and twenty-twoplants samples were collected in the vicinity of eleven industries and a thermal station was analyzed for zinc, copper, iron, lead and cadmium. Soil sample from Egbin thermal station had the highest concentration of Zn (141.06 mg/kg) and Cu (131.70 mg/kg). Soil from international textile had the highest level of Fe and the soil from Nichemtex had the highest concentration Pb and Cd was the highest in soil from Guinness (28.91 mg/kg, 59.80 mg/kg and 1.72 mg/kg respectively). The highest concentrations of the heavy metals were observed from different plants species. Analyses of variance (p < 0.05) showed that heavy metal variation in plant and soil samples were not significant (p > 0.5). There were positive correlations between the heavy metals in the soils and the plant samples indicated that the plants obtained the heavy metals from the soil. Plants having BCF values less than one had limited ability to accumulate, translocate and phytoextract heavy metals. These plants in this study with higher Bioconcentration Factor value especially those greater than one (Croton lobatus, Borreria sp., Cyathula prostrata, Lantana camara, Ficus sp., Mimosa pudica, Eclipta prostrata, Commelina sp. etc.) were suggested for further research and assessment on their bioaccumulation abilities and phytoremediation potential.

Summary The soil seed bank of limestone grassland plots was investigated after 6 years of manipulation of temperature, rainfall, fertility and disturbance. An inoculum of seeds of species alien to the site was also added to the experiment. The seed bank was largely made up of species that were native to the site and had small, persistent seeds. Large‐seeded species, whether native or introduced, were rare or absent in the seed bank. Small‐seeded species were generally more deeply buried than large‐seeded species. Total seed density was comparable with that of other limestone grasslands. Significant climate effects were few, although the seed bank of the winter annual Arabidopsis thaliana was increased by summer drought and that of Cerastium fontanum was increased by winter heating. The density of seeds of native species declined in response to disturbance and increased fertility treatments, while that of introduced species increased. Changes in the seed bank lagged behind changes in the vegetation, with introduced species making up a higher proportion of the vegetation than of the seed bank after 6 years of manipulation.

Twenty one sampling locations were assessed for carbon monoxide (CO), carbondioxide (CO 2 ), oxygen (O 2 ), sulphur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), nitrogen oxide (NO), suspended particulate matter (SPM) and noise level using air pollutants measurement methods approved by ASTM for each specific parameter. All equipments and meters were all properly pre-calibrated before each usage for quality assurance. Findings of the study showed that measured levels of noise (61.4 -101.4 dBA), NO (0.0 -3.0 ppm), NO 2 (0.0 -3.0 ppm), CO (1.0 -42.0 ppm) and SPM (0.14 -4.82 ppm) in all sampling areas were quite high and above regulatory limits however there was no significant difference except in SPM (at all the sampling points), and noise, NO 2 and NO (only in major traffic intersection). Air quality index (AQI) indicates that the ambient air can be described as poor for SPM, varied from good to very poor for CO, while NO and NO 2 are very good except at major traffic intersection where they were both poor and very poor (D-E). The results suggest that strict and appropriate vehicle emission management, industrial air pollution control coupled with close burning management of wastes should be considered in the study area to reduce the risks associated with these pollutants.© JASEM http://dx.doi.org/10.4314/jasem.v20i1.21

This work investigated six heavy metals (Pb, Cr, Zn, Cd, Ni and Cu) accumulation in five popular leafy vegetables: Telferia occidentalis (fluted pumpkin), Talinum triangulare (waterleaf), Ocimum gratissimum (scent leaves), Celosia argentea (plumed cockscomb), and Amaranthus viridis (slender amaranth) obtained from 4 popular markets in Lagos metropolis using an atomic absorption spectrophotometer (AAS), and evaluate the human health risks of their consumption. Heavy metals content in vegetables across the markets ranged as follow; Cd (0.05 -0.20 mg/kg); Pb (0.34 -5.44 mg/kg), .80 mg/kg), Cr (0.25 -1.51 mg/kg), Ni (0.13 -2.91 mg/kg) and Cu (2.34 -14.08 mg/kg). The concentrations of all metals are quite generally lower than the permissible levels by FAO/WHO in vegetables except for Pb. Statistical analysis of levels of the studied metals in A. viridis, T. occidentalis, C. argentea, and O. gratissimum in all the markets sample showed significant differences in levels of Zn, Cr, Cu and Ni (p<0.05). To assess the the health risk of the inhabitants of Lagos and the environs due to heavy metal intake from these vegetables consumption., the daily intake of metals (DIM), health risk index (HRI), and target hazard quotient (THQ) were calculated. The daily intake of metals in vegetables species for Zn (0.51 -1.46 mg/kg) and Ni (0.05 -0.22 mg/kg) are significantly lower than the recommended daily intake of metals and the upper tolerable daily intake level (UL). However, DIM of Cd (0.004 -0.017 mg/kg) and Pb (0.046 -0.182 mg/kg) exceed the recommended DIM but fall within the upper tolerable daily level. Cr (0.048 -0.082 mg/kg) is lower than the recommended oral reference dose (RFD) of 1.5 mg/kg (USEPA, 2010). The THQ values range showed that Cd was 0.048 -0.192, Pb was 0.150 -0.587, Zn was 0.021 -0.190, Cr was 0.0001 -0.001, Ni was 0.050 -0.120 and Cu was 0.148 -0.239. This result reflected the risk associated with exposure for the period of life expectancy considered, and the inhabitants are highly exposed to health risks associated to these metals in the order Pb > Cu > Cd > Ni > Zn > Cr. The THQ in all metals is less than 1 in all the vegetables species; therefore, it does not pose serious health risk concern. However, vegetable consumption was just one part of food consumption, the potential health risks for residents might actually be higher than in this study when other routes of heavy metals intake are considered. ©JASEM http://dx.doi.org/10.4314/jasem.v20i3.6

This study investigated pesticide residue levels in the two vegetables commonly eaten in Lagos state Nigeria. The vegetables (Telfairia occidentalis and Celosia argentea) were purchased from six markets (Oyingbo, Mile 12, Mushin, Ajah, Agege and Festac) in Lagos. The pesticide residue levels were determined using gas chromatography/mass spectrometry. Data obtained were statistically analysed using graph pad prism 6.0 software and were compared with WHO limits. The vegetables from all the markets had pesticide residue level above the WHO lower limit (0.02 mg/kg). The two vegetables from Oyingbo and Mile 12 markets had total pesticide residue levels above the WHO upper limit (0.7 mg/kg). T. occidentalis from Oyingbo market had the highest total pesticide residue level (2.35mg/kg) and the highest number of pesticides while C. argentea from Agege market had the least total pesticide residue level (0.08mg/kg).Aladrin was found in the two vegetables from all markets and generally more pesticide residue was found in the tissues of T. occidentalis than in the tissues of C. argentea. Significant differences (P<0.05; P<0.01) were noticed between some pesticides in T. occidentalis from Oyingbo and some pesticides in the vegetables from the other markets.Although the hazard quotient and hazard index values (being less than 1 and 0.2 respectively) indicate that there will be no health risk in consuming the vegetable, some of pesticides residues were above the maximum residue levels. The presence of pesticides in the vegetables calls for strict regulation of the application of the pesticides in farms and preservation chambers. This will help in preventing some of the diseases and other problems associated with pesticide accumulation.