Assessment of Trace Metal Levels In Commonly Edible Vegetables From Selected Markets In Lagos State, Nigeria
Consumption of food contaminated with heavy metals is a major source of health problems for man and animals. Three commonly edible Leafy vegetables (Amaranthus hybridus, Celosia argentea ,Cochorus olitoris) from Agboju and Iba markets , Lagos Nigeria were sampled, identified, digested and analyzed with the aid of Atomic Absorption Spectrophotometer (AAS) as directed by APHA (American Public Health Association) to determine heavy metals concentration in them with the aim of ascertaining their edibility for human consumption. The mean concentration for each heavy metal in the samples gotten from each market were calculated, the comparison of these data was done amongst the two markets, and compared with the permissible levels set by the FAO and WHO. The results showed that the levels of Lead, Cadmium, Copper, Zinc, Iron, Nickel, Selenium and Chromium present in the vegetable concentrated in the following order Fe>Pb>Zn>Cd>Ni>Cu>Cr>Se. With regards to vegetables in questions, analysis of variance showed that some vegetables accumulated metals more than each other and as such indicated that metals like copper, cadmium, selenium, iron and zinc are significant at P 0.05). With significant values of lead, cadmium and nickel, recorded in both Amaranthus hybridus and Celosia argentea vegetables, vegetables consumers must be weary of vegetables to buy and the market that is save to buy from, especially markets located very close to highways or close to major busy roads .
Speciation and Mobility of Selected Heavy Metals in Sediments of the Nun River System, Bayelsa State, Nigeria
The speciated fractions of some selected environmentally toxic heavy metals (Pb, Cu, Cr, Cd, Zn, Fe and Ni) were assessed in the bottom sediments of the Nun river system. The concentrations (mg/kg) of the selected heavy metals per fraction were analysed using the GBC AVANTA PM A6600 FAAS. Chemical speciation study applying the five-stage sequential extraction scheme revealed the prevalent fractions where the selected heavy metals were bound: Pb, Cu, Cr, Cd, Zn and Fe were prevalent in the residual fractions while Ni was mainly bound to the Fe-Mn oxide fraction. The mobility factor indices of the metals depicted the following trends: Pb>Cr>Zn>Cd>Ni>Cu>Fe and Pb>Cr>Cd>Ni>Zn>Fe>Cu for the samples and control points respectively. Mobility factor indices showed highest lability for Pb and Cr across the sample and control points, while the least lability and mobility was observed for Fe and Cu across all sampling points of the river. The sediments of the Nun river system revealed a high mobility and bioavailability for Pb and Cr. The two-way ANOVA statistical analysis of data showed significant variation (P<0.05) between metal fractions and the spatial distribution of sediment samples across the river system except for Pb which revealed the highest mobility and tendency for bioavailability.
Pig Vocalizations Under Selected Husbandry Practices
Acoustical characteristics of vocalizations of sows, piglets, and nursery pigs under selected husbandry practices were analyzed with a digital signal processing system. The duration (D) and major energy-resonance frequency (P) for each call were determined as follows: a) processing of piglets (D = 0.81 s and f* = 3 700 Hz); b) food anticipation of breeding-gest ation sows (2.50 s and 3 000 Hz); c) isolation of piglet (0.34 s and 500, 3 500 Hz); d) startling of nursery pigs (0.29 s and 900 Hz); e) sows in heat (3.07 s and 1 375 Hz); f) farrowing (0.10 s and 3 000 Hz); g) sow nursing (0.15 s and 1 000 Hz); and h) mate greeting of sow (0.13 s and 1 000 Hz). Calls a) to d) are responses to human generated stressors, and calls e) through h) responses to social and physiological states of the pigs. Thus, vocalizations can be segmented for different pig production situations.