Water samples, sediments, tilapia and cat fishes from each of Epe and Badagry lagoons in Lagos State, Nigeria were analyzed quantitatively for the presence of zinc, nickel and iron using Perking Elmer atomic absorption spectrophotometer. The sediment contains higher concentration of Fe with a value of 13.30 µg/g against 8.400 µg/g in fishes and 7.30 mg/L in water. Studies on the different parts of the fish revealed higher concentrations of 4.00 µg/g Ni on the head of tilapia fish followed by 2.40 µg/g Ni in the intestine of cat fish. The highest concentration of 1.95 µg/g Zn was detected on the head of the cat fish while the lowest concentration with a value of 0.16 µg/g was recorded in tilapia head. The concentration of Zn in the water is within the limits permitted by the Lagos State Environmental Protection Agency (LASEPA) of 1.0 mg/L Zn set for water. None of the trace metals investigated was above the maximum permissible level set by world health organization ( WHO).

Laboratory bioassays were conducted to investigate the bioactivity of powders, extracts, and essential oils fromAllium sativumL. (Alliaceae) andA. fistulosumL. (Liliaceae) against adults, eggs, and larvae ofCallosobruchus maculatusF. (Coleoptera: Bruchidae). On the basis of 48 hr median lethal toxicity (LC50), test plant powders and extracts fromA. sativumwere more toxic toC. maculatusadults than those fromA. fistulosum. The 48 hrLC50values for the powder against the test insect species were 9.66 g/kg and 26.29 g/kg forA. sativumandA. fistulosum, respectively. Also the 48 hrLC50values obtained show that aqueous extracts of the test plant species, 0.11 g/L (A. sativum) and 0.411 g/L (A. fistulosum) were more toxic toC. maculatusthan the corresponding ethanol extracts. There was no significant difference in the toxicity of vapours from the two test plant species againstC. maculatus, althoughA. sativumgave lower values. The study shows thatA. sativumandA. fistulosumhave potentials for protecting stored cowpea from damage byC. maculatus.

Toxicity ofChenopodium AmbrosioidesL. (Chenopodiaceae) Products From Nigeria Against Three Storage InsectsTests were carried out to study the toxicity, oviposition suppression, ovicidal and larvicidal effects ofChenopodium ambrosioidesL. as powder, extracts and essential oil againstCallosobruchus maculatusF. (Coleoptera: Bruchidae),Sitophilus zeamaisMotschulsky (Coleoptera: Curculionidae) andTribolium castaneumJacqueline du Val. (Coleoptera: Tenebrionidae). The powder formulation was more toxic toS. zeamaisthan eitherC. maculatusorT. castaneumwith 48 h LC50values of 0.46 g/kg, 1.60 g/kg and 2.14 g/kg, respectively. Ethanol extract was more toxic toC. maculatuswith a 48 h LC50value of 0.023 g/l, than other test insect species. The essential oil treatment demonstrated higher fumigant toxicity againstC. maculatusthanS. zeamaiswith 24 h LC50values of 1.33 μl/l and 1.90 μl/l respectively. The oil vapour showed activity againstC. maculatusegg, but had no appreciable larval mortality. The weight loss of grains admixed withC. ambrosioidespowder was lower than the controls after 150 days of field storage.

Vegetables, eaten fresh or boiled, are an important diet relished in many local Nigerian cuisines and delicacies. Increasing their production has therefore become a prime focus of governments in Nigeria. In the process of production, metals capable of impairing the health of consumers are inadvertently picked up. Studies were therefore conducted to determine the presence of cadmium (Cd), lead (Pb) and mercury (Hg) in fresh and boiled leafy vegetables grown in farms close (proximal) to highways (PS) and those distant from highways (DS). Composite samples of fresh lettuce (Lactuca sativa), fresh Amaranthus (Amaranthus speciosa), boiled A. speciosa, soil, irrigation water, and manure from farms located at the two sites were analyzed by Atomic Absorption Spectrophotometry (AAS). The results show that the fresh vegetables grown on sites close to highways (PS) had higher levels of Cd and Pb (0.313 microg g(-1), 16.933 microg g(-1) for Cd and Pb respectively in fresh Amaranthus, and 0.877 microg g(-1), 16.833 microg g(-1) for Cd and Pb respectively in Raw Lettuce) than those from DS farms (0.20 microg g(-1), 8.33 microg g(-1) for Cd and Pb respectively in fresh Amaranthus and 0.266 microg g(-1), 8.00 microg g(-1) for Cd and Pb respectively in Raw Lettuce). The irrigation water at the PS farms contained more Pb but similar levels of Cd and Hg. Soil from the PS was slightly more acidic (pH = 6.32 + 0.08) than those from the DS (pH = 6.49 + 0.02). Soils of PS farms gave very high Pb levels (4.13 microg g(-1)). Boiling had an effect on the levels of Cd and Pb but not Hg in Amaranthus, irrespective of the site of production. Cadmium (Cd) increased from 0.2 microg g(-1) to 1.036 microg g(-1) before and after boiling respectively in DS samples, while it increased from 0.3131 microg g(-1) to 1.037 microg g(-1) in samples from PS farms before and after boiling respectively. The level followed similar trend. Pb increased from 8.33 microg g(-1) to 5.667 microg g(-1) before and after boiling respectively in samples from DS whereas it decreased from 16.933 microg g(-1) to 14.20 microg g(-1) before and after boiling respectively in samples from the PS.

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