环境与分析毒理学

Introduction: Consumers are exposed to a diversity of chemicals in all areas of life. Air, water, soil and food are all unavoidable components of the human environment. Each of those elements influences the quality of human life, and each of them may be contaminated.
Objective: Levels of cadmium (Cd), lead (Pb), mercury (Hg) and nickel (Ni) in vegetables and soils from Ohaji, Umuagwo and Owerri in southern Nigeria were determined and the potential health risks assessed.
Methods: Commonly grown vegetables, fruits and food crops were collected from three different sites in southern Nigeria, washed, oven-dried in a hot air oven at 70–80°C for 24 h. Dried samples were powdered using pestle and mortar and sieved through muslin cloth. Samples (0.5 g each) were digested with perchloric acid and nitric acid (1:4) solution. The presence of lead, cadmium and nickel were analyzed in samples using the Unicam Atomic Absorption Spectrophotometer (AAS) Model 929.
Results: Concentrations of Cd, Ni and Pb in Ohaji exceeded maximum allowable concentrations for agricultural soil. Cadmium, Ni, and Pb in vegetables were highest in Murraya koenigii, Piper guineense and Amaranthus viridis Linn, respectively. The estimated yearly intake of Pb, Cd and Ni in commonly consumed vegetables, Green leaf (Amaranthus viridis), fluted pumpkin (Telfaria occidetalis) and Curry leaf (Murraya koenigii) in Nigeria were calculated to be 1,210, 150 and 456 mg.kg-1, respectively.
Conclusion: Taken together it might be concluded that these vegetables may contribute to the body burden of heavy metals especially lead.

Owing to the inevitability of man’s dependence on water, directly or indirectly and the sensitive nature of the largest Africa’s river delta, groundwater samples were collected from three functional boreholes in Gokana, Ogale and Trans-Amadi communities in Rivers State of Nigeria to appraise the suitability of the water samples for end-users.The hydrochemistry, physical property and expressed microbial load, using conventional field and laboratory techniques were assayed. The results gave significant variations in most water characteristics attributable to Petroleum production, Artisanal refining, Illegal tapping, and Industrial activities among others. Physicochemical properties like TSS, DO, NH3, Acidity, Colour, and pH levels exceeded set limits (Department of Petroleum Resources, DPR and Nigerian Standards for Drinking Water Quality, NSDWQ) for all locations and was comparable to the UNEP’s recent report findings on Ogoniland and environment. Also, at p ≤ 0.05, elevated levels of Benzene, a carcinogen was observed for Ogale water samples. Although the expressed microbial load did not comply with standards for all locations, there was no statistically significant difference (P ≤ 0.05) among the three different locations. These are suggestive of groundwater pollution as well as interrelationship with social and health implications.

This article explains that thermo cool, plastic beads, cork, teak wood and perlite were tried as carrier materials in the lab-scale reactor towards treating high strength organic wastewater by using inverse anaerobic fluidized bed reactor (IAFBR). Organic wastewater of great strength (molasses) is pronounced for its high chemical oxygen demand (COD) of 45,000 to 75,000 mg/l and low pH values of 4.3 to 5.3. The results of this study highlighted the selection, physical properties and performance of carrier materials on biomass retention. This study has also clearly indicated that perlite proves to be a suitable carrier material for high biomass retention and improvement of the reactor performances in a short time of operation.

Cadmium content and distribution as well as its effects on growth and oxidative stress were investigated in 17-day-old tomato seedlings (Solanum). The content of Cd increased with external Cd concentrations, and was considerably higher in roots than in shoots. Excess Cd suppressed biomass production of both roots and shoots and reduced chlorophyll content in leaves. Further, substantial increases of H2O2 and ascorbate contents, malondialdehyde formation, and antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (GPX) were observed in Cd-stressed plants in comparison with controls. The results suggest that the phytotoxic effects of Cd in tomato seedlings may be achieved by an enhanced production of active oxygen species (AOS) and subsequent lipid peroxidation with ascorbate synthesis as singe of tomato tolerance.

The effects of sub-acute exposure (7 days) to aflatoxins and the potential protective effects of Lactobacillus rhamnosus GG ATCC53013 (LGG) were studied in male Albino mice. Four experimental groups were used, each comprising 30 mice; control group, LGG-treated group (1 × 1010 CFU), AFs-treated group (0.7 mg/kg b.w.), and a group given LGG two hours before AFs intoxication. The malondialdehyde (MDA), glutathione (GSH) levels and superoxide dismutase (SOD) activity were measured in liver and kidney tissues. Chromosomal aberrations in bone marrow and in spermatocytes, as well as mitotic and meiotic activities were performed to assess the genotoxicity; besides sperm parameters were evaluated. Results showed that AFs significantly elevated the tissue levels of MDA, whereas the levels of GSH as well as SOD activity were significantly decreased in liver and kidney. AFs increased significantly the frequencies of structural and numerical chromosome aberrations in bone marrow and spermatocytes. In addition, mitotic and meiotic activities of somatic and germ cells were declined significantly. Also, AFs caused a high significant reduction in cauda epididymal sperm count, sperm motility and significant increase sperm abnormalities, as compared to control. Mice received LGG before AFs gavage, showed a significant amelioration in oxidative status in both liver and kidney, by increasing the contents of GSH and SOD activity. Cytogenetic analyses revealed that LGG administration before AFs gavage significantly reduced frequencies chromosomal aberrations in bone marrow and spermatocytes, and recovered mitotic and meiotic activities as well. Moreover, gavage LGG before AFs intoxication caused significant recovery in all sperm parameters studied. In conclusion, LGG was found to be safe and successful agent counteracting the oxidative stress and protected against the genotoxicity induced by AFs, in addition to reduction in spermatotoxic alterations.

Recent studies have linked air pollution in cities to chronic health problems like cardiovascular and cardio-respiratory deaths in the population. Pollution of the atmosphere in Harare, the capital of Zimbabwe, is a source of concern. In this study four pollutants (SO2, NO2, Pb, and total suspended particulate matter (TSPM)) were monitored at eight different sites scattered throughout the city for three months (July, August and September). SO2 was determined by bubbling the air into a solution of H2O2, followed by titration. The highest SO2 pollution of 820.0 μg/m3 was in an industrial area and the lowest pollution of 5.0 μg/m3 was in the Central Business District (CBD). SO2 pollution was generally above the World Health Organization (WHO) 24-hour guideline value of 125 μg/m3. NO2 was sampled from the air by passive samplers followed by spectrophotometric determination. The highest NO2 pollution was 46.14 μg/m3 at a site with a busy road nearby and the lowest was 11.09 μg/m3 in a high population residential area. NO2 pollution was generally lower than the WHO guideline value of 40.0 μg/m3 (annual mean). The total suspended particulate matter (TSPM) was determined as “black smoke” using the Soiling Index method. The highest total suspended particulate matter was 154.31 μg/m3 found in a high population density suburb located near some industries and lowest was 9.54 μg/m3 in a low density residential area which is far from pollution sources. Lead was determined by Graphite Furnace Atomic Absorption Spectrometry (GFAAS) for each month for every site and ranged from 0.01 to 0.72 μg/m3. The level of Pb pollution was highest in July and lowest in September at all sampling sites. A positive correlation was found between the levels of Pb and TSPM.

The gill is the respiratory organ in fish but it is also responsible for ion exchange with the environment, what makes it highly susceptible to pollutants. This study aimed to identify possible histological and histochemical changes in the gill of fish species Prochilodus lineatus exposed to biodegradable detergents and water from an urban lake. The results showed not only morphological alterations such as lamellae fusion and hyperplasia, as well as increase in collagen, changes in nuclear volume and increase in the number of chloride and mucous cells. These results show that common pollutants dumped into rivers and urban lakes can cause several changes in the respiratory organ, possibly leading to a metabolic deficit in fish.