环境与分析毒理学

Ecogenotoxicology (genetic ecotoxicology) is an approach that applies the principles and techniques of genetic toxicology to assess the potential effects of environmental pollution in the form of genotoxic agents on the health of the ecosystem. Contrary to human toxicology studies which focus on the fate of the individual, ecogenotoxicology evaluates the consequences of genotoxicants for population sizes and structure, but applies the principles of genetic toxicology in hazard and risk assessment. Genetic hazard assessment, thus, deals with changes in genetic material of organisms, either human or other natural origin. Several reviews demonstrate the presence and potency of genotoxins from a broad range of industrial and municipal effluents. There is a close association of DNA damage, mutation, and induction of various types of cancer. Fish serves as useful genetic model for the evaluation of pollution in aquatic ecosystems. Fish species from contaminated areas initiated studies in the aquatic environment and evidence is growing that environmental mutagens can reduce the reproductive success of populations. Different genotoxicity tests and their applications to environmental monitoring and assessment have been variously reported in fish. This review paper, thus, examines the use of ecogenotoxicology in environmental monitoring, the role of fish in genotoxicity testing of pollutants, genetic basis in genotoxicological assessment, cur rent methods of ecogenotoxicological hazard assessment using fish in vitro and in vivo, and their applications to environmental monitoring as well as recent advances in the field of fish ecogenotoxicology. Limitations and recommendations for further research on the use of ecogenotoxicology were also highlighted.

Pesticides and bacterial endotoxin have been implicated in variety of respiratory dysfunctions. In present study, mice were administered chlorpyrifos at 3 mg/Kg BW/day for 30 days (by oral gavage) and/or challenged with bacterial endotoxin at 80 μg/mice by intranasal route to investigate expression of apoptosis related proteins such as p53, Bax and caspase-3 in lung. The results of immunohistochemistry of lung showed significant increase in number of p53 expressing cells in chlorpyrifos treated mice as compared to control while endotoxin and chlorpyrifos+endotoxin treated mice showed increased number of p53 expressing cells as compared to control and chlorpyrifos treated mice. Chlorpyrifos or endotoxin administration resulted in increased expression of Bax and Caspase-3 while chlorpyrifos treated and endotoxin challenged mice showed synergistic effect on expression of these proteins. From these results, it is concluded that chlorpyrifos and/or endotoxin increased critical apoptosis related proteins such as p53, Bax and Caspase-3 in lung of mice, which may play pivotal role in pathophysiology of pulmonary dysfunctions resulting from exposure to pesticides and endotoxin.

The objective was to study the in-vivo protective effect of Al-Madinah Ajwa (name of the most famous date in Al-Madinah Al-Monwarah City) extract against lead acetate toxicity on the tissues of vital organs. Four rabbit groups were used as an animal model for this study. Ajwa extract treated group (300 mg/kg/day, for 14 days) were evaluated for lead acetate (500 ppm in drinking water for 14 days) intoxication compared to lead acetate alone-intoxicated group; Ajwa extract group and control group. This was done by assessment of liver and kidney functions, blood lead levels, levels of oxidants-antioxidants and histopathological changes in liver, kidney, heart and lung in different groups. The lead acetate intoxicated group showed significant elevation of serum glutamic pyruvic transaminase (SGPT), serum glutamic oxaloacetic transaminase (SGOT), alkaline phosphatase (ALP), total bilirubin (TB), serum creatinine-urea (Cr-U), lipid hydroperoxide (LPO), protein carbonyl content (PCC), and depression of Superoxide dismutase (SOD) and Glutathione peroxidase (GPX) levels as compared to control. The Agwa extract showed tissue protective effect by significant restoration of (SGPT), (SGOT), (ALP), (TB), (Cr-U) (LPO), (PCC), (SOD) and (GPX) levels compared to the previous group. The histopathological evaluation showed marked vascular congestion, interstitial hemorrhage, cellular degeneration and necrosis in different organs of lead acetate intoxicated group, while Agwa extract treated group showed mild congestion and slight focal cellular degeneration. Therefore, outcome of the present study validates the ameliorative and protective effects of Al-Madinah Ajwa dates against the toxic effects of lead acetate poisoning.

The study attempted to determine the occurrence of freshwater in the aquifers of the Deltaic Formation, Niger Delta Nigeria using Lithologic Logs, Electrical Resistivity and Borehole Parameter (Depth) as input data. The Geographical Information System technique that permit diverse geospatial analyses, modelling and data manipulation and Simple Regression Method that permits the assessment of relationship between two variables were adopted in this study. While the Lithologic Logs were adopted to delineate aquifers and aquitards, the Electrical Resistivity was employed to determine the occurrence of freshwater in the aquifers of the study area. The modelled Geological Sequence revealed that the geology of the study area is very complex and consists mostly of unconsolidated sedimentary materials from top soil to the deep horizon. Hence, all the aquifers have very high storage capacity. It was revealed that the nature of resistivity does significantly increases with depth, which indicates lower level of salinity with increasing depth of hole. The study established positive relationship between depth of hole and aquifer resistivity in 80% of the sampled locations indicating the occurrence of freshwater in deep aquifers of the study area. The study identified three distinct aquifers (shallow, intermediate and deep) within the Deltaic Formation. The study also emphasized the occurrence of near surface overlying aquitards in the eastern part of the study area, indicating that shallow aquifers of the eastern part are less vulnerable to near surface contamination. Finally, the study concluded that, in most cases, groundwater quality increases as the depth of well increases within the study area. Finally, this study demonstrated the capabilities of Geographic Information System in spatially referenced visualization of hydrogeological characteristics of complex geology.