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Nanoscale graphene oxide (NGO) has great potential in biomedicine by the virtue of its facile functionalization and tunable characteristics. Toxicity assessments have therefore become essential prior to its biomedical applications. This study examined the effects of NGO exposure on male reproductive function of adult Wistar rats. Rats were exposed intraperitoneally to three increasing doses, namely low-dose (0.4 mg/kg BW), mid-dose (2.0 mg/kg BW) and high-dose (10.0 mg/kg BW) of NGO. Repeated exposure of NGO for 15 and 30 days resulted in decreased epididymal sperm counts and elevated sperm abnormalities. Percentage of motile sperms was also significantly reduced due to the exposure. Activities of SOD, GPx and malondialdehyde concentration in the testes increased in a dose-specific manner. Results of the study demonstrated that high-dose of NGO resulted in considerable histological damage to testicular tissue which included atrophy of seminiferous tubules with reduction in germinal epithelium, germ cell loss and vacuolization. Low and mid-doses of NGO were not associated with sperm dysfunction or testis damage. Withdrawal of treatment for 30 days demonstrated significant recovery potential. Histology of epididymis and male fertility potential were not affected due to the NGO exposure. These findings are important for assessment of the risk involved in manufacturing, use and processing of the graphene oxide-based materials towards male reproductive function.

Extensive use of synthetic pyrethroids has resulted in serious human health issues. Induction of oxidative stress is an important mechanism of action of most pesticides including pyrethroids. In the present study, we have elucidated the possible role of oxidative stress in bifenthrin-induced neurotoxicity. Adult male Wistar rats were administered bifenthrin (3.5 and 7 mg per kg body weight p.o.) for 30 days. Behavioral studies were conducted on a set of randomly selected rats from each treatment group after completion of treatment. Neurochemical parameters were assessed 24 h after the last dose was administered. The selected behavioral and neurochemical endpoints were also assessed 15 days after cessation of exposure to reveal whether the neurobehavioral changes produced by bifenthrin were temporary or permanent. Deficits in motor activity, motor incoordination, and cognitive impairment were observed after exposure to bifenthrin. Levels of biogenic amines . dopamine (DA) and its metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), epinephrine (EPN), norepinephrine (NE), and serotonin (5-HT) altered in the frontal cortex, corpus striatum, and hippocampus of bifenthrin-treated rats. A decrease in the activity of acetylcholinesterase (AChE) occurred in all regions of the brain. Both doses of bifenthrin significantly induced lipid peroxidation (LPO) and increased protein carbonyl levels in the frontal cortex, corpus striatum, and hippocampus of rats. The activities of antioxidant enzymes, catalase, superoxide dismutase, and glutathione peroxidase, were also suppressed in all selected regions of the brain. A trend of recovery was, however, observed in all the behavioral and neurochemical endpoints 15 days after withdrawal of exposure. Oxidative stress seems to play an important role in bifenthrin-induced neurotoxicity. Our study suggests that long-term exposure to these compounds can produce detrimental effects.

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Water has become a major threat in today’s world. Collection of heavy metals, a few of them, is potentially toxic and these get distributed to different areas through different pathways. With an increase in the earth’s population, development and industrialization are taking place rapidly and these get the major source of water contamination. With heavy metals in lakes, rivers, groundwater, and various water sources, water gets polluted by the increased concentration of heavy metals and metalloids through release from the suddenly mine tailings, disposal of high metal wastes, growing industrial areas, leaded gasoline and paints, usage of fertilizers inland, animal manures, E-waste, sewage sludge, pesticides, wastewater irrigation, coal, etc. Exposure to heavy metals has been linked to chronic and acute toxicity, which develops retardation; neurotoxicity can damage the kidneys, lead to the development of different cancers, damage the liver and lungs; bones can become fragile; and there are even chances of death in case of huge amount of exposure. This chapter mainly focuses on heavy metal pollution in water and its toxic effect on living organisms.