The pesticides belong to a category of chemicals used worldwide as herbicides, insecticides, fungicides, ro-denticides, molluscicides, nematicides, and plant growth regulators in order to control weeds, pests and dis-eases in crops as well as for health care of humans and animals. The positive aspect of application of pesti-cides renders enhanced crop/food productivity and drastic reduction of vector-borne diseases. However, their unregulated and indiscriminate applications have raised serious concerns about the entire environment in general and the health of humans, birds and animals in particular. Despite ban on application of some of the environmentally persistent and least biodegradable pesticides (like organochlorines) in many countries, their use is ever on rise. Pesticides cause serious health hazards to living systems because of their rapid fat solu-bility and bioaccumulation in non-target organisms. Even at low concentration, pesticides may exert several adverse effects, which could be monitored at biochemical, molecular or behavioral levels. The factors af-fecting water pollution with pesticides and their residues include drainage, rainfall, microbial activity, soil temperature, treatment surface, application rate as well as the solubility, mobility and half life of pesticides. In India organochlorine insecticides such as DDT and HCH constitute more than 70% of the pesticides used at present. Reports from Delhi, Bhopal and other cities and some rural areas have indicated presence of sig-nificant level of pesticides in fresh water systems as well as bottled drinking mineral water samples. The ef-fects of pesticides pollution in riverine systems and drinking water in India has been discussed in this review

Almost all the environmental components including both the abiotic and biotic factors have been consistently threatened by excessive contamination of heavy metals continuously released from various sources. Different heavy metals have been reported to generate adverse effects in many ways. Heavy metals induced neurotoxicity and impairment in signalling cascade leading to cell death (apoptosis) has been indicated by several workers. On one hand, these metals are required by the cellular systems to regulate various biological functions of normal cells, while on the other their biomagnification in the cellular systems produces adverse effects. The mechanism by which the heavy metals induce neurotoxicity follows free radicals production pathway(s) specially the generation of reactive oxygen species and reactive nitrogen species. These free radicals produced in excess have been shown to create an imbalance between the oxidative and antioxidative systems leading to emergence of oxidative stress, which may cause necrosis, DNA damage, and many neurodegenerative disorders. This mini review summarizes the current knowledge available on the protective role of varied natural products isolated from different herbs/plants in imparting protection against heavy metals (cadmium, lead, arsenic, and mercury) mediated neurotoxicity.

Heavy metals especially lead, mercury, cadmium, arsenic and chromium are well known for causing birth defects. Although, the mother may be unaffected and unaware of the contamination, infants exposed to such agents in-utero may have a number of side effects as these substances readily move across the placental barrier. Heavy metals are dangerous because they have the tendency to bioaccumulate in biological organisms over a period of time. The foetus and newborns are much more sensitive to the effects at low levels of metal exposure and this is mainly due to body weight being less and higher rate of food consumption rate, higher gastrointestinal absorption rate, less effective renal excretion, and a less effective blood-brain barrier. On the other hand, lead is tightly bound to red blood cells, thereby enhancing the transfer from maternal circulation through the placenta to the foetus. Placental transfer begins as early as the twelfth week of gestation. Arsenic is found in drinking water and is a potent toxicant but scanty research has been done on its effect on maternal health. Chromium (Cr 6+) accumulates in placenta and impairs foetal development in the placenta. Therefore, the fertile population should prevent themselves from exposure to chemicals, drugs and other environmental agents.

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