PESTICIDES: AN OVEREVIEW

The majority of the farmers are unaware of pesticide types, a level of poisoning, safety precautions and potential hazards on health and environment. According to the latest estimate, the annual import of pesticides in Nepal is about 211t a.i. with 29.19% insecticides, 61.38% fungicides, 7.43% herbicides and 2% others. The gross sale value accounts the US $ 3.05 million per year. Average pesticides use in Nepal is 142 g a.i./ha, which is very low as compared to other Asian countries. Pesticidal misuse is being a serious concern mainly in the commercial pocket areas of agricultural production, where farmers are suffering from environmental pollution. An incidence of poisoning is also increasing because of intentional, incidental and occupational exposure. Toxic and environmentally persistent chemicals are being used as pesticides. Many studies showed that the chemical pollution of the environment has long-term effects on human life. It is therefore essential that manufacture, use, storage, transport and disposal of chemical pesticides be strictly regulated. Keywords: Environment, Human-health, Misuse, Pesticides, Pesticide-consumption Â

INVESTIGATION OF MECHANICAL PROPERTY OF VARIOUS MIX DESIGN IN CONCRETE BY REPLACING FINE SAND WITH FOUNDRY SAND

Nowadays, concrete become most widely used material in construction. The demand of concrete increases day by day. Other way, Foundry sand is the byproduct of Ferrous and Non-Ferrous metal casting foundries where the river sand is used many times for the core and mould production with the binders. After a time these sand become unusual for the core production n called waste foundry sand. In this research paper, replacement of fine sand of concrete is done with the foundry sand, so the disposal problem related with the foundries have to be reduce so minor environmental issues create and the cost of concrete also reduced so with the increase in the strength of concrete by using foundry sand in it. Mix design of M30 and M25 were adopted for the replacement of fine sand. The fine sand has been replaced by foundry sand accordingly at replacement of 10%, 20% & 30% by weight for M-30 and M-25 Grade concrete. Concrete mixtures were produced, tested and compared in terms of different strength and different grade with the conventional concrete. Testing of these samples were carried out to calculate the Compressive strength for 7, 14 and 28 days. As a result, the compressive increased up to 20% addition of used foundry sand in M-30 grade and for M-25 the strength increment noticed at 1% replacement. This research work is anxious with experimental investigation on strength of concrete and optimum percentage of the partial replacement of foundry sand by replacing fine aggregate via 10%, 20%, and 30% with M30 and M-25 Grade. Keeping all this view, the aim of investigation is the behavior of concrete while adding of waste foundry sand with various proportions of various mix in concrete by replacing fine sand using tests on various strength