**1. Introduction**

The growth of the population of the world is increasing at an alarming rate, which draws the attention of researchers, scientists, environmentalists, and policymakers across the globe. According to a scientific report, the global human population is likely to increase up to 9 billion by 2050 [1]. To meet the food requirement of this growing population as well as to cover their modified consumption patterns, there is an ultimate requirement of intensification and diversification of agricultural sectors. The current food production of the globe needs to be increased by 60% by 2050 [2].

Thanks to the green revolution that instigated the use of various agrochemicals that effectively increased agricultural productivity by many folds. Besides traditional agrochemicals (fertilizers and pesticides), new ones such as hormones, antibiotics, vaccines, growth promoters, etc., also brought revolutionary changes in different food production sectors. Undoubtedly, the use of agrochemicals has directly or indirectly benefitted millions of people all over the globe by increasing food production, there are instances that the action has put questions toward the well-being of the environment. Among all the environmental compartments, water resources are especially affected to a greater extent as agricultural works mostly depend on water and use about 70 % of total water resources globally [3]. In crop production sectors, some of the most important crops such as rice and wheat generally consume a huge amount of water and the total amount of water used; most part is for irrigation. Production of 1 kg of wheat requires approximately 1 m3 of water and 1 kg of rice requires 1.2 m3 of water [4]. Rice, which is the staple food for most people living in Asia, consumes about 80% of freshwater resources for irrigation. Apart from crop production, a huge amount of water is also used indirectly in livestock sectors through the production of fodder crops and forage. These amounts of water are directly or indirectly recycled back to surface water as well as groundwater sources carrying the pollutants such as pesticides, fertilizers, salts, sediments, hormones, antibiotics, etc., from crop fields. Now agriculture has become a major source of freshwater pollution in rivers and lakes, the second major source for wetland pollution, and the third major source for estuaries and groundwater pollution [5].
