In developing country like Nigeria, a marketable surplus of agriculture is the most important factor which influences the economic development of a country. To meet the demands of agriculture goods adequately and to feed the increasing population, the phenomenon of Green Revolution came into existence. Green Revolution, allowed developing countries like Nigeria to overcome continual food scarcity by producing more food and other agricultural products by using high-yielding varieties of seeds, modifying farm equipment, and substantially increasing use of chemical fertilizers. For an optimum production of agriculture produce and to feed the growing population, application of chemical fertilizers and pesticides has become necessary. Such type of agriculture practices allowed growth and sustainability of food grains but at the same time have the major impact on the environment and human health. This article provides a sketch of effects of chemical fertilizers and pesticides on human health and environment.

 A goal of agriculture is to meet the present food need of the society with the surplus amount of availability for exporting and future purposes. For increasing agricultural production and productivity, use of chemical inputs such as pesticides has increased. Pesticides are chemical substances that are meant to kill pests. In general, a pesticide is a chemical or a biological agent such as a virus, bacterium, antimicrobial, or disinfectant that deters, incapacitates, kills, pests. It is commonly used to eliminate or control a variety of agricultural pests that can damage crops and livestock and reduce farm productivity. Pesticides have proved to be a boon for the farmers as well as people all around the world by increasing agricultural yield. Basically, the input of pesticides in Nigeria agriculture increases after the announcement of Green Revolution which in turn helps our country to fight the major problem of food crises. Although the application of pesticides serves as a boon but also had a long term negative effect of harming the environment and human health.

The current issue of hazard posed by pesticides to human health and the environment has raised concerns. Production of better alternative to reduce pesticide formulations is an answer to this destruction condition. If the pesticides are used in appropriate quantities and used only when required or necessary or opting for organic farming, then pesticide risks can be tackled to some extent.

Water pollution is on the rise due to these pesticides, even at low concentration, these pesticides have serious threat to the environment (Agrawal et al. 2010).

Effects of Chemical Fertilizers and Pesticides on Human Health

Bhandari (2014) studied an overview of agrochemicals and their effects on the environment in Nepal concluded that agrochemicals are considered as a powerful weapon or magic bullets in the developing countries in order to enhance the agriculture productivity. However, it has been observed that agrochemicals are causing serious hazards and certain pesticides may affect the human endocrine and immune systems and may promote the development of cancer.

It has been administered that farmers do not use the safety masks, gloves and other protective gears during the spraying of pesticides which results into the access of pesticides in the blood stream through inhalation and dermal exposure which can adversely affect their eyes, skin and the respiratory system. When fertilizers and pesticides are used in farmlands, they are transmitted directly or indirectly into the corns and vegetable that affects the human health. Moreover, as pesticides are applied over the vegetable which are directly entered into human or livestock bodies. Excessive use of fertilizers may pollute the underground water with nitrate and it is so much hazardous to humans or livestock. Nitrate concentrated water can immobilize some of hemoglobin in blood. Organophosphate pesticides have increased in application, because they are both less persistent and harmful for environment than organochlorin pesticides. But, they are associated with acute health problems, such as abdominal pain, dizziness, headaches, nausea, vomiting, as well as skin and eye problems. There have been many studies intending to establish cancer – pesticides association. Organophosphate pesticides used in the vegetables gradually get deposit into human body and has a link with cancer (Miah et al. 2014).

Wimalawansa and Wimalawansa (2014) assessed the impact of changing agricultural practices on human health in Srilanka and concluded that detrimental agricultural habits, including the excessive and indiscriminate use of toxic agrochemicals, allowing continued environmental contamination and contamination of the human food chain. Contamination of soil and water with toxic agrochemicals (e.g., phosphate fertilizer contaminated with heavy metals, pesticides and herbicides etc.) are a particular concern. These pollutants in water generally are in small quantities, and thus, cannot be seen or tasted. Therefore, their harmful effects do not manifest in humans for several years but led to the escalation of deadly disease like chronic kidney disease.

The study shows that DDT was the most popular and effective pesticide to help people combat unwanted organisms and gain dramatically improvement in agriculture. However, since a number of adverse effects of this insecticide were reported, usage of DDT was banned international wide. Despite the severe restriction, DDT is still illegally used in many areas, especially in developing nations. Negative impacts of DDT on the human health were acknowledged and disseminated widely to warn population and prevent unexpected situations occur. Nevertheless, although DDT was not used in recent time, it still impacts on human health due to long residual efficacy and accumulation through food chain. In term of human health, DDT is the cause of many kinds of cancer, acute and persistent injury to the nervous system, lung damage, injury to the reproductive organs, dysfunction of the immune and endocrine systems, birth defects (Thuy, 2015).

Effects of chemical fertilizers and pesticides on environment

Soil, the basic need of farming may happen to pollute by the accumulation of various heavy metals, through emissions by industries, mining process, disposal of high metal wastes, gasoline, application of fertilizers, sewage sludge, pesticides, wastewater irrigation, coal combustion residues, etc. Historically, a large amount of chemicals is annually applied at the agricultural soils as fertilizers and pesticides. Such applications may result in the increase level of heavy metals, particularly Cd, Pb, and As in the soil (Atafar et al. 2010). Usage of pesticides, insecticides and other various chemicals in agriculture is very easy, quick and inexpensive solution for controlling weeds and insect pests. However, use of chemicals comes with a significant cost. They have contaminated almost every part of our environment and their residues are found in soil, water, land and air.

Kumar et al. (2013) concluded that pesticides are often considered a quick, easy and inexpensive solution for controlling weeds and insect pests in urban landscapes. Pesticides have contaminated almost every component of our environment. Pesticide residues are found in soil and air, and in surface and ground water across the nation, and urban pesticide uses contribute to the problem. Pesticide contamination poses significant risks to the environment and non-target organisms ranging from beneficial soil microorganisms, to insects, plants, fish, and birds. Contrary to common misconceptions, even herbicides can cause harm to the environment.

By reviewing the literature, it can be concluded that the farmers do not follow appropriate safety precautions with regard to pesticide application, large amounts of pesticides are inappropriately used by these farmers, leading to several human health disease, polluting our air, land, water. Since about major proportion of the population relies on agriculture for subsistence, the pesticides are used very widely in agricultural field to increase the production by protecting the yields from potential threat. To safeguard human life and environment from the toxic effects of pesticides, adequate steps need to be taken. Now it is a well-established fact that there is the foremost need to step forward towards our mother earth by nurturing it by going for the organic farming system. An answer to this havoc is the organic farming, an environmentally friendly agricultural approach which ultimately leads to proper human health. Moving back to our ancestor’s course by performing organic agriculture is a step towards sustainability. Organic agriculture is a holistic production and management system which is supportive of the environment, health and sustainability (uyo, 2013). Though the Government of Nigeria has been making concerted efforts to encourage farmers and people regarding organic produce and product, but it has not resulted in bridging the gap between the demand and supply of organic product in the market. A proper training should be given to the farmers regarding organic farming, its scope, potential, profit and environment sustainability. It has been administered that organic food consumption is increasing in Nigeria and this is evident from the fact that many organic food stores are prompt up in Nigeria. So, working upon niche area of organic farming is yet to be explored and flourish.