**1. Introduction**

**Global warming:** The temperature of the earth since 1950 has been increasing above average temperature. This can also be referred to as climate change. Both climate change and Global warming refer to increase in average global temperature. Climate change involves a change in climate measured using statistical properties such as mean surface temperature which can range from months to millions of years. One of the facets of climate change is global warming as it has been described as an average increase in global surface temperature. The causes of Global warming are both from natural and human events. One of the natural factors is Greenhouse effect. This effect is a blanketing one by which greenhouse gases keep the surface of the earth warm [1]. The human influenced greenhouse gases (CO2, CH4, and N2O) are also essential in climate change [2]. The energy that gets to the earth is absorbed by earth's surface and later re-radiated back as heat energy towards the space. Greenhouse gases equally and importantly trap this re-radiated energy within the atmosphere hence increase the temperature of earth's surface [3].

Climate change occurs as a result of high concentration of greenhouse gases (GHG) like carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4), sulfur dioxide (SO2) etc. [4]. The increase in high GHG emissions are associated with economic activity especially as related to industry, energy, transport and methods of land use (Agricultural production and deforestation [5]. Greenhouse gases are still building up in the atmosphere and prompting shifts across the globe in the climate.

Agriculture is a well-known source of global emission of greenhouse gases. Rearing of livestock and application of fertilizers and other related land clearing affects the levels of both GHG in the atmosphere and the possibilities of carbon sequestration and storage. Agricultural pollutants are the contaminants that are released into the environment as a by-product from growing and raising of food crops and livestock. However, these pollutants are biotic and abiotic by-products of farming practices (pesticides, fertilizers and livestock manure) that result in degradation or contamination of the environment and ecosystem hence leading to injury in humans and their economic interests. There has been an increasing concern over the emerging and growing increase in emission of Greenhouse gases such as CH4, CO2 and N2O, etc. as they have detrimental impact on the environment leading to global warming which results in climate change and environmental degradation [6, 7].

#### **1.1 Sources of emerging contaminants**

Different routes of release of emerging contaminants can be summed-up into 3 major categories as follows:

1.Use of Livestock: This includes manure and flatulent gas (methane) being released directly from animals and their compost-releasing Methane gas into the atmosphere, artificial fertilizers, hormones used in livestock and all other veterinary composts.

**151**

*Impact of Emerging Agricultural Contaminants on Global Warming*

**2. Emerging contaminants from agrochemicals**

resultant Green-House effects poses a disturbing concern.

2.Plant Protection Activities: These include mainly nanomaterials designed as "smart" chemicals or "smart" pesticides that have the ability for selective toxicities. Unfortunately, these nanomaterials enter the ecological system virtually undetected. Pesticides which include Rodenticides, Fungicides, bactericides, weed toxins, zootoxins which kill small animals like rodents, phycotoxins which inhibit the growth of algae, different personal and

household use products, all that have the ability to produce other compounds that are consequently released directly or indirectly into the environment

especially through air and wastewater as emerging contaminants.

3.Human Use Activities: These include chemicals such as new chemical compounds and pharmaceuticals synthesized by humans that are released directly and indirectly. These compounds usually pass into wastewater treatments to land resulting in sludge and biosolids, and or from irrigation to waste-water effluent. Pesticides which may be released as nanoparticles are also part of this group with increased absorption ability, increased solubilities, or increased toxicities.

Contaminants refer to biological, chemical, physical or radiological substances

What are the emerging agricultural contaminants? Agricultural contaminants can generally be grouped into some major classifications, but a major source of concern for the environment is the emergence of animal waste and its release of Methane gas (CH4) into the atmosphere. Another growing source of concern is the emergence of pharmaceutical wastes as contaminants which manifests typically in run-off water in the agricultural watersheds. Although there are many definitions of what constitutes "emerging contaminants" it is of paramount importance to explain the word "emerging" attached to the contaminants as chemical compounds which have not been known to be in existence or have not been extensively studied. Again, emerging contaminants can be classified into chemical compounds which have been known previously but whose impacts on health and environment have not been fully comprehended. The definitions of emerging contaminants are numerous and vary from region to region of the world. They may be chemicals that have been shown to be threatening to the environment or public health through different routes without enough data to assess their risk levels. Those with potential health and environmental threat without regulatory standards also fall into emerging contaminants just as chemicals or substances that penetrate the environment through different routes but lack not only risk stratification, but inadequate detection capabilities. Although detecting emerging contaminants can be more challenging, they can penetrate the environment causing adverse biological and ecological effects [8]. The United States Geological Survey describes emerging contaminants as chemicals or microorganisms which are not usually monitored in the environment but with known or suspected potential to cause ecological damage or adverse human effects. New Synthetic chemicals or changes in use and disposal of existing ones can also be referred to as a means of creating emerging contaminants. Emerging contaminants in another way is defined as chemical substances or compounds that are characterized by a perceived challenge to human health or the

found in considerable concentrations that can adversely affect human beings through soil, food contamination and air. For a long time now Contaminants from Agricultural practices have been known to be as a result of human activities both man-made and natural. Their increasing effect on the ecological system including

*DOI: http://dx.doi.org/10.5772/intechopen.94170*

*Impact of Emerging Agricultural Contaminants on Global Warming DOI: http://dx.doi.org/10.5772/intechopen.94170*

*Emerging Contaminants*

atmospheric Methane.

global warming

**1. Introduction**

be achieved through Biochemical methods on enteric fermentation, development of good environmental policies even Methanotrophs also aid in recycling the

**Global warming:** The temperature of the earth since 1950 has been increasing above average temperature. This can also be referred to as climate change. Both climate change and Global warming refer to increase in average global temperature. Climate change involves a change in climate measured using statistical properties such as mean surface temperature which can range from months to millions of years. One of the facets of climate change is global warming as it has been described as an average increase in global surface temperature. The causes of Global warming are both from natural and human events. One of the natural factors is Greenhouse effect. This effect is a blanketing one by which greenhouse gases keep the surface of the earth warm [1]. The human influenced greenhouse gases (CO2, CH4, and N2O) are also essential in climate change [2]. The energy that gets to the earth is absorbed by earth's surface and later re-radiated back as heat energy towards the space. Greenhouse gases equally and importantly trap this re-radiated energy within the

Climate change occurs as a result of high concentration of greenhouse gases (GHG) like carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4), sulfur dioxide (SO2) etc. [4]. The increase in high GHG emissions are associated with economic activity especially as related to industry, energy, transport and methods of land use (Agricultural production and deforestation [5]. Greenhouse gases are still building up in the atmosphere and prompting shifts across the globe in the climate. Agriculture is a well-known source of global emission of greenhouse gases. Rearing of livestock and application of fertilizers and other related land clearing affects the levels of both GHG in the atmosphere and the possibilities of carbon sequestration and storage. Agricultural pollutants are the contaminants that are released into the environment as a by-product from growing and raising of food crops and livestock. However, these pollutants are biotic and abiotic by-products of farming practices (pesticides, fertilizers and livestock manure) that result in degradation or contamination of the environment and ecosystem hence leading to injury in humans and their economic interests. There has been an increasing concern over the emerging and growing increase in emission of Greenhouse gases such as CH4, CO2 and N2O, etc. as they have detrimental impact on the environment leading to global warming which results in climate change and environmental

Different routes of release of emerging contaminants can be summed-up into

1.Use of Livestock: This includes manure and flatulent gas (methane) being released directly from animals and their compost-releasing Methane gas into the atmosphere, artificial fertilizers, hormones used in livestock and all other

**Keywords:** emerging contaminants, pesticides, fertilizers, livestock, manure,

atmosphere hence increase the temperature of earth's surface [3].

**150**

degradation [6, 7].

**1.1 Sources of emerging contaminants**

3 major categories as follows:

veterinary composts.


#### **2. Emerging contaminants from agrochemicals**

Contaminants refer to biological, chemical, physical or radiological substances found in considerable concentrations that can adversely affect human beings through soil, food contamination and air. For a long time now Contaminants from Agricultural practices have been known to be as a result of human activities both man-made and natural. Their increasing effect on the ecological system including resultant Green-House effects poses a disturbing concern.

What are the emerging agricultural contaminants? Agricultural contaminants can generally be grouped into some major classifications, but a major source of concern for the environment is the emergence of animal waste and its release of Methane gas (CH4) into the atmosphere. Another growing source of concern is the emergence of pharmaceutical wastes as contaminants which manifests typically in run-off water in the agricultural watersheds. Although there are many definitions of what constitutes "emerging contaminants" it is of paramount importance to explain the word "emerging" attached to the contaminants as chemical compounds which have not been known to be in existence or have not been extensively studied. Again, emerging contaminants can be classified into chemical compounds which have been known previously but whose impacts on health and environment have not been fully comprehended. The definitions of emerging contaminants are numerous and vary from region to region of the world. They may be chemicals that have been shown to be threatening to the environment or public health through different routes without enough data to assess their risk levels. Those with potential health and environmental threat without regulatory standards also fall into emerging contaminants just as chemicals or substances that penetrate the environment through different routes but lack not only risk stratification, but inadequate detection capabilities. Although detecting emerging contaminants can be more challenging, they can penetrate the environment causing adverse biological and ecological effects [8]. The United States Geological Survey describes emerging contaminants as chemicals or microorganisms which are not usually monitored in the environment but with known or suspected potential to cause ecological damage or adverse human effects. New Synthetic chemicals or changes in use and disposal of existing ones can also be referred to as a means of creating emerging contaminants. Emerging contaminants in another way is defined as chemical substances or compounds that are characterized by a perceived challenge to human health or the

environment lacking published health criteria. They may also be identified from sources that are unknown, new exposure to humans, or a new detection approach or technology [9]. Emerging contaminants (ECs) are not usually new chemicals. They could be substances or chemicals that have stayed long in the environment with their presence and importance being recognized now. There are many proposed and contradictory definitions of "Emerging Contaminants". Boxall [10] defines it as a contaminant from a chemical class that has not been studied extensively where either there is a concern from scientists, Regulators, NGOs or other Stakeholders that the contaminant class may be having an impact on human health or environment or where there is a concern that an existing environmental assessment paradigms are not appropriate for the contaminant class.

Recently, there has been a great concern on the environmental challenges caused by Emerging contaminants. These ECs emanate from by-products of a variety of materials such as paints and coatings, pharmaceuticals, personal care products, agrochemicals, veterinary medicines etc. Some natural products and those transformed through biochemical processes from synthetic chemicals may be formed in the environment as ECs.
