**1. Introduction**

Chemical pesticides are still considered as an essential tool used in the mass production of agricultural products in developing countries to control a wide range of pests, that is, insects, weeds, plant pathogens among others, and hence maintain high product quantity [1]. The consumption rate of chemical pesticides worldwide reached 2.4 megatons during 2006–2007 [2]. Pesticides have biological activity and toxic action on the targeted pests at the recommended concentration throughout various modes of action mechanisms exerted by the parent compounds and/or their metabolites [3]. If such concentration is exceeded through misuse or incorrect application, these pesticides become toxic to the non-target organisms, including humans [4].

Based on the enormous number of published studies related to the toxic effects of pesticides on non-targeted organisms and humans, some of these pesticides have been banned in developed countries. The most famous banned compounds included organochlorine pesticides (OCPs) in the 1970s [5], some organophosphorus during 2001–2006 [6], certain carbamates insecticides [7], and specific synthetic pyrethroids and neonicotinoids insecticides, among others [8]. Globally, the total number of banned pesticides reached 460 compounds distributed between insecticides, fungicides, and herbicides among other groups of pesticides in 36 and 128 developed and developing countries, respectively [8]. The ban decision is based on various factors, such as a) the high toxicity of such pesticides to the non-targeted organisms (extremely hazardous, i.e., acute oral LD50 for the rat <5 mg/kg and highly hazardous, i.e., acute oral LD50 for the rat 5–50 mg/kg) [9], b) their carcinogenic effects on humans causing various types of cancer [10], and c) hazardous effects on environmental elements among other reasons such as effects on the endocrine system, that is, hormone disruptors [11].

Practically, the toxic effects of pesticides on mammals, including humans, are the sum of the results obtained by the studies carried out and extrapolation processes through decades from two major categories of studies, that is, *in vivo* and *in vitro*. The *in vivo* studies were carried out using laboratory animals that lead to an understanding of the toxicity mechanisms of the tested pesticides.

Also, it was studied both the toxicokinetics, toxicodynamics of chemical pesticides [12], teratogenicity [13], and carcinogenicity [14] using different mammalian models and affected humans in the epidemiological studies. With carcinogenic pesticides, they were classified into various categories, that is, carcinogenic, probably, possibly be carcinogenic to humans, or not classifiable as carcinogenic to humans [15]. Other studies of pesticides toxicity have been carried out depending on the response of different biomarkers [16], that is, hematological toxicity [17], nephrotoxicity [18], hepatotoxicity [19], neurotoxicity [20], oxidative stress, and DNA damage [21], pulmonary toxicity, reproductive and developmental toxicity and carcinogenesis biomarkers [22].

The *in vitro* toxicity studies have emerged through an approach that has been known as alternative methods, which is based on the application of a principle called (3Rs) designed by Russell and Burch [23] using animal organs, tissues, fertilized eggs, embryos, transplanted organs, such as liver, kidneys, brain, pancreas, and/or tissue pieces [24]. Also, the cell culture techniques, that is, primary cell cultures or cell lines were used as another approach of the alternative methods to understand the cytotoxic effects of xenobiotics including pesticides either at a biological level and/or biochemical level and explaining the genotoxic effects of the tested pesticides [25]. Through such alternative methods in association with the *in vivo* investigation, it was studied the mutagenicity, genotoxicity, and the effects of pesticides at the molecular level [26].

Regarding human health, exposure to different banned chemical pesticides may lead to consequent intoxication symptoms as a result of cellular, biochemical, and genetic effects, that is, congenital malformation, neurochemical and behavioral dysfunctions among others [27]. In developing countries, such as India, it was documented various negative effects resulted from human exposure to pesticides, that is, neurological, respiratory, dermal, and reproductive effects in addition to the impact on general health [28]. In other epidemiological studies related to the usage of banned chemical pesticides in developing countries, it was mentioned the percentages of chemical pesticides that caused a significant number of dead people annually as a result of pesticides intoxication [29]. The mentioned developing countries in such a chapter include India, Egypt, and African countries, Romania, Thailand, Taiwan,

#### *Deleterious Effects of Banned Chemical Pesticides on Human Health in Developing Countries DOI: http://dx.doi.org/10.5772/intechopen.104571*

Costa Rica, and Nicaragua among others. In Venezuela, it was recorded various serious problems due to exposure to pesticides either through environmental and/or occupational routes. Such exposure is due to limitations in the regulation acts related to the use of pesticides and lack of health and safety measures [30].

As specific pesticides, it was found that *in utero* exposure to organochlorine insecticides, that is, dichlorodiphenyltrichloroethane (DDT), dieldrin, endosulfan, heptachlor, dicofol, and methoxychlor was associated with neurodevelopmental effects in children [31]. Organophosphorus insecticides, such as parathion, dimethoate, monocrotophos, and chlorpyrifos among others, cause cardiovascular diseases [32]. Moreover, some banned pyrethroids insecticides such as fenvalerate, permethrin, and other compounds including certain metabolites causing DNA damage in human sperm [33] and developmental neurotoxicity [34]. As for banned neonicotinoid pesticides, that is, imidacloprid thiacloprid, they may cause breast cancer by increasing the expression of the aromatase enzyme. Other banned chemical pesticides, such as some triazine herbicides, were associated with breast cancer [35].

As for human exposure to pesticides via oral feeding, it was documented that consumption of contaminated foods by pesticide residues when exceeded the Acceptable Daily Intake (ADI) and/or the Maximum Residue Limits (MRL) values listed by the Codex Alimentarius may lead to various undesirable effects. Based on such type of exposure, high levels of pesticide residues and their metabolites in foodstuff could reach the human blood, including maternal blood, cord blood, placenta, breast milk, and children.

In the case of occupational exposure to pesticides, it was documented that such exposure occurs directly during various processes, such as manufacturing, transporting, storing, retailers, preparation, application by the user, re-entry into treated fields, harvest, and equipment cleaning. The exposure may be due to the misuse during the application of pesticides without protective equipment, which is considered economically expensive in developing countries. In addition, other routes of exposure may occur, such as exposure of children and/or pregnant women, which affects their fetuses.

In recent studies, it was found that all the mentioned negative effects of pesticides exposure are results of bad practices, that is, inadequate, unsafe, and handling applications without wearing the protective instrument. Also, it was reported that the lack of awareness of suitable pesticide use is considered as the main reason behind the occurrence of various diseases in the farmers' works in the Tu Ky district, Vietnam [36]. To overcome such types of problems, the Agricultural Pesticides Committee [APC] in Egypt, has been introduced around 10.000 licensed applicators in the agriculture fields and targets to reach 50.000 during the next years after their training in the suitable pesticides application procedures [37].

Based on the mentioned facts, this chapter has been focused on the most deleterious effects linked to chronic human exposure to various banned chemical pesticides that affect the exposed individuals with various diseases, that is, obesity, Alzheimer's, Parkinson's, asthma, chronic bronchitis, type 2 diabetes, autism, erectile dysfunction, and psychological disorder. Such diseases were selected in this chapter based on the fact that they are affecting the quality of life of the affected individuals either at the health, social, and/or labor level. Based on the lack of scientific and investigation background in most developing countries, the identification of each disease and the different mechanisms followed by the banned pesticides and/or their metabolites to exhibit these diseases either in pregnant women, their fetuses, children, and/or adults who were exposed to the banned pesticides were discussed.
