**2. Exposure pathways**

Pesticides are used in 85% of homes in the US (Whitmore et al. 1992), but they or their resi‐ dues can be found even on surfaces that have never been directly or peripherally treated. POPs introduced into the environment years ago are still around today, transported by hu‐ man activity and through the food chain. Despite being banned in the US (and many other countries) some 30 years ago, traces of these insecticides are still found in the homes and bodies of individuals in the US who were not even alive when these products were used (Weiss et al. 2004; Wolff et al. 2007). Chlorpyrifos (a non persistent OP) has also been found to accumulate on newly‐introduced surfaces, such as pillows, carpet and soft toys, when brought into a treated area up to two weeks after application, even if applied according to manufacturer's instructions (Gurunathan et al. 1998).

**2.1. Dermal exposure**

**2.2. Oral exposure**

**2.3. Inhalational exposure**

**2.4. Exposure on respiratory system**

ing of dry formulations without wearing goggles.

on lip or in mouth also leads to oral exposure.

mulations; use of inadequate or poorly fitted respirators.

the problem (Kirkhorn& Garry 2000; Ross et al. 2001).

It occurs by not washing hands after handling pesticides or their containers. Splashing or spilling of pesticide on skin by wearing pesticide-contaminated clothing and applying pesti‐ cides in the windy weather. Touching treated plants or soil also leads to dermal exposure. Exposures occur by rubbing eyes or forehead with pesticides contaminated gloves or hands, splashing pesticides in eyes, application in windy weather, drift exposure and mixing/load‐

Pesticide-Residue and Its Effects on Occupational Workers

http://dx.doi.org/10.5772/54338

61

Hands not washed before eating, smoking or chewing, pesticide splashed into mouth. Acci‐ dental application of pesticides to food, storing pesticides in drinking containers and drift

Exposed to drift during or after spraying, mixing/loading, dusts, powders or other dry for‐

The crops, activities, and exposure agents that can lead to respiratory disease are extraordi‐ narily diverse and vary significantly by seasons, geography and type of agriculture. The number of substances affecting respiratory health to which a worker is exposed while work‐ ing in an agricultural setting is enormous: pesticides, including insecticides, herbicides, and fumigants; other agricultural chemicals, including fertilizers and plant growth regulators; the crops and related allergens, such as pollens, pests, and microorganisms; and the land it‐ self, including organic and inorganic dusts, to name just a few (Schenker et al 1998; Schenker 2005). Further complicating the issue, the likelihood that an individual worker has been ex‐ posed to but a single identifiable agent is small. Measuring exposure is also challenging, which makes dose-response relationships difficult to assess, and exposure limits have not been set for most relevant agents. Agricultural respiratory disease often goes untreated and unreported, especially by small operations not regulated by the Occupational Safety and Health Administration (OSHA), making it nearly impossible to determine the true extent of

All children are at risk for contact with environmental toxins, but the burden of toxic expo‐ sures is disproportionately allocated to poor ethnic minorities (Schell 1997; Moore 2003; Dil‐ worth-Bart & Moore 2006). ''Economic factors not only constrain choices but also inequitably distribute human made stressors.'' and the psychosocial stress and environmen‐ tal pollutants associated with poverty do not occur independently of one another. Rather, the effects may accumulate through risk focusing, a process by which exposures to toxic or infectious environmental materials are differentially allocated to a specific group partly be‐

cause of previous exposure to those materials (Schell 1997; Yassin et al. 2002).

In agricultural settings, work‐to‐home exposure, or a "take‐home pathway," has been identified as a key source of pesticide residues (primarily to OPs) in children's environ‐ ment ((Fenske et al. 2000; Curl et al. 2002; Thompson et al. 2003; Rao et al. 2006; Corona‐ do et al. 2006). Workers who are exposed on the job on a daily basis, whether as applicators or re‐entry workers, are likely to carry home pesticides on their shoes, clothes, skin, and vehicles. Most workers are not provided with adequate washing or changing facilities to remove residues and put on clean clothes before leaving the work‐ site. If these workers do not take basic precautions (e.g., removing work shoes outside the dwelling, showering before picking up a child); they may transfer residues to the in‐ door environment or directly to other household members.

The primary routes by which pesticides enter the body are ingestion in food, soil, or water; inhalation, through the skin, and through the eyes (Arcury et al. 2000). OCs are absorbed through the lungs, stomach and skin, and excreted only slowly, sometimes over a period of years (e.g., DDT) (Pohl &Tylenda 2000; Cohn et al. 2007). Dietary ingestion is a significant source of exposure, especially for infants and children (Garry 2004). The residue monitoring program conducted by the FDA in 2003 found measurable levels of pesticides in baby foods, including DDT (6% of samples), captan + THPI (a possible carcinogen) (9%), carbaryl (carba‐ mate) (6%), endosulfan (9%), dimethoate (4%), malathion (3%), and chlorpyrifos (all OPs) (2%) (FDA 2005; Sallam et al. 2006).

Post-natally, infants can be exposed to pesticides via breast feeding. The POPs, despite hav‐ ing mostly been banned, are still found in breast milk because they are stored in body fat (Weiss et al. 2004; Jurewicz et al. 2006). Postpartum weight loss increases the likelihood of the release of OCs into the breast milk (Jurewicz et al. 2006). There is some evidence that the maternal body burden is actually transferred to her children via breast feeding, as the pesti‐ cide concentrations decrease with the more times a mother has breastfed (Nickerson 2006). Fortunately, the benefits of breast feeding still far outweigh the possibility of harm from pes‐ ticide transfer in breast milk, and should be encouraged for all mothers regardless of expo‐ sure history (Nickerson 2006; Eskenazi et al. 2006). Pesticides exposure occurs in different ways: dermal, oral, respiratory and conjunctival routes.

#### **2.1. Dermal exposure**

**2. Exposure pathways**

manufacturer's instructions (Gurunathan et al. 1998).

60 Insecticides - Development of Safer and More Effective Technologies

door environment or directly to other household members.

ways: dermal, oral, respiratory and conjunctival routes.

(2%) (FDA 2005; Sallam et al. 2006).

Pesticides are used in 85% of homes in the US (Whitmore et al. 1992), but they or their resi‐ dues can be found even on surfaces that have never been directly or peripherally treated. POPs introduced into the environment years ago are still around today, transported by hu‐ man activity and through the food chain. Despite being banned in the US (and many other countries) some 30 years ago, traces of these insecticides are still found in the homes and bodies of individuals in the US who were not even alive when these products were used (Weiss et al. 2004; Wolff et al. 2007). Chlorpyrifos (a non persistent OP) has also been found to accumulate on newly‐introduced surfaces, such as pillows, carpet and soft toys, when brought into a treated area up to two weeks after application, even if applied according to

In agricultural settings, work‐to‐home exposure, or a "take‐home pathway," has been identified as a key source of pesticide residues (primarily to OPs) in children's environ‐ ment ((Fenske et al. 2000; Curl et al. 2002; Thompson et al. 2003; Rao et al. 2006; Corona‐ do et al. 2006). Workers who are exposed on the job on a daily basis, whether as applicators or re‐entry workers, are likely to carry home pesticides on their shoes, clothes, skin, and vehicles. Most workers are not provided with adequate washing or changing facilities to remove residues and put on clean clothes before leaving the work‐ site. If these workers do not take basic precautions (e.g., removing work shoes outside the dwelling, showering before picking up a child); they may transfer residues to the in‐

The primary routes by which pesticides enter the body are ingestion in food, soil, or water; inhalation, through the skin, and through the eyes (Arcury et al. 2000). OCs are absorbed through the lungs, stomach and skin, and excreted only slowly, sometimes over a period of years (e.g., DDT) (Pohl &Tylenda 2000; Cohn et al. 2007). Dietary ingestion is a significant source of exposure, especially for infants and children (Garry 2004). The residue monitoring program conducted by the FDA in 2003 found measurable levels of pesticides in baby foods, including DDT (6% of samples), captan + THPI (a possible carcinogen) (9%), carbaryl (carba‐ mate) (6%), endosulfan (9%), dimethoate (4%), malathion (3%), and chlorpyrifos (all OPs)

Post-natally, infants can be exposed to pesticides via breast feeding. The POPs, despite hav‐ ing mostly been banned, are still found in breast milk because they are stored in body fat (Weiss et al. 2004; Jurewicz et al. 2006). Postpartum weight loss increases the likelihood of the release of OCs into the breast milk (Jurewicz et al. 2006). There is some evidence that the maternal body burden is actually transferred to her children via breast feeding, as the pesti‐ cide concentrations decrease with the more times a mother has breastfed (Nickerson 2006). Fortunately, the benefits of breast feeding still far outweigh the possibility of harm from pes‐ ticide transfer in breast milk, and should be encouraged for all mothers regardless of expo‐ sure history (Nickerson 2006; Eskenazi et al. 2006). Pesticides exposure occurs in different It occurs by not washing hands after handling pesticides or their containers. Splashing or spilling of pesticide on skin by wearing pesticide-contaminated clothing and applying pesti‐ cides in the windy weather. Touching treated plants or soil also leads to dermal exposure. Exposures occur by rubbing eyes or forehead with pesticides contaminated gloves or hands, splashing pesticides in eyes, application in windy weather, drift exposure and mixing/load‐ ing of dry formulations without wearing goggles.

#### **2.2. Oral exposure**

Hands not washed before eating, smoking or chewing, pesticide splashed into mouth. Acci‐ dental application of pesticides to food, storing pesticides in drinking containers and drift on lip or in mouth also leads to oral exposure.

#### **2.3. Inhalational exposure**

Exposed to drift during or after spraying, mixing/loading, dusts, powders or other dry for‐ mulations; use of inadequate or poorly fitted respirators.

#### **2.4. Exposure on respiratory system**

The crops, activities, and exposure agents that can lead to respiratory disease are extraordi‐ narily diverse and vary significantly by seasons, geography and type of agriculture. The number of substances affecting respiratory health to which a worker is exposed while work‐ ing in an agricultural setting is enormous: pesticides, including insecticides, herbicides, and fumigants; other agricultural chemicals, including fertilizers and plant growth regulators; the crops and related allergens, such as pollens, pests, and microorganisms; and the land it‐ self, including organic and inorganic dusts, to name just a few (Schenker et al 1998; Schenker 2005). Further complicating the issue, the likelihood that an individual worker has been ex‐ posed to but a single identifiable agent is small. Measuring exposure is also challenging, which makes dose-response relationships difficult to assess, and exposure limits have not been set for most relevant agents. Agricultural respiratory disease often goes untreated and unreported, especially by small operations not regulated by the Occupational Safety and Health Administration (OSHA), making it nearly impossible to determine the true extent of the problem (Kirkhorn& Garry 2000; Ross et al. 2001).

All children are at risk for contact with environmental toxins, but the burden of toxic expo‐ sures is disproportionately allocated to poor ethnic minorities (Schell 1997; Moore 2003; Dil‐ worth-Bart & Moore 2006). ''Economic factors not only constrain choices but also inequitably distribute human made stressors.'' and the psychosocial stress and environmen‐ tal pollutants associated with poverty do not occur independently of one another. Rather, the effects may accumulate through risk focusing, a process by which exposures to toxic or infectious environmental materials are differentially allocated to a specific group partly be‐ cause of previous exposure to those materials (Schell 1997; Yassin et al. 2002).
