Health Risk Assessment: Pesticides Exposure and Childhood Cancer Risk

This report provides an environmental health risk assessment focusing on the relationship between pesticide exposure and childhood cancer. It begins by outlining the research question concerning the risk of childhood cancer among children exposed to residential pesticides, followed by background information on the history and controversies surrounding pesticide use. The literature review highlights concerns about pesticide residues in infant foods and the vulnerability of children and fetuses to agricultural chemicals. The report further discusses studies linking prenatal pesticide exposure to childhood brain tumors and parental occupational exposure to retinoblastoma. It emphasizes the importance of risk assessment in protecting human health and details the methods used to establish the relationship between pesticide emissions and childhood cancer incidence, considering factors such as children's vulnerability, residential exposures, bio-monitoring data, food supply, agricultural exposures, and water contamination. The report concludes by underscoring the need for continued research and stricter regulations to minimize pesticide exposure and protect children's health. Desklib offers solved assignments and past papers for students.

Running Head: PESTICIDES AND CANCER 1
Pesticides and Cancer: Is there a link?
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PESTICIDES AND CANCER: IS THERE A LINK?
Research Question: Among children exposed to indoor or outdoor residential pesticides, what
is the risk of developing childhood cancer?
Background Information
Introduction
The last few decades, many environmental concerns have aroused divergent debates and multi-
activism of the public as much as pesticides, the main concern being the health of children. There
are overlying deep controversies surrounding the issue of pesticides and the impact on human
health, regardless of many publications of studies on the subject. This assessment paper will to
elucidate how the pesticide use has contributed immensely to the rates of cancer in children. It
will also draw a true environmental health and risk assessment of the pesticides.
Looking back at the history of pesticide development and use will help us understand the
controversies surrounding the environmental concerns of pesticides. Pesticides gained
prominence use in World War II during warfare. In fact, those they were not referred to as
pesticides but rather chemicals weapons because their sole purpose was use during the war.
Some pesticides used today were developed those days. For instance, the organophosphate
insecticides were developed as nerve gases, and the phenoxy herbicides were developed to
eliminate Japanese rice crops and later applied to defoliate large areas in jungle warfare. The
chemicals were later used by farmers in agricultural production, mosquito eradication, and
backyard gardens.
In the late 1960s and early 1970s, the epidemiologists noted a rise in the incidences of non-
Hodgkin’s lymphoma (NHL). (1) The incidences were more concentrated around agricultural

PESTICIDES AND CANCER: IS THERE A LINK?
areas. (2) The increase in the use of pesticides in agricultural areas paralleled with the NHL
incidences. This prompted multi-agency interests into the study of the trend where they theorized
the existence of a causal relationship between chemicals uses in the farms with NHL disease.
Many scientific theories and works of literatures developed around the world trying to explain
the relationship between pesticide use and environmental health risk factors.
Literature review
Today, the main concerns about the pesticides use are the children and the unborn. A survey
conducted by 20th Australian Total Diet Survey found residues of pesticide chemicals in infant
foods, which it was regarded as insignificant because it was very low.
Considering the body size of children, they face the greatest biocide exposure. According to 20th
Australian Total Diet Survey, “in general, the dietary exposure to pesticides was highest for the
toddler age group. This is due to the high food consumption relative to body weight.” (3)
A the University of Wisconsin-Madison, researchers established that children and developing
fetus are affected by the amounts of agricultural chemicals found in foods regardless of the levels
considered safe by the authorities. The study found that there were diminishing learning ability
and aggression in children and newborn due to the influence of the low dosage mixture on
developing neurological, endocrine and immune systems.
An independent research was conducted on the exposures, where it was established that exposure
of fetus and juveniles to amounts more than 1000 times lower than previously regarded as safe
caused serious developmental problems. (4, 5)
At the Dukes University Medical Center, (6) and the Department of Pharmacology and Cancer
Biology, explained how the far lower than currently permitted quantities of agricultural

PESTICIDES AND CANCER: IS THERE A LINK?
chemicals by most regulatory agencies around the world, affect the developing fetus and the
newborn. They established that due to the lower concentration of protective serum proteins in the
fetus than adults, the fetus and the newborns are more vulnerable to chemical effects. (6) As
results of exposure to those chemicals, the fetus and newborns have developmental neurotoxicity
which damages the developing nervous system. (7)
A study conducted to analyze incidences in US found that cancer incidences were high in1992-
2001 for children below 15 years. It was also noted that a county with agricultural activities has
elevated cancer incidences of malignant bone tumors. These areas were also linked to higher
number of Ewing’s sarcoma and HL incidences. (2)
Research has established a link between pregnant mother exposure to pesticides and the elevated
risk to childhood brain tumors (CBT). A case study was conducted in Australia to investigate the
link between the pregnant mother exposure and development of CBT. The odds ratio (ORs) for
professional pest control treatments at homes in the period before pregnancy, during pregnancy,
and after the child’s birth were 1.54 and 1.04. The odds ratio for treatments exclusively before
pregnancy and during pregnancy were 1.90 and 1.02. The OR was found to be 1.79 if the father
was at home during treatment. The OR of 1.36 was observed as a result of parental occupational
exposure. The prenatal home pesticides exposure elevated the low and high-grade gliomas. The
findings concluded that preconception and during pregnancy exposure to pesticides was
associated with higher rates of children CBT. (8)
Retinoblastoma risk factors remain largely unknown. A researcher studied the relationships that
exist between the parental occupational exposures for 10 years and one year before the
conception and the development of children sporadic bilateral retinoblastoma. From 198

PESTICIDES AND CANCER: IS THERE A LINK?
incidents of bilateral retinoblastoma, parental data on occupation were obtained from 1998 to
2006. The findings were that there exist correlations between parental pesticides exposure
10years before conception and one year to conception. The cases for childhood sporadic bilateral
retinoblastoma were found to be higher in those of prior parental exposure. (9)
The Rationale for the risk assessment of pesticides
The environmental risk assessments of pesticides are well documented in the literature, mainly
the organophosphate poisoning. However, the assessment of pesticide exposure and the chronic
effect thereof is more difficult. A lot of researchers have tried to explain whether chronic
exposure to pesticides has adverse effects. Over time the reviews of pesticides health effects
have prompted lobby groups and activists to action. These groups have complained of the
adverse effects of the considered safe levels of chemicals and the continued use of pesticides
regardless of the impacts to the human health and other environmental impacts.
Conducting the risk assessment as part of protecting the human health is at the heart of this
paper. The market evaluation of the pesticides products is vested on the environmental protection
agencies. These evaluations are based on the specific standards for registration and studies
required by the legislations. Risk assessment is important in identifying potential hazards posed
by the active ingredients, the dosage levels of the pesticides exposure, and data evaluation of
potential risks of agricultural activities.
This risk assessment paper will also establish the relationship between the exposures to
environmental hazards to the health of the people. In this regard, the focus will be at link of
pesticides emission to the environment and the increasing number of cancer incidences among
children.

PESTICIDES AND CANCER: IS THERE A LINK?
Methods
Most studies on non-Hodgkin lymphoma and leukemia have established a relationship with
agricultural chemicals. The studies have shown the dosage-response to the pesticides exposure
and how specific pesticides have resulted in developmental and health issues to children and
unborn. The development of cancers to children has been strongly linked to the pregnant mothers
(1) and children exposure to pesticides (10). The studies have also established a link between
pesticide exposure and solid tumors, (10) and brain cancer. (11) Parent’s pesticides exposure at
work was linked to children kidney cancer. In the industrialized countries 1 child out of 500 has
cancer before attaining the age of 15 years. In European countries, childhood cancer cases have
increased to 1%. (12) The consistency in the association is high in prolonged exposure. There are
specific weaknesses and inherent limitations in epidemiology studies around especially around
ascertaining whether and how much exposure had taken place.
Children’s Vulnerability
Exposure Assessment
Because of children developmental, physiologic, and dietary factors, they are exceptionally
vulnerable to uptake and effects of pesticides. The studies have shown that childhood exposure
comes from ingestion, dermal contacts, and inhalations. The greater intake of food and fluids per
their body size has contributed to higher dose through ingestion compared to adults. Children
hand-to-mouth activities are also higher compared to adults, therefore increasing pesticides
exposure. (13)

PESTICIDES AND CANCER: IS THERE A LINK?
Residential Factors
There are few cases of acute toxicity as a result of pesticide poisoning but sub-acute and chronic
low-level exposures are common. The vulnerability is contributed to the use of insecticides and
rodenticides in households. Also exposure can come from insecticides and fungicides in home
gardens. The use of indoor spray applications leave particles in the air and floors and also form
part of the house specks dusts. (14) When children play around the house, they come into contact
with specks of dusts through inhalation, dermal and oral which increase their chances of
exposure to the chemicals. Continuous exposure happens and cumulatively has adverse effects
on the children. Pesticides can also be brought home from the workplace, for instance, herbicides
applied in home gardens can be traced in-house over time of build-up. (15) These traces are
brought by pets and shoes from the farm fields. (14)
The residential related exposures are also found in the schools, child care centers, etc. This
depends on the proximity of these areas to where pesticides are used. The traces of pesticides
from public areas can be traced in households over time after accumulation. (16)
Bio-monitoring data for exposure assessment
A population-based bio-monitoring program was conducted by the Centers for Disease Control
and Prevention (CDC) associated with the NHANES. The program report on the OP,
organochlorine, and carbamate insecticides; pyrethroid insecticides; herbicides etc. Test on the
pesticides metabolites has revealed traces of pesticides in the system of people aged 6 to 59 years
with OP and organochlorine insecticides being the most prevalent.
Children behaviors and metabolic rates position them at higher risk of absorption of pesticides
compared to adults. From the bio-monitoring data, chlorpyrifos was one of the chemical

PESTICIDES AND CANCER: IS THERE A LINK?
evidence in the samples of young children which was higher than young adults and adults.
Others like DDT, dieldrin, and chlordane show lower concentration in the same population.
However, the accumulations of these fat-soluble persist over the lifetime.
Exposure from the food supply
Food supply represents the main source of exposures to organochlorines and OPs. (17) Food
residues and household pest control products sources of pyrethroids. Food and Drug
Administration ensure adherence to standards of the legal and allowable pesticides residues. To
lower exposure to farm chemicals, people are encouraged to consume organic foods. The study
has established a drop in the urinary excretion of metabolites insecticides in the period of organic
food consumption. (18)
Agriculturally related exposures
Residential near agricultural farms or a family member working in such a farm present chances
of pesticides residuals in the house which increase exposure to the children. A study was
conducted to establish the level of exposure in children near agricultural areas. It was found that
pesticides on carpets dust and pesticides metabolites in urine of children increased with nearness
to farm areas especially during periods of applications, (19) and (20).The presence of farm
workers in those farms increase the level of dust particles in homes thus higher exposure to
children. Also, children living in those farms have higher chances of exposure to pesticides as
the study has proven with pesticides metabolites in their urine. (21)
Exposer form drinking water
Water contaminated with herbicides is another agent of children exposure. The US Geological
Survey’s National Water-Quality Assessment program, conducted a study that took 10 years,

PESTICIDES AND CANCER: IS THERE A LINK?
provided occurrence of pesticides in streams and groundwater. The traces were detected in more
than 50% of shallow wells tapping water from agricultural farms and 33% deeper wells tapping
water from aquifers. Herbicides, especially triazine class were the most frequent traces in
agricultural areas, while diazinon and carbaryl were frequently detected in urban areas. (22)
Risk communication
The public and other stakeholders need to be made aware of the health risks associated with
pesticide use. Despite many publications of the environmental pollution of many agricultural
chemicals and banning their use especially in foods, some of these chemical ingredients are still
in use in most modern pesticides. This has elicited continuous debates on the environmental
impacts and health effects of these pesticides.
Today, communication has been mostly influenced by the emergence of digital media which has
allowed easy information sharing through social media to the global audience. Communicating
environmental health and risk issues also need to adopt online strategy in risk communication so
as to reach more people and diverse population. More than 2 billion online users are the target
for this information. The method also elicit debate on the topic will help shed more light on the
environmental health issues and insights are able to give experiences in the environmental health
risk factors learning process.
Communication of how pesticides have contributed exponentially to the increase of cancer
incidences will be of help to the agricultural farms, workers, and children caretakers. They will
be able to look for alternative pest control methods such as practicing organic farming which has
proven to be more effective in reducing pesticides exposure to children. At homes, parents must

PESTICIDES AND CANCER: IS THERE A LINK?
have a way to protect their children and unborn from pesticides exposures. To reduce exposures,
pregnant mothers have to avoid environments which make her vulnerable to pesticide chemical.
Conclusion
From this environmental risk assessment, we can conclude that pesticide use pose higher risks to
children than adults which results to developmental and malignant diseases. The higher exposure
rate is attributed to their small body size, high rate of metabolism and being active both indoors
and outdoors. These make them vulnerable to chronic pesticide exposures. The studies have also
established that, regardless of the levels of the pesticides residuals to the acceptable levels,
cumulatively, they have developmental effects to children and newborn. Environmental pollution
from the use of pesticides has more effects than benefits to the human and animals. Thus, strict
control measures are necessary to regulate their use or ban. Alternative pesticides and herbicides
controls need to be explored, and in this case, use of organic farming practices should be
encouraged to reduce the environmental risks posed by pesticides.

PESTICIDES AND CANCER: IS THERE A LINK?
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