Autism Technical Report
HEAVY METAL TOXICITY ANALYSIS
Heavy Metals as Environmental Factors on Autism
for
Professor Stephanie Powers
Technical Report Writing Instructor
Florida State College of Jacksonville
Jacksonville, Florida
by
Jessica L. Cobb
Biomedical Science Student
October 14, 2013
HEAVY METAL TOXICITY ANALYSIS
October 14, 2013
Stephanie Powers
Professor of English
Florida State College of Jacksonville
601 W. State Street
Jacksonville, FL 32202
Dear Professor Powers:
I want to thank you for the opportunity to research a topic in my field of scientific interest. My report, Heavy Metals as Environmental Factors on Autism, follows this letter. During the few short weeks of researching environmental causes of autism, I found a …show more content…
great deal of information that, hopefully, will aid parents and clinicians in understanding the importance of finding effective methods of decreasing the amount of heavy metal toxicity.
As I started my research at the end of September, a United States Government shutdown was looming but I did not expect to have any trouble in gathering sources. On October 1, 2013, the shutdown occurred due to lack of funding. Unfortunately, my research was to include communication with the Center for Disease Control and Prevention (CDC), Environmental
Protection Agency (EPA) and United States Department of Agriculture (USDA), all government run organizations that would not be able to communicate with me due to their employees being laid off. Alternatively, I decided to use the information available on their websites as secondary sources of information.
Although autism is a controversial subject, I took great pleasure in being able to research the differences in opinion in order to come up with a recommendation of my own about heavy metal toxicity and the feasibility of the conducting a clean-up.
Thanks again for the assignment and approving my research. If you have any questions regarding any aspect of the report, please don 't hesitate to ask, as I will be happy to oblige.
Sincerely,
Jessica Cobb
HEAVY METAL TOXICITY ANALYSIS
Table of Contents
Letter of Transmittal..............................................................................................................ii
Abstract.................................................................................................................................iv
Introduction............................................................................................................................1
Data Section...........................................................................................................................3
Causes of Autism........................................................................................................3
Diagnosing Autism.....................................................................................................3
Treatment of Autism...................................................................................................4
Evidence Supporting Heavy Metal Toxicity..............................................................5
Managing Soil Toxicity..............................................................................................5
Types of Environmental Clean-ups............................................................................6
Phytoextraction...............................................................................................6
Rhizofiltration................................................................................................6
Phytostabilization...........................................................................................6
Conclusion.............................................................................................................................8
Recommendations......................................................................................................8
References..............................................................................................................................9
Appendix A...........................................................................................................................10
Figures and Tables
Figure 1 Identified Prevalence of Autism Spectrum Disorders ................................1
Table 1 USDA Estimated Costs of Remediation.......................................................6
Table 2 Comparative Costs for Different Types of Heavy Metal Soil Remediation.7
HEAVY METAL TOXICITY ANALYSIS iv ABSTRACT
Autism is a neurological developmental disorder characterized by difficulties with social interactions, communication, and repetitive behaviors.
Autism has no one cause and seems to be triggered by both genetic and environmental factors. The prevalence of autism has increased dramatically in the last 40 years, occurring 1 in every 88 American children.6 Many scientific research projects have closely examined heavy metal toxicity in children with autism to determine a link between the two. Although no definitive correlation has been made, research is still being conducted to find an absolute answer.
There is no way to avoid exposure to toxic chemicals and metals. Heavy metals are enriched in the environment by human activities of different kinds.13 Pollution levels are becoming destructive to humans and we are paying the price with our health. We are seeing more diagnoses of cancers and neurological disorders as a result of polluting our air, soil, water and food supply.
The Environmental Protection Agency has implemented several different methods of extracting toxic levels of heavy metals. Phytoremediation appears to be the most environmentally …show more content…
sound options. It does take longer to complete a clean-up, but as far as the EPA is concerned, it is a positive outcome.
HEAVY METAL TOXICITY ANALYSIS
1
Introduction
Quickly becoming a trend in pediatrics, autism has become more common than ever before.
Autism is a developmental disorder usually diagnosed by the age of three and is characterized by difficulties in developing communication and social skills. Likely causes have been linked to abnormal biology and chemistry in the brain. Exact causes are unknown, but many theories have been established in the scientific community over the last few decades. Many individuals believed the incidence of autism to be associated with the rate vaccines are administered to children. This theory has been debunked thanks to recent research. Others theorize the culprit to be genetic or environmental factors or a combination therein.
The incidence of autism has become so prevalent since the 1980 's where only 1 in 10,000 children were clinically diagnosed. In 2012, the Center for Disease Control and Prevention
(CDC) reported 1 in 88 children have Autism Spectrum Disorder or ASD.2 See figure 1, demonstrating the prevalence of ASD from 2000-2008.
So, are we seeing an increase in cases of autism because the diagnostic criteria are always changing or is it because the aforementioned genetic and environmental factors? The scientific minds in today 's society are extensively researching the many causes of autism and are trying to give the public some insight as to how we can develop treatments for this disorder.
One of the biggest problems with autism today seems to be the fact that a definitive answer is not available relating to its cause. Scientists, parents, and healthcare professionals would like to know what is causing this social and communicative disorder. Fortunately, with the ever-
HEAVY METAL TOXICITY ANALYSIS
2
evolving field of science, it is apparent answers will be available in this lifetime. Issues that have made headlines in the past have pointed to heavy metal toxicity as an environmental trigger that affects the genetic make-up and composition of our DNA. According to Richard Lathe of Pieta
Research in Edinburgh, UK, of the many unknown genetic and environmental causes, heavy metals are responsible for childhood autistic disorder in a majority of cases.¹ Aside from genetic factors, environmental factors like heavy metals are becoming more prominent in case studies in children with autism. Issues could be because individuals are residing in areas with toxic levels of heavy metals and it is affecting the genetic make-up and being passed on to future generations.
Studies across the globe have made connections with heavy metals to autism. I have chosen to examine this topic so I may provide a better perspective for parents, healthcare professionals and other interested persons who want to understand why autism is becoming so prevalent today and how we can improve autism incidence with the action of environmental clean-ups.
HEAVY METAL TOXICITY ANALYSIS
3
Data Section
Causes of Autism
Scientist are not completely sure what causes autism, despite numerous research efforts.
However, autism has been linked to both genetic and environmental cues. The combination of genetic and environmental factors influence early brain development.5 Preliminarily, researchers have identified a number of genes associated with the disorder. Studies of people with ASD have found irregularities in several regions of the brain. Other studies suggest that people with ASD have abnormal levels of neurotransmitters in the brain.3 Researchers are also exploring whether such factors as viral infections, complications during pregnancy and air pollutants play a role in triggering autism.4 A common misconception regarding the cause of autism was related to vaccines, specifically the measles, mumps and rubella or MMR. Several sources have the same conclusion: there is no link between vaccines and autism. The Autism Speaks organization actually encourages children to be vaccinated to protect against disease. Their recommendation for concerned parents is to contact their primary healthcare provider and discuss any issues they may have regarding the safety and efficacy of the vaccines.5
Regarding the environmental factors responsible for autism, it is important to know the word
“environmental” encompasses many risk factors. Focus, here, is placed on heavy metal toxicity.
The introduction of pollutants can come from a pregnant woman being exposed to chemicals by living in an environment where one may be unaware of such exposure before and during pregnancy and after the child 's first year of life when brain development is essential. Toxins like heavy metals are more prevalent in our environment than in the past. 7 Many scientists have their theories on specific heavy metals that may cause autism including mercury, lead, arsenic, copper, zinc, cadmium, chromium, cobalt, nickel, aluminum, tin, uranium, and manganese.
Diagnosing Autism
Autism is not a disorder you can simply diagnose with a test like you can strep throat or the flu.
Because autism is a neurological issue, evaluations by physicians who are skilled and welleducated about developmental disorders must be conducted. Most autistic cases are diagnosed by the age of three.
The general consensus among professionals seems to be observation as the key to diagnose autism correctly. Observing the child 's milestones and behavioral skills are essential.
Mayo Clinic offers that autism specialists will observe the child and ask the parent about the child 's social skills, language skills, and about the behavior development and how its changed over time. They will also give the child developmental tests covering speech, language, developmental level, and social and behavioral issues. The specialist will also present structural social and communication interactions for the child and through observation will score the performance.4 The CDC lists on their website some popular screening tools used to help professionals diagnose autism: Ages and Stages Questionnaires (ASQ), Communication and Symbolic Behavior Scales
(CSBS), Parents ' Evaluation of Developmental Status (PEDS), Modified Checklist for Autism in
Toddlers (MCHAT), and Screening Tool for Autism in Toddlers and Young Children (STAT).6
HEAVY METAL TOXICITY ANALYSIS
4
In a candid interview with Dr. Barbara O 'Reilly, a highly regarded Pediatrician specializing in behavioral disorders like autism and ADHD, she provided me with her opinions on autism
and the effects heavy metals may have on diagnosing the disorder. She and her staff use Ages and
Stages Questionnaires, also known as an ASQ to determine if a child 's developmental milestones are being met according to standards set by the National Autism Center. She also uses a modified autism checklist to aid in diagnosing autism.12
Treatment of Autism
There is no cure for autism. However, there are trained professionals that offer behavioral therapies to improve communication and social skills which autistic children may lack. In many cases, such skills are either underdeveloped or are non-existent. There are several different approaches regarding treatment of autism including non-medical and biomedical interventions.
Non-medical intervention includes behavioral intervention with Applied Behavioral Analysis and other therapies like Floortime, Pivotal Response Therapy, and Verbal Behavior Therapy. 6
Biomedical interventions include prescribing medications. Biomedical treatments include alternative medications, chelation therapy and nutritional interventions.
Medications are most effective when used in conjunction with behavioral therapies according to
Dr. O 'Reilly. Medication only treats three core symptoms of autism-communication difficulties, social challenges and repetitive behavior. Few drugs on the market today effectively relieve these symptoms. Commonly prescribed medications are given for Attention Deficit Hyperactivity
Disorder or ADHD, sleep disturbances and depression.6 Dr. O 'Reilly said medications like
Prozac, Paxil, Namenda and Aricept can be used in concert with behavioral therapies. She further explained the use of Namenda is to help with socialization and Aricept, which is still being clinically studied, helps with word acquisition and short term memory retrieval. Prozac and Paxil help to ease anxiety. She said she prescribes the medication for one month and if well-tolerated and symptoms are alleviated, she will continue alternative medication therapy. If no change is seen, then she discontinues the medication and proceeds with behavioral therapy.12 Although the effects seen after giving these medications are promising, more research is definitely required.
Therapies that Dr. O 'Reilly refers her patients to include physical, occupational, speech and language, developmental, and play therapies. Each of the therapies in combination with each other help develop sensory and fine motor skills. Dr. O 'Reilly 's most promising advise on the matter of treating autism was to continue research and find the causes to prevent it. “Finding the trigger is key. Then we can work backwards to treat the symptoms.”12 She was adamant that physical, occupational and speech therapies as well as developmental and play or group therapies are key in treating autism.
Chelation therapy, according to Mayo Clinic, is said to remove mercury and other heavy metals from the body. Chelation therapy for autism is not supported by research evidence and can be very dangerous. In some cases, children treated with chelation therapy have died.4 Dr. O 'Reilly speculated that most people do not participate in this therapy because its very alternative and dangerous. HEAVY METAL TOXICITY ANALYSIS
5
Special diets are another option in treating symptoms of autism. However, Dr. O 'Reilly 's opinion is that majority of the time, they don 't work. She said usually, specialists tend to promote dieting changes when treating autism. Nutritionists and dieticians recommend gluten-free/casein-free diets, addressing food sensitivities, use of supplements, gut treatments, sulfation and immune system regulation.7 Dr. James Adams of Arizona State University has a great article titled
“Summary of Biomedical Treatments for Autism” with further detail on biomedical treatments with regard to diet, chelation, and immune system regulation. See Appendix A for link to full article. Evidence Supporting Heavy Metal Toxicity
A study by William Walsh, PhD. and Anjum Usman, MD found alterations in the functioning of metallothionein (MT) protein in children with autism. This impairment impacts brain development and causes extreme sensitivity to toxic metals and other environmental substances.
During their study, abnormal levels of copper and zinc were found in blood samples. The MT proteins regulate blood levels of these trace minerals, detoxify mercury and other heavy metals, and assist in development of the nervous system.8
Another study in 2009 at the University of Texas Health Science Center was done to determine if proximity to sources of mercury pollution in 1998 were related to autism prevalence in 2002.
They found for every 1000 lbs of industrial release, there was a corresponding 2.6% increase in autism rates and a 3.7% increase associated with power plant emissions. For every 10 miles from industrial or power plan sources, there is a decrease in autism rates.8
In 2006, the same group of investigators revealed an association between environmentally released mercury and autism rates in Texas. For each 1,000 lb of environmentally released mercury, there was a 43% increase in the rate of special education services and a 61% increase in the rate of autism.9
These studies were of particular interest to me because they provided me with a means explore where such toxic levels of heavy metals exist. Pollution does occur in the air, soil, water and food supply. Majority of the studies I read pointed in the direction of mercury poisoning in the soils. Managing Soil Toxicity
According to to a study by the United States Department of Agriculture or USDA, heavy metal soil contamination is toxic to human and other animals. The most severe damage noted by the
USDA was from lead causing mental lapse, cadmium affecting the kidneys, liver and gastrointestinal tract and arsenic affecting the kidneys, central nervous system and poisoning the skin. The USDA also stated the most common problem causing cationic metals (metallic elements whose forms in soil are positively charged cations) are mercury, cadmium, lead, nickel, copper, zinc, chromium and manganese. The most common anionic compounds (elements whose forms in soil are combined with oxygen and are negatively charged) are arsenic, molybdenum, selenium and boron. Preventing heavy metal pollution is critical because cleaning contaminated soils is extremely expensive and difficult.10Although, a combination of heavy metals are
HEAVY METAL TOXICITY ANALYSIS
6
presumably the culprit, it would benefit the public if a national effort to clean up the toxins were implemented. Types of Environmental Clean-ups
According to the USDA, there are ways to prevent uptake of pollutants. Remediation of contaminated soil, management of contaminated soil, and treating metal contaminated soils by phytoextraction, rhizofiltration and phytostabilization are common practices of removing toxic levels of heavy metals in soil. Treatments can be done on- or off-site. Remediation treatments available include high temperature treatments, solidifying agents and washing.
Methods of managing contaminated soils will leave the pollutants in the soil and immobilize them to reduce negative effects from toxicity. Those methods include increasing the soil pH to
6.5 or higher, draining wet soils, applying phosphate, and carefully selecting plants for use on metal-contaminated soils.10
Phytoextraction. Phytoextraction is when plants are grown in the contaminated soil and metals are translocated from the roots into above-ground portions of the plant. After plants have grown for some time, they are harvested and incinerated or composted to recycle the metals. Several crop growth cycles may be needed to decrease contaminant levels to allowable limits. This mechanism of removal is easiest with nickel, zinc and copper because the metals are preferred by hyperaccumulator plants used in the extraction. For lead uptake, a chelator like EDTA
(ethylenediaminetraacetic acid) must be added to make lead available to the plant.10
Rhizofiltration. Rhizofiltration is the adsorption onto plant roots or absorption into plant roots of contaminants that are in solution surrounding the root zone or rhizosphere. This mechanism is used to decontaminate groundwater. This method proved effective in Chernobyl, Ukraine as cited by USDA in a report by the EPA in 1998.10
Phytostabilization. Phytostabilization is the use of perennial, non-harvested plants to stabilize or immobilize contaminants in the soil and groundwater. Metals are absorbed and accumulated by roots, adsorbed onto roots, or precipitated within the rhizosphere. Metal tolerant plants can be used to restore vegetation where natural vegetation is lacking. It also reduces the mobility of the contaminant and prevents further movement of the contaminant into groundwater or the air and reduces the bioavailability for entry into the food chain.10 Table 1 shows the cost of these cleanup methods.
Table 1. USDA Estimated Costs of Remediation. (2000)
Type of Remediation
Cost per cubic meter
Traditional in situ
$10-100
Traditional ex situ
$30-$300
Phytoremediation
$0.05
HEAVY METAL TOXICITY ANALYSIS
7
Kansas State University 's Michael Lambert, PhD, Blase Leven and Ryan Green have examined methods of solving the toxicity issue. Noted in an article in Environmental Science and
Technology Briefs for Citizens, heavy metals most frequently encountered in their research were arsenic, cadmium, chromium, copper, lead, nickel, and zinc. Cleanup technologies used in their report mentioned excavation, stabilization on-site, and phytoremediation. Excavation and physical removal of the soil is perhaps the oldest remediation method. Advantages include complete removal of contaminants, but on the negative side, the contaminants are just moved somewhere else, possibly contaminating other areas as air pollutants during transport.
Stabilization and phytoremediation have the same definition as mentioned in the previous study. Costs at the time of KSU 's research are listed in Table 1 for different types of heavy metal soil remediation.11
Table 2. Comparative Costs for Different Types of Heavy Metal Soil Remediation. (2004)
Type of Remediation
Cost/cubic meter
Time Required
Excavation and removal
$100-$400
6-9 months
In situ fixation (including soil amendments)
$90-$200
6-9 months
Phytoextraction
$15-$40
18-60 months
Evidence clearly shows that costs do differ from the USDA estimations from those published in
Kansas State 's report, but both are in agreement that phytoremediation is the best option for removal of heavy metal toxins. Although phytoremediation is slower than traditional clean-up methods, it is extremely cost-effective and better for the environment.
I mentioned to Dr. O 'Reilly about the solution I proposed to help decrease the incidence of autism and she agreed it would be a good plan, albeit a costly option.12 She held fast to her opinion of heavy metals not being the cause of autism, though. She did digress and recall that the the Roman term for lead was plumbum in Latin, which is where the word plumber originated from. The fall of the Holy Roman Empire could have very well come from the Romans being poisoned by lead. Connections outside of her theory may not be justified, but was an interesting point regarding heavy metal toxicity.
HEAVY METAL TOXICITY ANALYSIS
8
Conclusion
It was my goal with this research opportunity to explore the environmental risk factors of heavy metal toxicity and propose methods of removing the heavy metal toxins seemingly responsible for autism.
There seems to be an overwhelming number of scientists that agree on the negative effects heavy metals have on children and the role it plays in diagnosing autism. My research initially focused on collecting general information regarding different heavy metals and the role they play in behavioral issues with children. Subsequent research had me looking for a way to rid the environment of toxic levels of heavy metals and determining the feasibility of clean-ups to improve toxicity levels in residential areas that have high rates of ASD.
My humble conclusion is that heavy metals do play a role in autism, but if they are the actual cause of it, I do not know. Genetic predisposition plays such a pivotal role in diagnosing many diseases and other ailments that plague our society today I feel the combination of the two is really the cause. It seems hasty to take the opinion of one study and not explore other considerations with which to compare and make a bona fide conclusion. Furthermore, I conclude that environmental clean-ups are important and necessary in order to lessen the burden heavy metal toxicity has on our communities. The most environmentally sound option for removal of such toxins lies in phytoremediation. The price is right and there seems to be a positive response from environmentalists.
Recommendations
In order to find answers to the unknown, obviously, research is warranted. So, I propose further research to be conducted in the way of heavy metal toxicity to see which metals individually or in combination are polluting areas with a high incidence of autism. With regard to having environmental clean-ups, consider the type of pollution affecting the geographic location and determine which clean-up mechanisms is best suited for the job. Its apparent with our government shutdown and lack of funding, the EPA, CDC and USDA will be unable to continue research using government grants. To continue their research efforts, the agencies may need to find funding as privatized organizations.
On the residential side of the spectrum, I would recommend decreasing the potential for excess exposure to toxins. This can be done by carefully considering the chemicals we come in contact with on a daily basis. We must make a conscious effort to be more aware of our surroundings.
For more information on tips to reduce exposure to toxic chemicals, please visit the Agency for
Toxic substances and Disease Registry 's website http://www.atsdr.cdc.gov and review the article titled “How to Reduce Your Exposure to Chemicals at Home, Work, and Play.”
HEAVY METAL TOXICITY ANALYSIS
9
References
1. Academic OneFile. (2006). “Heavy metals may be implicated in autism.” Brief article.
New Scientist. Vol 190(2553), p. 21. Retrieved 21 Sept 2013. http://resolver.linccweb.org:9003/FLCC0800?ctx_ver=Z39.882004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2013-1012T20%3A08%3A47IST&url_ver=Z39.882004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:pri mo3-Articlegale_ofa&rft_val_fmt=info:ofi/fmt:kev:mtx:&rft.genre=article&rft.atitle=Heavy
%20metals%20may%20be%20implicated%20in%20autism.(Brief
%20article)&rft.jtitle=New
%20Scientist&rft.btitle=&rft.aulast=&rft.auinit=&rft.auinit1=&rft.auinitm=&rft.ausuffix
=&rft.au=&rft.aucorp=&rft.date=20060527&rft.volume=190&rft.issue=2553&rft.part=& rft.quarter=&rft.ssn=&rft.spage=21&rft.epage=&rft.pages=&rft.artnum=&rft.issn=02624079&rft.eissn=&rft.isbn=&rft.sici=&rft.coden=&rft_id=info:doi/&rft.object_id=&svc_v al_fmt=info:ofi/fmt:kev:mtx:sch_svc&svc.fulltext=yes&rft_dat=%3Cgale_ofa
%3E146632284%3C/gale_ofa%3E&rft.eisbn=&rft_id=info:oai/
2. Centers for Disease Control and Prevention. (2012). Morbitity and Mortality Weekly
Report, 30 March 2012. "Prevalence of Autism Spectrum Disorders — Autism and
Developmental Disabilities Monitoring Network, 14 Sites, United States, 2008."
Retrieved 21 Sept 2013.
3. NIH National Institute of Neurological Disorders and Stroke. (2013). “Autism Fact
Sheet.” Retrieved 24 Sept 2013. http://www.ninds.nih.gov/disorders/autism/detail_autism.htm#243573082 4. Mayo Clinic Health Information. (2013). “Autism.” Retrieved 24 Sept 2013. http://www.mayoclinic.com/health/autism/DS00348 5. Autism Speaks. (2013). “Vaccines and Autism.” Retrieved 24 Sept 2013. http://www.autismspeaks.org/science/policy-statements/information-about-vaccines-andautism 6. Autism Speaks. (2013). “What is Autism?” Retrieved 24 Sept 2013 from http://www.autismspeaks.org/what-autism 7. Autism Society. (2013). “Living with Autism: Treatment Options.” Retrieved 24 Sept
2013. http://www.autism-society.org/living-with-autism/treatment-options/
8. Treat Autism & ADHD. (n.d.). “Heavy Metals and Autism, PDD and ADHD.” Retrieved
26 Sept 2013. http://treatautism.ca/detoxification/heavy-metals/
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10
9. Palmer, RF, et al. (2006). Environmental mercury release, special education rates, and autism disorder: an ecological study of Texas [Abstract]. Health Place, 12(2): 203-9.
Abstract Retrieved 26 Sept 2013. http://www.ncbi.nlm.nih.gov/pubmed/16338635
10. Heavy Metal Soil Contamination. (2000). United States
Department of Agriculture: Natural Resources Conservation Service. Soil Quality
Institute. Urban Technical Note No. 3. Retrieved 29 Sept 2013. http://soils.usda.gov/sqi/management/files/sq_utn_3.pdf 11. Lambert, M. Leven, B.A., Green, R.M. (2004). Environmental Science and Technology
Briefs for Citzens. “New Methods of Cleaning up Heavy metal in Soils and Water.”
Retrieved 29 Sept 2013. http://www.engg.ksu.edu/chsr/outreach/resources/docs/metals.pdf 12. O 'Reilly, Barbara. Personal interview. October 11, 2013.
13. Rahimi, M., Farhadi, R., Mehdizadeh, R. (2013). “Phytoremediation: Using Plants to
Clean Up Contaminated Soils with Heavy Metals.” Retrieved 5 Oct 2013. http://ecisi.com/wp-content/uploads/2013/02/148-152.doc.pdf Appendix A
http://autism.asu.edu/Docs/2013/Summary_of_Treatments_for_Autism-2013.pdf
Heavy Metals as Environmental Factors on Autism
for
Professor Stephanie Powers
Technical Report Writing Instructor
Florida State College of Jacksonville
Jacksonville, Florida
by
Jessica L. Cobb
Biomedical Science Student
October 14, 2013
HEAVY METAL TOXICITY ANALYSIS
October 14, 2013
Stephanie Powers
Professor of English
Florida State College of Jacksonville
601 W. State Street
Jacksonville, FL 32202
Dear Professor Powers:
I want to thank you for the opportunity to research a topic in my field of scientific interest. My report, Heavy Metals as Environmental Factors on Autism, follows this letter. During the few short weeks of researching environmental causes of autism, I found a …show more content…
great deal of information that, hopefully, will aid parents and clinicians in understanding the importance of finding effective methods of decreasing the amount of heavy metal toxicity.
As I started my research at the end of September, a United States Government shutdown was looming but I did not expect to have any trouble in gathering sources. On October 1, 2013, the shutdown occurred due to lack of funding. Unfortunately, my research was to include communication with the Center for Disease Control and Prevention (CDC), Environmental
Protection Agency (EPA) and United States Department of Agriculture (USDA), all government run organizations that would not be able to communicate with me due to their employees being laid off. Alternatively, I decided to use the information available on their websites as secondary sources of information.
Although autism is a controversial subject, I took great pleasure in being able to research the differences in opinion in order to come up with a recommendation of my own about heavy metal toxicity and the feasibility of the conducting a clean-up.
Thanks again for the assignment and approving my research. If you have any questions regarding any aspect of the report, please don 't hesitate to ask, as I will be happy to oblige.
Sincerely,
Jessica Cobb
HEAVY METAL TOXICITY ANALYSIS
Table of Contents
Letter of Transmittal..............................................................................................................ii
Abstract.................................................................................................................................iv
Introduction............................................................................................................................1
Data Section...........................................................................................................................3
Causes of Autism........................................................................................................3
Diagnosing Autism.....................................................................................................3
Treatment of Autism...................................................................................................4
Evidence Supporting Heavy Metal Toxicity..............................................................5
Managing Soil Toxicity..............................................................................................5
Types of Environmental Clean-ups............................................................................6
Phytoextraction...............................................................................................6
Rhizofiltration................................................................................................6
Phytostabilization...........................................................................................6
Conclusion.............................................................................................................................8
Recommendations......................................................................................................8
References..............................................................................................................................9
Appendix A...........................................................................................................................10
Figures and Tables
Figure 1 Identified Prevalence of Autism Spectrum Disorders ................................1
Table 1 USDA Estimated Costs of Remediation.......................................................6
Table 2 Comparative Costs for Different Types of Heavy Metal Soil Remediation.7
HEAVY METAL TOXICITY ANALYSIS iv ABSTRACT
Autism is a neurological developmental disorder characterized by difficulties with social interactions, communication, and repetitive behaviors.
Autism has no one cause and seems to be triggered by both genetic and environmental factors. The prevalence of autism has increased dramatically in the last 40 years, occurring 1 in every 88 American children.6 Many scientific research projects have closely examined heavy metal toxicity in children with autism to determine a link between the two. Although no definitive correlation has been made, research is still being conducted to find an absolute answer.
There is no way to avoid exposure to toxic chemicals and metals. Heavy metals are enriched in the environment by human activities of different kinds.13 Pollution levels are becoming destructive to humans and we are paying the price with our health. We are seeing more diagnoses of cancers and neurological disorders as a result of polluting our air, soil, water and food supply.
The Environmental Protection Agency has implemented several different methods of extracting toxic levels of heavy metals. Phytoremediation appears to be the most environmentally …show more content…
sound options. It does take longer to complete a clean-up, but as far as the EPA is concerned, it is a positive outcome.
HEAVY METAL TOXICITY ANALYSIS
1
Introduction
Quickly becoming a trend in pediatrics, autism has become more common than ever before.
Autism is a developmental disorder usually diagnosed by the age of three and is characterized by difficulties in developing communication and social skills. Likely causes have been linked to abnormal biology and chemistry in the brain. Exact causes are unknown, but many theories have been established in the scientific community over the last few decades. Many individuals believed the incidence of autism to be associated with the rate vaccines are administered to children. This theory has been debunked thanks to recent research. Others theorize the culprit to be genetic or environmental factors or a combination therein.
The incidence of autism has become so prevalent since the 1980 's where only 1 in 10,000 children were clinically diagnosed. In 2012, the Center for Disease Control and Prevention
(CDC) reported 1 in 88 children have Autism Spectrum Disorder or ASD.2 See figure 1, demonstrating the prevalence of ASD from 2000-2008.
So, are we seeing an increase in cases of autism because the diagnostic criteria are always changing or is it because the aforementioned genetic and environmental factors? The scientific minds in today 's society are extensively researching the many causes of autism and are trying to give the public some insight as to how we can develop treatments for this disorder.
One of the biggest problems with autism today seems to be the fact that a definitive answer is not available relating to its cause. Scientists, parents, and healthcare professionals would like to know what is causing this social and communicative disorder. Fortunately, with the ever-
HEAVY METAL TOXICITY ANALYSIS
2
evolving field of science, it is apparent answers will be available in this lifetime. Issues that have made headlines in the past have pointed to heavy metal toxicity as an environmental trigger that affects the genetic make-up and composition of our DNA. According to Richard Lathe of Pieta
Research in Edinburgh, UK, of the many unknown genetic and environmental causes, heavy metals are responsible for childhood autistic disorder in a majority of cases.¹ Aside from genetic factors, environmental factors like heavy metals are becoming more prominent in case studies in children with autism. Issues could be because individuals are residing in areas with toxic levels of heavy metals and it is affecting the genetic make-up and being passed on to future generations.
Studies across the globe have made connections with heavy metals to autism. I have chosen to examine this topic so I may provide a better perspective for parents, healthcare professionals and other interested persons who want to understand why autism is becoming so prevalent today and how we can improve autism incidence with the action of environmental clean-ups.
HEAVY METAL TOXICITY ANALYSIS
3
Data Section
Causes of Autism
Scientist are not completely sure what causes autism, despite numerous research efforts.
However, autism has been linked to both genetic and environmental cues. The combination of genetic and environmental factors influence early brain development.5 Preliminarily, researchers have identified a number of genes associated with the disorder. Studies of people with ASD have found irregularities in several regions of the brain. Other studies suggest that people with ASD have abnormal levels of neurotransmitters in the brain.3 Researchers are also exploring whether such factors as viral infections, complications during pregnancy and air pollutants play a role in triggering autism.4 A common misconception regarding the cause of autism was related to vaccines, specifically the measles, mumps and rubella or MMR. Several sources have the same conclusion: there is no link between vaccines and autism. The Autism Speaks organization actually encourages children to be vaccinated to protect against disease. Their recommendation for concerned parents is to contact their primary healthcare provider and discuss any issues they may have regarding the safety and efficacy of the vaccines.5
Regarding the environmental factors responsible for autism, it is important to know the word
“environmental” encompasses many risk factors. Focus, here, is placed on heavy metal toxicity.
The introduction of pollutants can come from a pregnant woman being exposed to chemicals by living in an environment where one may be unaware of such exposure before and during pregnancy and after the child 's first year of life when brain development is essential. Toxins like heavy metals are more prevalent in our environment than in the past. 7 Many scientists have their theories on specific heavy metals that may cause autism including mercury, lead, arsenic, copper, zinc, cadmium, chromium, cobalt, nickel, aluminum, tin, uranium, and manganese.
Diagnosing Autism
Autism is not a disorder you can simply diagnose with a test like you can strep throat or the flu.
Because autism is a neurological issue, evaluations by physicians who are skilled and welleducated about developmental disorders must be conducted. Most autistic cases are diagnosed by the age of three.
The general consensus among professionals seems to be observation as the key to diagnose autism correctly. Observing the child 's milestones and behavioral skills are essential.
Mayo Clinic offers that autism specialists will observe the child and ask the parent about the child 's social skills, language skills, and about the behavior development and how its changed over time. They will also give the child developmental tests covering speech, language, developmental level, and social and behavioral issues. The specialist will also present structural social and communication interactions for the child and through observation will score the performance.4 The CDC lists on their website some popular screening tools used to help professionals diagnose autism: Ages and Stages Questionnaires (ASQ), Communication and Symbolic Behavior Scales
(CSBS), Parents ' Evaluation of Developmental Status (PEDS), Modified Checklist for Autism in
Toddlers (MCHAT), and Screening Tool for Autism in Toddlers and Young Children (STAT).6
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In a candid interview with Dr. Barbara O 'Reilly, a highly regarded Pediatrician specializing in behavioral disorders like autism and ADHD, she provided me with her opinions on autism
and the effects heavy metals may have on diagnosing the disorder. She and her staff use Ages and
Stages Questionnaires, also known as an ASQ to determine if a child 's developmental milestones are being met according to standards set by the National Autism Center. She also uses a modified autism checklist to aid in diagnosing autism.12
Treatment of Autism
There is no cure for autism. However, there are trained professionals that offer behavioral therapies to improve communication and social skills which autistic children may lack. In many cases, such skills are either underdeveloped or are non-existent. There are several different approaches regarding treatment of autism including non-medical and biomedical interventions.
Non-medical intervention includes behavioral intervention with Applied Behavioral Analysis and other therapies like Floortime, Pivotal Response Therapy, and Verbal Behavior Therapy. 6
Biomedical interventions include prescribing medications. Biomedical treatments include alternative medications, chelation therapy and nutritional interventions.
Medications are most effective when used in conjunction with behavioral therapies according to
Dr. O 'Reilly. Medication only treats three core symptoms of autism-communication difficulties, social challenges and repetitive behavior. Few drugs on the market today effectively relieve these symptoms. Commonly prescribed medications are given for Attention Deficit Hyperactivity
Disorder or ADHD, sleep disturbances and depression.6 Dr. O 'Reilly said medications like
Prozac, Paxil, Namenda and Aricept can be used in concert with behavioral therapies. She further explained the use of Namenda is to help with socialization and Aricept, which is still being clinically studied, helps with word acquisition and short term memory retrieval. Prozac and Paxil help to ease anxiety. She said she prescribes the medication for one month and if well-tolerated and symptoms are alleviated, she will continue alternative medication therapy. If no change is seen, then she discontinues the medication and proceeds with behavioral therapy.12 Although the effects seen after giving these medications are promising, more research is definitely required.
Therapies that Dr. O 'Reilly refers her patients to include physical, occupational, speech and language, developmental, and play therapies. Each of the therapies in combination with each other help develop sensory and fine motor skills. Dr. O 'Reilly 's most promising advise on the matter of treating autism was to continue research and find the causes to prevent it. “Finding the trigger is key. Then we can work backwards to treat the symptoms.”12 She was adamant that physical, occupational and speech therapies as well as developmental and play or group therapies are key in treating autism.
Chelation therapy, according to Mayo Clinic, is said to remove mercury and other heavy metals from the body. Chelation therapy for autism is not supported by research evidence and can be very dangerous. In some cases, children treated with chelation therapy have died.4 Dr. O 'Reilly speculated that most people do not participate in this therapy because its very alternative and dangerous. HEAVY METAL TOXICITY ANALYSIS
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Special diets are another option in treating symptoms of autism. However, Dr. O 'Reilly 's opinion is that majority of the time, they don 't work. She said usually, specialists tend to promote dieting changes when treating autism. Nutritionists and dieticians recommend gluten-free/casein-free diets, addressing food sensitivities, use of supplements, gut treatments, sulfation and immune system regulation.7 Dr. James Adams of Arizona State University has a great article titled
“Summary of Biomedical Treatments for Autism” with further detail on biomedical treatments with regard to diet, chelation, and immune system regulation. See Appendix A for link to full article. Evidence Supporting Heavy Metal Toxicity
A study by William Walsh, PhD. and Anjum Usman, MD found alterations in the functioning of metallothionein (MT) protein in children with autism. This impairment impacts brain development and causes extreme sensitivity to toxic metals and other environmental substances.
During their study, abnormal levels of copper and zinc were found in blood samples. The MT proteins regulate blood levels of these trace minerals, detoxify mercury and other heavy metals, and assist in development of the nervous system.8
Another study in 2009 at the University of Texas Health Science Center was done to determine if proximity to sources of mercury pollution in 1998 were related to autism prevalence in 2002.
They found for every 1000 lbs of industrial release, there was a corresponding 2.6% increase in autism rates and a 3.7% increase associated with power plant emissions. For every 10 miles from industrial or power plan sources, there is a decrease in autism rates.8
In 2006, the same group of investigators revealed an association between environmentally released mercury and autism rates in Texas. For each 1,000 lb of environmentally released mercury, there was a 43% increase in the rate of special education services and a 61% increase in the rate of autism.9
These studies were of particular interest to me because they provided me with a means explore where such toxic levels of heavy metals exist. Pollution does occur in the air, soil, water and food supply. Majority of the studies I read pointed in the direction of mercury poisoning in the soils. Managing Soil Toxicity
According to to a study by the United States Department of Agriculture or USDA, heavy metal soil contamination is toxic to human and other animals. The most severe damage noted by the
USDA was from lead causing mental lapse, cadmium affecting the kidneys, liver and gastrointestinal tract and arsenic affecting the kidneys, central nervous system and poisoning the skin. The USDA also stated the most common problem causing cationic metals (metallic elements whose forms in soil are positively charged cations) are mercury, cadmium, lead, nickel, copper, zinc, chromium and manganese. The most common anionic compounds (elements whose forms in soil are combined with oxygen and are negatively charged) are arsenic, molybdenum, selenium and boron. Preventing heavy metal pollution is critical because cleaning contaminated soils is extremely expensive and difficult.10Although, a combination of heavy metals are
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presumably the culprit, it would benefit the public if a national effort to clean up the toxins were implemented. Types of Environmental Clean-ups
According to the USDA, there are ways to prevent uptake of pollutants. Remediation of contaminated soil, management of contaminated soil, and treating metal contaminated soils by phytoextraction, rhizofiltration and phytostabilization are common practices of removing toxic levels of heavy metals in soil. Treatments can be done on- or off-site. Remediation treatments available include high temperature treatments, solidifying agents and washing.
Methods of managing contaminated soils will leave the pollutants in the soil and immobilize them to reduce negative effects from toxicity. Those methods include increasing the soil pH to
6.5 or higher, draining wet soils, applying phosphate, and carefully selecting plants for use on metal-contaminated soils.10
Phytoextraction. Phytoextraction is when plants are grown in the contaminated soil and metals are translocated from the roots into above-ground portions of the plant. After plants have grown for some time, they are harvested and incinerated or composted to recycle the metals. Several crop growth cycles may be needed to decrease contaminant levels to allowable limits. This mechanism of removal is easiest with nickel, zinc and copper because the metals are preferred by hyperaccumulator plants used in the extraction. For lead uptake, a chelator like EDTA
(ethylenediaminetraacetic acid) must be added to make lead available to the plant.10
Rhizofiltration. Rhizofiltration is the adsorption onto plant roots or absorption into plant roots of contaminants that are in solution surrounding the root zone or rhizosphere. This mechanism is used to decontaminate groundwater. This method proved effective in Chernobyl, Ukraine as cited by USDA in a report by the EPA in 1998.10
Phytostabilization. Phytostabilization is the use of perennial, non-harvested plants to stabilize or immobilize contaminants in the soil and groundwater. Metals are absorbed and accumulated by roots, adsorbed onto roots, or precipitated within the rhizosphere. Metal tolerant plants can be used to restore vegetation where natural vegetation is lacking. It also reduces the mobility of the contaminant and prevents further movement of the contaminant into groundwater or the air and reduces the bioavailability for entry into the food chain.10 Table 1 shows the cost of these cleanup methods.
Table 1. USDA Estimated Costs of Remediation. (2000)
Type of Remediation
Cost per cubic meter
Traditional in situ
$10-100
Traditional ex situ
$30-$300
Phytoremediation
$0.05
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Kansas State University 's Michael Lambert, PhD, Blase Leven and Ryan Green have examined methods of solving the toxicity issue. Noted in an article in Environmental Science and
Technology Briefs for Citizens, heavy metals most frequently encountered in their research were arsenic, cadmium, chromium, copper, lead, nickel, and zinc. Cleanup technologies used in their report mentioned excavation, stabilization on-site, and phytoremediation. Excavation and physical removal of the soil is perhaps the oldest remediation method. Advantages include complete removal of contaminants, but on the negative side, the contaminants are just moved somewhere else, possibly contaminating other areas as air pollutants during transport.
Stabilization and phytoremediation have the same definition as mentioned in the previous study. Costs at the time of KSU 's research are listed in Table 1 for different types of heavy metal soil remediation.11
Table 2. Comparative Costs for Different Types of Heavy Metal Soil Remediation. (2004)
Type of Remediation
Cost/cubic meter
Time Required
Excavation and removal
$100-$400
6-9 months
In situ fixation (including soil amendments)
$90-$200
6-9 months
Phytoextraction
$15-$40
18-60 months
Evidence clearly shows that costs do differ from the USDA estimations from those published in
Kansas State 's report, but both are in agreement that phytoremediation is the best option for removal of heavy metal toxins. Although phytoremediation is slower than traditional clean-up methods, it is extremely cost-effective and better for the environment.
I mentioned to Dr. O 'Reilly about the solution I proposed to help decrease the incidence of autism and she agreed it would be a good plan, albeit a costly option.12 She held fast to her opinion of heavy metals not being the cause of autism, though. She did digress and recall that the the Roman term for lead was plumbum in Latin, which is where the word plumber originated from. The fall of the Holy Roman Empire could have very well come from the Romans being poisoned by lead. Connections outside of her theory may not be justified, but was an interesting point regarding heavy metal toxicity.
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Conclusion
It was my goal with this research opportunity to explore the environmental risk factors of heavy metal toxicity and propose methods of removing the heavy metal toxins seemingly responsible for autism.
There seems to be an overwhelming number of scientists that agree on the negative effects heavy metals have on children and the role it plays in diagnosing autism. My research initially focused on collecting general information regarding different heavy metals and the role they play in behavioral issues with children. Subsequent research had me looking for a way to rid the environment of toxic levels of heavy metals and determining the feasibility of clean-ups to improve toxicity levels in residential areas that have high rates of ASD.
My humble conclusion is that heavy metals do play a role in autism, but if they are the actual cause of it, I do not know. Genetic predisposition plays such a pivotal role in diagnosing many diseases and other ailments that plague our society today I feel the combination of the two is really the cause. It seems hasty to take the opinion of one study and not explore other considerations with which to compare and make a bona fide conclusion. Furthermore, I conclude that environmental clean-ups are important and necessary in order to lessen the burden heavy metal toxicity has on our communities. The most environmentally sound option for removal of such toxins lies in phytoremediation. The price is right and there seems to be a positive response from environmentalists.
Recommendations
In order to find answers to the unknown, obviously, research is warranted. So, I propose further research to be conducted in the way of heavy metal toxicity to see which metals individually or in combination are polluting areas with a high incidence of autism. With regard to having environmental clean-ups, consider the type of pollution affecting the geographic location and determine which clean-up mechanisms is best suited for the job. Its apparent with our government shutdown and lack of funding, the EPA, CDC and USDA will be unable to continue research using government grants. To continue their research efforts, the agencies may need to find funding as privatized organizations.
On the residential side of the spectrum, I would recommend decreasing the potential for excess exposure to toxins. This can be done by carefully considering the chemicals we come in contact with on a daily basis. We must make a conscious effort to be more aware of our surroundings.
For more information on tips to reduce exposure to toxic chemicals, please visit the Agency for
Toxic substances and Disease Registry 's website http://www.atsdr.cdc.gov and review the article titled “How to Reduce Your Exposure to Chemicals at Home, Work, and Play.”
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References
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2. Centers for Disease Control and Prevention. (2012). Morbitity and Mortality Weekly
Report, 30 March 2012. "Prevalence of Autism Spectrum Disorders — Autism and
Developmental Disabilities Monitoring Network, 14 Sites, United States, 2008."
Retrieved 21 Sept 2013.
3. NIH National Institute of Neurological Disorders and Stroke. (2013). “Autism Fact
Sheet.” Retrieved 24 Sept 2013. http://www.ninds.nih.gov/disorders/autism/detail_autism.htm#243573082 4. Mayo Clinic Health Information. (2013). “Autism.” Retrieved 24 Sept 2013. http://www.mayoclinic.com/health/autism/DS00348 5. Autism Speaks. (2013). “Vaccines and Autism.” Retrieved 24 Sept 2013. http://www.autismspeaks.org/science/policy-statements/information-about-vaccines-andautism 6. Autism Speaks. (2013). “What is Autism?” Retrieved 24 Sept 2013 from http://www.autismspeaks.org/what-autism 7. Autism Society. (2013). “Living with Autism: Treatment Options.” Retrieved 24 Sept
2013. http://www.autism-society.org/living-with-autism/treatment-options/
8. Treat Autism & ADHD. (n.d.). “Heavy Metals and Autism, PDD and ADHD.” Retrieved
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9. Palmer, RF, et al. (2006). Environmental mercury release, special education rates, and autism disorder: an ecological study of Texas [Abstract]. Health Place, 12(2): 203-9.
Abstract Retrieved 26 Sept 2013. http://www.ncbi.nlm.nih.gov/pubmed/16338635
10. Heavy Metal Soil Contamination. (2000). United States
Department of Agriculture: Natural Resources Conservation Service. Soil Quality
Institute. Urban Technical Note No. 3. Retrieved 29 Sept 2013. http://soils.usda.gov/sqi/management/files/sq_utn_3.pdf 11. Lambert, M. Leven, B.A., Green, R.M. (2004). Environmental Science and Technology
Briefs for Citzens. “New Methods of Cleaning up Heavy metal in Soils and Water.”
Retrieved 29 Sept 2013. http://www.engg.ksu.edu/chsr/outreach/resources/docs/metals.pdf 12. O 'Reilly, Barbara. Personal interview. October 11, 2013.
13. Rahimi, M., Farhadi, R., Mehdizadeh, R. (2013). “Phytoremediation: Using Plants to
Clean Up Contaminated Soils with Heavy Metals.” Retrieved 5 Oct 2013. http://ecisi.com/wp-content/uploads/2013/02/148-152.doc.pdf Appendix A
http://autism.asu.edu/Docs/2013/Summary_of_Treatments_for_Autism-2013.pdf