Arsenic Final Presentation

Arsenic

Brief History of Arsenic Brief History of Arsenic DiscoveryDiscovery

History is convoluted Not sure who first discovered

Greeks and Romans had slaves mine for arsenic

Used in Alchemy

Albertus Magnus German chemist First to isolate in 1250 AD

www.en.wikipedia.com

General Information of General Information of ArsenicArsenic

Chemical Formula = As

Atomic Number = 33

Molecular Weight = 74.92 grams

Color = lead gray, gray, white

Hardness of 3.5 Similar to calcite or flourite Talc is 1 and diamond is 10

Nonmagnetic

Metallic

Poor conductor of heat & electricity

http://periodictable.com/Elements/033/index.html

Inorganic vs. Organic Inorganic vs. Organic ArsenicArsenic

Inorganic

Occurs naturally in soil and many minerals and ores that contain copper and lead

When heated, arsenic rises up smokestack as a fine dust

Cannot be used in agriculture

Used to pressure treat wood

Arsenate V is found in water

Organic

Mainly found in marine organisms

Can still be used on agriculture Primarily cotton

Improve properties when added to an allow or metal

Greatest use in lead acid batteries

Semiconductors and LED’s

Arsenate III found in water

http://www.finegardening.com/design/articles/pressure-treated-wood-in-beds.aspx

Uses of ArsenicUses of Arsenic ‘Poison of Kings’

Marsh and Reinsch Tests

Bronze alloy

Lead alloy

Medicinal uses Syphili, yaws, psoriasis, and other viruses

Industrial uses Ammunition production, pigments, insecticides,

rat poison, wood preservative, semiconductors, & others

http://biologyze.com/tag/arsenic-and-bacteria/

Environmental Environmental Sources of ArsenicSources of Arsenic

Marine animals

In drinking water

~200 mineral species Most common is arsenopyrite

Emitted from volcanoes

http://deepbluehome.blogspot.com/2010/10/deep-blue-home-snapshot-2000-2010.html

http://ebt2010.blogspot.com/2010/07/understand-whats-arsenic-and-how-it.html

http://www.ecowaternorthwest.com/arsenic.php

Anthropogenic Anthropogenic Sources of ArsenicSources of Arsenic

Reduction of Arsenic Trioxide (As2O3 - Arsenite) with charcoal As2O3 is created during the

metal smelting process

Industrial uses Ammunition production,

pigments, insecticides, rat poison, wood preservative, semiconductors, & others

http://www.ehow.com/how_6160537_preserve-pressure-treated-wood.html

http://serc.carleton.edu/woburn/issues/pesticides.html

http://www.indiamart.com/alchemylaboratories/analytical-reagents.html

MechanismMechanism

Inorganic Arsenate – exists in +5 oxidation state

Arsenite – exists in +3 oxidation state

Mechanism Mechanism (Continued)(Continued)

Organic As – methylated (both in +3 oxidation state)

Monomethylarsonous acid (MMAIII)

Dimethylarsinous acid (DMAIII)


+ 5 oxidation state (pentavalent) + 3 oxidation state (trivalent)

Arsenate Monomethylarsonous acid (MMAIII)

Dimethylarsinous acid (DMAIII)

Arsenite


In general, As terrorizes the metabolic processes of the mitochondria

http://www.phschool.com/science/biology_place/biocoach/cellresp/overview.html


Pentavalent toxicity

Very similar to phosphate

Can substitute for inorganic phosphate in glycolytic and cellular respiration pathways


Pentavalent toxicity

ADP-phosphate = ATP

ADP-arsenate = biologically useless

High energy phosphate bonds are lost

Stopping the production of ATP will stop all processes that require ATP


Trivalent toxicity

Reacts readily with thiol-containing molecules (-SH functional group) Amino acid cysteine contains thiol group

Cysteine rich proteins are vulnerable to As binding


Trivalent toxicity

Pyruvate Dehydrogenase (PDH) requires lipoic acid cofactor – a dithiol

As inhibits this enzyme by binding to the cofactor

The citric acid cycle cannot proceed because the pathway is terminated

http://upload.wikimedia.org/wikipedia/commons/0/0b/Citric_acid_cycle_with_aconitate_2.svg


Oxidative Stress

Reductase enzymes are present in the cell to reduce reactive oxygen species (ROS)

As binds and inhibits some of these reductases, resulting in the accumulation of ROS

ROS can bind/damage DNA and other cellular components Part of As carcinogenicity


Carcinogenicity

Researchers have yet to fully elucidate carcinogenic mechanisms of As

It is widely accepted that As is a carcinogen and several mechanisms have been proposed


Carcinogenicity

ROS accumulation

DNA Excision Repair and DNA Ligase inhibited by Arsenic

Co-mutagenic effect with ROS, UV radiation, X-Rays, and other chemicals

DNA methylation alterations

Also noted as a tumor promoter in mouse ovarian cancers

http://www.biol.unt.edu/~jajohnson/DNA_sequencing_process

Health Effects and Health Effects and SymptomsSymptoms

Acute As poisoning Nausea Vomiting Blood in the urine Cramping muscle Hair loss Stomach pain Convulsions Organ failure Comma to death (interferes with glycolysis)


Chronic arsenic poisoning High oxidative stress

affect the structure of function of cardiovascular system

Increases the risk of cancer Vitamin A deficiency

Night blindness Heart disease

Skin color change Eye inflammation Hyperkeratosis and hyperpigmentation

Blushed complexionhttp://wewinwater.com/2011/09/03/addressing-arsenic-poisoning-in-bangladesh/


Bangladesh 77 million people (1/2 population of crowded

Bangladesh) may have been exposed to toxic levels of arsenic.

More than 20% of deaths are caused by arsenic.

Groundwater is contaminated with As

http://www.who.int/topics/arsenic/en/


United Kingdom (1990 and 1991) In UK, 6000 people had the arsenic poisoning

and 70 of them died. The beer contained 15ppm of arsenic

Glucose (ingredient of beer) is contaminated to arsenic

Contaminated during the refining process

http://www.beer100.com/beercalories.htm


Japan (1955) In Japan, 12,130 children suffered from the arsenic

poisoning and 130 of them died. Milk from Tokushima factory was contaminated to

arsenic Symptoms

loss of appetite, vomiting, diarrhea, boil, skin color changed to black, anemia, hypertrophy of the liver

Aftereffect blurred vision, hard of hearing, low score in

school record, abnormal brainwave, epilepsy, headache, dizziness, cold hands and feet

http://romanianrecipes.wikia.com/wiki/Milk


Arsenic and ADHD study (Roy et al 2010) 526 6-7 years old children in Torreon Mexico

Urinary arsenic levels were measured

No significant relationship found between any measure of urinary arsenic and parents ratings of behavior

However, higher urinary arsenic was associated with high scores on Cognitive Problem exams


Pre- and Postnatal Arsenic Exposure and Body Size – a cohort study (Saha et al 2012) Purpose - to assess potential effects of early

life As exposure on weight and length of children from birth to 2 years of age

2372 children born in Bangladesh. Measured arsenic concentrations in urine (U-As) with

child body weight and length Compared to girls in the first quintile of U-As (<16

µg/L), those in the fourth quintile (26-46 µg/L) were almost 300 g lighter and 0.7 cm shorter.

Postnatal arsenic exposure was associated with lower body weight and length among girls, but not boys.

Arsenic Regulation & Arsenic Regulation & LegislationLegislation

EPA Proposed a maximum contaminant level (MCL)

of 5mcg/L in 2000 and established at 10mcg/L on Jan 22, 2001

This rule became enforceable on Jan 23, 2006

This standard protects public health based on the best available science and ensures that the cost of the standard is achievable


FDA Currently only has a standard for maximum levels of As in

bottled water

No inorganic As regulations in Europe and U.S. in relation to food

Only China has a regulatory limit (150 ppb)

Today, FDA is testing apple juice and trying to determine an appropriate level

Apple juice containing >23 ppb of organic arsenic represent a potential health risk


Organic Food Organic food is not exempt from being

contaminated by toxic chemicals

Organic standard do not prohibit the presence of As

Two brands of organic infant formula – 20 times more As than other regular brands

Institute for Agriculture and Trade Policy (IATP) and FDA move toward regulating As contaminant levels in the food supply

References References http://www.sciencedirect.com/science/article/pii/S037842740200084Xhttp://emedicine.medscape.com/article/812953-overview#a0104http://www.sciencedirect.com/science/article/pii/S0013935111000739http://www.ncbi.nlm.nih.gov/pubmed/22504586http://www.who.int/bulletin/archives/78(9)1093.pdfhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC1026413/pdf/westjmed00133-0060.pdf

http://www.ehjournal.net/content/5/1/31http://www.weitzlux.com/arsenic/historyofarsenic_403021.htmlhttp://webmineral.com/data/Arsenic.shtmlhttp://drugstoremuseum.com/sections/level_info2.php?

level_id=150&level=3http://www.weitzlux.com/arsenic/historyofarsenic_403021.htmlhttp://www.greenfacts.org/en/arsenic/l-3/arsenic-2.htm#0p0http://water.epa.gov/lawsregs/rulesregs/sdwa/arsenic/

regulations.cfmhttp://www.foodqualitynews.com/Legislation/Congress-

representatives-urge-FDA-to-move-on-inorganic-arsenic-levelshttp://www.foodqualitynews.com/Legislation/US-rice-arsenic-level-

regulations-imperative-report

Arsenic Final Presentation

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