25 JEFSR Vol. 5 No. 1 2020

Degradation of Fingernail Composition from Exposure to Industrial Chemicals

Theresa Tran, B.FSc.and Dr. Pardeep Jasra

Abstract

The application of fingernails as biomarkers have increased within forensic science as a better tissue sample to analyze when it comes to chemical exposure and biological substances being accumulated within fingernails. Due to their structure and properties, they have the ability to retain a discrete record of detailed information on drug use, pathology, diet and location history as well as exposure to explosives residues, occupational chemicals or other pollutants. This research observed how certain industrial chemicals affect the composition of fingernails when exposed to them for a certain prolonged period of time Hydrochloric acid was the most destructive chemical used, degrading fingernail samples within a week. Sodium hydroxide was the second most destructive chemical, where samples after week 1 became degraded. Sulfuric acid was the third most destructive chemical, degrading samples after week 3. Paint and cyanoacrylate did not degrade samples but concealed all morphological features. Acetone and bleach had an insignificant effect in degradation.

Keywords: Fingernail, Human exposure, Industrial chemicals, Forensics, Biomarker 26 JEFSR Vol. 5 No. 1 2020

Introduction

Fingernails and toenails are a characteristic feature that are only seen on primates. They are dead cells that are comprised of 3 layers of highly keratinous tissue: narrow dorsal, harder intermediate, and narrow ventral, that are laid down by the matrix at the base and below the nail (Farren, Shayler, & Ennos, 2004). As the cells are produced continuously and become keratinized, they will be compacted and eventually adhere together before being forced down the nail bed. It is sealed by the hyponychium, where the free edge of the nail is connected. Because of how keratinized our nails are, the toughness protects our nails from any exterior damage that could affect our nail health. Any interruptions will cause the nail to thin, discolour, split or continue degrading.

The human nail is as permeable as skin, so substances can be absorbed in the nail to determine long- term exposure, whether it is identifying systemic intoxication from alcohol, drugs, or certain environmental exposures (Ibrahim et al, 2014). Sources of exposure could be from occupational exposure to certain chemicals or from the environment that a body has been found in, whether it was intentional or accidental. Chemicals used intentionally as a mean to dispose victims because depending on the corrosiveness of the chemical, it is able to destroy and dissolve the body, which makes it possible to prevent positive identification. The body can even dissolution in various household chemicals because they are easily obtainable (Hartnett, Fulginiti, & Modica, 2011). Properties of fingernails depend on the stress from occupations and environment.

When exposed to chemicals that are potentially harmful or toxic, it will have an effect on the structure and composition of fingernails and can be utilized in examining any degradation, which can be useful within forensics because it can be used as a method for human identification and can employ morphological traits that assists in forensic onychology: the study of fingernails and toenails for better administration of justice in the court of law (Parmar & Rathod, 2012). Fingernails are also easier to collect than other biological samples, easy to handle and store and are able to be reproduced to repeat an experiment. Only a small sample size is required for analysis and the sampling process is relatively noninvasive and non-destructive, which are important for human identification.

There have been limited researches done that examined occupational exposure, with less extent applicable to forensic science. An analysis by Schumachera, Dindorf, & Dittmarc (2009) examined how exposure to toxic agents altered organic elemental composition in human fingernails, using painters & hairdressers as participants since those professions are often in contact with chemical agents. They observed that there were significant alterations in elemental composition. In addition, Peters, Gammelgaard and Menne (1991) study used adult fingernails to examine nickel concentration, due to contact dermatitis caused by nickel sensitivity and investigated if there is a correlation between the nickel concentration in nails and the duration 27 JEFSR Vol. 5 No. 1 2020

of the exposure. Within the first 12 months of exposure, they found no correlation between the nickel content in nails and the duration of exposure. They did find however, the heavier the nickel exposure, the higher the nickel levels in the fingernails were, proving that nickel concentration in fingernails is dependent on intensity of the exposure.

There has been no research done that solely focused on the degradation effect of fingernails, but there has been research that examined corrosive substances and the damage they have on both hard and soft tissue for human remains. A targeted area of the human body that is often corroded is the craniofacial region (Maki, 2017), specifically the teeth because dentition has been studied to examine the effects using strong chemicals, as well as using dental records for positive identification (Tuominen et al, 1989; Ubelaker & Sperber, 1988; Mazza et al, 2005; Cope & Dupras, 2009). Notable exception includes the analysis hard and soft tissue by Hartnett, Fulginiti, & Modica, 2011. They used 6 commonly available chemical substances: hydrochloric acid, sulfuric acid, household lye, bleach, a 100% natural active bacteria and enzyme product, and a cola soft drink on bone, teeth, hair, fingernails and soft tissue (skin, fat, muscle).

The primary objective of this project is two-fold. The first objective will examine how certain industrial chemicals affect the composition of fingernails when exposed to them in fume for a prolonged period of time, which will represent workplace exposure. The second objective will determine how long it will take for the fingernails to be dissolved in a particular chemical, which will represent the disposal of a body and how to link it to a specific chemical for environmental purposes for forensic investigations.

Methodology

Questionnaire

All participants completed a self-designed questionnaire with respect to their health and dietary lifestyle. The questionnaire for each participant was filled out to obtain information to take into account their gender, age, ethnicity, if they have taken any supplements provided on the questionnaire and if they have a specific dietary restriction. This was to take in account any differences in the rate of degradation or no degradation.

Participants The participation of adults in this research were voluntary and were contacted through the research recruitment poster for this experiment in January 2018 on the University of Windsor campus. The research protocol was approved by the University of Windsor Research Ethics Board (REB) prior to data collection and all participants signed a consent form, informing them of this experiment. Composition of the free edge of the nail 28 JEFSR Vol. 5 No. 1 2020

were examined from 7 healthy adults (3 females and 4 males) with the age range between 19-23. Out of these adults, 5 are Caucasian, 1 is Asian-Canadian and 1 is Caribbean-Canadian. Exclusion criteria were nail polish, coatings and the use of nail cosmetics, such as acrylic nails currently present on the nail. In all participants, hands were washed prior to removal. Free edges of the fingernail clippings were collected from each finger on both hands to collect a total of 25 fingernail clippings using stainless steel nail clippers and were sanitized with hot water and soap.

Materials and Methods

The fingernail samples were placed in either a paper envelope or druggiest fold using bindle paper to be stored. A total of 7 chemicals were used: Sodium hydroxide (NaOH), Cyanoacrylate, Paint (Tremclad® rust paint

in semi-gloss white), Comet bleach powder, Hydrochloric acid (HCl) Acetone & Sulfuric acid (N2SO4). MSDS was researched to ensure proper handling of chemicals for safety precautions (Chemical Safety Software, 2018). Of these chemicals, paint was bought, bleach and sodium hydroxide were prepared by dissolving them, and the rest were provided by the University of Windsor. They were chosen for this experiment because they are chemicals that we come into contact with, either through occupational exposure or environmental exposure and have been categorized (Table 1). Distilled water was used to clean all the nails prior to exposure. Nails prior to being submerged were cut to eliminate the curvature of each nail to make it easier to place on a microscopic slide. Degradation was observed on a weekly basis, up to 4 weeks. For each week, there were 3 test tubes trials that were filled approximately halfway for each of the chemicals used. Hydrochloric acid was only tested up to 3 weeks because of how rapidly hydrochloric acid dissolves human tissues (Hartnett, Fulginiti, & Modica, 2011). 2 fingernails were placed in each test tube to maintain accuracy throughout the experiment. 24 fingernails were submerged for each individual chemical, except for hydrochloric acid, which had 18 fingernails submerged. Each test tube was placed in a test tube rack inside a fume hood in a laboratory setting with ambient temperature. The specimens were not disturbed during the course of the experiment, and additional amounts of the chemicals were not added to the test tubes after the experiment had started, except for acetone because it evaporates quickly, even when covered with aluminum foil. After each week has passed, the fingernails were removed from their test tube and rinsed with distilled water before preparing each sample to create a wet mount microscope slide. Each sample were viewed to examine degradation at a microscopic level, using a compound microscope. Pictures were taken each week to view the degradation. Controls for this experiment were unexposed fingernails that were cleaned just by distilled water and were prepared on a microscope slide. 29 JEFSR Vol. 5 No. 1 2020

Chemical Acid/ Base Acid/ Base Concentration (%)

Sulfuric acid Acidic 95-98%

Sodium hydroxide Basic 50%

Cyanoacrylate N/A N/A

Paint N/A N/A

Acetone Acidic ACS grade bulk ≥99.5%

Bleach Basic Active Ingredients: • Calcium Carbonate 60-100% • Silica, quartz 0.1-1%

Hydrochloric Acid Acid 36.5-38%

TABLE 1- Chemicals products used in experiment. Each is listed with acidity or basicity and concentration based on manufacturer information.

Results

The control of each sample and the effects of each chemical agent on the fingernail samples are outlined below. All changes in physical descriptions before being viewed under a microscope are reported on Table 10. Hydrochloric acid was the most corrosive chemical used. The nail sample control for hydrochloric acid under a microscope (Table 2) shows details of the translucent keratin protein on both magnification. The nails after being submerged in hydrochloric acid were present but were dissolved, even within week 1, which shows that the keratin is destroyed and there is no structure left for the sample to become completely fragile and dissolved (Table 10). What was viewed were degraded fingernail keratin cell fragments under the microscope.

All control samples show details of the keratin protein, where they appear porous under 10x magnification and scale-like under 40x magnification, due to ridges on the nails appearing generally longitudinally. Fingernail samples when submerged under sulfuric acid in 1 week appears unaffected but in weeks 2 and 3, there were changes in ridge patterns. In 4 weeks, samples were degraded that cells were viewed. Fingernail samples when submerged under sodium hydroxide in 1 week appears that ridging patterns were lost compared to ridges in the control. After week 1, samples became degraded, where keratin cell 30 JEFSR Vol. 5 No. 1 2020

fragments and crystals from the chemical were examined. In cyanoacrylate for all 4 weeks, morphological features in the nails appeared unchanged compared to the control. Morphological features in all samples in paint for all 4 weeks were not visible. Each sample looks blurry and opaque under each magnification that ridges cannot be seen. Samples submerged in acetone showed no changes in morphological features. Samples submerged in bleach showed also showed no changes in morphological features.

Control

NaOH Cyanoacrylat Acetone Bleach H2SO4 Control- Paint HCl control- Control-10x e Control-10x Control-10x Control-10x 10x Control-10x 10x

H2SO4 Control- NaOH Cyanoacrylat Paint Acetone Bleach HCl control- 40x Control-40x e Control-40x Control-40x Control-40x Control-40x 40x

TABLE 2- Control fingernails for each chemical, viewed at both 10x and 40x magnifications. 31 JEFSR Vol. 5 No. 1 2020

Sulfuric Acid (H2SO4)

Weeks 10x Magnification 40x Magnification

Week 1

Week 2

Week 3 32 JEFSR Vol. 5 No. 1 2020

Week 4

TABLE 3-Microscopic photos of fingernails submerged in sulfuric acid (H2S04) over 4 weeks, viewed at both 10x and 40x magnifications.

Sodium Hydroxide (NaOH)

Weeks 10x Magnification 40x Magnification

Week 1 33 JEFSR Vol. 5 No. 1 2020

Week 2

Week 3

Week 4

TABLE 4- Microscopic photos of fingernails submerged in sodium hydroxide (NaOH) over 4 weeks, viewed at both 10x and 40x magnifications. 34 JEFSR Vol. 5 No. 1 2020

Cyanoacrylate

Weeks 10x Magnification 40x Magnification

Week 1

Week 2

Week 3 35 JEFSR Vol. 5 No. 1 2020

Week 4

TABLE 5- Microscopic photos of fingernails submerged in cyanoacrylate over 4 weeks, viewed at both 10x and 40x magnifications.

Paint

Weeks 10x Magnification 40x Magnification

Week 1 36 JEFSR Vol. 5 No. 1 2020

Week 2

Week 3

Week 4

TABLE 6- Microscopic photos of fingernails submerged in paint over 4 weeks, viewed at both 10x and 40x magnifications. 37 JEFSR Vol. 5 No. 1 2020

Acetone

Weeks 10x Magnification 40x Magnification

Week 1

Week 2 38 JEFSR Vol. 5 No. 1 2020

Week 3

Week 4

TABLE 7- Microscopic photos of fingernails submerged in acetone over 4 weeks, viewed at both 10x and 40x magnifications.

Bleach

Weeks 10x Magnification 40x Magnification

Week 1 39 JEFSR Vol. 5 No. 1 2020

Week 2

Week 3

Week 4

TABLE 8- Microscopic photos of fingernails submerged in bleach over 4 weeks, viewed at both 10x and 40x magnifications. 40 JEFSR Vol. 5 No. 1 2020

Hydrochloric Acid (HCl)

Weeks 10x Magnification 40x Magnification

Week 1

Week 2

Week 3

TABLE 9- Microscopic photos of fingernails submerged in hydrochloric acid (HCl) over 3 weeks, viewed at both 10x and 40x magnifications. 41 JEFSR Vol. 5 No. 1 2020

Duration Chemical

NaOH Bleach H2SO4 Cyanoacrylat Paint Acetone HCl e

Week 1 Chemical Morpholo Chemical Chemical Paint still Morpholog Chemical & sample gy was and became remained y was not appeared appeared not sample completely on each affected, purple. opaque affected, became adhered to sample, no signs of Trial #1 with no signs brown. samples and even after degradatio remains minimal of created a washing n. All were crystals degradati hard layer on with samples All samples collected formed on. top of distilled were were All on sample. water. All retrieved retrieved samples surface. samples but No signs of All were All were became degradation. samples completel samples retrieved so fragile were y fragile All samples were they retrieved and broke were retrieved broke apart retrieved apart creating pieces of nail

Week 2 Chemical Morpholo Chemical Chemical Paint still Morpholog Chemical & sample gy was and became remained y was not appeared appeared not sample completely on each affected, purple. opaque affected, appeared adhered to sample no signs of All with large no signs brown. samples and and degradatio samples amounts of created a hardened n. All were of crystals degradati hard layer on , even samples All samples completel formed on. top of after were were y fragile sample. washing retrieved retrieved and with 42 JEFSR Vol. 5 No. 1 2020

on the All but were No signs of distilled remains surface. samples so fragile degradation water. were were they collected Only trial All samples All retrieved broke #3 was were samples apart retrieved, retrieved were but retrieved completel y lost keratin structure, became fragile.

Trial #1 and #2 were irretrieva ble, dissolved

Week 3 Chemical Morpholo Chemical Chemical Paint still Morpholog Chemical & sample gy was and became remained y was not appeared appeared not sample completely on each affected, purple. opaque affected, appeared adhered to sample no signs of All with large no signs brown. samples and and degradatio samples amounts of created a hardened n All were of crystals degradati hard layer on , even samples All samples completel formed on. top of after were were y fragile on the sample. washing All retrieved retrieved and surface. with samples but were No signs of remains distilled Trial #2 & were so fragile degradation were water #3 was retrieved they collected retrieved, 43 JEFSR Vol. 5 No. 1 2020

trial #1 broke All samples All was apart were samples irretrieva retrieved were ble, retrieved dissolved

Week 4 Chemical Morpholo Only Chemical Paint still Morpholog & sample gy was chemical became remained y was not appeared not became completely on each affected, opaque affected, brown. adhered to sample no signs of with large no signs samples and and degradatio Only trial amounts of created a hardened n. #2 was of crystals degradati hard layer on , even retrieved All samples formed on. top of after and were on the sample. washing All samples retrieved surface. with samples appeared No signs of distilled Only trial were transpare degradation water. #1 was retrieved nt. All samples retrieved, All Trial #1 were trial #2 & samples and #3 retrieved #3 were were were irretrieva retrieved irretrieva ble, ble, dissolved dissolved

TABLE 10- Qualitative description of the effects of all the chemicals on each fingernail samples for each week.

Discussion

This study was conducted to determine if these various chemicals are capable of degrading fingernails and thus provide information on chemical exposure due to workplace environment over a period of time, or from disposing evidence to eliminate human morphological features during identification. Based on these 44 JEFSR Vol. 5 No. 1 2020

results, hydrochloric acid was the most destructive chemical to consume all the fingernail samples within the first week. If hydrochloric acid was used in large quantities at a higher percentage, this chemical can consume an entire human body or portions of a human body (Hartnett, Fulginiti, & Modica, 2011). Although hydrochloric acid completely degraded the keratin in the fingernails to lose structure, it did not completely consume the samples as they were present in the test tubes but became reduced in miniscule sizes when removed. Hydrochloric acid, in higher concentrations, is used industrially to process steel, which is the material of choice for suspension bridges and cars and truck, as well as used in the production of batteries, photoflash bulbs and fireworks (Chlorine Chemistry, 2003). In lower concentrations can be found in household products such as Febreeze Air Refreshers, toilet bowl cleaners, fabric softeners etc. (Household Products Database). This correlates with Hartnett, Fulginiti & Modica (2011) study, where they also found that hydrochloric acid was the most destructive agent, where it didn’t completely consume the entire fingernail samples since nails were present but became unrecognizable. There nails also sank and turned a slight purple color around the edges. If workers are exposed to higher concentrations of hydrochloric acid, they are more likely to damage themselves because of how corrosive it is, which can become a workplace hazard. This acid is also a preferable choice to dispose a body because of how quickly it can dissolve a body. Using HCl is also distinguishable because it can degrade tissue to the point where it becomes unrecognizable, only such acidic chemicals like HCl have that affect so if a human had similar or identical degraded affects, it can be linked to HCl.

Sodium hydroxide at a 50% concentration also dissolved the fingernail samples, but not as fast as hydrochloric acid. Toxicity depends on the concentration of the sodium hydroxide solution and the duration of its contact with tissue (National Research Council (US) Committee on Toxicology, 1984). Within the industry, sodium hydroxide can be found to adjust the pH, produce biodiesel from vegetable oils, clean food processing

equipment and bottles, de-ink water (pulp and paper industry), absorb CO2 from gases, extract alumina, remove grease and paint from metal, mercerize cotton (textile industry) and many more. It can also be found in consumer products such as paint stripping products, drain cleaning products and other cleaning products. Direct skin contact with products containing a low concentration of sodium hydroxide (< 0.5% in water) is not a concern for human health because the substance is not irritating or corrosive. Direct contact with products containing high concentrations of sodium hydroxide (>2% in water) will have corrosive effects causing immediate degeneration of tissues, such as dermatitis, loss of hair, and necrosis due to irritation (National Research Council (US) Committee on Toxicology, 1984). Workers are able to handle and be exposed to sodium hydroxide during manufacturing if it’s in solid form and if the solution is very concentrated. If NaOH was used on a human, it can be traced back to that chemical because of its effect on human tissue and direct contact produces crystal residue (Table 10). Cope & Dupras (2009) found that sodium hydroxide on teeth at a concentration of 28% from a liquid drain cleaner showed that the teeth was more sheen and polished and no 45 JEFSR Vol. 5 No. 1 2020

signs of corrosion, which may suggest that sodium hydroxide may not have a large effect on human tissue. The use of sodium hydroxide to dispose a human body is still undetermined in this study. Even though sodium hydroxide at 50% degraded fingernail samples at Week 2 (Table 10), more samples such as bone, teeth, hair and skin tissues should be tested and at various concentrations to verify because there is a lack in literature to examine the effects of sodium hydroxide on human remains.

Sulfuric acid was the third most degraded chemical that affected the fingernail samples. Within industrial settings, it is used in the manufacture of fertilizers, detergents, explosives, other acids, glue, the purification of petroleum, pickling of metal, and is commonly found in lead-acid batteries in motor vehicles (Agency for Toxic Substances and Disease Registry (ATSDR), 1998). Sulfuric acid known for being used in acid attacks because it is affordable and more readily available to obtain from car batteries, and other products, and this chemical has severe affects when in contact with tissue such as full-thickness burns, which can produce profound facial disfigurement, blindness and deafness (Lewis, n.d.). Hartnett, Fulginiti & Modica (2011) also found that nails were present but unrecognizable after 14 days and observed a darker colour. They also found that it was the second most destructive acid to flesh, after hydrochloric acid, consuming flesh in less than 5 hours. By examining these effects and the discoloration sulfuric acid produces (Table 10), one can link the use of sulfuric acid as the main cause of damage.

Although cyanoacrylate and paint observed had no degradation affects and cannot correspond to disposing a body, they consistently concealed the morphology of the fingernail samples, making them difficult to observe any features under the microscope. They do however, affect human health in the workplace from occupational exposure. Cyanoacrylate can be found not only in forensics developing latent fingerprints, but in the beauty industry, where it can be used for lash extension and acrylic nails. 'Preformed plastic nails' are attached to the nail plate using a cyanoacrylate instant glue and should not be left on for <18 hours, or nail diseases such as onycholysis and severe nail dystrophy may occur (Fitzgerald, Bhaggoe, & English, 1995). With paint, there are a variety of solvents found in paint, which can cause some health affects when exposed for too long. Wieslander, Norback, & Edling, (1994) studied the different effects between water-based paint and solvent based paint and found that by using solvent paint, workers were more exposed to solvents such as formaldehyde, ammonia and volatile organic compounds to cause work related symptoms, such as eye irritation cough with sputum, and itchy hands, compared to water-based paint, where the environment improved to reduce exposure of solvents and symptoms.

For acetone and bleach, no degradation was observed. These results for bleach contradicts Hartnett, Fulginiti & Modica (2011) results where their fingernail samples were consumed in 6 hours. Fingernails in this study did not degrade due to possibility of using different methods of bleach since a bleach solution was 46 JEFSR Vol. 5 No. 1 2020

created in this study from Clorox bleach powder, creating a diluted bleach solution with a lower concentration, while they used liquid bleach at a different concentration. Bleach can be found in any cleaning product, so it is easily obtainable from any store. For acetone, it is considered to be one of the least toxic chemicals and non- carcinogenic that won’t produce any serious health risks (Arora & Tosto, 2017; Roberts, 2011). Acetone can be found in common products such as nail polish remover and used in industrial products. In Satoh et al (1996) study, they found that factory workers exposed to acetone in an acetate fiber manufacturing plants mainly suffered from irritation of eyes, nose and throat. Ingestion of acetone has more health effects, where it causes lethargy, confusion, and decreased arousability for several hours (Arora & Tosto, 2017). Limited studies are available that have observed the effects of long-term (Chronic) exposure of acetone, but direct skin contact with acetone can cause dry, red, cracked skin (dermatitis) (Centre for Occupational Health, n.d.)

Conclusion

The outcome of this study proved that various chemicals found in either industrial workplaces or household products can cause numerous effects on fingernails, which can provide information about the why the chemical is found on a human and if it had any negative effects. While some of the chemicals used showed degradation properties when tissues are exposed, hydrochloric acid has shown to be the most effective chemical to cause extreme degradation. Sulfuric acid and sodium hydroxide have shown that they are also effective to cause degradation and are easily obtainable. The remaining chemicals in this study have shown that they were effective in covering morphological features of tissue (paint and cyanoacrylate) or had an insignificant effect (acetone and bleach). The current experiment in this research can provide information on how certain degradation time and effects are associated with a particular chemical used to dispose of a body, and how health is affected when workers are exposed to a certain chemical.

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