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