Effects of dose and human N-acetyltransferase 1 genetic polymorphism in benzidine metabolism and genotoxicity

Benzidine undergoes N-acetylation and following CYP1A2-catalyzed N-hydroxylation undergoes O-acetylation catalyzed by N-acetyltransferase 1 (NAT1). Benzidine exposure is associated with urinary bladder cancer but the effect of NAT1 genetic polymorphism on individual risk remains unclear. We used Chinese hamster ovary (CHO) cells transfected with human CYP1A2 and NAT1*4 allele (reference) or NAT1*14B (variant) to investigate the effects of dose and NAT1 polymorphism on benzidine metabolism and genotoxicity. Rates of benzidine N-acetylation in vitro were higher in CHO cells transfected with NAT1*4 compared to NAT1*14B. CHO cells transfected with NAT1*14B exhibited greater N-acetylation rates in situ than cells transfected with NAT1*4 at low doses of benzidine expected with environmental exposures but not at higher doses. NAT1*14B exhibited over tenfold lower apparent KM which resulted in higher intrinsic clearance for benzidine N-acetylation compared to CHO cells transfected with NAT1*4. Benzidine-induced hypoxanthine phosphoribosyl transferase (HPRT) mutations were higher in CHO cells transfected with NAT1*14B than with NAT1*4 (p < 0.001). Benzidine caused concentration-dependent increase in γ-H2AX signal (indicative of DNA double-strand breaks) in CHO cells transfected with NAT1*4 or NAT1*14B. CHO cells transfected with NAT1*14B exhibited significantly higher level of DNA damage than with NAT1*4 (p < 0.0001). Benzidine-induced ROS did not differ significantly (p > 0.05) between CHO cells transfected with NAT1*4 or NAT1*14B except at 50 μM. Levels of benzidine-induced DNA damage and reactive oxygen species (ROS) showed strong dose-dependent correlation. Our findings support human studies associating NAT1*14B with increased incidence or severity of urinary bladder cancer in workers exposed to benzidine.

Quantitative analysis of restricted metals and metalloids in tattoo inks: A systematic review and meta-analysis

The various ingredients and impurities that can be detected within tattoo inks have been associated with a myriad of dermatologic complications. Legislation regarding these antigenic substances varies widely around the world, with Europe serving as both the research and regulatory center on these intradermal formulations. Although industry is said to be moving away from metallic and metalloid pigments in exchange for organic or organometallic dyes, surveys of commercially available inks continue to detect these elements at concentrations considered unsafe for application into the dermis. In order to better assess the formulation and safety of tattoo ink, we present a systematic review and meta-analysis of studies quantifying restricted metals and metalloids in commercially available tattoo ink products. Among the papers selected, inconsistencies were noted in the degree of specificity by which ink products were identified and the elements sampled for. In addition, the analytical targets' valency and/or solubility were not always considered in accordance with regulation criteria. Of note, chromium, by total content and that of its regulated +6 valency, exceeded its maximum allowed concentration in nearly every sample tested. Total copper content exceeded the limit for soluble copper in half of inks sampled. In descending order, concentrations of cadmium, barium, mercury, soluble copper, arsenic, zinc, antimony, and lead violated regulations in one-sixth or fewer of samples tested. Cobalt and tin levels never violated regulation. Overall, our findings indicate that unsafe levels of restricted elements continue to be detected across studies, warranting further investigation under a regulatory lens.

Are Some Metals in Tattoo Inks Harmful to Health? An Analytical Approach

Tattoo application is widely performed all over the world; however, injection of coloring substances into the skin as metals may pose a risk for allergies and other skin inflammations and systemic diseases. In this context, tattoo inks in green, black, and red colors of three brands were purchased. Before starting the analysis, the acid mixture suitable for microwave burning was determined, and according to these results, the inks were digested with nitric acid, hydrochloric acid, and hydrofluoric acid. Then, method validation was performed for tattoo inks using inductively coupled plasma-mass spectrometry. The relative contribution of metals to the tattoo ink composition was highly variable between colors and brands. Elements found in the main components of inks are as follows (in mg kg^-1): Al, 1191.1-3424.9; Co, 0.04-1.07; Cu, 1.24-2523.4; Fe, 16.98-318.42; Ni, 0.63-17.53; and Zn, 2.6-46.9. It has been determined by the Environmental Protection Agency that in some products, especially the copper element is above the determined limit. The analysis results obtained were classified by chemometric analysis, and the color and brand relationship were determined. More toxicological studies are necessary to understand the effects of tattoo inks containing heavy metals and/or organic components.

“For Asia Market Only”: A Green Tattoo Ink between Safety and Regulations

Due to the increasing tattoo practicing in Eastern countries and general concern on tattoo ink composition and safety, the green tattoo inks Green Concentrate by Eternal, for European and “for Asia Market Only” were analyzed, under the premise that only the former falls under a composition regulation. A separation of the additives from the pigment was carried out by successive extraction in solvents of different polarities, i.e., water, acetone and dichloromethane. The solid residues were analyzed by IR and Raman spectroscopies, the liquid fractions by GC/mass spectrometry. The relative pigment load and element traces were also estimated. We found that the European and the Asian inks are based on the same pigment, PG7, restricted in Europe, though at different loads. They have a similar content of harmful impurities, such as Ni, As, Cd and Sb and both contain siloxanes, including harmful D4. Furthermore, they have different physical-chemical properties, the European ink being more hydrophilic, the Asian more hydrophobic. Additionally, the Asian ink contains harmful additives for the solubilization of hydrophobic matrices and by-products of the phthalocyanine synthesis. Teratogenic phthalates are present as well as chlorinated teratogenic and carcinogenic compounds usually associated to the laser treatment for removal purposes, to a larger extent in the European ink. The composition of the inks does not seem to reflect regulatory restrictions, where issued.

Consumer exposure and risk assessment to selected chemicals of mold stain remover use in Korea

Mold stain remover (MSR) is used to clean mold and mildew spots from surfaces and contains a variety of chemical substances. In this study, we estimated the inhalation and dermal exposures associated with the use of trigger spray MSRs, and performed screening-level risk assessments for the use of this type of product in Korea. Inhalation and dermal exposures were estimated using exposure algorithms based on exposure factors obtained from a nationwide survey of 10,000 participants and chemical analyses of the four most popular trigger spray MSRs. The hazard quotients (HQs) for noncancer risk and excess cancer risk (ECR) were calculated for each chemical. The mean inhalation exposure estimates for formaldehyde, benzene, chloroform, and carbon tetrachloride were 6.9 × 10^-7, 1.7 × 10^-7, 5.4 × 10^-6, and 2.7 × 10^-5 mg/kg/day, respectively. Dermal exposures of the chemicals were 5.7-6.5 times higher than inhalation exposures. The HQs for total exposure were all below 1, which indicated little noncancer risk from the use of MSRs. The safe ECR value of 1 × 10^-6, was exceed in one subject for inhalation exposure of benzene and four subjects for dermal exposure of formaldehyde, while 19.8% for dermal exposure of benzene were above this value. Therefore, use of trigger spray MSRs in Korea should require more detailed exposure and risk assessment, especially for benzene.

Determination of polycyclic aromatic hydrocarbons (PAHs) in cosmetic products by gas chromatography-tandem mass spectrometry

A gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) method is developed to determine 18 representative polycyclic aromatic hydrocarbons (PAHs) in cosmetics, including Benzo[a]pyrene (BaP) and others. The method offers high sensitivity and selectivity under selected reaction monitoring (SRM) mode to satisfy the requirements of both quantitation and qualitation. The extraction solvent system used in this study is acetone/hexane 1:1 (v/v) and other purification procedure is unnecessary. The linearities of 18 PAHs are validated in different concentration in the range of 0.25–20 ng/mL individually with coefficient correlation (r) higher than 0.996. The recoveries for spiking 3 different concentrations are from 87.40% to 120.44% for 18 PAHs and the coefficient of variation (CV) are below 12.32%. Limit of quantification (LOQ) of 18 PAHs is in the range of 0.05–0.2 mg/kg. A matrix enhancement effect is observed and can be compensated with deuterated internal standard. The method has been successfully applied to 73 samples, over 40 of them are lipsticks. The results show none of the samples detect Benzo[a]pyrene (BaP) and Dibenzo[a,h]anthracene (DBA), both are classified as the most carcinogenic. 8 PAHs are detected and the average value between 0.08 and 0.27 mg/kg. This study offers a sensitive and simple method to analyze 18 representative PAHs successfully and can be applied to cosmetic products and raw materials.

Sensitive Determination of Volatile Organic Compounds and Aldehydes in Tattoo Inks

As the popularity of body art including tattoo ink has increased, the safety associated with it has become an important interest. In this study, twenty volatile organic compounds (VOCs) and two aldehydes in tattoo inks were identified and quantified. Headspace and gas chromatography-mass spectrometry (HS GC-MS) for the VOCs and HS GC-MS based on derivatization with 2,2,2-trifluoroethylhydrazine (TFEH) for aldehydes was developed. Benzene, chloroform, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene, propylbenzene, chlorobenzene, tert-butylbenzene, 1,3,5-trimethylbenzene, styrene, 1,2,4-trimethylbenzene, 2-chlorotoluene, 4-chlorotoluene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene and isopropyl alcohol were detected with the concentration range of 0.02-207,000 mg/kg in 16 different tattoo inks. Formaldehyde and acetaldehyde were detected with the concentration range of 0.4-308 mg/kg in the same samples. Our analytical results represent solvents used intentionally or non-intentionally in tattoo inks, and thus they may provide important information for national regulation.