Dermal Exposure Research Articles

Skin Permeability of Perfluorocarboxylic Acids Using Flow-Through Diffusion on Porcine Skin.

Per- and polyfluoroalkyl substances (PFAS) are found in a variety of places including cosmetics, rain jackets, dust, and water. PFAS have also been applied to occupational gear to protect against water and oils. However, PFAS have been identified as immunosuppressants and perfluorooctanoic acid (PFOA), a specific PFAS, has been identified as carcinogenic. Since there is a risk for dermal exposure to these compounds, there is a need to characterize their dermal absorption. Using in vitro flow-through diffusion, skin permeabilities were determined for 14C-labeled perfluorooctanoic acid (PFOA), perfluorohexanoic acid (PFHxA), and perfluorobutanoic acid (PFBA) using porcine skin. Tests were conducted over 8 h with either acetone or artificial perspirant as the vehicle. PFBA was found to have greater permeability than PFHxA, likely due to having a smaller molecular weight. The dosing vehicle did not appear to impact permeability rates but impacted the disposition through the skin model. While these PFAS compounds showed a low permeability rate through the skin membranes, they can stay in the skin, acting as a reservoir.

Ecotoxicity of bromate and human health risks resulting from wastewater treatment units' effluents associated with some key physicochemical parameters in two hotspots connected to the Egyptian Mediterranean Sea

This study is the first of its kind in terms of focusing on the seasonal monitoring of bromine species (bromide− and bromate) and some of the main physicochemical parameters in the surface water of stations inside and in front of the El Noubareya and El-Umum drains that flow directly or indirectly to the Egyptian Mediterranean coast at A (El Noubareya Drain) and B (El-Mex Bay) sites. Among the bromine species, bromate (BrO3−) is a disinfection byproduct considered by many international agencies to have a potential carcinogenic effect in humans and is also known to be ecologically toxic to aquatic organisms. Drain water samples collected from the studied sites A and B had a bromide/chlorinity ratio (3.85E-03 - 6.25E-03 and 3.27E-03 - 6.97E-03, respectively) significantly higher than the typical value for open seawater (3.50E-03), showing significant dilution with wastewater at drain stations in the investigated sites. The source and origin of bromine species and the major ions studied associated with the wastewater units were identified and tracked by calculating the ion/chlorinity ratio and multivariate analysis. The total hazard quotient (THQ) for bromate intake and dermal exposure in children, females, and males demonstrates negligible harm to human health. The toxic unit (TU) and the sum of toxic units (STU) values of the three trophic levels in the surface water for the two sites under investigation yielded approximately comparable values for risk quotient (RQ) and mixture risk characterization ratios (RCRmix(MEC/PNEC)), indicating that invertebrates are more sensitive to bromate dangers than fish and algae. The study highlights the importance of conducting large-scale laboratory tests on the effluents resulting from wastewater treatment units, including bromide levels, to prevent the formation of dangerous side compounds such as bromate, which may have negative effects on populations and may lead to the toxicity of trophic levels in ecosystems.

Preliminary human health risk assessment of antibiotic exposures in human waste handling occupations

Exposure to biosolids in human waste handling occupations is associated with a risk for illness due to microbial infections. Although several years of exposure to biosolids might be hypothesized to be a prophylaxis against infection, the risks associated with infections from antibiotic-resistant organisms can also be a potential concern. Therefore, this study aimed to conduct a screening level risk assessment by deriving occupational exposure limits (OELs) characterizing the risks of adverse health effects among workers in human waste handling occupations with a focus on exposure to two pharmaceuticals commonly found in biosolids: ciprofloxacin (CIP) and azithromycin (AZ). Epidemiological and exposure studies of workers exposed to biosolids were identified through searches of major scientific databases. Screening OELs (sOELs) for these antibiotics were derived using a standardized methodology. The airborne concentrations of CIP and AZ antibiotics were determined using an exposure factors approach. The health-based exposure limits (i.e., sOELs) and the acceptable daily exposure (ADE) values for both of these antibiotics were derived as 80 μg/m3 and 12 μg/kg-day, respectively. An exposure factor approach suggested that inhalation route exposures to CIP and AZ are well below the sOELs and ADE daily doses, and likely too low to cause direct adverse health effects through antibiotic inhalation. A critical review of epidemiological studies on different occupations handling biosolids showed that the workers in industries with potential biosolids exposure have experienced an increased incidence of microbial-exposure-related illness. The health effects seen in the workers have been attributed to bacterial, viral, and protozoan infections. To the extent that bacteria are the pathogen of concern, it is not clear whether these bacteria are resistant to antibiotics commonly found in biosolids. It is also unclear whether the presence of antibiotics or antibiotic-resistant bacteria increases the susceptibility of these workers. Additional studies will provide more definitive estimates of inhalation and dermal exposures to CIP and AZ and could verify the exposure estimates in this study based on the literature and common exposure factors.

Evaluation of dermal exposure to phthalates and parabens resulting from the use of hair relaxers

ABSTRACT Hair relaxers have been suggested as a source of exposure to parabens and phthalates. However, dermally absorbed doses of these chemicals resulting from consumer use of hair relaxers have yet to be quantified, and results from epidemiological studies have consistently demonstrated that there is no increased risk for hormone-sensitive, reproductive cancers associated with use of hair relaxers among Black women. Therefore, dermal absorption of parabens and phthalates associated with hair relaxer use for several commercially available hair relaxer kits was modeled using IH SkinPerm™. The chemicals detected in the hair relaxer kits included methylparaben (MP), ethylparaben (EP), butylparaben (BP), diethyl phthalate (DEP), bis(2-ethylhexyl) phthalate (DEHP), and the phthalate substitute bis(2-ethylhexyl) adipate (DEHA). The daily absorbed dose ranges (mg/kg/day), standardized over a year of product use, were as follows: 8.64 × 10−5-0.00116 MP, 2.30 × 10−8-3.07 × 10−6 EP, 3.24 × 10−8-4.33 × 10−6 BP, 8.65 × 10−9-1.15 × 10−6 DEP, and 8.94 × 10−7-0.000119 DEHP for Kit #1; 8.44 × 10−5-0.00113 MP and 7.91 × 10−5-0.00106 DEP for Kit #2; and 2.49 × 10−6-3.33 × 10−5 MP, 1.52 × 10−8-2.03 × 10−6 EP, 3.29 × 10−9-4.39 × 10−7 DEP, and 3.11 × 10−6-4.14 × 10−5 DEHA for Kit #3. These absorbed doses were well below applicable health-based guidance values, indicating consumer exposure from product use is not expected to pose a health risk. These results provide valuable information for health risk evaluations for hair relaxer use.

Dermal Exposure to Alkylphenol Ethoxylates in As-Purchased Garments: Human Health Risk Assessment

Textile production involves using various chemicals that may remain in clothing and pose health risks. Alkylphenol ethoxylates are non-ionic surfactants which may be involved in various textile printing and dyeing auxiliaries due to their excellent emulsification, wetting and decontamination abilities. This study aimed to determine the dermal exposure doses and health risks of alkylphenol ethoxylates in 10 unwashed textile samples for infants, toddlers and pregnant women. The concentrations of alkylphenol ethoxylates and alkylphenols (APs) were determined by liquid chromatography–mass spectrometry (LC-MS/MS). The total concentrations of alkylphenol ethoxylates (nonylphenol ethoxylates and octylphenol ethoxylates) in 10 textile samples were 113.21–1431.18 mg/kg, among which nonylphenol ethoxylates with ethoxy groups of 2–10 were the dominant chemicals. The highest dermal exposure dose was found in the toddler group, which was 1.27 and 4.14 times higher than those in the infant and pregnant women groups. When the maximum concentration was used for risk assessment based on tolerable daily intake, the hazard indices ( HI) for toddlers and infants were estimated to be 10.62 and 8.37, which may pose a higher risk to human health. Our assessment was specifically focused on new garments before washing. The garments containing alkylphenol ethoxylates can be washed to significantly reduce the exposure risk. The results of our study offer important information on human exposure to alkylphenol ethoxylates in textiles and clothing and provide a scientific basis for planning risk management measures for alkylphenol ethoxylates.

Dermal exposure assessment of formal e-waste dismantlers to flame retardants and plasticizers using passive sampling methodologies

The recycling of e-waste can lead to the release of organic chemicals when materials containing additives are subjected to dismantling and grinding. In this context, the exposure of workers from a Catalonian e-waste facility to flame retardants and plasticizers (including organophosphate esters (OPEs), polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs) and dechloranes) was assessed using T-shirts and wristbands as passive samplers. The study area includes an area exclusively dedicated to cathodic ray-tube (CRT) TVs dismantling, and a grinding area where the rest of e-waste is ground. All the families of compounds were detected in both T-shirts and wristbands, with the highest concentration levels corresponding to OPEs, followed by PBDEs, NBFRs, and dechloranes. The CRT area presented higher concentration levels than the grinding area. The compounds with higher concentrations in T-shirts were 2-ethylhexyl diphenyl phosphate (EHDPP), diphenyl cresyl phosphate (DCP) and triphenyl phosphate (TPHP), and the total concentration of all groups ranged between 293 and 8324 ng/dm2-h (hour). In the case of the wristbands, the most abundant compounds were DCP, TPHP, and BDE-209, with total concentrations between 188 and 2248 ng/dm2-h. The two sampling methods appear to be complementary, as T-shirts collect coarser particles, while wristbands also capture volatile compounds. Based on normalized surface and time concentrations, the estimated daily intake (EDI) through dermal contact was calculated and carcinogenic and non-carcinogenic risks (CR and non-CR) associated with this activity assessed. The results show median CR 29 and 16 times below the threshold in CRT and grinding areas respectively. The non-CR medians were 2 and 3 times below the threshold, although in the CRT area one exceptional value surpassed the threshold, suggesting that risk can exist for some workers in the facility.

Distribution and ecological health risk assessment of heavy metals in damietta branch of Nile River, Egypt

ABSTRACT The Nile River is one of the longest rivers in the world, serving as the lifeline of many countries. The river is subjected to significant anthropogenic pressures, and thus, understanding the magnitude of contamination and its possible consequences is needed. This research aimed to evaluate the presence of heavy metals in the surface water of an understudied region within the Nile River. The distribution and level of 18 elements along the Damietta branch were assessed, and their potential sources were estimated. Additionally, pollution indices and health risks were calculated. The results showed that most metals were within the acceptable levels of USEPA and WHO. However, Na, Mg, and Ca were higher than the permissible level of WHO, and K was higher than the permissible levels for irrigation. Furthermore, heavy metal pollution indicators, degree of contamination indices, heavy metal evaluation indices, Nemerow pollution indices, and water quality indices all pointed to very high standards for water quality. Also, the noncarcinogenic health risk index indicated a safe limit for dermal and oral exposure for adults and children. Overall, this study recommends management focus on anthropogenic activities in the Damietta branch of the Nile River.

Silicone Wristbands as a Personal Passive Sampler to Evaluate Indoor Exposure to Volatile and Non-volatile PFASs.

Exposure to per- and polyfluoroalkyl substances (PFASs) primarily occurs via consumption of contaminated drinking water and food; however, individuals can also be exposed dermally and via inhalation indoors. This study developed an analytical method for measuring volatile PFASs in silicone wristbands and used them to assess personal exposure in a Midwestern community (n = 87). Paired samples of blood and wristbands were analyzed for PFASs using LC-MS/MS and GC-HRMS to monitor both non-volatile and volatile PFASs. The most frequently detected PFASs in wristbands were: 6:2 diPAP, 6:2 FTOH, MeFOSE and EtFOSE. Females had a 4-fold higher exposure to 6:2 diPAP compared to males and age-dependent differences in exposure to 6:2 FTOH, MeFOSE and EtFOSE were observed. Exposure to MeFOSE and EtFOSE differed based on the average time spent in the home. Frequently detected PFASs in blood were: PFOA, PFOS, PFHxS, PFHpS, and N-MeFOSAA. A strong correlation was found between MeFOSE in the wristbands and N-MeFOSAA in serum (rs = 0.90, p-value <0.001), suggesting exposure to this PFAS was primarily via inhalation and dermal exposure. These results demonstrate that wristbands can provide individual level data on exposure to some polyfluoroalkyl precursors present indoors that reflect serum levels of their suspected biotransformation products.

Spatial distribution, sources, and health risk assessment of elements in road dust (

This research delves into the spatial distribution of 17 elements (Al, B, Ba, Bi, Cd, Co, Cr, Cu, Fe, Li, Mg, Mn, Ni, Pb, Sr, Te, and Zn) within the < 20 μm size fraction of road dust samples collected from 177 locations within 65 grid cells (each 5×5 km2) throughout Delhi in February 2021. Notably, Fe and Al emerge as the predominant elements in the road dust samples. Using Principal Component Analysis (PCA), Absolute Principal Component Score (APCS), and Multiple Linear Regression (MLR) techniques, it is observed that crustal sources (58%), non-exhaust vehicular emissions (21%), and two distinct industrial origins (2% and 19%) are major contributors to the road dust composition. Bi and Te exhibited the highest geo-accumulation indices, indicating significant pollution levels, with notably high contamination factors, surpassing a contamination degree of 24. Elements like Cd posed the highest potential ecological risk, dominating 95% of the risk assessment. The hazard index analysis highlighted that urban populations, especially children, face the greatest risk through ingestion, followed by dermal exposure, and least through inhalation. Notably, Cd, Pb, Cr, and Ni were identified as elements posing a very high carcinogenic risk to the general populace.

P07-08 BIOBRAND II: Interventions to reduce dermal and internal PAH exposure among firefighters and conscripts during education as firefighters

P07-08 BIOBRAND II: Interventions to reduce dermal and internal PAH exposure among firefighters and conscripts during education as firefighters

P23-09 Occupational dermal exposure assessment: an overview of the most relevant exposure estimation tools

P23-09 Occupational dermal exposure assessment: an overview of the most relevant exposure estimation tools

Occurrence, distribution and risk assessment of phthalate esters in dust deposited in the outdoor environment of Yazd industrial park using Monte Carlo simulation

In this study, the distribution of eight phthalate esters (PAEs), namely (dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), bis (2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DnOP)) were examined across fifteen sampling stations in Yazd industrial Park. All the PAEs in dust deposited in the outdoor environment were analyzed using a Gas-mass chromatography (GC-MS/MS) device. Both probabilistic and deterministic approaches were utilized to assess the non-carcinogenic and carcinogenic health risks for adult occupational population groups. These risks were associated with three exposure pathways: inhalation, ingestion, and dermal exposure to six phthalates in the dust samples. The findings revealed, among the fifteen sampling stations, highest and lowest concentrations of the PAEs in dust deposited in the outdoor environment were observed in S8 and S6, with BEHP (326.21 ± 4.35) μg/g and DMP (0.00 ± 0.02) μg/g, respectively. The total hazard index (HI) values were below one in all samples, indicating that the combined non-carcinogenic health risk from exposure to phthalates via inhalation, ingestion, and dermal pathways is within acceptable levels in each studied area. The total cancer risk (CR) values for BBP across all exposure routes were consistently low, with magnitudes ranging from 10- x 10−15to 10 x 10−11. The order of cancer risk from phthalate exposure in outdoor environments was ingestion > dermal > inhalation. The sensitivity analysis (SA) results indicated that the influential parameters in the carcinogenic risk in adult occupational population groups were concentration for inhalation and dermal pathways, as well as ingestion rate for the ingestion pathway. The result of this study provides new insight in to PAEs pollution and risk assessments related to the dust deposited in the outdoor environment of industrial Park. Furthermore, this finding is beneficial to the controlling the exposure and promoting steps to reduce PAEs contamination and manage health in the industrial area.

Bisphenols in daily clothes from conventional and recycled material: evaluation of dermal exposure to potentially toxic substances

Given the increasing concern about chemical exposure from textiles, our study examines the risks of dermal exposure to bisphenol A (BPA), bisphenol S (BPS), bisphenol B (BPB) and bisphenol F (BPF) from conventional and recycled textiles for adults, aiming to obtain new data, assess exposure, and evaluate the impact of washing on bisphenol levels. A total of 57 textile samples (33 from recycled and 24 from conventional material) were subjected to ultrasound-assisted extraction (UAE) followed by ultra-high performance liquid chromatography with tandem mass spectrometry analysis (UHPLC-MS/MS). The BPA and BPS concentrations varied widely (BPA: < 0.050 to 625 ng/g, BPS: 0.277–2,474 ng/g). The median BPA content in recycled textiles (13.5 ng/g) was almost twice as high as that of 7.66 ng/g in conventional textiles. BPS showed a median of 1.85 ng/g in recycled textiles and 3.42 ng/g in conventional textiles, indicating a shift from BPA to BPS in manufacturing practices. Simulated laundry experiments showed an overall reduction in bisphenols concentrations after washing. The study also assessed potential health implications via dermal exposure to dry and sweat-wet textiles compared to a tolerable daily intake (TDI) of 0.2 ng/kg bw/day for BPA set by the European Food Safety Authority (EFSA). Exposure from dry textiles remained below this threshold, while exposure from wet textiles often exceeded it, indicating an increased risk under conditions that simulate sweating or humidity. By finding the widespread presence of bisphenols in textiles, our study emphasises the importance of being aware of the potential risks associated with recycling materials as well as the benefits.

Chemical Dermal Exposure Risk Assessment in the Water Treatment Plant of Fertilizer Industry

Introduction:In water treatment plants (WTP), chemicals play a crucial role. However, some of these chemicals are hazardous. This study aims to conduct a dermal risk assessment in the WTP of an ammonia and urea production facility. Methods: The study was performed in August 2023 and assessed dermal exposure risk for four hazardous chemicals: NaOCl (30%), HCl (60%), H2SO4 (98%), and NaOH (48%), utilizing the Tier 2 RISKOFDERM model. Intrinsic toxicity was evaluated using risk phrases and toxicity information. Potential dermal exposure rates (PERBODY and PERHANDS) were determined based on task group and exposure modifier, while actual dermal exposure rates (AERBODY and AERHANDS) were determined based on clothing type and activity time. Health risk was assessed using actual exposure scores and intrinsic toxicity levels, which were categorized into 10 different levels ranging from 1 to 10. Results: The risk phrases indicated that four chemicals possessed a high level of intrinsic toxicity in terms of local effect but no systemic effect. PERBODY and PERHANDS were high (NaOCl, HCl) and low (H2SO4, NaOH). The actual exposure scores were determined to be 1 (high) for NaOCl and HCI, 0.01 (low) for H2SO4, and 0.03 (medium) for NaOH. Health risk values were 8 for NaOCl and HCI, 5 for H2SO4, and 6 for NaOH. Conclusion: Health risks in NaOCl and HCl were assigned action priority (AP) 1, followed by NaOH at AP-2, and H2SO4 at AP-3. The study recommends the implementation of control measures encompassing engineering solutions, administration, and personal protective equipment.

Contribution of Continued Dermal Exposure of PFAS-Containing Sunscreens to Internal Exposure: Extrapolation from In Vitro and In Vivo Tests to Physiologically Based Toxicokinetic Models.

Per- and polyfluoroalkyl substances (PFASs) are widely present in sunscreen products as either active ingredients or impurities. They may penetrate the human skin barrier and then pose potential health risks. Herein, we aimed to develop a physiologically based toxicokinetic (PBTK) model capable of predicting the body loading of PFASs after repeated, long-term dermal application of commercial sunscreens. Ten laboratory-prepared sunscreens, generally falling into two categories of water-in-oil (W/O) and oil-in-water (O/W) sunscreens, were subject to in vitro percutaneous penetration test to assess the impacts of four sunscreen ingredients on PFAS penetration. According to the results, two sunscreen formulas representing W/O and O/W types that mostly enhanced PFAS dermal absorption were then selected for a subsequent 30 day in vivo exposure experiment in mice. PBTK models were successfully established based on the time-dependent PFAS concentrations in mouse tissues (R2 = 0.885-0.947) and validated through another 30 day repeated exposure experiment in mice using two commercially available sunscreens containing PFASs (R2 = 0.809-0.835). The PBTK model results suggest that applying sunscreen of the same amount on a larger skin area is more conducive to PFAS permeation, thus enhancing the exposure risk. This emphasizes the need for caution in practical sunscreen application scenarios, particularly during the summer months.

Percutaneous Absorption of Fireground Contaminants: Naphthalene, Phenanthrene, and Benzo[a]pyrene in Porcine Skin in an Artificial Sweat Vehicle.

Firefighters face significant risks of exposure to toxic chemicals, such as polycyclic aromatic hydrocarbons (PAHs), during fire suppression activities. PAHs have been found in the air, on the gear and equipment, and in biological samples such as the skin, breath, urine, and blood of firefighters after fire response. However, the extent to which exposure occurs via inhalation, dermal absorption, or ingestion is unclear. In this study, three PAHs, naphthalene, phenanthrene, and benzo[a]pyrene, were applied to porcine skin in vitro in an artificial sweat solution to better gauge firefighters' dermal exposures while mimicking their sweaty skin conditions using an artificial sweat dosing vehicle. Multiple absorption characteristics were calculated, including cumulative absorption, percent dose absorbed, diffusivity, flux, lag time, and permeability. The absorption of the PAHs was greatly influenced by their molecular weight and solubility in the artificial sweat solution. Naphthalene had the greatest dose absorption efficiency (35.0 ± 4.6% dose), followed by phenanthrene (6.8 ± 3.2% dose), and lastly, benzo[a]pyrene, which had the lowest absorption (0.03 ± 0.04% dose). The lag times followed a similar trend. All chemicals had a lag time of approximately 60 min or longer, suggesting that chemical concentrations on the skin may be reduced by immediate skin cleansing practices after fire exposure.

Toxicokinetics of 2-ethylhexyl salicylate (EHS) and its seven metabolites in humans after controlled single dermal exposure to EHS

The chemical UV filter 2-ethylhexyl salicylate (EHS) is used in various personal-care products. The dermal and oral metabolism of EHS have already been targeted by different studies. However, toxicokinetic data after a single dermal exposure to EHS was missing. In our study, three volunteers were dermally exposed to a commercial EHS-containing sunscreen for 9 h with an application dose of 2 mg sunscreen per cm2 body surface area. The exposure was performed indoors, and sunscreen was applied on about 75% of the total skin area. Complete urine voids were collected over 72 h and eight blood samples were drawn from each subject. Urine samples were analyzed for EHS and seven known metabolites (5OH-EHS, 4OH-EHS, 2OH-EHS, 6OH-EHS, 4oxo-EHS, 5oxo-EHS, and 5cx-EPS) by online-SPE UPLC MS/MS. The peaks of urinary elimination occurred 10–11 h after application. The elimination half-lives (Phase 1) were between 6.6 and 9.7 h. The dominant urinary biomarkers were EHS itself, followed by 5OH-EHS, 5cx-EPS, 5oxo-EHS, and 4OH-EHS. 2OH-EHS, 6OH-EHS, and 4oxo-EHS were detected only in minor amounts. An enhanced analysis of conjugation species revealed marginal amounts of unconjugated metabolites and up to 40% share of sulfate conjugates for 5OH-EHS, 5oxo-EHS, and 5cx-EPS. The results demonstrated a delayed systemic resorption of EHS via the dermal route. Despite an extensive metabolism, the parent compound occurred as main urinary parameter. The delayed dermal resorption as well as the slow elimination of EHS indicate an accumulation up to toxicological relevant doses during daily repeated dermal application to large skin areas.

Impact of Skin Exposure to Benzo[a]pyrene in Rat Model: Insights into Epidermal Cell Function and Draining Lymph Node Cell Response.

The skin is a direct target of the air pollutant benzo[a]pyrene (BaP). While its carcinogenic qualities are well-studied, the immunotoxicity of BaP after dermal exposure is less understood. This study examines the immunomodulatory effects of a 10-day epicutaneous BaP application, in environmentally/occupationally relevant doses, by analyzing ex vivo skin immune response (skin explant, epidermal cells and draining lymph node/DLN cell activity), alongside the skin's reaction to sensitization with experimental hapten dinitrochlorobenzene (DNCB). The results show that BaP application disrupts the structure of the epidermal layer and promotes immune cell infiltration in the dermis. BaP exposure led to oxidative stress in epidermal cells, characterized by decreased reduced glutathione and increased AHR and Cyp1A1 expression. Production and gene expression of proinflammatory cytokines (TNF, IL-1β) by epidermal cells decreased, while IL-10 response increased. Decreased spontaneous production of IFN-γ and IL-17, along with unchanged IL-10, was observed in DLC cells, whereas ConA-stimulated production of these cytokines was elevated. Local immunosuppression caused by BaP application seems to reduce the skin's response to an additional stimulus, evidenced by decreased effector activity of DLN cells three days after sensitization with DNCB. These findings provide new insight into the immunomodulatory effects and health risks associated with skin exposure to BaP.

Assessing the health risks of dermal exposure to heavy metals dust among nail salon technicians.

Nail salon technicians are susceptible to potential exposure to a diverse array of hazardous chemicals in the form of dust or vapors. One of the main routes of exposure is dermal contact. The aim of present study was to health risk assessment of dermal exposure to dust containing heavy metals in nail salon technicians. Dust sampling was done on the work surface of 20 available nail salon technicians. The concentration of five metals including cadmium, lead, chromium, nickel, and manganese were determined using ICP-MS. Afterwards, the United States Environmental Protection Agency (USEPA) guideline was used to estimate the potential health risks, including carcinogenic and non-carcinogenic risks, associated with the analyzed metals. Results indicated the mean concentrations of Pb, Cd, Ni, Cr and Mn were 0.7953±0.4373, 0.0952±0.0264, 0.7666±0.8629, 0.4900±0.5994 and 1.134±0.4736, respectively. The hazard quotient (HQ) of all metals was within the permissible value, while hazard index (HI) was greater than 1. The probability of cancer risk (CR) resulting from dermal exposure to Ni, Cd and Cr exceeded the acceptable risk levels (10-6-10-4), but CR calculated for Pb was less than allowable value. Implementation of engineering controls such as downdraft vented nail tables and portable source capture systems is necessary. Besides, the use of personal protective equipment such as disposable nitrile gloves, N95 respirator masks, and ensuring proper training on safe work practices is recommended.

Advanced approach combines integrated weight water quality index and potential toxic elements for environmental and health risk assessment supported by simulation technique in Oued Souf, Algeria

The current research study evaluated the health and environmental risks issues associated with potentially toxic elements (PTEs) in the complex terminal aquifer located in the Algerian desert. The methods used included principal component and cluster (dendrogram) analysis to estimate source of ions and contamination. Various indices such as the Heavy Metal Pollution Index (HPI), Metal Index, hazard quotient, hazard index (HI), and cancer risk (CR) were applied to assess both environmental and human health risks. Furthermore, the Monte Carlo method was applied for probabilistic assessment of carcinogenic and non-carcinogenic risks through oral and dermal exposure routes in both adults and children. The results revealed that approximately 16% of the samples fell within the low pollution category (HPI < 100), indicating relatively lower levels of heavy metal contamination. However, the remaining 84% of the samples exhibited high pollution levels, indicating a significant presence of heavy metal pollutants in the northeastern part of the investigated area. The calculated average risk index (RI) for the collected samples was 18.99, with a range from 0.03 to 103.21. This indicates that a large portion, 82% of the samples, could cause low ecological risk (RI < 30), whereas the remaining 18% indicate a significant environmental pollution risk. The HI for oral ingestion showed that adults had HI values ranging from 0.231 to 1.54, while children exhibited higher values, ranging from 0.884 to 5.9 (Fig. 5a). For dermal exposure, HI values in adults ranged from 2.71E−07 to 8.74E−06 and in children, from 2.18E−06 to 7.03E−05. These findings highlight the potential non-carcinogenic risks associated with oral exposure to PTEs and underscore the increased vulnerability of children to metals such as Fe, Mn, Pb, and Cr. Most samples showed CR exceeding 1 × 10−4 for chromium (Cr) and lead (Pb), indicating a significant vulnerability to carcinogenic effects in both children and adults.