Potential Human Carcinogens Research Articles

Ethyl carbamate in retail market condiments and risk assessment of its dietary exposure for the Korean population

ABSTRACT Ethyl carbamate (EC), a potential human dietary carcinogen, is found in fermented foods including the fermented soybean-based condiments, the major part of the Korean diet. Therefore, it is expected that their EC contents might pose health risks. Herein, we collected 111 condiments and estimated their EC contents via gas chromatography-mass spectrometry. Further, dietary intake of EC was evaluated, and the risk levels were assessed via the margin of exposure (MOE) approach and excess cancer risk assessment. EC contents of the condiments ranged from not detectable to 39.47 μg/kg, and the daily EC exposure ranged from 1.4 to 2.0 ng/kg BW per day, depending on gender and age groups in Korea. Of the condiments, soy sauce was the largest contributor to EC exposure. MOE and excess cancer risks for the average consumer were 166,300 and 9.0 × 10−8, respectively, and those for the consumers in the 95th percentiles (P95) were 53,504 and 2.8 × 10−7, respectively, indicating that the risk of exposure to EC is of lower concern in average consumers than heavy consumers. However, the EC exposure from condiments was higher than that in other Asian countries. Abbreviations: EC: ethyl carbamate; GC-MS: gas chromatography-mass spectrometry; MOE: margin of exposure; MRL: maximum residue level; IDL: instrumental detection level; IQL: instrumental quantification level; MDL: method detection level; MQL: method quantification level; EDI: estimated daily intakes; BMDL10: benchmark dose lower confidence limit

Evaluation of sex steroid hormones and reproductive irregularities in diethyl phthalate-exposed premature mice: modulatory effect of raw honey against potential anomalies.

Phthalates, plasticizing chemicals, are top-rated environmental contaminants. Diethyl phthalate (DEP), a chief member of this family, was declared a potent endocrine disruptor and carcinogen in animals and humans. The current study was designed to explore the probable reproductive damage induced by DEP and the therapeutic efficacy of raw honey in male albino mice. Four-week-old 50 male mice were randomized equally in five groups, as control (C) received 0.1 ml distilled water; vehicle control (VC) received corn oil (0.1 ml/mouse); DEP (3mg/g/BW) dissolved in corn oil; honey control (HC) administered with honey (0.2 mg/g/day); and phthalate plus honey (P+H) administered with DEP and honey (3mg and 0.2 mg/g/BW/day respectively). Mice were treated through oral gavage for 54 days routinely, acclimatized for 6 days, and dissected. In the first instance, the antioxidant potential and total phenolic contents (TPC) of honey were analyzed through ferric reducing antioxidant power (FRAP) assay and Folin-Ciocalteu assay to confirm the antioxidant capacity of honey. The morphological, morphometric, histological, micrometric, sperm count, and hormonal analyses, and antioxidant capacity test in tissue homogenates were conducted by using tissues (testis, epididymis) and blood samples of mice. Mice exposed to DEP have a significant increase in body weight, LH level, and seminiferous tubule lumen diameter and decrease in the gonado-somatic index, testosterone level, sperm count, and seminiferous tubule diameter. Additionally, histopathology of testes showed interstitial space dilations, exfoliations, Leydig cell atrophy, germ cell degenerations, and spermatid retention in DEP-exposed testes sections. However, concomitant use of honey and DEP had shown a significant improvement in histopathological lesions, steroid hormone levels, and healthy sperm count. By these results, it is concluded that honey possessed antioxidant potential that can efficiently protect DEP-induced anomalies in male mice.

Assessment of different heavy metals in cigarette filler and ash from multiple brands retailed in Saudi Arabia

Tobacco smoking is considered one of the major global health concerns due to its known carcinogenic effects on the human body. In this study, 36 samples of tobacco products were evaluated for the approximation of the heavy metal content, including chromium (Cr), cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), manganese (Mn) and zinc (Zn) using the inductively coupled plasma - optical emission spectrometry (ICP-OES). The heavy metal content was evaluated in the tobacco filler, ash, and tobacco products (with and without filters). The average concentrations in filler tobacco products were 0.66 mg/kg, 0.09 mg/kg, 2.61 mg/kg, 245.55 mg/kg, 0.38 mg/kg, 3.985 mg/kg, and 1.64 mg/kg, for Cr, Cd, Cu, Fe, Pb, Mn, and Zn, respectively. Ash obtained from the combustion of different tobacco products had various toxic metals in different concentrations. Furthermore, the concentration of heavy metals in tobacco products (with and without filters) was also analyzed to evaluate the effect of filters. The results of the study showed that the number of heavy metals present, and their concentrations vary in different brands of tobacco products. Moreover, the concentrations for both Pb and Cd, the potent human carcinogens, were greater than the recommended threshold set forth by WHO and FAO.

Toxicokinetic and Genotoxicity Study of NNK in Male Sprague Dawley Rats Following Nose-Only Inhalation Exposure, Intraperitoneal Injection, and Oral Gavage.

The tobacco-specific nitrosamine NNK [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone] is found in tobacco products and tobacco smoke. NNK is a potent genotoxin and human lung carcinogen; however, there are limited inhalation data for the toxicokinetics (TK) and genotoxicity of NNK in vivo. In the present study, a single dose of 5 × 10-5, 5 × 10-3, 0.1, or 50 mg/kg body weight (BW) of NNK, 75% propylene glycol (vehicle control), or air (sham control) was administered to male Sprague-Dawley (SD) rats (9-10 weeks age) via nose-only inhalation (INH) exposure for 1 h. For comparison, the same doses of NNK were administered to male SD rats via intraperitoneal injection (IP) and oral gavage (PO). Plasma, urine, and tissue specimens were collected at designated time points and analyzed for levels of NNK and its major metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and tissue levels of DNA adduct O6-methylguanine by LC/MS/MS. TK data analysis was performed using a non-linear regression program. For the genotoxicity subgroup, tissues were collected at 3 h post-dosing for comet assay analysis. Overall, the TK data indicated that NNK was rapidly absorbed and metabolized extensively to NNAL after NNK administration via the three routes. The IP route had the greatest systemic exposure to NNK. NNK metabolism to NNAL appeared to be more efficient via INH than IP or PO. NNK induced significant increases in DNA damage in multiple tissues via the three routes. The results of this study provide new information and understanding of the TK and genotoxicity of NNK.

Environmental and economic concerns surrounding restrictions on glyphosate use in corn

Since the commercialization of transgenic glyphosate-tolerant (GT) crops in the mid-1990s, glyphosate has become the dominant herbicide to control weeds in corn, soybean, and other crops in the United States and elsewhere. However, recent public concerns over its potential carcinogenicity in humans have generated calls for glyphosate-restricting policies. Should a policy to restrict glyphosate use, such as a glyphosate tax, be implemented? The decision involves two types of tradeoffs: human health and environmental (HH-E) impacts versus market economic impacts, and the use of glyphosate versus alternative herbicides, where the alternatives potentially have more serious adverse HH-E effects. Accounting for farmers' weed management choices, we provide empirical evaluation of the HH-E welfare and market economic welfare effects of a glyphosate use restriction policy on US corn production. Under a glyphosate tax, farmers would substitute glyphosate for a combination of other herbicides. Should a 10% glyphosate tax be imposed, then the most conservative welfare estimate is a net HH-E welfare gain with a monetized value of US$6 million per annum but also a net market economic loss of US$98 million per annum in the United States, which translates into a net loss in social welfare. This result of overall welfare loss is robust to a wide range of tax rates considered, from 10 to 50%, and to multiple scenarios of glyphosate's HH-E effects, which are the primary sources of uncertainties about glyphosate's effects.

Strategies of the International Agency for Research on Cancer (IARC/WHO) to reduce the occupational cancer burden

The main mission of the International Agency for Research on Cancer (IARC/WHO) is to conduct research for cancer prevention worldwide. The strategies of the IARC to reduce the occupational cancer burden include enhancing cancer surveillance, evaluating and classifying potential human carcinogens, and conducting epidemiological research to fill gaps in knowledge on occupationally related cancers. Beyond the IARC work, it is essential to systematically monitor occupational exposures in workplaces, in order to effectively protect workers. There are multiple sources of information about occupational exposures in workplaces, but they are often not used for hazard surveillance or for research. The Russian Federation has great potential to advance research and worker protection due to their strong tradition to monitor and record exposure concentrations in workplaces. Currently most evidence regarding occupational cancer burden comes from Western Europe and North America. Estimation of the burden of occupational cancer requires accurate data from local settings as extrapolating data from other settings may be misleading due to major differences in exposures, exposure pathways and baseline cancer risks. To fill this knowledge gap, it is important to conduct exposure surveillance and epidemiological studies on occupational cancer in the Russian Federation.

Sensitivity of Aspergillus flavus Isolates from Peanut Seeds in Georgia to Azoxystrobin, a Quinone outside Inhibitor (QoI) Fungicide.

Aspergillus flavus infects peanuts and produces a mycotoxin called aflatoxin, a potent human carcinogen. In infected peanuts, it can also affect peanut seed quality by causing seed rot and reducing seed viability, resulting in low germination. In 2020, peanut seeds in Georgia had lower than expected germination and a high frequency of A. flavus contamination. A total of 76 Aspergillus isolates were collected from seven seed lots and their identity and in vitro reaction to QoI (quinone outside inhibitor) fungicide (azoxystrobin) were studied. The isolates were confirmed as A. flavus by morphological characteristics and a PCR (polymerase chain reaction)-based method using species-specific primers. In vitro, these isolates were tested for sensitivity to azoxystrobin. The mean EC50 values ranged from 0.12 to 297.22 μg/mL, suggesting that some isolates were resistant or tolerate to this fungicide. The sequences of cytochrome b gene from these isolates were compared and a single nucleotide mutation (36.8% isolates) was found as Cyt B G143A, which was associated with the total resistance to the QoIs. Another single mutation (15.8% isolates) was also observed as Cyt B F129L, which had been documented for QoI resistance. Therefore, a new major single mutation was detected in the A. flavus natural population in this study, and it might explain the cause of the bad seed quality in 2020. The high frequency of this new single nucleotide mutation exists in the natural population of A. flavus and results in the ineffectiveness of using azoxystrobin seed treatment. New seed treatment fungicides are needed.

Reduction of Ochratoxin A during the Preparation of Porridge with Sodium Bicarbonate and Fructose.

Ochratoxin A (OTA) is a potential human carcinogen that poses a significant concern in food safety and public health. OTA has been found in a wide variety of agricultural commodities, including cereal grains. This study investigated the reduction of OTA during the preparation of rice- and oat-based porridge by a simulated indirect steam process. The effects of sodium bicarbonate (NaHCO3) and fructose on the reduction of OTA were also investigated. During the processing, OTA in rice- and oat-porridge was decreased by 59% and 14%, respectively, from initial OTA artificially added at 20 μg/kg (dry weight basis). When 0.5% and 1% of sodium bicarbonate were added to rice porridge, increased reduction of OTA was observed as 78% and 68%, respectively. The same amounts of added sodium bicarbonate also further reduced OTA in oat porridge to 58% and 72%, respectively. In addition, increased reduction of OTA in the presence of fructose was observed. A combination of the two, i.e., 0.5% sodium bicarbonate and 0.5% fructose, resulted in a 79% and 67% reduction in rice porridge and oat porridge, respectively. These results indicate that indirect steaming may effectively reduce OTA in preparation of porridge-type products, particularly when sodium bicarbonate and/or fructose are added.

Perchloroethylene and Dry Cleaning: It's Time to Move the Industry to Safer Alternatives.

Perchloroethylene (PERC) is the most common solvent used for dry cleaning in the United States. PERC is a reproductive toxicant, neurotoxicant, potential human carcinogen, and a persistent environmental pollutant. The Environmental Protection Agency is evaluating PERC under the Frank R. Lautenberg Chemical Safety for the 21st Century Act, which amended the Toxic Substances Control Act (amended TSCA), and has mandated that PERC dry cleaning machines be removed from residential buildings. Some local and state programs are also requiring or facilitating transitions to alternative cleaning technologies. However, the potential for these alternatives to harm human health and the environment is not well-understood. This review describes the issues surrounding the use of PERC and alternative solvents for dry cleaning while highlighting the lessons learned from a local government program that transitioned PERC dry cleaners to the safest current alternative: professional wet cleaning. Implications for future public health research and policy are discussed: (1) we must move away from PERC, (2) any transition must account for the economic instability and cultural aspects of the people who work in the industry, (3) legacy contamination must be addressed even after safer alternatives are adopted, and (4) evaluations of PERC alternatives are needed to determine their implications for the long-term health and sustainability of the people who work in the industry.

Carcinogenic hazard assessment of cobalt-containing alloys in medical devices: Review of in vivo studies

Cobalt (Co) alloys have been used for over seven decades in a wide range of medical devices, including, but not limited to, hip and knee implants, surgical tools, and vascular stents, due to their favorable biocompatibility, durability, and mechanical properties. A recent regulatory hazard classification review by the European Chemicals Agency (ECHA) resulted in the classification of metallic Co as a Class 1B Carcinogen (presumed to have carcinogenic potential for humans), primarily based on inhalation rodent carcinogenicity studies with pure metallic Co. The ECHA review did not specifically consider the carcinogenicity hazard potential of forms or routes of Co that are relevant for medical devices. The purpose of this review is to present a comprehensive assessment of the available in vivo preclinical data on the carcinogenic hazard potential of exposure to Co-containing alloys (CoCA) in medical devices by relevant routes. In vivo data were reviewed from 33 preclinical studies that examined the impact of Co exposure on local and systemic tumor incidence in rats, mice, guinea pigs, and hamsters. Across these studies, there was no significant increase of local or systemic tumors in studies relevant for medical devices. Taken together, the relevant in vivo data led to the conclusion that CoCA in medical devices are not a carcinogenic hazard in available in vivo models. While specific patient and implant factors cannot be fully replicated using in vivo models, the available in vivo preclinical data support that CoCA in medical devices are unlikely a carcinogenic hazard to patients.

Photocatalytic degradation of ranitidine and reduction of nitrosamine dimethylamine formation potential over MXene–Ti3C2/MoS2 under visible light irradiation

Photocatalysis is an effective method to degrade ranitidine (RAN), which is a typical precursor of nitrosamine dimethylamine (NDMA), an extremely potent human carcinogen. Herein, MXene-Ti3C2/MoS2 composites were prepared by a hydrothermal treatment aiming to use them for the photocatalytic degradation of RAN and the reduction of NDMA formation potential (NDMA-FP) under visible light irradiation for the first time. The analysis of the morphology, chemical composition and structure of these composites as well as the results of electrochemical experiments showed that a heterojunction was formed between MoS2 and Ti3C2, which facilitated the separation of electron-hole pairs and charge transfer, and thereby the photocatalytic performance. The MXene-Ti3C2/MoS2 composite (MT-4) exhibited the best photocatalytic performance in 60 min, with the highest RAN degradation and mineralization efficiencies of 88.4% and 73.58%, and the lowest NDMA-FP of 2.01%. Active species, including •O2- radicals, h+ and •OH radicals, all contributed to the degradation of RAN, among which •OH radicals were the main active species involved in the photocatalytic activity. The mechanism of the photocatalytic degradation of RAN over MXene-Ti3C2/MoS2 photocatalyst under visible light irradiation was proposed. This work opens up a new perspective on the applications of MXene-based materials for photocatalytic degradation of challenging pollutants.

Diverse genetic backgrounds play a prominent role in the metabolic phenotype of CC021/Unc and CC027/GeniUNC mice exposed to inorganic arsenic

Arsenic methyltransferase (AS3MT) is the key enzyme in the pathway for the methylation of inorganic arsenic (iAs), a potent human carcinogen and diabetogen. AS3MT converts iAs to mono- and dimethylated arsenic species (MAs, DMAs) that are excreted mainly in urine. Polymorphisms in AS3MT is a key genetic factor affecting iAs metabolism and toxicity. The present study examined the role of As3mt polymorphisms in the susceptibility to the diabetogenic effects of iAs exposure using two Collaborative Cross mouse strains, CC021/Unc and CC027/GeniUnc, carrying different As3mt haplotypes. Male mice from the two strains were exposed to iAs in drinking water (0, 0.1 or 50 ppm) for 11 weeks. Blood glucose and plasma insulin levels were measured after 6-h fasting and 15 min after i.p. injection of glucose. Body composition was determined using magnetic resonance imaging. To asses iAs metabolism, the concentrations of iAs, MAs and DMAs were measured in urine. The results show that CC021 mice, both iAs-exposed and controls, had higher body fat percentage, lower fasting blood glucose, higher fasting plasma insulin, and were more insulin resistant than their CC027 counterparts. iAs exposure had a minor effect on diabetes indicators and only in CC027 mice. Blood glucose levels 15 min after glucose injection were significantly higher in CC027 mice exposed to 0.1 ppm iAs than in control mice. No significant differences were found in the concentrations or proportions of arsenic species in urine of CC021 and CC027 mice at the same exposure level. These results suggest that the differences in As3mt haplotypes did not affect the profiles of iAs or its metabolites in mouse urine. The major differences in diabetes indicators were associated with the genetic backgrounds of CC021 and CC027 mice. The effects of iAs exposure, while minor, were genotype- and dose-dependent.

Evaluation of tertiary butyl alcohol (TBA) impact on groundwater: application to California

Leaking underground storage tanks can contaminate the groundwater. Since the 1980s, California leaking underground storage tanks have released millions of gallons of petroleum containing tertiary butyl alcohol into the subsurface. This compound was banned in early 2000 due to human health concerns. The United States Environmental Protection Agency considers tertiary butyl alcohol an animal carcinogen and a potential human carcinogen. California has not established a maximum contaminant level for tertiary butyl alcohol. (1) Based on the documented health hazards, a maximum contaminant level should be developed for tertiary butyl alcohol in California. (2) The California Water Resources Control Board’s “Low Threat Closure Policy”, which is a tool to evaluate closure of leaking underground storage tank sites, does not require regulators to consider tertiary butyl alcohol contamination in soil or groundwater in their closure review. This practice should be revisited based upon tertiary butyl alcohol’s toxicity data, its biotransformation from methyl tertiary butyl ether, and its stability in the environment. This review summarizes toxicity, sources, and environmental transformation of tertiary butyl alcohol, aims to raise awareness regarding the magnitude of the tertiary butyl alcohol problem in groundwater, and urges California regulators to develop more stringent protocols for tertiary butyl alcohol treatment. The nine Regional Water Quality Control Boards regulate and oversee cleanup at leaking underground storage tank sites in California. This study will directly impact Regional Water Quality Control Boards regulatory practices and will help provide a framework for developing monitoring and cleanup strategy for tertiary butyl alcohol around the world.

Antibody- and aptamer-based competitive fluorescence polarization/anisotropy assays for ochratoxin A with tetramethylrhodamine-labeled ochratoxin A.

Ochratoxin A (OTA) is one of the mycotoxins that often contaminate a variety of food stuffs, and it is a potential carcinogen for humans. Taking advantage of selective affinity binding and simple, rapid, and sensitive fluorescence polarization (FP)/fluorescence anisotropy (FA) analysis, here, we report two competitive FP/FA assays for OTA using tetramethylrhodamine (TMR)-labeled OTA as a fluorescence tracer and either antibody or aptamer as an affinity ligand to recognize OTA. In the absence of OTA, the TMR-labeled OTA binds with a large-sized affinity ligand, showing a high FA value due to the slow rotation of the affinity complex. When OTA is present, OTA competes with the TMR-labeled OTA tracer in binding limited amount of affinity ligand, causing more free TMR-labeled OTA and a significant FA decrease. We found that the antibody showed a stronger affinity towards TMR-labeled OTA compared to the aptamer. The antibody-based FA assay showed higher signal changes than the aptamer based FA assay due to the larger size of antibody over aptamer. The antibody-based competitive FA assay enabled the detection of 2.4 nM OTA, while the aptamer-based FA assay also achieved a detection limit of 2.4 nM OTA at 10 °C with the help of streptavidin conjugation to increase the molecular size and to improve aptamer affinity. These two competitive FA assays were selective, showing capability for analysis in diluted red wine.

Rapid and long-lasting acceleration of zero-valent iron nanoparticles@Ti3C2-based MXene/peroxymonosulfate oxidation with bi-active centers toward ranitidine removal

Advanced oxidation processes (AOPs) can effectively degrade ranitidine, a pharmaceutical that is a typical precursor of nitrosamine dimethylamine (NDMA), an extremely potent human carcinogen.

Histomorphological Assessment of Formalin versus Nonformalin Fixatives in Diagnostic Surgical Pathology

Introduction Fixation is the critical step in the preservation of tissues in diagnostic pathology. The formalin is an economical and excellent fixative with the inherent property of adequate fixation. The well-established side effects of formalin include mucosal irritation, upper respiratory diseases, and corrosive injury to the gastrointestinal tract. In addition, substantial evidence exists regarding the potential role of formaldehyde as a human carcinogen. The carcinogenic and toxic effects of formalin encourage searching for alternative fixatives for tissue fixation. However, “the formalin dogma” has severely hampered the search for alternative fixatives for many years. Material and Methods Ninety tissues of liver and skeletal muscle obtained during autopsies were immersed in adequate amounts of the following fixatives: formalin (10%), methyl alcohol (70%), and acetone (100%). The comparison among the three was made based on time for fixation, preservation of tissue architecture, cell borders, cytoplasm, nuclear contours, chromatin texture, and uniformity of staining. Results The tissue preserved in formalin undergoes rapid fixation compared with alcohol and acetone. The tissue architecture, cell border characteristics of alcohol and acetone was found satisfactory compared with formalin. The cytoplasm and nuclear contour were superior with the formalin. The chromatin texture and uniformity of staining were similar with all the three fixatives. Conclusion The formalin is considered superior to most of the parameters, whereas both methyl alcohol and acetone showed nearly equivalent scores. Hence, owing to the potential human health hazards and carcinogenicity of formalin, no rational reasons hamper the complete substitution of formalin with alternative fixatives such as alcohol and acetone in diagnostic pathology and medical research.

Mutagenicity assessment of aflatoxin B1 exposed to essential oils

Alternative decontamination strategies focusing on the reduction and detoxification of mycotoxins in food and feed products have gained increasing attention in recent years. In the present study, we explored the potential of thyme, clove and rosemary essential oils (EOs) to inactivate aflatoxin B1 (AFB1) in vitro, the most potent human carcinogen produced by fungi. Furthermore, we investigated changes in the mutagenic activity of the EO on the inactivated AFB1 products by the Ames test. The AFB1 inactivation assay was performed under different incubation times (2, 24 and 72 h) and EO concentrations (10 and 50 μL mL−1) and was quantitatively monitored by high-performance liquid chromatography (HPLC). The results indicated that the in vitro exposure of AFB1 to the thyme, clove and rosemary EOs at 50 μL mL−1 for 72 h effectively inactivated AFB1 products at rates of 92, 90.8, and 82.8%, respectively. Moreover, a complete loss of mutagenicity was observed in the EO-inactivated AFB1 products when compared with the untreated samples. Therefore, our findings suggest the use of EOs as a promising approach for AFB1 reduction in the agri-food industry.

Carcinogenic effects of N-nitroso compounds in the environment

N-nitroso compounds (NOC) are produced by the acid catalyzed reaction of nitrite with certain nitrogen compounds. The gastrointestinal tract (GI) is the main site for the formation of reactive nitrogen species (RNS). Bacteria present on the GI tract surface reduced the dietary nitrate or nitrite into Nitric oxide NO and other related compounds. The clinical sign of NOC carcinogenicity varies according to species, dose, and route of administration. Humans are exposed to preformed N-nitroso compounds and endogenous NOC via the environmental food chain. Several NOC are potential human carcinogens, including DENA and NDMA, but evidence from population studies is inconsistent.

Highly sensitive, selective and naked-eye detection of bromide and bromate using distance–based paper analytical device

Bromine (Br) can usually be found as a bromide (Br‾) form contained in drinking water. Bromate (BrO3‾) formation often occurred during the ozonation process in the presence of Br‾. BrO3‾ is classified as a potential human carcinogen, so both the Br‾ and BrO3‾ concentrations must be strictly controlled before and after an ozone-based treatment procedure, respectively. This work reports on distance-based paper analytical devices (dPADs) that have been modified with silver hexagonal nanoprisms (AgNPrs) for highly sensitive and selective determination of both Br‾ and BrO3‾. The measurement of BrO3‾ is based upon its conversion to bromine vapor (Br2) when gauged with a paper-based headspace extractor (PAD-HS) that is coupled with dPADs (PAD-HS-dPADs). For Br‾ analysis, O2 plays an important role in the change from Br‾ to Br2 within an acid media. Br2 changes rapidly in water to give us HBrO which is a strong oxidizing agent of AgNPrs. Then, the oxidative reaction of the AgNPrs (pink color) within the presence of Br‾ and BrO3‾ establishes both silver bromide (AgBr) and the silver nanosphere (AgNPs, yellow color), which can then be easily observed as a change of a pink color band to a yellow color band by the naked eye. Quantification of Br‾ and BrO3‾ is then achieved by measuring the length of the yellow color band. Under the optimal conditions, the calibration curve will be linear in the range of 25 μg L−1 to 2 mg L−1, and from 0.5 to 50 μg L−1 for Br‾ and BrO3‾, respectively. The naked-eye detection limits were found to be 10 and 0.5 μg L−1 for Br‾ and BrO3‾, respectively. The proposed dPADs for the Br‾ and BrO3‾ detection exhibited an exceptional sensor performance combined with a low detection limit. They also have the benefits of ease of use, an instrument-free convenience, coupled with portability and a low-cost efficiency. Consequently, our sensing device should be applied to the low-level detection of Br‾ and BrO3‾ in real samples, including drinking water, rice, and flour.

Urinary metabolites of furan in waterpipe tobacco smokers compared to non-smokers in home settings in the US

ObjectivesDetermine uptake of furan, a potential human carcinogen, in waterpipe tobacco (WPT) smokers in home settings. MethodsWe analysed data from a US convenience sample of 50 exclusive WPT smokers, mean age 25.3 years, and 25 non-smokers, mean age 25.5 years. For WPT smokers, data were collected at a home visit by research assistants during which participants smoked one WPT head of one brand for a mean of 33.1 min in their homes. Research assistants provided and prepared a WP for participants by weighing and loading 10 g of WPT in the WP head. At the completion of the smoking session, research assistants measured the remaining WPT. Cotinine and six furan metabolites were quantified in first morning urine samples provided on 2 consecutive days for non-smokers, and on the morning of a WPT smoking session and on the following morning for smokers. ResultsWPT smokers consumed a mean of 2.99 g WPT. In WPT smokers, urinary cotinine levels increased significantly 26.1 times the following morning; however, urinary metabolites of furan did not increase significantly. Compared to non-smokers, 2 furan metabolites, N-acetyl-S-[1-(5-acetylamino-5-carboxylpentyl)-1H-pyrrol-3-yl]-L-cysteine and N-acetyl-S-[1-(5-amino-5-carboxypentyl)-1H-pyrrol-3-yl]-L-cysteine sulfoxide, were significantly higher in WPT smokers in pre and in post WPT smoking levels. ConclusionsTo enable a more rigorous assessment of furan exposure from WPT smoking, future research should determine furan concentrations in WPT smoke, quantify furan metabolites from users of various WPT brands; and extend the investigation to social settings where WPT smoking is habitually practiced.