Cariton Kubwabo

Health Canada | HC · Department of Health

This study investigates associations between house characteristics and chemical contaminants in house dust, collected under the nationally representative Canadian House Dust Study (2007–2010). Vacuum samples (<80 µm fraction) were analysed for over 200 synthetic organic compounds and metal(loid)s. Spearman rank correlations between contaminant conc...

Exposure to organophosphate esters (OPEs) is extensive, yet few studies have investigated their association with hormone levels or semen quality. Here, we studied the association between urinary concentrations of OPEs and their metabolites with hormone levels and semen parameters in men (n = 117) predominantly in the 20-29 years age range who were...

The occurrence of thirty-nine contaminants including plasticizers, bisphenols, and flame retardants in potable water from Montreal and South Africa was analyzed to determine their presence and concentrations in different water sources. In Montreal, five bottled water (BW) brands and three drinking water treatment plants (DWTP) were included. In Sou...

During the summer of 2019, cases of lung injury associated with vaping emerged in North America, including among individuals who reported exclusive use of nicotine vaping liquids. Once vitamin E acetate was identified as a potential causative agent a quantitative method based on a simple sample dilution, separation by gas chromatography and analysi...

Currently, there is a lack of comprehensive data on the diversity of chemicals present in vaping liquids. To address this gap, a non-targeted analysis of 825 vaping liquids collected between 2017 and 2019 from Canadian retailers was conducted. Prior to mass spectrometry analysis, samples were diluted 1:500 v/v with methanol or acetonitrile. Chemica...

Bisphenol A (BPA) is used as a monomer in a number of consumer products, including baby bottles and sippy cups. Some jurisdictions around the world (including Canada) have regulated the production, advertising or selling polycarbonate baby bottles with BPA. Following the ban, makers have opted for alternative materials to BPA [named BPA analogues,...

Bisphenol A (BPA) is a high production volume (HPV) chemical used to make polycarbonate (PC) plastics and epoxy resins. Due to its potential adverse health effects, BPA has been restricted or banned in some products and thus many alternatives to BPA have been introduced into the market. Most of these alternatives such as bisphenol S (BPS), bispheno...

This study investigated the occurrence of 19 aryl phosphates and mixed alkyl-aryl phosphates in dust samples (n = 144) collected under the Canadian House Dust Study (CHDS). The predominant target analytes, detected in 100 % of the samples, were isodecyl diphenyl phosphate (IDDPP), cresyl diphenyl phosphate (CDPP), and isopropylated triaryl phosphat...

Extensive use of synthetic musk compounds (SMs) in numerous consumer and personal care products has resulted in direct human exposures via dermal absorption, inhalation of contaminated dust and volatilized fragrances, and oral ingestion of contaminated foods and liquids. SMs and their metabolites are lipophilic, hence commonly detected in various b...

Tobacco use, of which cigarette smoking is the most common, is a global health concern and is directly linked to over 7 million premature deaths annually. Measurement of the levels of tobacco-related biomarkers in biological matrices reflects human exposure to the chemicals in tobacco products. Nicotine, nicotine metabolites, anatabine, and anabasi...

Background Synthetic musk compounds are widely used as fragrances in many consumer products; however, information on human exposure and health effects is limited. Also, analytical methods for their quantification in biological matrices are limited. Objective In this study, an integrated method was developed and validated for the analysis of select...

Type 2 Diabetes Mellitus (T2DM) is a metabolic disorder, which results from a defect in insulin production, impaired insulin action or both. It is now regarded as one of the major non-communicable diseases on the rise worldwide. This exponential rise in incidence of T2DM, especially in children, adolescents and women of childbearing age, may be par...

Tris(2-ethylhexyl) phosphate (TEHP, CAS no. 78-42-2) is a plasticizer and a flame retardant, while di(2-ethylhexyl) phosphoric acid (DEHPA, CAS no. 298-07-7) is an oil additive and extraction solvent. Publicly-available information on repeated exposure to these two related organophosphate compounds is fragmentary. Hence, adult male and female Fisch...

A method for the analysis of short-chain and medium-chain chlorinated paraffins (SCCPs and MCCPs) in house dust was developed. The method is based on sonication extraction, sample cleanup by solid phase extraction (SPE), and separation and detection by gas chromatography coupled with mass spectrometry (GC/MS) operated in electron capture negative i...

While adult exposure to total bisphenol A (BPA) has been well documented, developmental exposure to BPA and fetal exposure to the bioactive form (free BPA) remains poorly defined. Therefore, pregnant women (n = 199) between 28 and 35 weeks of pregnancy were invited to participate in this study. Maternal serum free of hemolysis (n = 189) and urine (...

BACKGROUND: Exposure to organophosphate ester (OPE) flame retardants and plasticizers is widespread and is of concern due to their toxicity. OBJECTIVES: To investigate relationships between and within OPE concentrations in air, dust, hands, electronic product wipes and urinary metabolites with the goal of identifying product sources and exposure pa...

Background: Ingestion of house dust has been demonstrated to be an important exposure pathway to several contaminants in young children. These compounds include bisphenol A (BPA), alkylphenols (APs), and alkylphenol ethoxylates (APEOs). Analysis of these compounds in house dust is challenging because of the complex composition of the sample matrix....

Malaria devastates sub-Saharan Africa; the World Health Organization (WHO) estimates that 212 million people contract malaria annually and that the plasmodium virus will kill 419 000 in 2017. The disease affects rural populations who have the least economic means to fight it. Impregnated mosquito nets have reduced the mortality rate but the Anophel...

The incidence of breast cancer is on a rise worldwide; it is a disease having a complex etiology. Besides genetics, environmental and other lifestyle factors play a role in the development of the disease. There has been a keen interest in studying associations between breast cancer and exposures to emerging environmental chemicals, which mimic estr...

Phthalates have been used as plasticisers for several decades in various industry and consumer products. A method was developed for the determination of 13 not commonly monitored phthalates in household dust. The method was based on solvent extraction using sonication, sample clean-up by solid phase extraction (SPE), and analysis using isotope dilu...

A method based on gas chromatography coupled with triple quadrupole mass spectrometry (GC- MS/MS) was chosen over liquid chromatography coupled with triple quadrupole mass spectrometry (LC-MS/MS) for the simultaneous measurement of bisphenol A (BPA), 4-tert-octylphenol (OP), 4-n-nonylphenol (n-NP), 4-nonylphenol (NP), 4-nonylphenol monoethoxylate (...

An analytical method was developed for the measurement of 18 novel halogenated flame retardants in house dust. Sample preparation was based on ultrasound-assisted solvent extraction and clean up with solid phase extraction (SPE). Sample extracts were analyzed by gas chromatography-mass spectrometry (GC/MS) operated in electron capture negative ion...

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in many applications; however, certain PBDE congeners are persistent, bioaccumulative, and toxic to both humans and the environment. PBDEs have been found in human specimens, and a variety of analytical techniques have been used for their determination in biological matrixes. Never...

Over the last few years, the use of organophosphate flame retardants (OPFRs) has been on the rise; however, there are knowledge gaps in both the human health effects of OPFRs and levels of human exposure. Currently, human biomonitoring data on the levels of OPFR metabolites in the Canadian population are still non-existent. Herein we describe a nov...

Introduction Organophosphate flame retardants (OPFRs) are being used at an increased rate in consumer products due to the fact that they are perceived by the industry to be more environmentally friendly and thus safer alternatives than the halogen-based flame retardants 1. However, little in known about the human health effects of OPFRs and levels...

UICC World Cancer Congress, December 3–6 2014, Melbourne, Australia

Perfluorooctanoic acid (PFOA) is a persistent environmental contaminant. Activation of the peroxisome proliferator activated receptor alpha (PPARα) resulting from exposure to PFOA has been extensively studied in rodents. However, marked differences in response to peroxisome proliferators prevent extrapolation of rodent PPARα activation to human hea...

Bisphenol A (BPA) is a widely used industrial chemical in the manufacturing of polycarbonate plastic bottles, food and beverage can linings, thermal receipts, and dental sealants. Animal and human studies suggest that BPA may disrupt normal hormonal function and hence, potentially, have negative effects on the human health. While total BPA is frequ...

An analytical method for the simultaneous determination of 13 organophosphate esters (OPEs) in house dust was developed. The method is based on solvent extraction by sonication, sample cleanup by solid phase extraction (SPE), and analysis by gas chromatography-positive chemical ionization-tandem mass spectrometry (GC/PCI-MS/MS). Method detection li...

Phthalates have been used extensively as plasticizers to improve the flexibility of polymers, and they also have found many industrial applications. They are ubiquitous in the environment and have been detected in a variety of environmental and biological matrices. The goal of this study was to develop a method for the determination of 17 phthalate...

Polyfluoroalkyl phosphate surfactants (PAPS) are used on food contact paper to impart oil/grease resistance and have been shown to be able to migrate into food. The biotransformation of the congeners belonging to this class of compounds is considered to be a potential source of perfluorinated carboxylic acids (PFCAs). In this study, two methods wer...

A new method for the simultaneous determination of 11 synthetic musks and one fragrance compound in house dust was developed. The nitro musks included musk ketone (MK, 4-tert-butyl-3,5-dinitro-2,6-dimethylacetophenone), musk xylene (MX, 1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene), musk ambrette (1-tert-butyl-2-methoxy-4-methyl-3,5-dinitrobenze...

Bisphenol A is widely used as a monomer in the manufacture of polycarbonates and epoxy resins, as an antioxidant in polyvinyl chloride (PVC) plastics and as an inhibitor of end polymerisation in PVC. Several different methods have been used to quantify total BPA in biological specimens. However, quantification of both free and conjugated BPA contin...

Perfluoroalkyl acids (PFAAs) and polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants representing two classes of environmental contaminants of toxicological concern, especially for infants. Canadian biomonitoring data on these chemicals are limited. The objectives of this study were to measure PFAAs and PBDEs in umbilical cord...

Polybrominated diphenyl ethers (PBDEs), widely used as flame retardants in commercial products, have become ubiquitous environmental contaminants. Although adult human exposure to PBDEs is well documented, developmental exposure is less well characterized. The objectives of this study were to measure maternal and fetal exposure to nine PBDE congene...

An integrated analytical method for the simultaneous determination of five parabens (methyl-, ethyl-, propyl-, butyl-, and benzyl-), triclosan, and methyl triclosan in indoor house dust was developed based on gas chromatographic-mass spectrometric technique (GC/MS). Analytes were extracted from dust samples by sonication. After sample cleanup by so...

The quantification of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (Mutagen X or MX) in drinking water is difficult due to the low concentration of MX in drinking water, its high sensitivity to pH change, and matrix effects that interfere with the derivatization and analysis. Typically, the quantification of MX involves derivatization by me...

ISO/CD 18857-2 (International Organization for Standardization, Geneva) describes a new international standard method for the determination of octylphenol, nonylphenol, their mono- and diethyoxylates, and bisphenol A in nonfiltered samples of drinking, ground, surface, and wastewater. The method is based on the extraction of the analytes from an ac...

Human exposure to bisphenol A (BPA) has recently received special attention. It has been shown that exposure to BPA may occur through the consumption of beverages or foods that have been in contact with polycarbonate (PC) plastic containers or epoxy resins in food packaging. A BPA migration study was conducted using a variety of plastic containers,...

Perfluoroalkyl compounds (PFCs) are end-stage metabolic products from industrial flourochemicals used in the manufacture of plastics, textiles, and electronics that are widely distributed in the environment. The objective of the present study was to quantify exposure to perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorodecanoic...

A series of perfluorinated compounds (PFCs) including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have been recently measured in a variety of environmental samples and biological matrices. In order to better understand the human exposure routes of these chemicals, levels of PFOS, PFOA, perfluorobutane sulfonate (PFBS), perflu...

The efficiency of the in-source collision-induced dissociation (in-source CID) technique for the structural characterization of microcystins (MCYSTs) was evaluated. Microcystins that did not contain arginine underwent facile fragmentation to produce characteristic product ions at relatively low cone voltage and could be fully characterized based on...

Three different commercial standards of microcystin-RR were assessed for purity by the liquid chromatography coupled with electrospray ionization mass spectrometry (LC/ESI/MS) technique. Although the liquid chromatograms with photodiode array detector for each standard looked virtually identical, the analysis of corresponding mass spectra revealed...

A pilot study was conducted to provide preliminary data on the concentrations of perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorooctanesulfonamide (PFOSA) in the blood of Canadians. A set of 56 human serum samples was collected from non-occupationally exposed Canadians and analyzed by microbore HPLC-negative ion electros...

Microcystins (MCYSTs) were isolated from surface water using reusable immunoaffinity columns. Individual MCYST were determined by high performance liquid chromatography equipped with a photo-diode array detector (HPLC-PDA, 200-300 nm). Subsequent analysis of the samples by liquid chromatography-electrospray ionization mass spectrometry (LC-ESMS) pr...

Reversed-phase preparative HPLC has been successfully used to isolate several sulphonated azo dyes (Acid Red 1, Acid Red 8, Acid Red 106, Acid Violet 5, Chromotrope 2R, Reactive Orange 16 and Cibacron Brilliant Red 3B-A) from their impurities. The separations were achieved using mobile phases of methanol and ammonium acetate. The major components o...

A biological certified reference material for nine 2,3,7,8-chlorine substituted dibenzo-p-dioxin and dibenzofuran congeners and nine common polychlorinated biphenyl congeners is available for the first time. This material (CARP-1) is in the form of a slurry comprising approximately 9 g of carp homogenate sealed in a glass ampoule. The only foreign...

The alkaloid composition of the aerial parts and roots of PHYSALIS PERUVIANA was analysed by capillary GC (GC (2)), GC (2)-MS and GC (2)-FTIR. Eight alkaloids were identified, three of those alkaloids are 3beta-acetoxytropane and two N-methylpyrrolidinylhygrine isomers, which were not previously found in the genus PHYSALIS. A reproduction of the id...

Potentially-harmful chemicals could be released from many indoor materials, including consumer products and building materials, into indoor environments. Semi-volatile chemicals (SVOCs) due to their lower vapor pressure, are often present, either primarily in indoor dust or in both indoor air and indoor dust. Several types of SVOCs have been measur...