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Departing from the regularly made references to Kenya's economy in the post-independence period by Ngugi wa Thiong'o in his works Matigari (1989) and Wizard of the Crow (2006), this essay argues that Ngugi, under the influence of Marxist aesthetics and Walter Rodney's dependency theory, has both chastised and offered strategies/suggestions to counter the persistent economic problems of Kenya and, to a broader scale, of Africa. Considering the developments in the Kenyan economy in the 20th century onward, this paper comparatively sketches Ngugi's treatment of economy-related problems in their evolving process in Matigari and Wizard of the Crow for Kenyans and syncretizes the changing economic conditions in Kenya with the Ngugi's literary criticisms and approaches to the issue., INTRODUCTION Although economy and literature are separate fields, it is always possible to read a literary piece of work within the framework of real economic conditions. There is a large [...]

BACKGROUND: A broad suite of bisphenol S (BPS) derivatives as alternatives for BPS have been identified in various human biological samples, including 4-hydroxyphenyl 4-isopropoxyphenylsulfone (BPSIP) detected in human umbilical cord plasma and breast milk. However, very little is known about the health outcomes of prenatal BPS derivative exposure to offspring. OBJECTIVES: Our study aimed to investigate the response of hepatic cholesterol metabolism by sex in offspring of dams exposed to BPSIP. METHODS: Pregnant ICR mice were exposed to 5 lg=kg body weight (BW)/day of BPSIP, BPS, or E2 through drinking water from gestational day one until the pups were weaned. The concentration of BPSIP, BPS, or E2 in the plasma and liver of pups was determined by liquid chromatographytandem mass spectrometry. Metabolic phenotypes were recorded, and histopathology was examined for liver impairment. Transcriptome analysis was employed to characterize the distribution and expression patterns of differentially expressed genes across sexes. The metabolic regulation was validated by quantitative real-time PCR, immunohistochemistry, and immunoblotting. The role of estrogen receptors (ERs) in mediating sex-dependent effects was investigated using animal models and liver organoids. RESULTS: Pups of dams exposed to BPSIP showed a higher serum cholesterol level, and liver cholesterol levels were higher in females and lower in males than in the controls. BPSIP concentration in the male liver was 1:22 [+ or -] 0:25 ng=g and 0:69 [+ or -] 0:27 ng=g in the female liver. Histopathology analysis showed steatosis and lipid deposition in both male and female offspring. Transcriptome and gene expression analyses identified sex-specific differences in cholesterol biosynthesis, absorption, disposal, and efflux between pups of dams exposed to BPSIP and those in controls. In vivo, chromatin immunoprecipitation analysis revealed that the binding of ERa protein to key genes such as Hmgcr, Pcsk9, and Abcg5 was attenuated in BPSIP-exposed females compared to controls, while it was enhanced in males. In vitro, the liver organoid experiments demonstrated that restoration of differential expression induced by BPSIP in key genes, such as Hmgcr, Ldlr, and Cyp7a1, to levels comparable to the controls was only achieved when treated with a combination of ERa agonist and ERb agonist. DISCUSSION: Findings from this study suggest that perinatal exposure to BPSIP disrupted cholesterol metabolism in a sex-specific manner in a mouse model, in which ERa played a crucial role both in vivo and in vitro. Therefore, it is crucial to systematically evaluate BPS derivatives to protect maternal health during pregnancy and prevent the transmission of metabolic disorders across generations. https://doi.org/10.1289/EHP14643, Introduction The use of bisphenol A (BPA) has been severely restricted due to proven adverse health effects, (1,2) leading to the widespread utilization of bisphenol S (BPS) and BPS derivatives [...]

Lakes and reservoirs are frequently monitored by researchers for elevated mercury concentrations in sportftsh. Rivers and streams, especially those of smaller orders, are less frequently monitored for mercury contamination and nonsport fishes and invertebrates, although important components of the food web, are rarely examined. We addressed this gap by surveying mercury' levels in a stream community in the Kiamichi River in southeastern Oklahoma, U.S., by sampling fish and macroinvertebrates at ten sites in the river. We found elevated levels of mercury across taxa within the river including individuals of smallmouth bass populations 10-25 cm in length hating concentrations (2986 [+ or -] 1053 ng/g dry weight) above the U.S. Environmental Protection Agency human limit. Furthermore, we observed high concentrations in darters and logperch (1133 [+ or -] 464 ng/g dry weight), nonsport fishes found predominantly in rivers and streams. Our results indicate mercury contamination can reach elevated concentrations in rivers and stream food webs, posing risks to both humans and wildlife., INTRODUCTION Mercury is an environmental contaminant negatively affecting the health of both humans and wildlife (Scheulhammer et aL, 2007). Mercury released into the atmosphere from human activities, predominantly coal fired [...]

The concentrations of halogens in serpentinised olivine-rich lithologies in the lower oceanic crust (e.g. troctolites and wehrlites) and altered-gabbros, recovered from IODP Hole U1309D on the Atlantis Massif of the Mid-Atlantic Ridge, are contrasted. The aims were to evaluate if serpentinisation of lower crustal lithologies could significantly contribute to the volatile budget of oceanic lithosphere and test if serpentinites formed from seawater preserve seawater-like halogen signatures. The olivine-rich lithologies are variably serpentinised by lizardite with minor chrysotile. The maximum concentrations of halogens in the most strongly serpentinised samples are 70 [micro]g/g F, 2,100 [micro]g/g Cl, 9,800 ng/g Br and 8 ng/g I. In comparison, the maxima in interlayered gabbros are 200 [micro]g/g F, 130 [micro]g/g Cl, 400 ng/g Br and 9 ng/g I. The Br/Cl ratios of the altered gabbros are strongly influenced by the presence of amphibole, which preferentially incorporates the smaller halides. The serpentinised lithologies have low F/Cl ratios, due to their strong enrichment in seawater-derived Cl, and they have Br/Cl and I/Cl ratios intermediate of unaltered oceanic crust and seawater-derived fluids. Br/Cl and I/Cl ratios similar to seawater are best preserved in the most Cl-rich samples consistent with these ratios fingerprinting the fluid responsible for serpentinisation. Serpentinites formed from seawater in the lower ocean crust and lithosphere are likely to have low I/Cl ratios. Serpentinsed lithologies in the lower crust (and mantle lithosphere) could, therefore, significantly contribute to halogen subduction helping to explain the range of I/Cl ratios in arc lavas and a proposed decrease of mantle I/Cl over time., Author(s): Mark A. Kendrick [sup.1], Michael A. W. Marks [sup.2], Marguerite Godard [sup.3] Author Affiliations: (1) grid.1003.2, 0000 0000 9320 7537, The School of Earth and Environmental Sciences, The University [...]

Author(s): V. G. Amelin [sup.1] [sup.2], D. S. Bol'shakov [sup.2], I. V. Podkolzin [sup.2] Author Affiliations: (1) grid.171855.f, 0000 0000 9825 6119, Vladimir State University, , 600000, Vladimir, Russia (2) [...], We developed procedures for the rapid screening and sensitive determination of residues of 19 [beta]-lactam antibiotics in matrices of various food products (meat, kidneys, liver, bacon, milk, eggs, honey) using ultrahigh-performance liquid chromatography-high-resolution quadrupole time-of-flight mass spectrometry. Acetonitrile was used to precipitate proteins and extract analytes; the extract was used for analysis without further purification. Identification was performed by exact masses and retention times of analyte ions and by assessing the ion isotope distribution (mSigma). Penicillins form positively charged protonated adducts with methanol, while cephalosporins form protonated ions or adducts with sodium. We estimated matrix effect in the analysis of various samples. The matrix effect is slightly different for milk, meat, liver, kidneys, eggs, and salted pork fat (RSD [less than or equal to] 7%) and significantly different for honey. The detected analytes were quantified both by the standard addition method and using matrix calibration (RSD [less than or equal to] 5%). The recovery of [beta]-lactam antibiotics from different matrices in two versions of sample preparation ranged from 75 to 110%; RSD [less than or equal to] 11% under the conditions of matrix calibration. The limits of detection were 0.05-5 ng/g; the analytical ranges were from 1-10 to 200 ng/g (R.sup.2 [greater than or equal to] 0.99); the duration of screening the samples was 15-20 min; the duration of the analysis of the samples was 20-30 min.

Author(s): Mir-Michael Mousavi [sup.1], Fardin Javanmardi [sup.1], Hashem Andishmand [sup.2], Mojtaba Momeni [sup.2], Mansour Mahmoudpour [sup.2] [sup.3] Author Affiliations: (1) grid.411600.2, Student Research Committee, Department of Food Science and Technology, [...], A novel sample pre-treatment technique based on vortex and ultrasound-assisted surfactant-enhanced emulsification microextraction followed by gas chromatographic-mass spectrometric detection has been developed to determine the selected pesticide residues in honey samples. The key parameters which have affected extraction efficiency were investigated and optimized. Under optimal conditions, the extraction recovery was 90-101% and the enrichment factors were 173-191. The concentration ranges of detection and quantification limits were from 0.03 to 0.9 ng/g and from 0.1 to 3 ng/g, respectively, in honey samples. The relative standard deviation was 5% for intra-day (n = 6) and 8% for inter-day precision (n = 4). Target pesticides were observed in 25% of the samples. The results of this study showed that the residues of such pesticides as bifenthrin, fenpyroximate and thiamethoxam were more than the maximum amount in some honey samples, which causes serious harm to human health.

Author(s): V. G. Amelin [sup.1] [sup.2], N. M. Avdeeva [sup.1] Author Affiliations: (Aff1) Federal Center for Animal Health, , 600901, Vladimir, Russia (Aff2) 0000 0000 9825 6119, grid.171855.f, Vladimir State [...], A procedure is developed for the rapid screening and sensitive determination of penicillins G and V in vegetables and fruits using ultra-high-performance liquid chromatographyâquadrupole time-of-flight high resolution mass spectrometry for exact masses of ions of protonated penicillin adducts with methanol. A simple and quick method of sample preparation (simplified QuEChERS method) is proposed for the analysis of fruits and vegetables (oranges, lemons, plums, pears, peaches, cabbage, potatoes, onions, carrots, beets, avocados, cucumbers, tomatoes, eggplants). Identification is carried out by the exact ion masses of analytes, retention time, and the pattern of the isotope distribution of ions (mSigma). Because of the significant matrix effect, analysis should be performed by the method of standard additions, by internal standard method (oxacillin), or using matrix grading. The limits of detection were 0.05â0.3 ng/g, the analytical ranges were 0.2 (0.9)â10 ng/g (R.sup.2 [greater than or equal to] 0.99), the duration of analysis was 15â20 min, RSD [less than or equal to] 10%.

The improper use of veterinary drugs (VDs) used to treat and prevent diseases of dairy animals leads to the appearance of residual amounts of these drugs in milk. At present, [...], A rapid screening and determination of 150 veterinary drugs of various classes in milk by UHPLC--high-resolution quadrupole time-of-flight mass spectrometry is proposed. One gram of milk was used for the analysis; the precipitation of proteins and extraction were performed with acetonitrile; the extract was analyzed without purification or preconcentration. Veterinary drugs were identified by accurate masses of analyte ions produced by electrospray ionization, their retention time, and the pattern of ion isotope distribution (mSigma). The quantitative analysis of the detected analytes was carried out by the standard addition method. The limits of detection were 0.1-0.5 ng/g; the analytical ranges were (0.1)1-500 ng/g; the duration of screening was 20-30 min; and the analysis time was 30-40 min. The relative standard deviation of the results for all analytes did not exceed 15%. Keywords: UHPLC, high-resolution time-of-flight mass spectrometry, milk analysis, veterinary drugs DOI: 10.1134/S1061934818060023

Pesticides from different classes are currently used in agriculture; some organic compounds are applied the most widely. 2,4-Dichlorophenoxyacetic acid (2,4-D) is a systemic herbicide used for weed control in cereal [...], A fluorescence polarization immunoassay (FPIA) procedure is developed for the determination of 2,4-dichlorophenoxyacetic acid in cereal grains using a Sentry-200 portable device. We synthesized tracers, that is, antigens labeled with fluorescein derivatives, based on two fluorescent compounds and two chlorophenoxyacids. The tracer synthesized from 2,4-dichlorophenoxyacetic acid and 4-aminomethylfluorescein is found to be optimal for the FPIA of 2,4-dichlorophenoxyacetic acid. The limit of detection for 2,4-dichlorophenoxyacetic acid in flour was 40 ng/g; the analytical range is from 80 to 1000 ng/g. The percentage of recovery was 85 [+ or -] 7% at the relative standard deviation (RSD) 2-10%. Keywords: fluorescence polarization immunoassay, pesticide, 2,4-dichlorophenoxyacetic acid, chlorophenoxyacids

Growth stimulants of [beta]-agonist class affect the productivity of livestock and poultry, enhance muscle weight gain, and have significant fat-burning effect, which favor the production of lean meat. The use [...], A method is proposed for the simultaneous identification and determination of 19 [beta]-agonists by exact ion masses in feed, meat, liver, and kidneys of animals using high-resolution time-of-flight mass spectrometry combined with HPLC and simple and fast sample preparation. Matrix effects under the conditions of electrospray ionization were eliminated by the dilution of the extract with a 10-fold volume of deionized water. A scheme of the identification and determination of analytes by the standard addition method is proposed. The limits of detection are 0.11-10 ng/g and limits of quantification, 0.34-31 ng/g. The relative standard deviation of the results of analysis does not exceed 13%. The time of analysis is 1-2 h. Keywords: [beta]-agonists, feed, food, HPLC, high-resolution time-of-flight mass spectrometry

Author(s): Liane Correia-Costa[sup.1] [sup.2] [sup.3] , Manuela Morato[sup.4] [sup.5] [sup.6] , Teresa Sousa[sup.4] [sup.5] , Dina Cosme[sup.1] [sup.4] , João Tiago Guimarães[sup.1] [sup.7] [sup.8] , Antonio Guerra[sup.3] [sup.9] , Franz [...], Background Fibrogenic cytokines are recognized as putative drivers of disease activity and histopathological deterioration in various kidney diseases. We compared urinary transforming growth factor [beta]1 (U-TGF-[beta]1) and endothelin 1 (U-ET-1) levels across body mass index classes and assessed their association with the level of urinary angiotensinogen (U-AGT), a biomarker of intrarenal renin-angiotensin-aldosterone system (RAAS). Methods The was a cross-sectional evaluation of 302 children aged 8-9 years. Ambulatory blood pressure (BP), insulin resistance (HOMA-IR), aldosterone level and renal function were evaluated. U-ET-1, U-TGF-[beta]1 and U-AGT levels were determined by immunoenzymatic methods. Results Obese children presented with the lowest levels of U-ET-1 and U-TGF-[beta]1, but the difference was only significant for U-ET-1. In obese children, the median levels of both U-ET-1 and U-TGF-[beta]1 tended to increase across tertiles (T1-T3) of U-AGT (U-ET-1: T1, 19.9 (14.2-26.3); T2, 32.5 (23.3-141.6); T3, 24.8 (18.7-51.5) ng/g creatinine, p = 0.007; U-TGF-[beta]1: T1, 2.2 (1.8-4.0); T2, 4.3 (2.7-11.7); T3, 4.9 (3.8-10.1) ng/g creatinine, p = 0.004]. In multivariate models, in the obese group, U-ET-1 was associated with HOMA-IR and aldosterone and U-AGT levels, and U-TGF-[beta]1 was associated with U-AGT levels and 24 h-systolic BP. Conclusions Whereas the initial hypothesis of higher levels of urinary fibrogenic cytokines in obese children was not confirmed in our study, both TGF-[beta]1 and U-ET-1 levels were associated with U-AGT level, which likely reflects an early interplay between tissue remodeling and RAAS in obesity-related kidney injury.

This application outlines a QuEChERS extraction of a subset of PPD-Qs in salmon, combined with push-thru cartridge clean-up using UCT's Quick QuEChERS[R], C18, and LipiFiltr[R] in series to achieve the best level of sensitivity in the fatty matrix. The extracts are analyzed on UCT's SelectraCore[R] C18 HPLC column using LC-MS/MS., Introduction Tire degradation releases 6PPD, which reacts with ozone to form toxic 6PPD-quinone (6PPD-Q), threatening aquatic life, particularly juvenile coho salmon, at LC50 as low as 0,094 ng/g, This concern [...]

Recent studies documented the potential transfer of microcystin, a hepatotoxin produced by some cyanobacteria, from aquatic to terrestrial ecosystems. Using enzyme linked immunosorbent assay, we measured microcystins in emergent Hexagenia limbata mayflies and fecal samples collected from a maternity colony of little brown bats (Myotis lucifugas) located adjacent to a Michigan (U.S.A.) lake that experiences seasonal blooms of toxicogenic Microcystis aeruginosa. All H. limbata and M. luafugus fecal samples contained microcystin (H. limbata'. mean = 293.88 ng/g dw ± 35.99 SE, n = 39; M. lucifugus'. mean = 262.10 ng/g dw ± 31.08 se, n = 20). Ingestion of this toxin may represent a previously unrecognized stressor on bat populations in this region., INTRODUCTION Most North American bats are insectivorous (Hutson et at, 2001), and many are generalist and opportunistic feeders. For example Lee and McCracken (2005) documented significant differences in insect composition [...]

Polybrominated diphenyl ethers are a group of persistent organic pollutants (POPs) consists of 209 PBDE congeners, distinguished by the number and position of their bromine atoms in the molecule [1-3]. [...], A comprehensive and efficient method is presented for the determination of 9 polybrominated diphenyl ether congeners (PBDEs), 2,4,4'-tribromodiphenyl ether (PBDE-28), 2,3',4,4'-tetrabromodiphenyl ether (PBDE-47), 2,2',4,4',6-pentabromodiphenyl ether (PBDE-66), 2,2',4,4',5-pentabromodiphenyl ether (PBDE-100), 2,2',3,4,4'-pentabromodiphenyl ether (pBdE-99), 2,2',4,4',5,6'-hexabromodiphenyl ether (pBDE-85), 2,2',4,4',5,5'-hexabromodiphenyl ether (PBDE-154), 2,2',4,4',5,5'-hexabromodiphenyl ether (PBDE-153) and 2,2',3,4,4',5,6'-heptabromodiphenyl ether (PBDE-183), in mollusc bivalve samples. An experimental design was used to evaluate the influence of several operational parameters on the extraction performance and to obtain the best experimental conditions. Under the final working conditions, freeze-dried mollusc was placed in the Soxtec thimble in order to extract PBDEs with 100 mL of n-hexane-acetone (4 : 1) after 1.5 h and 1 h of boiling and rinsing times, respectively. Soxtec extracts were additionally purified on a multilayered column and after injected in the gas chromatography combined with mass spectrometry (GC-MS) system. Quantitative recoveries of the analytes at three concentration levels ranged between 80 and 108%, and limits of quantification of the method (LOQs) between 0.5 and 20 ng/g. Analysis of mussel and clam samples showed that PBDE-47 and PBDE-99 were presented in almost all samples with concentrations between 0.6 and 2.6 ng/g dry weight. Moreover, a certified reference material (NIST 2974a) was used. The obtained concentrations were in agreement with the certified values. Keywords: polybrominated diphenyl ethers, soxtec device, GC-MS, bivalve mollusc DOI: 10.1134/S1061934815050111

OA16.04 K. Ho (1); C. Hoesley (2); P. Anderson (3); C. Kelly (4); Y. Jiao (4); S. Edick (5); N. Reddy (2); R. Brand (5); R.K. Ayudhya (6); J. Piper [...], Background: On demand topical PrEP may meet the needs of those who prefer episodic, non-systemic PrEP or struggle with or reject daily oral PrEP. PC-1005 gel, which contains MIV-150, is active against HIV-1, HPV, and HSV-2 - an attractive multipurpose prevention technology candidate. We evaluated rectal safety and pharmacokinetics (PK) of PC-1005 gel applied rectally. Methods: HIV-uninfected persons >18 years of age each received a series of 3 rectal gel doses at increasing volumes of 4, 16, and 32 mL with a washout period between doses. Following each dose, plasma, rectal tissue and fluid, and vaginal fluid were collected up to 7 times over 48 hours. Results: We enrolled 13 participants, 7 men and 6 women (birth sex), median 34 years of age, including 6 white, 5 black, and 2 mixed race/ethnicity. 12 participants completed all 3 doses. Thirteen adverse events were reported, all Grade 1 or 2, of which 5 were judged related to study drug without relationship to dose volume. Median (interquartile range) plasma MIV-150 concentration peaked 1 or 2 hours after dosing at 0.074 ng/mL (0.052, 0.086), 0.184 (0.162, 0.211), and 0.171 (0.098, 0.316), after 4, 16, and 32 mL doses, respectively; median concentrations were below assay quantitation limits (BLQ) 24 hours after dosing. Median half-life was 1.4 to 1.9 hours across dose volumes. Rectal Tissue MIV-150 peaked 0.5 to 1 hours after dosing at 1.4 ng/g (ng/mL) (0.8, 1.9), 46.0 (30.7, 831.0), and 79.7 (11.9, 116.0), respectively, after each dose volume. Median tissue concentrations were BLQ (0.7 ng/g) at 1.5 to 3, 24, and 3.5 to 5 hours after each escalating dose volume, respectively. Median rectal fluid concentrations were >14 ng/mL (ng/g) through 5 hours in all arms; vaginal fluid samples were all BLQ (0.2 ng/mL). Across dose volumes, 83%-92% of participants rated the gel as comfortable or very comfortable. Conclusions: PC-1005 gel was well-tolerated with low systemic exposure. MIV-150 rectal tissue concentrations were transient and below the 100 ng/g target; no MIV-150 was detectable in vaginal fluids. Based on concentration data, a longer-acting reformulation delivering more MIV-150 to rectal tissues is likely needed to support further development of PC-1005 as an on demand HIV rectal microbicide.

Introduction Minimal change disease (MCD) is by far the most common cause of nephrotic syndrome in children [1]. It accounts for approximately 80-90% of cases. The second most common type [...], Background Early diagnosis of minimal change disease (MCD) in nephrotic syndrome (NS) patients remains challenging. Doctors often make a diagnosis of MCD using invasive renal biopsy. CD80, a transmembrane protein, is present on podocytes in a number of experimental models of NS. Urinary CD80 levels are significantly elevated in MCD but not in focal segmental glomerulosclerosis (FSGS) or other glomerulopathies. The purpose of this study was to investigate the feasibility of using urinary CD80 levels as a biomarker for the diagnosis of MCD. Materials and methods A total of 165 subjects, 129 men and 36 women, were enrolled in this study. Urinary samples were collected from 37 patients with MCD, 27 patients with FSGS, 30 patients with other glomerulopathies, and 71 healthy people. Using ELISA, experimental values were compared with those produced by kidney biopsy samples. Results The concentration of urinary CD80 was significantly higher in the active MCD group (689.66 [+ or -] 378.21 ng/g creatinine) than in the FSGS group (123.49 [+ or -] 167. 88 ng/g creatinine, P Conclusions This experiment has preliminarily confirmed urinary CD80 as a non-invasive diagnostic biomarker. It may have significant value in the diagnosis of MCD. Keywords MCD * FSGS * CD80 * Children

Background Chronic stress is known to negatively impact overall health status (McEwen 2012). Many individuals in sub-Saharan Africa are believed to be stressed about their job and employment status, their [...], Stress is known to contribute to overall health status. Many individuals in sub-Saharan Africa are believed to be stressed about their employment, income, and health. This study aimed to investigate hair cortisol as a biomarker of chronic stress in settlement communities in Kenya. Hair samples were collected from 108 volunteers from settlement communities in Kenya. An enzyme-linked immunosorbent assay technique was used to measure hair cortisol concentrations. In parallel, a health survey was completed. The mean [+ or -] SD for the cortisol concentration in the hair of volunteers from the settlement communities in Naivasha was 639 [+ or -] 300 ng/g, which was higher than found for a Caucasian reference group (299 [+ or -] 110 ng/g; one-way ANOVA, P = 0.0003). There were no differences in hair cortisol concentrations between members of slum settlements adjacent to large floriculture farms in Naivasha (Karagita, Kamere/Kwa Muhia/DCK, and Kasarani) compared with those well-removed from all floriculture in Mogotio (Mogotio and Westlands/Katorongot). However, hair cortisol concentrations were significantly higher in females, divorced volunteers, those who made below minimum wage, and those who reported feeling unsafe collecting water or using sanitation facilities within these 2 settlement groups. We found no evidence for increased chronic stress (measured by hair cortisol content) between members of slum settlements adjacent to versus distant to large floriculture farms. Cultural and socio-economic conditions that prevail in much of sub-Saharan Africa were found to be factors contributing to chronic stress. Key words: hair, cortisol, socioeconomic status, Kenya, chronic stress, floriculture. On sait que le stress contribue a l'etat de sante global. On soup^onne que plusieurs individus habitant l'Afrique sub-saharienne sont stresses a cause de leur emploi, de leur revenu et de leur sante. Cette etude visait a examiner le cortisol de cheveux comme bio-marqueur du stress chronique de collectivites de peuplement au Kenya. Les echantillons de cheveux ont ete recoltes de 108 volontaires habitant des collectivites de peuplement au Kenya. Les concentrations de cortisol des cheveux ont ete mesurees a l'aide d'un dosage par ELISA. En parallele, une enquete sur la sante a ete completee. La concentration moyenne [+ or -] E.-T. de cortisol des cheveux des collectivites de peuplement de Naivasha etait de 639 [+ or -] 300 ng/g, ce qui etait superieur a la concentration du groupe de reference Caucasien (299 [+ or -] 110 ng/g; ANOVA; P = 0,0003). Il n'y avait pas de difference entre les concentrations de cortisol des collectivites de peuplement des bidonvilles adjacents aux fermes floricoles de Naivasha (Karagita, Kamere/Kwa Muhia/DCK et Kasarani), et celles bien retirees de toute floriculture de Mogotio (Mogotio et Westlands/Katorongot). Cependant, les concentrations de cortisol des cheveux etaient significativement plus elevees chez les femmes, les volontaires divorces, les personnes vivant sous le salaire minimum, et celles qui rapportaient ne pas se sentir en securite en allant chercher de l'eau ou en utilisant les lieux d'hygiene et ce, au sein de ces deux collectivites de peuplement. Les auteurs n'ont pas etabli la preuve d'un stress chronique accru (mesure par le contenu en cortisol des cheveux) entre les membres des collectivites de peuplement des bidonvilles adjacentes ou distantes des grandes fermes floricoles. Les conditions culturelles et socioeconomiques qui prevalent dans une grande partie de l'Afrique sub-saharienne se sont averees constituer des facteurs contribuant au stress chronique. [Traduit par la Redaction] Mots-cles: cheveux, cortisol, statut socioeconomique, Kenya, stress chronique, floriculture.

A microwave-assisted extraction technique was developed for the determination of nine sulfonamide antibiotics (sulfaguanidine, sulfacetamide, sulfadiazine, sulfathiazole, sulfapyridine, sulfamethazine, sulfamerazine, sulfamethoxazole, and sulfadimethoxine) in six sediments and soils of varying organic carbon content. Method optimization was performed using Lake Erie sediment and revealed the optimum extraction solvent to be methanol, with an extraction time of 45 min. After extraction, samples were 'cleaned up' via filtration and quantified using LC-MS/MS spectroscopy. Method calibration curves were constructed in each environmental solid with sulfonamides ranging from 10 to 2000 ng/g; method detection limits were typically in the sub- to low nanograms per gram range. Method validation entailed spiking each solid at three different concentrations spanning the calibration curve (40, 300, and 800 ng/g); generally, method accuracy for spiked solids exceeded 80%, with precision being within 20%. Finally, we extracted sulfonamides from environmental solids (two sediments and one soil) that had been aged for 21 days and found that our method accuracy remained in excess of 80%. Moreover, absolute recoveries generally agreed with method accuracies (at the 95% confidence interval) in all environmental solids, demonstrating the efficiency of our microwave-assisted extraction procedure and its suitability for application to environmental samples. Key words: sulfonamide antibiotics, sediment, soil, organic carbon content, microwave-assisted extraction, LC-MS/MS. Une technique d'extraction assistee par micro-ondes a ete mise au point pour la determination de neuf antibiotiques sulfamides (sulfaguanidine, sulfacetamide, sulfadiazine, sulfathiazole, sulfapyridine, sulfamethazine, sulfamerazine, sulfamethoxazole et sulfadimethoxine) dans six sediments et sols de compositions en carbone organique differentes. L'optimisation de la methode a ete effectuee a l'aide de sediment originaire du lac Erie et a montre que le meilleur solvant d'extraction etait le methanol, associe a un temps d'extraction de 45 min. Apres extraction, les echantillons ont ete << nettoyes >> par filtration et quantifies en utilisant la LC-MS/MS. Des courbes de calibration ont ete tracees pour chaque solide environnemental, les concentrations des sulfonamides variant entre 10 et 2000 ng/g. Les limites de detection de la methode etaient generalement a (ou en dessous du) niveau des nanogrammes par gramme. La validation de la methode a ete realisee par la contamination et l'extraction de chaque solide a trois concentrations differentes chevauchant la courbe de calibration (40, 300 et 800 ng/g). Generalement, la precision de la methode pour les solides contamines a depasse les 80%, l'incertitude etant au maximum de 20%. Enfin, nous avons extrait des sulfonamides de solides environnementaux (deux sediments et un sol) qui avaient matures pendant 21 jours et avons decouvert que la precision de notre methode restait superieure a 80%. En outre, les recouvrements absolus ont generalement coincide avec les precisions de methode (dans l'intervalle de confiance de 95%) pour tous les solides environnementaux, ce qui demontre l'efficacite de notre procedure d'extraction assistee par micro-ondes et qu'elle s'applique particulierement bien aux echantillons environnementaux. [Traduit par la Redaction] Mots-cles: antibiotiques sulfamides, sediment, sol, composition en carbone organique, extraction assistee par micro-ondes, LC-MS/MS., Introduction In recent years, the occurrence, fate, and biological impacts of pharmaceuticals in the environment have been recognized as serious issues warranting greater study. (1) Investigations of effluent from municipal [...]

A special concern is raised by the contamination of the environment and foods by compounds with the properties of estrogenic hormones exerting negative effect onto human endocrine status. Similarly to [...], A procedure has been developed for the determination of bisphenol A (BPA) in foods by gas chromatography/mass spectrometry as 2,2-bis-(4-(isopropoxycarbonyloxy)phenyl)propane formed in the reaction with isopropyl chloroformate. Optimal conditions have been found for BPA derivatization, providing its quantitative conversion into diether derivative in aqueous media. The concentration of BPA has been determined in some samples of canned foods and beverages (from 2.15 to 42.91 ng/g). The detection limit is 0.05-0.1 ng/g. Keywords: bisphenol A, isopropyl chloroformate, gas chromatography, mass spectrometry. DOI: 10.1134/S1061934812030057

Polar bears (Ursus maritimus Phipps, 1774) are exposed to heavy metal and lipophilic contaminants that are known to bioaccumulate and biomagnify. Few studies concurrently report both chemical classes in the same individuals and are thus unable to assess drivers of observed tissue concentrations, and the potential adverse biological responses to combined exposures. We examined blood concentrations of mercury (Hg) and the sum of seven polychlorinated biphenyls (Σ7PCB) from free-ranging Southern Beaufort Sea polar bears to assess which factors contributed to variations among cohorts (adult males, adult females, young) during spring. Concentrations of Hg ranged from 10.3 to 228.0 ng/g wet mass, but mean concentrations were similar between males and females independent of age. Concentrations of Σ7PCB (range 2.0-132.8 ng/g wet mass) were greater among females and young than among males. Toxicant concentrations were related to packed cell δ[sup.15]N, an estimate of trophic position, after the inclusion of packed cell δ[sup.13]C. Concentrations of Σ7PCB were also positively correlated with concentrations of neutral lipids (triglycerides and free fatty acids) and inversely correlated to body condition indices. Elevated concentrations of toxicants and lower body condition indices in females and young compared with males may be a sentinel to a changing arctic environment. Further assessment of the potential adverse health impacts of contaminants and nutritional stress in these cohorts is warranted. Les ours polaires (Ursus maritimus Phipps, 1774) sont exposes a des metaux lourds et a des contaminants lipophiles qu'on sait soumis a la bioaccumulation et a la bioconcentration. Peu d'etudes traitent a la fois de ces deux classes chimiques chez un meme individu et sont donc incapables d'evaluer les facteurs explicatifs des concentrations observees dans les tissus et les reactions biologiques adverses potentielles a ces expositions combinees. Nous avons mesure les concentrations sanguines de mercure (Hg) et d'un ensemble de sept biphenyles polychlores (Σ7PCB) chez des ours polaires en liberte dans le sud de la mer de Beaufort afin d'evaluer les facteurs qui contribuent aux variations entre les cohortes (adultes males, adultes femelles, oursons) au printemps. Les concentrations de Hg varient de 10,3 a 228,0 ng/g masse fraiche, mais les concentrations moyennes sont semblables chez les males et les femelles, independamment de l'age. Les concentrations de Σ7PCB (etendue 2,0-132,8 ng/g masse fraiche) sont plus elevees chez les femelles et les jeunes que chez les males. Les concentrations de produits toxiques sont reliees au δ[sup.15]N des globules compactes, une estimation de la position trophique, apres l'inclusion du δ[sup.13]C des globules compactes. Les concentrations de Σ7PCB sont aussi en correlation positive avec les concentrations de lipides neutres (triglycerides et acides gras libres) et en correlation inverse avec les coefficients de condition corporelle. Des concentrations elevees de produits toxiques et des coefficients de condition plus faibles chez les femelles et les jeunes par comparaison avec les males peuvent jouer le role de sentinelle pour le changement dans l' environnement arctique. Il y a lieu de faire des evaluations supplementaires des effets nefastes potentiels de ces contaminants et des stress alimentaires sur la sante de ces cohortes. [Traduit par la Redaction], Introduction Many contaminants undergo long-range transport from southern latitudes and are deposited in arctic ecosystems via biota, air, and water (Macdonald et al. 2005; Swain et al. 2007). Climate changes [...]

The importance of ensuring food safety through the reduction of chemical residues in our food supply cannot be overemphasized. Food safety remains a major challenge confronting contemporary society. To ensure wholesomeness of food of animal origin, the level of drug residues must be below the maximum residue limits (MRLs) set by World Health Organization (WHO) and Food and Agriculture Organization (FAO). This calls for cost effective and efficient analytical methods for both quality assurance and monitoring. Diminazene aceturate is one of the few treatment drugs for animal trypanosomosis in the market. Because of its wide use in food producing animals, unwanted residues may be a risk to consumers. A competitive enzyme-linked immunosorbent assay (cELISA) for determination of diminazene residues in edible animal tissues after extraction in 0.1 M borax pH 9.7 is described. The assay has advantages of speed, high throughput and lower cost of analysis compared to the other conventional methods. The assay uses rabbit anti-diminazene polyclonal antibodies bound on a 96-well microtiter plate. Horseradish peroxidase-labeled diminazene and diminazene in a test sample were allowed to compete overnight at 4°C for the limited number of antibodies bound on the microtiter plate. After six washes with buffer, enzyme activity was determined by adding tetramethyl-benzidine and hydrogen peroxide as substrate. The assay detection limits for diminazene were 2.4 ng/g in muscle, 2.5 ng/g in liver and 2.2 ng/g in kidney while limits of quantification were 7.2 ng/g, 7.5 ng/g and 6.6 ng/g respectively. The recoveries for muscle liver and kidney spiked with 5 ng/g were 78%, 77% and 80% respectively while for 1,000 ng/g were 74%, 76.% and 84% respectively. The within-and between assay coefficients of variation (CV) were 2.4% and 15.5% respectively while assay specificity was above 99.9%. It is concluded that as a result of the good recoveries, high specificity and repeatability, the method could be used in the determination and monitoring of diminazene residues in tissues. These activities aimed at ensuring the safety of food of animal origin could play a major role in enhancing consumer confidence in these products which are very essential for health. Key words: Diminazene, Residues, cELISA, Animal tissues, Trypanosomosis, INTRODUCTION Antimicrobial drugs have been used for over fifty years in food producing animals to control, prevent and treat infections resulting in increased growth, feed efficiency and increased economic return [...]

Internal exposure from naturally occurring radionuclides (including the inhaled long-lived actinides [sup.232]Th and [sup.238]U) is a component of the ubiquitous background radiation dose (National Council on Radiation Protection and Measurements. Ionizing radiation exposure of the population of the United States; NCRP Report No. 160; NCRP: Bethesda, MD, 2009). It is of interest to compare the concentration distribution of these natural [alpha]-emitters in the lungs and respiratory lymph nodes with those resulting from occupational exposure, including exposure to anthropogenic plutonium and depleted and enriched uranium. This study examines the application of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS) to quantifying and visualizing the mass distribution of uranium and thorium isotopes from both occupational and natural background exposure in human respiratory tissues and, for the first time, extends this application to the direct imaging of plutonium isotopes. Sections of lymphatic and lung tissues taken from deceased former nuclear workers with a known history of occupational exposure to specific actinide elements (uranium, plutonium, or americium) were analyzed by LA-ICPMS. Using a previously developed LA-ICPMS protocol for elemental bio-imaging of trace elements in human tissue and a new software tool, we generated images of thorium ([sup.232]Th), uranium ([sup.235]U and [sup.238]U), and plutonium ([sup.239]Pu and [sup.240]Pu) mass distributions in sections of tissue. We used a laboratory-produced matrix-matched standard to quantify the [sup.232]Th, [sup.235]U, and [sup.238]U concentrations. The plutonium isotopes [sup.239]Pu and [sup.240]Pu were detected by LA-ICPMS in 65 [micro]m diameter localized regions of both a paratracheal lymph node and a sample of lung tissue from a person who was occupationally exposed to refractory plutonium (plutonium dioxide). The average (overall) [sup.239]Pu concentration in the lymph node was 39.2 ng/g, measured by high purity germanium (HPGe) [gamma]-spectrometry (Lynch, T. P.; Tolmachev, S. Y.; James, A. C. Radiat. Prot. Doshn. 2009, 134, 94-101). Localized mass concentrations of thorium ([sup.232]Th) and uranium ([sup.238]U) in lymph node tissue from a person not occupationally exposed to these elements (chronic natural background inhalation exposure) ranged up to 400 and 375 ng/g, respectively, in lung samples of occupationally nonexposed to thorium and uranium workers, [sup.232]Th and [sup.238]U concentrations ranged up to 200 and 170 ng/g, respectively. In a person occupationally exposed to air-oxidized uranium metal (Adley, F. E.; Gill, W. E.; Scott, R. H. Study of atmospheric contaminiation in the melt plant buiding. HW-23352(Rev.); United States Atomic Energy Commission: Oakridge, TN, 1952, p 1-97), the maximum [sup.235]U and [sup.238]U isotopic mass concentrations in a lymph node, measured at higher resolution (with a 30 [micro]m laser spot diameter), were 70 and 8500 ng/g, respectively. The ratio of these simultaneously measured mass concentrations signifies natural uranium. The current technique was not sufficiently sensitive, even with a 65 [micro]m laser spot 'diameter, to detect [sup.241]Am (at an overall tissue concentration of 0.024 ng/g, i.e., 3 Bq/g). 10.1021/ac902650w

Vitamin D exists in two major forms, vitamin [D.sub.3] and vitamin [D.sub.2]. Vitamin D helps the body absorb calcium and promote optimal bone health. Both forms of vitamin D are metabolized to 25-hydroxyvitamin D in the body, and the levels of 25-hydroxyvitamin [D.sub.3] [25(OH)[D.sub.3]] and 25-hydroxyvitamin [D.sub.2] [25(OH)[D.sub.2]] in serum are considered the best indicators of vitamin D status. A candidate reference measurement procedure for serum 25(OH)[D.sub.3] and 25(OH)[D.sub.2] has been developed and critically evaluated. The deuterated compounds 25(OH)[D.sub.3]-[D.sub.3] and 25(OH)[D.sub.2]-[D.sub.3] are used as internal standards for 25(OH)[D.sub.3] and 25(OH)[D.sub.2], respectively. The 25(OH)[D.sub.3] and 25(OH)[D.sub.2] and their respective labeled internal standards are simultaneously extracted from serum using liquid liquid extraction prior to reversed-phase liquid chromatography--tandem mass spectrometry (LC-MS/MS). Chromatographic separation was performed using a cyano (CN) column for both 25(OH)[D.sub.3] and 25(OH)[D.sub.2]. Atmospheric pressure chemical ionization (APCI) in the positive ion mode and multiple reaction monitoring (MRM) were used for LC-MS/MS. The accuracy of the method was evaluated by recovery studies of measuring 25-hydroxyvitamin D [25(OH)D] in spiked samples with known 25(OH)D levels. The recoveries of the added 25(OH)[D.sub.3] and 25(OH)[D.sub.2] ranged from 99.0% to 101.0%. The absolute recoveries with this method were 97% and 92% for 25(OH)[D.sub.3] and 25(OH)[D.sub.2], respectively. Excellent precision was obtained with between-set coefficients of variation (CVs) of 0.2-0.6% for 25(OH)D levels > 1 ng/g and within 2% for the level of < 1 ng/g. Chromatographic separation of 25(OH)[D.sub.3] and 25(OH)[D.sub.2] from their respective isomers 3-epi25(OH)[D.sub.3] and 3-epi-25(OH)[D.sub.2] was achieved. The limit of detection at a signal-to-noise ratio of ~3 was 40 pg of 25(OH)D on column (or ~0.15 ng/g as expressed as a concentration). This candidate reference measurement procedure for serum 25(OH)[D.sub.3] and 25(OH)[D.sub.2] demonstrates good accuracy and precision and low susceptibility to interferences. It can be used to provide an accuracy base to which clinical methods for 25(OH)[D.sub.3] and 25(OH)[D.sub.2] can be compared and that will serve as a standard of higher order for measurement traceability. 10.1021/ac9026862

Methyl mercury (MeHg) concentrations in zooplankton were compared from four experimental reservoirs at the Experimental Lakes Area in northwestern Ontario, Canada, to test the hypothesis that increases in concentrations of MeHg in zooplankton would be proportional to C availability. The experimental reservoirs included three upland reservoirs flooded between 1999 and 2003 that differed in amounts of flooded organic terrestrial C (high, medium, and low C) and an experimental reservoir created over a wetland--peatland complex in 1993. After flooding, MeHg in zooplankton increased from 500 ng*g dry [weight.sup.-1] in all reservoirs. In the first two years of flooding, MeHg in zooplankton was not correlated with amounts of flooded C, but the rates of decline in mean annual concentrations were negatively correlated with the amount of C stored in flooded catchments. Concentrations of MeHg in zooplankton were highly correlated with MeHg concentrations in unfiltered water, with reductions in bioaccumulation associated with increases in dissolved organic C and decreases in pH. Overall, our results suggest that reservoir designs that minimize the amount of flooded terrestrial C should result in shorter periods of elevated MeHg in the food web. Resume: Nous avons compare les concentrations de methylmercure (MeHg) du zooplancton dans quatre reservoirs experimentaux dans la Region des lacs experimentaux dans le nord-ouest de l'Ontario, Canada, afin de verifier l'hypothese selon laquelle l'augmentation des concentrations de MeHg dans le zooplancton est proportionnelle a la disponibilite du C. Les reservoirs experimentaux consistaient en trois reservoirs sur des terres hautes mis en eau entre 1999 et 2003 qui differaient par la quantite de C organique terrestre obtenue de l'inondation (C faible, moyen et eleve) et un reservoir experimental etabli sur un complexe de terres humides--tourbieres en 1993. Apres la mise en eau, le MeHg dans le zooplancton a augmente de 500 ng*g de masse [seche.sup.-1] dans l'ensemble des reservoirs. Durant les deux premieres annees d'inondation, il n'y a pas de correlation entre le MeHg dans le zooplancton et les quantites de C obtenues par inondation, mais les taux de declin des concentrations moyennes annuelles sont en correlation negative avec la quantite de C accumulee dans les bassins versants inondes. Les concentrations de MeHg dans le zooplancton sont en forte correlation avec les concentrations de MeHg dans l'eau non filtree et avec des reductions de bioconcentration associees aux augmentations de C organique dissous et aux diminutions de pH. Globalement, nos resultats laissent croire que les conceptions de reservoirs qui minimisent la quantite de C terrestre libere par l'inondation devraient resulter en des periodes plus courtes d'augmentation du MeHg dans le reseau alimentaire. [Traduit par la Redaction], Introduction Flooding following the creation of new reservoirs stimulates the decomposition of inundated terrestrial organic matter, which in turn stimulates the activity of bacteria that convert inorganic Hg to methyl [...]

A method has been developed for the analysis of 170 organohalogen and organophosphorous pesticides, isomers, and metabolites in dried ground ginseng root. Pesticides were extracted with ethyl acetate and purified with gel permeation chromatography (GPC) and primary/ secondary amine modified silica (PSA)/graphitized carbon black (GCB) combination SPE column. Each purified pesticide extract was determined by both gas chromatography single quadrupole mass spectrometry using selected ion monitoring (GC-qMS-SIM) and by gas chromatography high resolution time-of-flight mass spectrometry (GC-HR-TOFMS). The geometric mean LOQs using the qMS and TOFMS were 4 and 3 ng/g ginseng, respectively. Mean recoveries from ginseng were 83, 79, and 75% with standard deviations of 4, 5, and 3%, respectively, for 25, 100, and 500 ng/g using GC-qMS-SIM. Mean recoveries using GC-HR-TOFMS were 93, 85, and 81% with mean standard deviations of 7, 7, and 8% for 25, 100, and 500 ng/g, respectively. Seven dried ginseng root products were found to contain combinations of the following pesticides: dacthal, diazinon, DDT, hexachlorobenzene, iprodione, lindane, procymidone, and quintozene (1-460 ng/g). No significant differences were found in the concentrations measured for these pesticides on commercial ginsengs using either of the two GC/MS techniques.

A method has been developed for the simultaneous analysis of hydroxylated and methoxylated analogs of tetrabromodiphenyl ethers (OH-tetraBDEs and MeO-tetraBDEs) and of hydroxylated and methoxylated analogs of tetrabromobiphenyl (diOH-tetraBB and diMeO-tetraBB) using high performance liquid chromatography/ atmospheric pressure chemical ionization tandem mass spectrometry (APCI-LC/MS/MS) in negative ion mode. Chromatographic separation was performed on a 150 mm ODS column with acetonitrile:water (9:1, v/v) in mobile phase. Multiple reaction monitoring (MRM) was performed using the precursor [[M-H].sup.-] ion for hydroxylated analogs, and the [[M-Br+O].sup.-] ion for tetraBDEs and tetraBB, and their methoxylated analogs. The method was validated using cod liver oil samples spiked with nine analytes (100 ng/g) for linearity ([r.sup.2] > 0.998), recovery (75-95%), repeatability (8-36% RSD), and sensitivity (limits of quantification (LOQ), 0.1-0.25 ng/g lipid for phenolic analytes and 6-80 ng/g lipid for neutral brominated compounds). The APCI-LC/MS/MS was applied to analyze tiger shark and bull shark liver samples, where their concentrations were up to 8 ng/g (lipid weight) for OH-BDEs, whereas they were up to 540 ng/g (lipid weight) for MeO-BDEs. The results were consistent with values determined by electron ionization (EI)-GC/MS. The first detection of 2,2'-dihydroxy-3,3',5,5'-tetrabromobiphenyl (2,2'-diOH-BB80) by this method was in marine sponge from Micronesia. The advantage of the LC/MS/MS method over GC/MS is that it provides rapid and simultaneous determination of OH-BDEs, MeO-BDEs, and their related analogs with a single preparation step and without the involvement of chemical derivatives. Although the method provides the different LOQ ranges between hydroxylated and neutral brominated analogs, future work could apply the method to the full range of PBDE-like contaminants present in the environment and in biota tissues.

The anadromous Chinese sturgeon (Acipenser sinensis) is endangered and listed among the first class of protected animals in China. The possible causes for the decline of this species are the effects of synthetic chemicals, and loss of critical habitat. Chinese sturgeon in the Yangtze River have accumulated triphenyltin (TPT) to 31-128 ng/g wet weigh (ww) in liver, which is greater than the concentrations of tributyltin (< 1.0 ng/g ww). Maternal transfer of TPT has resulted in concentrations of 25.5 [+ or -] 13.0 ng/g ww in eggs of wild Chinese sturgeon, which poses a significant risk to the larvae naturally fertilized or hatched in the Yangtze River. The incidence of deformities in fry was 7.5%, with 1.2% of individuals exhibiting ocular abnormal development, and 6.3% exhibited skeletal/morphological deformations. The incidences of both ocular and skeletal/morphological deformations were directly proportional to the TPT concentration in the eggs of both the Chinese sturgeon and the Siberian sturgeon (Acipenser baerii) in controlled laboratory studies. The rates of deformities in the controlled studies were consistent with the rates caused at the similar concentrations in eggs collected from the field. Thus, TPT is the causal agent to induce the malformation of larvae of Chinese sturgeon. The incidence of deformed larvae of Chinese sturgeon is an indicator of overall population-level effects of TPT on Chinese sturgeon, because TPT at environmentally relevant concentrations can result in significantly decrease both quality and quantity of eggs and spawning frequency of fish. teratogenesis | fish | triphenyltin | Yangtze River

Periluorooctane sulfonate (PFOS) is found globally as an environmental contaminant and is highly bioaccumulative in exposed biota including humans. However, there is a dearth of environmental information on the isomeric profile of PFOS, especially in biological samples, which requires suitable analysis methods for the identification and quantification of ultratrace amounts. In the present study, a novel method was developed that incorporates clean up by solid-phase extraction (SPE) WAX cartridges and in-port derivatization-gas chromatography-mass spectrometry (GC/MS) to identify and quantitatively determine linear PFOS (L-PFOS) and branched (monotriiluoromethyl and bistrifluoromethyl) isomers in PFOS technical product and in environmentally relevant biological samples. Tetrabutylammonium hydroxide (TBAH) was used for derivatization via an in situ pyrolytic alkylation reaction that occurred in the GC injector and generated butyl PFOS isomer derivatives. In addition to L-PFOS, ten branched PFOS isomers were identified in the technical product. The environmental relevance of branched PFOS isomers in addition to L-PFOS was evidenced by the presence of six branched and L-PFOS in representative herring gull and double-crested cormorant egg, and polar bear liver and plasma samples from the Great Lakes and Arctic, respectively. For all PFOS isomers in the technical product and biota samples the method demonstrated high sensitivity with the limit of detection (LOD) ranging from 0.05 to 0.25 ng/mL, with exception of L-PFOS where the LOD was 1.46 ng/mL. For the biotic samples, the method detection limits (MDLs) were slightly higher than the LODs and ranged from 0.09 to 0.46 ng/g wet weight (w.w.) with exception of L-PFOS (MDL = 6.87 ng/g w.w.).

Following unexpectedly variable results from an international comparison study of the determination of selected polychlorinated biphenyl (PCB) congeners in shellfish tissue, a group of national metrology institutes collaboratively explored the analytical characteristics of their measurement systems using a designed study with four sample materials. This 'Uncertainty Suite' consisted of a 10-congener mixture of PCBs in relatively nonvolatile isooctane, a 5-congener mixture in relatively volatile methylene chloride, a methylene chloride extract of freeze-dried mussel (Mytilus edulis) tissue, and the (homogenized) mussel tissue itself. These related-but-different samples presented the participants' measurement processes with a linked series of analytical challenges. Data evaluation tools were developed to combine and visualize measurement results for the different congeners of interest for each material and, exploiting the linkages among the samples, to help identify causes for observed changes in performance. In addition to characterizing individual measurement processes, (1) the limiting sources of measurement uncertainty were found to be chromatographic separation and signal quantification in a natural matrix, (2) the achievable among-participant total measurement uncertainty for PCB calibration solutions is ~1.9% over the mass fraction range from 40 to 500 ng/g, and (3) the achievable among-participant measurement precision for the determination of PCB congeners in mussel tissue at levels above 0.5 ng/g mass fraction is ~5.4%.

We tested the suitability of fecal sexual steroid hormone metabolites for use in endocrinological studies of freeranging, small bats. We monitored estrogen and 20-oxo-pregnane metabolites in fecal samples collected daily from 19 free-ranging female Saccopteryx bilineata during the assumed mating season. Median fecal estrogen metabolite levels equaled 0.09 ng/g for the pre- and postovulatory periods and 4.2 ng/g for the follicular phase of the estrous cycle in female S. bilineata. Median fecal 20-oxo-pregnane metabolite levels were 50.9 ng/g in preestrous, 88.8 ng/g in estrous, and 190.2 ng/g in postestrous females. Reliability of fecal steroid metabolite analysis was supported by results of video observations. Two successful copulations for a single male-female pair were recorded; mating coincided with peak fecal estrogen levels (7.0 ng/g) in the copulating female. In contrast, 2 observed mating attempts in a 2nd male-female pair occurred approximately 19 days after the female's physiological estrus and fecal estrogen metabolites in the rejecting female were only 0.2 ng/g. Fecal 20-oxo-pregnane levels were almost 3 times lower in fecal samples collected from the copulating female than those from the rejecting female (157 ng/g versus 410 ng/g). All females that were still present in the colony 6 months later gave birth to a single offspring between late May and early June. Gestation length averaged (mean [+ or -] SE) 169 [+ or -] 2 days. During the 20 days preceding parturition, fecal 20-oxo-pregnane metabolites were approximately 100 times higher than during the mating period. Fecal 20-oxo-pregnane metabolites of lactating females were comparable to those during the mating season. Noninvasive fecal steroid analysis can be a valuable tool for monitoring reproductive events in colonies of free-ranging small-sized bats. Key words: Chiroptera, estrus, fecal estrogen metabolites, fecal pregnane metabolites, mating, noninvasive analysis, ovulation, seasonal reproduction, tropics

Flow injection high field asymmetric waveform ion mobility spectrometry (FAIMS)-mass spectrometry (MS) methodology was developed for the detection and identification of chemical warfare (CW) agents in spiked food products. The CW agents, soman (GD), sarin (GB), tabun (GA), cyclohexyl sarin (GF), and four hydrolysis products, ethylphosphonic acid (EPA), methylphosphonic acid (MPA), pinacolyl methylphosphonic acid (Pin MPA), and isopropyl methylphosphonic acid (IMPA) were separated and detected by positive ion and negative ion aanospheric pressure ionization-FAIMS-MS. Under optimized conditions, the compensation voltages were 7.2 V for GD, 8.0 V for GA, 7.2 V for GF, 7.6 V for GB, 18.2 V for EPA, 25.9 V for MPA, -1.9 V for PinMPA, and +6.8 V for IMPA. Sample preparation was kept to a minimum, resulting in analysis times of 3 min or less per sample. The developed methodology was evaluated by spiking bottled water, canola oil, cornmeal, and honey samples at low microgram per gram (or [micro]g/mL) levels with the CW agents or CW agent hydrolysis products. The detection limits observed for the CW agents in the spiked food samples ranged from 3 to 15 ng/mL in bottled water, 1-33 ng/mL in canola oil, 1-34 ng/g in cornmeal, and 13-18 ng/g in honey. Detection limits were much higher for the CW agent hydrolysis products, with only MPA being detected in spiked honey samples.

BACKGROUND: Polybrominated diphenyl ethers (PBDEs) are widely used in Western countries. OBJECTIVES: Because the prevalence of cryptorchidism appears to be increasing, we investigated whether exposure to PBDEs was associated with testicular maldescent. METHODS: In a prospective Danish-Finnish study, 1997-2001, all boys were examined for cryptorchidism. We analyzed whole placentas (for 95 cryptorchid/185 healthy boys) and individual breast milk samples (62/68) for 14 PBDEs and infant serum samples for gonadotropins, sex-hormone binding globulin, testosterone, and inhibin B. RESULTS: In 86 placenta-milk pairs, placenta PBDE concentrations in fat were lower than in breast milk, and a larger number of congeners were nondetectable. There was no significant difference between boys with and without cryptorchidism for individual congeners, the sum of 5 most prevalent, or all 14 congeners. The concentration of PBDEs in breast milk was significantly higher in boys with cryptorchidism than in controls (sum of BDEs 47, 153, 99, 100, 28, 66, and 154: median, 4.16 vs. 3.16 ng/g fat; p < 0.007). There was a positive correlation between the sum of PBDEs and serum luteinizing hormone (p < 0.033). The sum of PBDEs in breast milk did not differ between Denmark and Finland (median, 3.52 vs. 3.44 ng/g fat), but significant differences in some individual congeners were found. CONCLUSIONS: Two different proxies were used for prenatal PBDE exposure, and levels in breast milk, but not in placenta, showed an association with congenital cryptorchidism. Other environmental factors may contribute to cryptorchidism. Our observations are of concern because human exposure to PBDEs is high in some geographic areas. KEY WORDS: breast milk, cryptorchidism, exposure, human, infant, polybrominated diphenyl ethers. Environ Health Perspect 115:1519-1526 (2007). doi:10.1289/ehp.9924 available via http://dx.doi.org/ [Online 31 May 2007], Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants, and the general population is exposed through products such as upholstery, building materials, insulation, electronic equipment, and contaminated food. PBDEs [...]

A simple sample preparation method for the determination of four parabens and triclosan in indoor dust is presented. Analytes were extracted from the sample and isolated from interfering species using the matrix solidphase dispersion technique. After that, they were silylated and determined by gas chromatography combined to tandem mass spectrometry (GC/MS/MS). The influence of several factors on the yield and selectivity of the extraction was evaluated in detail. Under final working conditions, samples (0.5 g) were mixed with the same amount of anhydrous sodium sulfate and dispersed on 1.25 g of C18. This blend was transferred to the top of a polypropylene cartridge containing 2 g of Florisil. After removing less polar species with 10 mL of dichloromethane, analytes were recovered using 10 mL of acetonitrile. This extract was concentrated to 1 mL, derivatized, and injected in the GC/MS/MS system. Derivatization was carded out at 45[degrees]C in 5 min using 100 [micro]L of N-methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide. Quantification limits from 0.6 to 2.6 ng/g and absolute recoveries between 80 and 114% were achieved. Analysis of dust samples demonstrated the presence of the target species in indoor dust from private houses. The highest average concentration (702 ng/g) corresponded to triclosan.