Associations of multiple exposures to persistent toxic substances with the risk of hyperuricemia and subclinical uric acid levels in BIOAMBIENT.ES study.

Hyperuricemia is becoming a serious public health issue, which is highly influenced by environmental factors, although there is still controversial information on the potential influence of the exposure to Persistent Toxic Substances (PTSs) in the general population. In this study we aimed to assess the association. PTS exposure with uric acid homeostasis in a sample of the Spanish population. Participants were recruited during 2009-2010 in all the main geographical areas of Spain. Exposure to 34 PTSs was estimated by chemical analyses of serum levels of 6 Polychlorinated Biphenyls (PCBs, n = 950), 13 Organochlorine Pesticides (OCPs, n = 453), 6 Perfluoroalkyl Substances (PFAs, n = 755), 7 Polybrominated Diphenyl Ethers (PBDEs, n = 365), urinary Cadmium (n = 926), and Lead in whole blood (n = 882). The two study outcomes were defined as the prevalence of hyperuricemia in the study population and uric acid levels, the latter only in individuals with no previous diagnosis of hyperuricemia. Statistical analyses were performed by means of binomial logistic regression and linear regression, and mixture effects were screened using Weighted Quantile Sum Regression (WQS). Serum concentrations of γ-HCH, o,p´-DDE, PCB-138, PCB-153, PFOA, and urinary Cadmium were associated with an increased risk of hyperuricemia, while PBDE-153 showed an inverse association with the effect. Furthermore, exposure to Cadmium, PCB-138, and to PCB-153 was positively associated with uric acid levels. Results were consistent after lipid adjustment or standardization. WQS analyses revealed a major contribution of PCB-153 within the PCB mixture on both the risk of hyperuricemia and uric acid levels. Sensitivity analyses were performed by adjusting for dietary habits, fasting glucose and estimated glomerular filtration rate. Overall, we found novel associations between human exposure to mixtures of PTSs and disturbances in uric acid homeostasis. However, we cannot completely rule out potential residual confounding effect or reversed-causality related to the cross-sectional design.

Differential contribution of animal and vegetable food items on persistent organic pollutant serum concentrations in Spanish adults. Data from BIOAMBIENT.ES project.

Diet is considered the main source of Persistent Organic Pollutant (POP) exposure in the general population, although there are still several gaps of knowledge regarding the differential contribution of main food groups. The aim of this study was to identify dietary patterns that contribute to human exposure to organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and Perfluoroalkyl Substances (PFASs). Study population (n=1880, 18-65years old) was recruited during 2009-2010 in all the main geographical areas of Spain. For this work, exposure was estimated by chemical analyses of serum levels of 6 PCBs (n=1880), 13 OCPs (n=934), and 6 (PFASs) in a subsample of 755 (n=755). Dietary habits and covariates were gathered via self-administered questionnaires. Data analyses were performed by means of multivariable linear regression and weighted quantile sum regression. Both the consumption of animal-based and plant-based food were positively associated with the individual concentrations of p,p´-DDE, hexachlorobenzene, and PCB-congeners -138, -153, and-180. The contribution of animal-based products was 2.1-4.0× stronger except in p,p´-DDE, to which both patterns had similar contributions. In PFASs only animal food was positively associated with the exposure levels. The main animal-based contributors to PCB exposure were fish (49-64%) and eggs (19-36%), while OCP concentrations were mainly influenced by dairy products (32-48%) and fish (47-48%). PFOA and PFHxS were mainly explained by cold-meat (34-37%), fish (25-26%), and eggs (19-21%), while PFOS and PFDA were primarily influenced by fish consumption (44-77%). In the case of plant-based items, fruits (25-82%) and vegetables (18-63%) accounted for the majority of the variability of PCB and OCP concentrations. Our results highlight the relevance of dietary POP exposure as well as the need for the consideration of nutritional interventions in public health programs aiming to reduce POP exposure in the general population.

Perfluorinated alkyl substances in Spanish adults: Geographical distribution and determinants of exposure.

Per- and polyfluoroalkyl substances (PFAS) are widely found in humans and the environment. Their persistence, bioaccumulation and toxicity make them a source of increasing public health concern. In this study, we analyzed the concentrations and geographical distribution of six PFAS in the serum of 755 Spanish adults aged 18-65. The geometric mean concentrations (and P95 values) for PFOS (perfluoroctane sulfonate), PFOA (perfluorooctanoic acid), PFHxS (perfluorohexane sulfonate), PFNA (perfluorononanoic acid) and PFDA (perfluorodecanoic acid) were 7.67 (19.3), 1.99 (5.48), 0.91 (2.84), 0.96 (2.44) and 0.42 (0.99) µg/L, respectively. N-Methylperfluorooctane sulfonamide (N-MeFOSAA) was detected in only 3.3% of samples. Residents in northeast (Catalonia) and northwest of Spain (Galicia) were found to have the highest serum values, whereas residents in the Canary Islands had the lowest values for almost all PFAS. Men presented higher levels than women, and we confirm that lactation (breastfeeding) contributes to a reduced body burden for all PFAS in women. Our data provide new information on exposure to PFAS in a national cross section sample of Spanish adults, thus providing a proxy for reference values for the Spanish population and forming the base for following temporal trends in the future.

On-line flow injection molecularly imprinted solid phase extraction for the preconcentration and determination of 1-hydroxypyrene in urine samples.

New analytical strategies tend to automation of sample pre-treatment and flow analysis techniques provided a number of enhanced analytical methods allowing high throughput. Flow techniques are usually faster, more robust and more flexible than their batch equivalents. In addition, flow methods use less sample and reagent amounts and reduce analytical costs and waste. A flow injection solid-phase extraction pre-concentration system using a molecularly imprinted polymer (MIP) packed micro-column was developed for the determination of 1-hydroxypyrene in human urine with fluorescence detection. The pre-concentration of 1-hydroxypyrene on the MIP was carried out based on the specific retention of analyte by on-line introducing the sample into the micro-column system. Methanol and dichloromethane mixture was used to elute the retained analyte for fluorometric analysis. Important influencing factors were studied in detail, in batch and in flow (MISPE procedure optimisation, sample and eluent volumes, flow rate, dimensions of MIP micro-column and amounts of packing material, etc). To the best of our knowledge, this is the first on-line flow injection molecularly imprinted solid phase extraction for the pre-concentration and determination of hydroxylate PAH metabolite in urine samples. The optimised method was successfully applied to the determination of 1-Hydroxypyrene in spiked urine samples, with recoveries in the range of 74-85% and RSD<4.6%. Under optimum experimental conditions, the linearity concentration range used was 10-400µgL-1, R2>0.996. We obtained limit of detection and quantification of 3.1µgL-1 and 10.5µgL-1, respectively.

A fast method for analysing six perfluoroalkyl substances in human serum by solid-phase extraction on-line coupled to liquid chromatography tandem mass spectrometry.

We have developed and validated an on-line TurboFlow solid-phase extraction procedure coupled to high-performance liquid chromatography with tandem mass spectrometry for the analysis of six perfluoroalkyl substances (PFAS), two sulfonates (perfluorooctane sulfonate and perfluorohexane sulfonate), three carboxylates (perfluorooctanoic acid, perfluorononanoic acid and perfluorodecanoic acid), and one sulfonamide (N-methylperfluorooctane sulfonamide), in human serum samples. This method requires only 100 µL of sample and involves a short pre-treatment with acetonitrile followed by addition of a labelled internal standard for quantification and ultracentrifugation. All PFAS were detected with a run time of 8.5 min. Linearity ranges stay between 0.1 and 20 µg L(-1) (R (2) > 0.9960). Recoveries were determined by spiking blank serum samples with a mixture of six PFAS and found to be in the range 96-110 % for all compounds. Isotopic dilution was used to quantify the selected analytes. The low limits of quantification obtained, between 0.16 and 0.34 µg L(-1), small volume of sample required and short run time used (from two to three times shorter than any other described method), make this validated method highly recommended for human biomonitoring studies.

Urinary polycyclic aromatic hydrocarbon metabolites levels in a representative sample of the Spanish adult population: The BIOAMBIENT.ES project.

In 2009, the Spanish Ministry of Agriculture, Food and Environment promoted the BIOAMBIENT.ES project, a Human Biomonitoring program on the national scale to estimate reference levels of environmental pollutants on a representative sample of the Spanish adults. The present study focuses on polycyclic aromatic hydrocarbons (PAHs). The urinary metabolites 1-hydroxypyrene, 1-,2-,3-,4- and 9-hydroxyphenanthrene and 3-hydroxybenzo[a]pyrene were selected as indicators of PAH exposure. Urine samples from 957 subjects (16-65 years old) were collected during year 2009-2010. Geometric mean and 95th percentile for 1-hydroxypyrene in µg g(-1) creatinine were 0.117 (non-smoker: 0.079, smokers: 0.184) and 0.67 µg g(-1) creatinine (non-smokers: 0.31, smokers: 0.69) respectively. GM and 95th percentile for sum of hydroxyphenanthrenes in µg g(-1) creatinine were 0.130 (non-smokers: 0.089, smokers: 0.317) and 1.29 (non-smokers: 0.71, smokers: 1.51) respectively. 3-Hydroxybenzo[a]pyrene was below the limit of quantitation (0.05 µg L(-1)) in all cases. Significant differences (p<0.05) regarding smokers and non-smokers, coal and wood heating, body mass index and second hand smoke were found, while other variables like gender, age, or diet showed no significant association. The geographical distribution of the metabolites showed higher levels in people who lived in the north and northwest of Spain. The PAH metabolites levels found were in the same range or lower than those reported from other European countries and they were higher than those found in the U.S. This study represents the first nationwide survey of exposure to PAHs in Spain and provides a background reference range for exposure to PAHs in the Spanish adult occupied population.

Anti-smoking legislation and its effects on urinary cotinine and cadmium levels.

Anti-smoking legislation has been associated with an improvement in health indicators. Since the cadmium (Cd) body burden in the general population is markedly increased by smoke exposure, we analyzed the impact of the more restrictive legislation that came into force in Spain in 2011 by measuring Cd and cotinine in first morning urine samples from 83 adults in Madrid (Spain) before (2010) and after (2011) introduction of this law. Individual pair-wise comparisons showed a reduction of creatinine corrected Cotinine and Cd levels for non-active smokers, i. e. those which urinary cotinine levels are below 50 µg/L. After the application of the stricter law, cotinine levels in urine only decreased in non-active smokers who self-reported not to be exposed to second-hand smoke. The reduction in second hand smoke exposure was significantly higher in weekends (Friday to Sunday) than in working days (Monday to Thursday). The decrease in U-Cd was highly significant in non-active smokers and, in general, correlated with lower creatinine excretion. Therefore correction by creatinine could bias urinary Cd results, at least for cotinine levels higher than 500 µg/L. The biochemical/toxicological benefits detected herein support the stricter application of anti-smoking legislation and emphasize the need to raise the awareness of the population as regards exposure at home.

High-performance liquid chromatography with diode-array detection cotinine method adapted for the assessment of tobacco smoke exposure.

Smoking is considered to be one of the main risk factors for cancer and other diseases and is the second leading cause of death worldwide. As the anti-tobacco legislation implemented in Europe has reduced secondhand smoke exposure levels, analytical methods must be adapted to these new levels. Recent research has demonstrated that cotinine is the best overall discriminator when biomarkers are used to determine whether a person has ongoing exposure to tobacco smoke. This work proposes a sensitive, simple and low-cost method based on solid-phase extraction and liquid chromatography with diode array detection for the assessment of tobacco smoke exposure by cotinine determination in urine. The analytical procedure is simple and fast (20 min) when compared to other similar methods existing in the literature, and it is cheaper than the mass spectrometry techniques usually used to quantify levels in nonsmokers. We obtained a quantification limit of 12.30 µg/L and a recovery of over 90%. The linearity ranges used were 12-250 and 250-4000 µg/L. The method was successfully used to determine cotinine in urine samples collected from different volunteers and is clearly an alternative routine method that allows active and passive smokers to be distinguished.