Rapid liquid chromatographic method for the control of doxycycline and tiamulin residues and their metabolites in vivo assays with pigs: Treatment and depletion.

Results gained from in vivo metabolism could be more authentic to reflect the biotransformation of drugs than in vitro metabolism. This paper discusses the development and characterization of an analytical method for controlling tiamulin (TIA) and doxycycline (DOX) residues in pig plasma and urine, as well as their in vivo biotransformation during treatment and suppression steps at pig farms. For such a purpose, urine samples were taken daily (24-hr intervals) during treatment and until day 8 after last dose. Plasma samples were collected on the last treatment day and up to days 4 and 7 after the last dose. Only traces of TIA and their metabolites have been still detected 8 days after the last day of therapy, in agreement with the period of suppression of both antibiotics set by the manufacturers in 7 days. It was estimated that TIA and DOX half-lives were of two days and one day, respectively. TIA and DOX metabolites have been identified for the first time in plasma and urine pig samples during treatment and suppression steps.

Determination of kinetic bioconcentration in mussels after short term exposure to polycyclic aromatic hydrocarbons.

The kinetic bioconcentration of N-heterocyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons in mussels (Mytilus galloprovincialis) after short waterborne exposure was studied. Benzo[a]pyrene (BaP), its analogue azaarene 10-azabenzo[a]pyrene (AzaBaP), and their mixture (Mix), were selected to monitor the changes in water concentrations over three days. Decay of both PAHs concentrations in water after 24 h of waterborne exposure to mussels at levels of 10 and 100 µg/L follows a first order kinetic with half-lives of 4-5 h, with residual levels of PAHs below 7%. While steady-state scenarios are well studied, there is a lack of information of what happens under non-steady-state conditions, the main purpose of our paper. A synergistic bioconcentration of the mixture was found (around 800 in the mix vs. around 400 for individual PAHs at 100 µg/L of waterborne exposure). It could be explained by the following reasons. The most polar AzaBaP does not compete with the most non-polar BaP for the same tissue compartments. Whereas BaP aggregate in hydrophobic areas, AzaBaP can also do in hydrophilic areas. Moreover, a chance for complex formation between them by charge-transfer stabilization mechanisms could make possible a higher bioaccumulation as a mixture. Instead, toxicological results suggest an additive behaviour in the mixture performance, dominated by BaP, which is the key PAH controlling phase I metabolization in mussels, since is approx. three times more toxic. These experiments provide useful indications for a rapid assessment of PAHs kinetic bioconcentration in mussels.

Organic pollutants profiling of wood ashes from biomass power plants linked to the ash characteristics.

PURPOSE: Wood ash, characterized by high content of certain nutrients and charcoal, can be applied to soils as a means of managing this waste product improving the soil quality. The associated environmental risk must be assessed. The objective of this study was to characterize the bottom and fly ash collected from 15 biomass power plants in Spain by determining the benzene, toluene, ethylbenzene, xylene and styrene (BTEX+S), PAHs and aliphatic hydrocarbon contents of both types of ash. Biochar was also used for comparison purposes. METHODS: Gas chromatography-mass spectrometric methods were used for the identification and determination of both BTEX+S and aliphatic hydrocarbon contents in bottom and fly ashes, as well as biochar. High performance liquid chromatography with fluorescence detection was used for PAHs measurements. Multivariate correlation analysis was used to determine the relationship between sample characteristics and pollutants identified by partial least squares regression analysis. RESULTS AND DISCUSSION: In general, the degree to which organic matter in the sample is burned increases with T50 or the "50% burn off" temperature (possibly due to the addition of fuel), and the BTEX+S also tended to increase. However, as the Q/MO (the heat of combustion divided by organic matter mass) increased, the combustion decreased or proceeded with less oxygen, which appears to be related to an increased presence of PAHs. The results confirm that the amounts of organic pollutants (PAHs and BTEX+S, together with total aliphatic hydrocarbons) in the wood ash do not exceed limits established for different soil or industrial uses. CONCLUSIONS: Both types of ash, together with biochar, may therefore be suitable for application to soil as a fertilizer and an organic amendment, taking into account the target organic pollutants.

Liquid chromatography-mass spectrometry method development for monitoring stress-related corticosteroids levels in pig saliva.

Biochemical response stressors results in an increase of adrenocortical activity. Before knowing the corticosteroid levels in saliva in a stressful situation, baselines salivary levels should be established. A method for simultaneous determination of five corticosteroids was developed, validated and applied to pig saliva at farms. The method employs solid-phase extraction (SPE) coupled with clean-up extraction step using silica cartridge in the same step followed by liquid chromatography/tandem mass spectrometry (LC-MS/MS), using electrospray ionization (ESI) in positive mode. The overall method quantification limits range from 0.050 to 0.30µg/L for the enrichment of 1.0mL saliva samples and analyte recoveries are between 60 and 90% (RSD<11%). Some factors studied were: pig sex, breeds, and time at farm. The analytical method clearly shows that CRL and CRS levels of, respectively, 3.0 and 4.0µg/L in saliva can be indicative of maxima non-stress levels in different pig breeds at farm.

The first demonstration of CYP1A and the ABC protein(s) gene expression and activity in European seabass (Dicentrarchus labrax) primary hepatocytes.

Primary hepatocytes are a model for studying various effects of different xenobiotics, including detoxification strategies. In this study we have isolated and cultured European seabass (Dicentrarchus labrax) primary hepatocytes and assessed gene transcription and activity of CYP1A (phase I of cellular detoxification) and ABCC1 and ABCC2 (phase III) transport proteins after exposure to benzo(a)pyrene (BaP). A dose dependent increase in Abcc2 and Cyp1a mRNA transcripts was observed in seabass primary hepatocytes upon exposure to BaP. The activity of ABC proteins, as key mediators of the multixenobiotic resistance (MXR), was further confirmed by assessing the accumulation of the model fluorescence substrate rhodamine 123 in the absence and presence of model inhibitors. A weak interaction between BaP and ABC proteins was observed. CYP1A dependent ethoxyresorufin-O-deeethylase (EROD) activity was significantly induced by the presence of BaP. After the 24h exposure period only 10% of the initial BaP was present in the incubation medium, clearly demonstrating biotransformation potential of primary seabass hepatocytes. Furthermore, the presence of the 3-hydroxybenzo(a)pyrene, a BaP metabolite, in the medium implies its active efflux. In conclusion, we showed that seabass primary hepatocytes do express important elements of the cellular detoxification machinery and may be a useful in vitro model for studying basic cellular detoxification mechanisms and their interaction with environmental contaminants.

Training of panellists for the sensory control of bottled natural mineral water in connection with water chemical properties.

As bottled mineral water market is increasing in the world (especially in emergent and developed countries), the development of a simple protocol to train a panel to evaluate sensory properties would be a useful tool for natural drinking water industry. A sensory protocol was developed to evaluate bottled natural mineral water (17 still and 10 carbonated trademarks). The tasting questionnaire included 13 attributes for still water plus overall impression and they were sorted by: colour hues, transparency and brightness, odour/aroma and taste/flavour/texture and 2 more for carbonated waters (bubbles and effervescence). The training lasted two months with, at least, 10 sessions, was adequate to evaluate bottled natural mineral water. To confirm the efficiency of the sensory training procedure two sensory groups formed the whole panel. One trained panel (6 persons) and one professional panel (6 sommeliers) and both participated simultaneously in the water tasting evaluation of 3 sample lots. Similar average scores obtained from trained and professional judges, with the same water trademarks, confirmed the usefulness of the training protocol. The differences obtained for trained panel in the first lot confirm the necessity to train always before a sensory procedure. A sensory water wheel is proposed to guide the training in bottled mineral water used for drinking, in connection with their chemical mineral content.

Metal accumulation and oxidative stress biomarkers in octopus (Octopus vulgaris) from Northwest Atlantic.

Metals are ubiquitous in the environment and accumulate in aquatic organisms and are known for their ability to enhance the production of reactive oxygen species (ROS). In aquatic species, oxidative stress mechanisms have been studied by measuring antioxidant enzyme activities and oxidative damages in tissues. The aim of this study was to apply and validate a set of oxidative stress biomarkers and correlate responses with metal contents in tissues of common octopus (Octopus vulgaris). Antioxidant enzyme activity (catalase--CAT, superoxide dismutase--SOD and glutathione S-transferases--GST), oxidative damages (lipid peroxidation--LPO and protein carbonyl content--PCO) and metal content (Cu, Zn, Pb, Cd and As) in the digestive gland and arm of octopus, collected in the NW Portuguese coast in different periods, were assessed after capture and after 14 days in captivity. CAT and SOD activities were highly responsive to fluctuations in metal concentrations and able to reduce oxidative damage, LPO and PCO in the digestive gland. CAT activity was also positively correlated with SOD and GST activities, which emphasizes that the three enzymes respond in a coordinated way to metal induced oxidative stress. Our results validate the use of oxidative stress biomarkers to assess metal pollution effects in this ecological and commercial relevant species. Moreover, octopus seems to have the ability to control oxidative damage by triggering an antioxidant enzyme coordinated response in the digestive gland.

Pre-industrial accumulation of anthropogenic polycyclic aromatic hydrocarbons found in a blanket bog of the Iberian Peninsula.

Studies on the temporal deposition of polycyclic aromatic hydrocarbons (PAHs) in peatlands are scarce, and none have been carried out in the Iberian Peninsula. To address this gap, ten PAHs were determined in a short peat core (spanning the last 1000 years) sampled in NW Iberian Peninsula, by HPLC-fluorescence. Fluoranthene, pyrene, benzo[b]fluoranthene and indeno[1,2,3-cd]pyrene predominated in the upper layers (10 cm), whereas fluoranthene and pyrene were the most abundant in the lower layers (40 cm), which showed an absence of high molecular weight PAHs (benzo[ghi]perylene and Indeno[1,2,3-cd]pyrene). Although increased PAH contents have been detected since 1700 A.D., coinciding with the beginning of the Metallurgical and Industrial Revolution, high levels of fluoranthene and pyrene were present in peat samples dating back to the 12th century A.D. The results suggest that changes in sources, type of emission (global or local) and transport could be responsible for the different PAH content and composition of the peat core. These changes are consistent with the history of the use of natural resources in the NW of the Iberian Peninsula.

Comparision of the waterborne and dietary routes of exposure on the effects of Benzo(a)pyrene on biotransformation pathways in Nile tilapia (Oreochromis niloticus).

BaP is one of the most studied PAH, due to its ubiquitous presence in aquatic environments and toxicity to aquatic organisms. The main goal of this study was to assess BaP effects in Nile Tilapia after waterborne and dietary exposures, through the evaluation of EROD and GST activities in liver, gills and intestine, and BaP metabolites in bile; and also to evaluate the usefulness of these commonly used biomarkers after two different routes of exposure. Waterborne exposure to BaP led to a significant induction of EROD in all tissues analyzed (644%, 1640% and 2880% in relation to solvent in liver, gill and intestine respectively) while in dietary exposures EROD was induced only in intestine (3143%) after exposure to high BaP concentrations. GST activities with CDNB were slightly induced in liver (40%) and in gill (66%) after water exposure to BaP, and in intestine after dietary exposure to low BaP concentrations (182%). BaP metabolites in bile increased after both exposure routes, and were highly correlated with EROD activity after water exposure. In summary, this work has shown that the effects of BaP on biotransformation pathways depend on the route of exposure. Moreover, barrier tissues like gills and intestine also have an important role in the first-pass metabolism of BaP, reducing the amount of parent compound that reaches the liver to be metabolized. For that reason, EROD activity as a biomarker of exposure should also be applied in extrahepatic organs, like gills and intestine, in monitoring studies. Biliary BaP type metabolites are good reflectors of contamination levels under both exposure routes, while GST activity with CDNB as substrate, as a phase II enzyme, does not seem a reliable biomarker of exposure to BaP regardless the route of exposure.

Comparative performance of extraction strategies for polycyclic aromatic hydrocarbons in peats.

The assessment of historical trends in atmospheric deposition of organic contaminants by using peat samples has been reported on several occasions because these samples represent an almost ideal medium for recording temporal changes in organic contaminant deposition rates. The determination of polycyclic aromatic hydrocarbons (PAHs) in peat samples is complicated due to the high content of organic matter in peat, which affects both extraction efficiency and analytical quality. A rapid and simple method is proposed for the determination of 10 US Environmental Protection Agency indicator PAHs in complex matrices such as peat. This article reviews and addresses the most relevant analytical methods for determining PAHs in peat. We discuss and critically evaluate three different extraction procedures, such as ultrasound-assisted solvent extraction (UASE), shaking and pressurized liquid extraction (PLE). Clean-up of extracts was performed by solid-phase extraction using silica cartridges. Detection of the selected PAHs was carried out by high-performance liquid chromatography coupled with fluorescence detection for determination. Optimization of the variables affecting extraction by the selected extraction techniques was conducted, concluding that the UASE extraction method using hexane:dichloromethane (80:20) as extractant was robust enough to determine the selected PAHs in peat samples with estimated quantification limits between 0.050 and 3.5 microg/kg depending on the PAH. UASE did not demand sophisticated equipment and long extraction times. PLE involved sophisticated equipment and showed important variations in the results. The method proposed was applied to the determination of PAHs in peat samples from Xistral Mountains (Galicia, Spain).

The use of manures for detection and quantification of polycyclic aromatic hydrocarbons and 3-hydroxybenzo[a]pyrene in animal husbandry.

PAHs from a polluted atmosphere are generally transferred to plants by particle-phase deposition on the waxy leaf cuticle or by uptake in the gas phase through stomata. Thus, they are also present in ingredients for animal feed. Generally, toxic substances are metabolized before or after absorption through the intestinal tract. This is the case of 3-hydroxybenzo[a]pyrene, which can be found free or in its glucuronide and/or sulphate conjugate forms. This article develops a procedure to monitor the carry-over of PAHs from feed to food of animal origin based on the analysis of animal manure. Eleven PAHs and 3-hydroxybenzo[a]pyrene were measured in four animal manures (cow, horse, rabbit and pig) by liquid chromatography with fluorescence detection. benzo[a]pyrene, benzo[b]fluoranthene and benzo[k]fluoranthene were found in all the selected samples, but their total levels were not alarming (benzo[a]pyrene equivalents (microg/kg)<3.1). 3-hydroxybenzo[a]pyrene was quantified in all the samples exempting rabbit manure. The highest total PAH levels were detected in cow manure (9.0 microg/kg), while the highest 3-OH-B[a]P level was determined in horse samples (13 microg/kg).

Effects of toasting procedures on the levels of polycyclic aromatic hydrocarbons in toasted bread.

Some polycyclic aromatic hydrocarbons (PAHs), particularly those with a high molecular weight, have been classified as probably carcinogens to humans by the International Agency for Research on Cancer (IARC). The significance of the determination of PAHs is reflected by the special attention of the European Union, which is paying to regulate the maximum allowed levels of PAHs in foodstuffs such as smoked foods. Like other thermally processed foodstuffs, toasted bread can contain these carcinogenic chemicals, not only due to a contamination at source but also during toasting. In order to check PAHs generated from toasting in sandwich bread, several treatment conditions were evaluated: direct toasting (flame-toasting, coal-grilling or gas oven-toasting) or indirect toasting (electric oven-toasting). PAHs were extracted by solid-liquid extraction (SLE) and determined by liquid chromatography with fluorescence detection (LC-FD). Based on the results, the used toasted technique would strongly affect in PAH levels in the final product. No samples obtained by electric oven and toaster were polluted; otherwise the samples toasted by charcoal and flame grilling presented very important levels. Up to 350µg/kg of total PAHs were detected in toasted samples by wood flame. Differences between different ways of toasting could be ascribed to deposition of PAHs from smoke. Finally, several commercial toasted samples of bread were tested to determine PAHs. Overall, the PAH levels were very low. Benzo[a]pyrene ranged from no detectable to 0.23µg/kg.