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).     

Survey of polycyclic aromatic hydrocarbons in canned bivalves and investigation of their potential sources

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in the marine environment derived from uncontrolled petroleum spills, marine transports, discharges from ships, and urban runoff. The NW coast of Spain (Galicia) has a characteristic hydrography, defined by a continuous suite of estuarine systems called “Rías Gallegas”. Some of these estuaries support important industrial and urban centres while others are preserved from human influence. The PAH contents in invertebrate organisms, such as bivalves, have been widely investigated because they are good bioindicators of pollution due to their ability to filter the water. 12 PAHs were determined in canned mussels (Mytilus galloprovincialis), clams (Venerupis pullastra), cockles (Cerastoderma edule) and knives (Ensis ensis) from the Galician “Rías Gallegas” to perform a possible risk assessment on these contaminants. Pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene were detected in all the selected samples by liquid chromatography coupled with fluorescence spectroscopy. With regard to benzo[a]pyrene, which represents the most potentially carcinogenic PAHs, European Regulation 1881/2006/EC fixed at 10 μg/kg of wet weight the MRL (maximum residual level) in bivalve molluscs. None of these marine invertebrates showed values higher than the MRL and therefore, they do not suppose risk for human health. Mussels hydrocarbon body burden levels were highest than exhibited by others bivalves. Some factors may determine this feature, as lipid content or habitat. Lower PAH levels of five and six benzene rings were detected in canned mussels in pickle sauce (vegetable oil, vinegar, paprika, salt and other spices) than in mussels in natural sauce (water, salt and other spices). PAHs migration from mussels to the vegetable oil in pickle sauce was verified to be the reason.     

Stirring bar sorptive extraction in the determination of PAHs in drinking waters

The application of a new extraction technique which is known as stir bar sorptive extraction (SBSE), followed by high-performance liquid chromatography with a fluorescence detector, was assessed for determining eight polycyclic aromatic hydrocarbons (PAHs) in water samples. The extraction conditions such as acetonitrile addition; effects of temperature and salt; and finally, extraction and desorption time profiles were studied. Once SBSE was optimized, analytical method parameters such as linearity (r(2)>0.991), precision (<9%), detection (0.5-7.3 ng/L) and quantitation (1.0-22 ng/L) limits were estimated. To correct for the 43-57% absolute recovery depending on the PAH, calibration was done with a line obtained submitting standard-spiked blank tap waters to the complete sample treatment and analysis. Consequently, relative recovery was about 100% because all water samples (those for calibration purposes and those for recovery estimation) were processed in the same way and the absolute recovery remained constant. SBSE method characteristics were checked with the analysis of real drinking waters in the search for PAHs.     

Determination of polycyclic aromatic hydrocarbons in alcoholic drinks and the identification of their potential sources.

Some polycyclic aromatic hydrocarbons (PAHs), particularly those with a high molecular mass, have been classified as probably being carcinogenic to humans by the International Agency for Research on Cancer (IARC). The significance of the determination of PAHs is reflected by the special attention the European Union is paying to regulating their maximum allowed levels in various types of foodstuffs. Like tobacco and smoked meats, alcoholic drinks can also contain these carcinogenic chemicals, as the latter have been detected in the charred insides of barrels, some ingredients such as caramel or the smoke released during the drying of germinated barley in beer or whisky. This paper determined the contents of seven PAHs in alcoholic beverages of variable alcoholic strength that had been aged in charred barrels for different times (months, years). The aim was to elucidate the dependence of the formation of seven PAHs on the type of charring (traditional or convective) used and the charring intensity (light, medium or heavy). Based on the results, the way the tree raw material is toasted strongly influences PAH levels in alcoholic drinks; thus, traditional charring produces increased amounts of PAHs from the wood relative to convective toasting. The sum of the analysed PAH concentrations in the aged alcoholic beverages studied ranged from zero for a white wine to 172 ng l(-1) for a 'brandy de jerez solera'. The carcinogenic indicator benzo[a]pyrene was found at concentrations below 10 ng l(-1). These PAH concentrations in alcoholic beverages are very low relative to those in smoked and char-broiled foodstuffs. Any health hazards, however, can be minimized by using convective toasting to manufacture the barrels where the drinks are to be aged.     

Evolution of the concentrations of polycyclic aromatic hydrocarbons in burnt woodland soils

Little is known of the fate of polycyclic aromatic hydrocarbons (PAHs) in soils under burnt woodland. It is not clear what the behavior of the overlying wood ash layer will be along months. In this study, the levels of eight representative PAHs in the 1-5 cm layer of a periurban woodland soil that had undergone wildfire were compared with those measured in nearby and distant unburnt periurban woodland soils and in a distant unburnt rural woodland soil, and the levels at the burnt site were monitored during some 10 months. The analytical method optimized for the purpose afforded recoveries of 74-111% (depending on PAH) and repeatabilities (RSDs) better than 9%, with limits of detection ranging from 1 to 7 microg/kg. PAH levels in the 1-5 cm layer of the burnt periurban soil were very similar to those of distant unburnt periurban soil (188 vs 173 microg/kg), about seven times the 26 microg/kg measured in unburnt rural soil, which furthermore contained no detectable quantities of the highest molecular weight PAHs typical of traffic and other urban sources, as the periurban soils did. At the burnt site, PAH levels fell along the months (the total PAH level from 188 to 119 microg/kg), apparently as the result of rainfall and the prevention of further input from the atmosphere by the overlying layer of wood ash, which had a very high PAH adsorption capacity (1169 microg/kg) and did not itself appear to act as a source of PAHs. PAH transport may have been assisted by increased mobilization of PAHs associated with dissolvable organic matter due to an increase in soil pH due to alkaline ash components.