Comparative analysis of emissions and diffusion of air PAHs at a coastal arid site (Patagonia, Argentina)

Atmospheric PAHs in rural, urban, industrial and beach locations in Buenos Aires Province, Argentina: sources and health risk assessment

The first atmospheric PAHs levels and associated inhalation cancer risk were assessed over southwest Buenos Aires region by deploying PUF disk PAS samplers. Eight sampling location included coastal zones, touristic beaches, and rural inland areas were considered. PUF disks were fortified with surrogate standards and extracted by automated Soxhlet prior to GC-MS analysis. Σ₁₆ PAHs ranged from 1.13 to 44.5 ng m^-3 (10.3 ± 9.8), while urban locations showed up to 10 times higher PAH levels than rural or beach locations. Direct sources of PAHs, such as intensive vehicle traffic, heating, and general combustion activities, were identified. PAHs with four to six rings (46.62%) were predominantly Flt, Pyr, BbF, and BkF, and carcinogenic risk was expressed by BaP (0.10 ± 0.07 ng m^-3) and BaPTEQs (0.26 ± 0.22 ng m^-3). Inhalation ECR (2.23E-5, WHO) presented the lowest risk at beach locations. Molecular ratios and PCA showed a strong dominance in pyrolytic sources, such as biomass and coal combustion, with a particular signature in fires at inland locations. Overall, this study demonstrated that PUF disk passive air sampling provided a sound and simple approach for tracking air PAHs, their sources and public health risks, bringing a cost-effective tool for pollution control measures, even at small and remote towns. This is particularly relevant in extensive countries with medium or low income, such as Argentina.

Polycyclic aromatic hydrocarbons in the South American environment

Pollution of the environment with polycyclic aromatic hydrocarbons (PAHs) should be a global concern, especially in urbanized areas. In South American countries, where notable increase in urban populations has been observed in the past few years, reliable information about the pollution status of these urban environments is not always easily accessible, and therefore an effort to collect updated information is required. This review attempts to contribute by analyzing the existing information regarding environmental levels of PAHs in some South American countries. A regional trend for environmental PAH information is an uneven contribution, because some countries, such as Bolivia, Peru, Paraguay, and Ecuador, have reported no information at all in the scientific literature, reflecting to a certain extent the different patterns of economic, technical, and scientific development. PAH air monitoring is one of the areas that has received the most attention during the last few years, mainly in Brazil, Chile, and Argentina, where data represent a few geographical areas within the region. PAH levels in air from some urban areas in Argentina, Brazil, and Chile, considered moderate to high (100-1000ng/m3), are probably among the highest values reported in the open literature. Urbanization, vehicle pollution, and wood fires are the principal contributors to the high reported levels. In more temperate areas, a clear distinction is observed between summer and winter levels. PAH monitoring in soils is very limited within the region, with few data available, and most information indicates widespread pollution. In Brazil, values for many representative ecosystems were found. In Chile, data from forestry and agricultural areas indicate in general low concentrations, in spite of a relatively high detection frequency. Pollution levels in soils are highly dependent on their closeness to PAH sources and certain cultural practices (agricultural burnings, forest fires, etc.). Water PAH levels are rarely reported in the scientific literature for South American countries. Few data were available, even though many regulatory agencies perform routine analysis of hydrocarbons in waters. No information was found specifically related to PAH compounds, which could indicate generally low PAH levels in waters. Regional PAH information for sediments also indicates higher levels. Overall, as observed for water, sediment data indicate a complex situation in densely populated areas affected by urban-industrial inputs where high PAH levels are found. In contrast, in remote areas a typical profile of diagenetic PAHs dominates. Concentrations are greatly variable and are principally related to several highly contaminated sites in Argentina and Brazil (hot spots) with levels four to five orders of magnitude higher. Even though PAHs have carcinogenic properties, little attention has been paid to the analysis of aquatic organisms except in the case of bivalves. As observed for other environmental receptors, the regional data distribution is uneven and is heavily centered in coastal environments and in a few countries (Argentina, Brazil, Chile, and Peru). The most comprehensive PAH monitoring program in the South American coastal environment is the Mussel Watch. Baseline PAH concentrations range from 200 to 700 microg kg(-1) lipids in unpolluted sites; from 1,000 to 3,000 microg kg(-1) in moderately contaminated sites; and from 4,000 to 13,000 microg/kg lipids in the most affected bivalves that come from areas of Río de la Plata (Argentine side), Recife (Brazil), and Punta Arenas (Chile). Critical data gaps exist with respect to PAH analysis in biota, including humans, in foodstuffs, and subsequent effects. Considering the high levels reported in the air compartment, risk assessment procedures in highly populated areas need to be performed. Additionally, few countries within the region have information on PAH levels. In these countries, this type of analysis needs to be performed, and the laboratory capacity needs to be built to assure the accomplishment of these objectives.

Assessment of polynuclear aromatic hydrocarbons ecotoxicity threshold in marine sediments through in situ input/decay measurements

: The ability of decomposers to process variable amounts of xenobiotics in the marine sediment is a useful aggregate indicator of their capacity to prevent their accumulation and eventual ecotoxic effects. Since decomposition processes depend on environmental factors at the sediment which are difficult to mimic in laboratory systems, in situ evaluations in undisturbed sediments are of great interest. A method and its results are presented to evaluate the decomposition rates of PAHs (polynuclear aromatic hydrocarbons) in coastal undisturbed marine sediments at different levels of pollution input. The method is based on the application of pulse chromatography concepts to interpret trap and bed sediment monitoring data obtained at regular time intervals, using models of the water column as an anisotropic carrying medium. The results are for a 14 month data series from moderately polluted sediments near an urban site and at a more distant nearly pristine site on the south Atlantic coast. QSAR (quantitative structure activity relations) indicate that decay rates increase with higher UV absorption and lipidic solubility. At low levels of total PAH input to the sediments (<0.05 μg day(-1) g(-1)), decomposition mechanisms effectively process these compounds within a few days. At higher input levels (up to 0.12 μg day(-1) g(-1)), decomposition lags behind the inputs by approximately 25% and PAHs accumulate in the sediment. In situ estimates of the PAH input/decay ratios provide reliable ecosystem indicators of a safe threshold for anthropogenic inputs of PAHs to the marine environment and a basis for receptor-based standards aimed at their regulation.