{"id":37841,"date":"2026-02-13T11:07:47","date_gmt":"2026-02-13T10:07:47","guid":{"rendered":"https:\/\/www.vtei.cz\/2026\/02\/atmosfericka-depozice-polycyklickych-aromatickych-uhlovodiku-v-pilotnim-povodi-vyrovky-a-mestskych-oblastech-prahy-a-ostravy-2\/"},"modified":"2026-02-26T16:23:33","modified_gmt":"2026-02-26T15:23:33","slug":"atmospheric-deposition-of-polycyclic-aromatic-hydrocarbons-in-the-pilot-catchment-area-of-vyrovka-and-urban-areas-of-prague-and-ostrava","status":"publish","type":"post","link":"https:\/\/www.vtei.cz\/en\/2026\/02\/atmospheric-deposition-of-polycyclic-aromatic-hydrocarbons-in-the-pilot-catchment-area-of-vyrovka-and-urban-areas-of-prague-and-ostrava\/","title":{"rendered":"Atmospheric deposition of polycyclic aromatic hydrocarbons in the pilot catchment area of V\u00fdrovka and urban areas of Prague and Ostrava"},"content":{"rendered":"

ABSTRACT<\/h2>\n

Atmospheric deposition is the most significant source of polycyclic aromatic hydrocarbons (PAHs) in surface waters in the Czech Republic. These substances originate predominantly from combustion processes. Through deposition, PAHs reach the Earth\u2019s surface and are subsequently washed into surface waters. Although the state and the private sector have implemented a number of measures in recent decades to reduce emissions, not only from major pollution sources but also from households (local heating), these substances continue to have a significant impact on the aquatic environment. Selected PAHs are included on the list of priority substances due to their proven adverse effects on aquatic organisms and human health, and strict environmental quality standards have been set for them in surface water and biota matrices. Consequently, most surface water bodies do not achieve good chemical status according to the Water Framework Directive 2000\/60\/EC. Research in the V\u00fdrovka river basin (a tributary of the Elbe river) comprehensively addressed PAH contamination in relevant matrices of the aquatic environment and in Schreber\u2019s big stem red moss (Pleurozium schreberi<\/em>), which is a suitable indicator of air pollution. At the same time, PAH fluxes in wet deposition in selected urban locations were monitored for comparison. The origin of PAHs was assessed using fingerprinting, based on the analysis of ratios between individual PAHs in the monitored matrices, enabling the distinction between petrogenic and pyrogenic sources.<\/p>\n

INTRODUCTION<\/h2>\n

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous substances in\u00a0the\u00a0environment\u00a0[1]. Their presence is due not only to the\u00a0widespread use of\u00a0substances and final products containing PAHs, but primarily to combustion processes, during which PAHs are formed by the\u00a0incomplete combustion of\u00a0fossil fuels and organic materials\u00a0[2]. Primary emissions of\u00a0PAHs into the\u00a0atmosphere occur predominantly in\u00a0the\u00a0gaseous phase; however, relatively rapid condensation and sorption onto fine particulate matter take place as flue gases cool. The\u00a0rate of\u00a0sorption increases with increasing molecular weight\u00a0[3], while very strong particle sorption and hydrophobicity are characteristic of\u00a0PAHs with three or more aromatic rings. PAHs reach the\u00a0Earth\u2019s\u00a0surface through atmospheric deposition. Only a\u00a0portion of\u00a0them is subsequently transferred into surface waters by erosion, as confirmed in\u00a0the\u00a0model catchments of\u00a0the\u00a0Such\u00fd and Martinick\u00fd streams\u00a0[3]. A\u00a0substantial proportion of\u00a0PAHs remains bound to the\u00a0Earth\u2019s\u00a0surface (vegetation, soil). In\u00a0soils, PAHs undergo degradation at different rates depending on the\u00a0specific hydrocarbon. This process is fastest in\u00a0the\u00a0case of\u00a0naphthalene, which, due to its physicochemical properties, deviates from the\u00a0behaviour of\u00a0other PAHs; its DT50 is reported to be 6.1 weeks. In\u00a0higher-molecular-weight PAHs, degradation is substantially slower: 168\u00a0weeks for benzo(a)pyrene and 522 weeks for benzo(k)fluoranthene\u00a0[4].<\/p>\n

Another important source comprises point and diffuse sources of\u00a0pollution, including stormwater overflows of\u00a0public sewer systems. PAHs enter waters both through runoff from impervious surfaces associated with roads and traffic\u00a0[5] and from areas treated with coating materials and polyaromatic-based waterproofing products, as well as from the\u00a0combustion of\u00a0fossil fuels and smoking; according to Skupinsk\u00e1\u00a0[6], a\u00a0single cigarette releases 20\u201340\u00a0ng of\u00a0benzo(a)pyrene into the\u00a0environment.<\/p>\n

Many PAHs exhibit toxic properties affecting aquatic organisms, animals, birds, and humans; mutagenic, carcinogenic and teratogenic effects, as well as adverse impacts on the\u00a0immune system, have been demonstrated\u00a0[7]. For these reasons, selected PAHs were classified as priority substances for the\u00a0aquatic environment and designated as priority hazardous substances under Directive 2008\/105\/EC of\u00a0the\u00a0European Parliament and of\u00a0the\u00a0Council, as amended by Directive 2013\/39\/EU [8, 9]. Current environmental quality standards (EQS) are in\u00a0the\u00a0order of\u00a0nanograms per litre; the\u00a0strictest standard applies to the\u00a0carcinogenic benzo(a)pyrene, at 1.7\u00a0\u00d7\u00a010-4<\/sup> \u03bcg\u00a0\u2219\u00a0L-1<\/sup> (annual average). The\u00a0forthcoming amendment to Directive 2008\/105\/EC of\u00a0the\u00a0European Parliament and of\u00a0the\u00a0Council extends the\u00a0list of\u00a0PAHs for which environmental quality standards are established; some of\u00a0these standards are revised, and a\u00a0new comparison with EQS recalculated to a\u00a0benzo(a)pyrene ecotoxicity equivalent is introduced. Although the\u00a0environmental quality standard expressed as an annual average is abolished, a\u00a0value at a\u00a0comparable concentration level is newly established for fluoranthene (a\u00a0tightening from the\u00a0current 6.3\u00a0\u00d7\u00a010-3<\/sup> \u03bcg\u00a0\u2219\u00a0L-1<\/sup> to 7.62\u00a0\u00d7\u00a010-4<\/sup> \u03bcg\u00a0\u2219\u00a0L-1<\/sup>). For the\u00a0above reasons, it remains necessary to continue addressing PAH emissions and their impacts on the\u00a0environment and the\u00a0status of\u00a0waters.<\/p>\n

The\u00a0following article focuses on the\u00a0assessment of\u00a0PAH concentrations in\u00a0atmospheric deposition, in\u00a0Schreber\u2019s\u00a0big red stem moss (Pleurozium schreberi), and in\u00a0other environmental matrices within\u00a0the\u00a0V\u00fdrovka model catchment. It also presents a\u00a0comparison with PAH loads from wet deposition in\u00a0an urbanised environment.<\/p>\n

Based on the\u00a0ratios of\u00a0individual PAHs, their origin\u00a0was also assessed. For the\u00a0purposes of\u00a0this article, two main\u00a0categories of\u00a0pollution sources were considered: petrogenic (PETRO) and pyrogenic (PYRO).<\/p>\n

The\u00a0purpose of\u00a0this comparison is to contribute to understanding the\u00a0sources and pathways through which PAHs enter surface waters, where they lead to the\u00a0failure to achieve good status under the\u00a0Water Framework Directive. The\u00a0Czech Republic ranks among the\u00a0countries with the\u00a0highest proportion of\u00a0water bodies failing to achieve good status due to PAHs. This is associated with an obligation to implement measures aimed at reducing their inputs. In\u00a0the\u00a0model catchment, a\u00a0substance balance was established with the\u00a0objective of\u00a0comparing atmospheric deposition of\u00a0PAHs with their substance export under typical agricultural landscape conditions. The\u00a0inclusion of\u00a0additional matrices and sites was intended to confirm further risk factors and to address the\u00a0following questions:<\/p>\n

\n
    \n
  1. What is the\u00a0PAH load from atmospheric deposition (short-term\u00a0\u2013 precipitation, and long-term\u00a0\u2013 moss and humus), and how is it influenced by additional factors such as urbanised areas, traffic, and industry?
    \n
    \n<\/li>\n
  2. What is the\u00a0relationship between atmospheric deposition of\u00a0PAHs and their occurrence in\u00a0the\u00a0watercourse\u00a0\u2013 is there an influence of\u00a0rainfall\u2013runoff events? What proportion of\u00a0deposited substances is exported from the\u00a0catchment, and what proportion is retained by the\u00a0environment?
    \n
    \n<\/li>\n
  3. Which PAH source is dominant for the\u00a0aquatic environment, and how does the\u00a0composition of\u00a0PAHs differ among individual matrices?<\/li>\n<\/ol>\n

    METHODOLOGY<\/h2>\n

    PAHs were monitored and evaluated that contribute to the\u00a0failure to achieve good status of\u00a0water bodies and at the\u00a0same time exhibit a\u00a0significant potential for long-range atmospheric transport, often over considerable distances from primary pollution sources.<\/p>\n

    For the\u00a0purposes of\u00a0the\u00a0project, the\u00a0V\u00fdrovka catchment was selected, specifically its upper part upstream of\u00a0Pla\u0148any hydrological station (operated by the\u00a0Czech Hydrometeorological Institute; CHMI).<\/p>\n

    The\u00a0V\u00fdrovka is a\u00a0left-bank tributary of\u00a0the\u00a0Elbe, and its catchment lies entirely within\u00a0the\u00a0Central Bohemian Region. The\u00a0part of\u00a0the\u00a0catchment upstream of\u00a0the\u00a0Pla\u0148any profile covers an area of\u00a0264.35 km\u00b2 and consists of\u00a030 fourth-order sub-catchments. Catchment elevation ranges from 208 to 550\u00a0m\u00a0a.s.l. The\u00a0hydrographic network has a\u00a0total length of\u00a0362 km of\u00a0watercourses and includes 70 reservoirs.<\/p>\n

    According to data from the\u00a0Land Parcel Identification System (LPIS), there is 19,000\u00a0ha of\u00a0agricultural land within\u00a0the\u00a0area of\u00a0interest, of\u00a0which 94\u00a0% consists of\u00a0arable land. The\u00a0main\u00a0crops that were the\u00a0most widely cultivated in\u00a02022 included winter wheat, winter oilseed rape, maize, spring barley, and sugar beet.<\/p>\n

    To compare the\u00a0distribution of\u00a0PAHs across different components of\u00a0the\u00a0environment, the\u00a0following matrices were sampled:<\/p>\n