Humus Quality in Hydromorphic Soils of the Island of Rab

The aim of the study was to determine humus quality in hydromorphic soils of the island of Rab. The study was conducted on 16 samples collected from the anthropogenic top-soil horizon in which were determined total organic carbon according to Walkley-Black method (1934) and fractional composition of humic substances following the procedure given by Schnitzer (1982) using 0.1 M NaOH and 0.1 M Na4P2O7 as extraction solution. Spectroscopic characterization of isolated humic substances was carried out by measuring absorbance in VIS spectral range of 400-700 nm and optical indices (Q4/6, E4/6) were calculated. Investigated soils had sandy silty loam texture, acidic to alkaline pH, low content of physiologically active phosphorus and potassium, hydroameliorated by channels and were used as pastures. The total organic carbon content was low (0.95% in average) and varied from 0.42 to 1.86%. The average C/N ratio was 12.7. The humic acid content varied from 0.09 to 0.38% and fulvic acid content varied from 0.10 to 0.55%. The humification degree was low to medium, in average 21.5%. The average HA/FA ratio was 0.84 that indicated the domination of fulvic-humic type of isolated humic substances. The average optical indices Q4/6 and E4/6 were 5.92 and 5.62, respectively, which corresponded to the presence of more aliphatic and fewer aromatic compounds. The obtained results indicated low humus quality of investigated hydromorphic soils

Usporedba masenih koncentracija PAU-a u lebdećim česticama zraka priobalnog područja srednjeg Jadrana i središnje Hrvatske

Polycyclic aromatic hydrocarbons (PAHs) are considered priority pollutants due to their distribution, persistence, bioaccumulation, and adverse effects on human health. The aim of this study was to obtain the first insight into PAHs mass concentrations bound to airborne particulate matter (PM) in the mid Adriatic coast area of Croatia, and compare them with the PAH levels in Croatia’s urban central area. Relatively low values of PAH mass concentrations were measured in the coastal area, compared to the continental urban region of Croatia impacted by increased emissions due to intensive traffic, industry, and residential heating. A high PM10 contribution of four-ring PAHs (Flu and Pyr) at Martinska site indicated that wood burning heating as well as open fire events, including waste incineration, could be important emission sources of PAHs in the mid Adriatic coast region. This work is licensed under a Creative Commons Attribution 4.0 International License.Policiklički aromatski ugljikovodici (PAU) zbog rasprostranjenosti, postojanosti, bioakumulacije i štetnih utjecaja na zdravlje ljudi te biljnog i životinjskog svijeta smatraju se prioritetnim onečišćujućim tvarima. Cilj istraživanja je po prvi put dobiti uvid u masene koncentracije specifičnih PAU-a u lebdećim česticama u zraku priobalnog područja srednjeg Jadrana te napraviti usporedbu s razinama PAU-a urbanog područja središnje Hrvatske. Koncentracije PAU-a u priobalnom području bile su relativno niske u odnosu na koncentracije u urbanoj središnjoj Hrvatskoj, gdje se i očekuju njihove povišene emisije uslijed znatno jačeg intenziteta prometa, industrije te izgaranja biomase uslijed loženja u kućanstvima. Veća zastupljenost PAU-a četirima aromatskim prstenovima (Flu i Pyr) u ukupnoj masi PM10 čestica na mjernoj postaji Martinska upućuju na to da izgaranje drvne biomase uslijed grijanja kućanstava te uslijed požara otvorenog tipa mogu biti važan izvor PAU-a na obalnom dijelu srednjeg Jadrana. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

Carcinogenic organic content of particulate matter at urban locations with different pollution sources

Polycyclic aromatic hydrocarbons (PAHs) are compounds known for their adverse effects on human health. Many of them are proven carcinogens, especially those with 5 and 6 aromatic rings, which under normal tropospheric conditions are found in the particle-phase. Benzo(a)pyrene (BaP) is often measured as their general representative. Sarajevo, the capital of Bosnia and Herzegovina, is among the European cities with the poorest air quality. However, in Sarajevo PAHs are neither routinely measured within the air quality monitoring network nor have been a subject of extended, continuous field studies during the most polluted cold periods of the year. The capital of Croatia, Zagreb, is located approximately 300 km air distance north-west from Sarajevo. PAH mass concentrations in Zagreb have been measured continuously since 1994 within air quality monitoring networks. During winter 2017/2018, the SAFICA project (Sarajevo Canton Winter Field Campaign 2018) was carried out in order to characterize the chemical composition of organic and inorganic aerosol in the Sarajevo Canton. This paper presents the results of PAH measurements in the cities of Sarajevo and Zagreb at one urban location per city. Daily (24 h), continuous samples of PM10 (particulate matter with aerodynamic diameters ≤10 μm) were collected during heating season, from December 27, 2017 to February 27, 2018. Mass concentrations of eleven particle-phase PAHs in Sarajevo and Zagreb from filter samples collected during the same period were compared. The average BaP ambient mass concentrations in Sarajevo and Zagreb were 6.93 ng m−3 and 3.11 ng m−3, respectively. The contribution of BaP to the total PAH mass concentration was similar at both locations (11%). However, much higher contributions of particle-phase fluoranthene and pyrene were found in Sarajevo. Contributions of individual PAH, diagnostic ratios and factor analysis indicate that combustion of gasoline and diesel from vehicle traffic are a potential source of PAHs at both locations, as well as combustion of other liquid fossil fuels (petroleum and fuel oil). Wood burning was occasionally indicated as a PAH emission source in Zagreb, while in Sarajevo the contribution of PAHs from wood and coal combustion was more evident. Calculated value for total carcinogenic potency (TCP) of PAHs, which was estimated using toxic equivalence factors from the literature, in PM10 samples collected in Sarajevo was more than twice higher than in Zagreb (10.6 ng m−3 and 4.7 ng m−3, respectively). BaP had the highest contribution to the TCP at both locations (69 and 67%)