The thoracic fraction of road dust (PM₁₀) was measured for the first time in Portugal in parking areas, both outdoors and indoors, with the aim of completing existing studies carried out in active lanes of various roads. An in situ resuspension chamber was used to collect a total of 23 samples in three parking areas of Aveiro, whilst the laboratory procedures included determination of carbonaceous content (OC and EC) by a thermo-optical technique, elemental composition by ICP-MS and ICP-OES after acid digestion, and the Aliivribrio fisherii bioluminescent bacteria ecotoxicity bioassay. Dust loadings (DL10) obtained were 18.5 ± 9.8 mg PM₁₀ m⁻², in outdoor parking, and 1.8–23.7 mg PM₁₀ m⁻² for indoor parking, corresponding to emission factors of 476 and 75–589 mg veh⁻¹ km⁻¹, respectively. OC represented 9–30 % of PM₁₀ for the indoor parking areas. However, for the outdoor samples, the high iron oxide content jeopardised the OC-EC separation. In those samples, carbonates accounted for 10.0 ± 3.3% of the PM₁₀ mass. The analysis of elemental components focused on major elements (Al, Ca, Fe, K, and Mg) as well as minor elements. The total mass fraction of element oxides accounted for 27.1% (outdoor) and 23.6–34.3% (indoor). Σ_PAH calculated for all parking areas accounted for 8.38–36.9 μg g⁻¹ PM₁₀. The ecotoxicological bioassay showed that all aqueous solutions were toxic to bioluminescent bacteria, whereas no clear correlations could be made with specific component groups, with the exception of Σ_PAH and EC₅₀.

Open burning of agricultural waste is a common practice in both developed and developing regions of the world, and the emissions pose serious inputs for ambient concentrations of atmospheric particulate matter (PM). In addition, when agricultural waste burning is combined with open-air burning of domestic waste such as plastic, rags, or tires, the potential risk of generating toxic emissions increases. PM samples produced via controlled burning of selected waste types were tested in our laboratory using the No. 227 OECD Guideline for the Testing of Chemicals: Terrestrial Plant Test. Comparing two recommended test species, lettuce (Lactuca sativa) and mustard (Sinapis alba), L. sativa showed significantly higher sensitivity, as treatment elucidated biomass reduction (Df = 1, F = 16.43, p = 0.000385), the biomass of the treated plants was 61.4-91.7% of the control plants. In our investigation inhibition in photosynthetic pigment activity chlorophyll-b in lettuce (Df = 1, F = 3.609, p = 0.0701) was found. The levels of the stress enzyme peroxidase increased significantly in the case of both test species (L. sativa: Df = 1, F = 6.76, p = 0.0112; S. alba: Df = 1, F = 49.99, p = 1.63 × 10⁻⁹), indicating that peroxidase could be regarded as the most sensitive indicator of air pollution. The bioaccumulation pattern was also assessed, proving the risk of significant bioaccumulation of potentially toxic compounds in edible parts of the vegetables tested. Both test plants accumulated higher molecular weight PAHs in significant quantities, as the concentration of 5-ring PAHs was 43.2 μg/kg in mustard and 49.35 μg/kg in lettuce.

Wet deposition of atmospheric polycyclic aromatic hydrocarbons (PAHs) is considered an important source of these potentially toxic compounds in soils. In addition to affecting soil quality, they might be taken up by higher plants, potentially causing phytotoxicity or being accumulated in various organs. Plants are exposed to atmospheric PAHs via the aerial parts and via the soil-root system. The primary aim of this study was to present an experimental setup which can be properly used to quantify PAH accumulation investigating both potential pathways. Rocket (Eruca sativa Mill.) was selected as the model species. The test was conducted following the No. 227 OECD Vegetative Vigor Test. Plants were sprayed with the extract of particles generated during the operation of a diesel-powered vehicle simulating the air–aerial parts–root pathway, while the same extract was used to treat the soil simulating the soil–root–aerial parts pathway. In the soil–root–stem–leaf pathway, the total PAH concentration was 108 μg/kg in the soil, 143 μg/kg in the roots, 92.3 μg/kg in the stems, and 62.5 μg/kg in the leaves. Results showed that higher molecular weight PAHs were mostly accumulated in the roots, but their transfer to above-ground parts cannot be excluded. This study supports the importance of wet deposition in transferring atmospheric PAHs to soils.

Emissions from diesel-powered vehicles are an important source of atmospheric polycyclic aromatic hydrocarbons (PAHs). These PAHs, in turn, are easily accumulated in different vegetable species. As such, the key question of the study was whether PAHs that are already accumulated in plants can be transferred through the trophic chain, thereby affecting ecosystems. Under laboratory conditions, lettuce plants were treated with extracts of PM10 samples collected from the diesel exhaust of a light-duty vehicle. Test plants, which accumulated considerable quantities of PAHs, were used to feed Spanish slugs (Arion vulgaris L.), and PAH accumulation was measured in the slugs’ intestines. Trophic transfer, indicated by higher PAH concentrations in the slugs, was demonstrated in the case of several PAHs, both for light-molecular-weight and high-molecular-weight compounds. The concentration of total PAHs was also higher in the slug intestines compared to the concentrations found in lettuce. Measuring peroxidase (POD) levels in the slugs’ intestines revealed that accumulated PAHs induced an antioxidative response in the test animals, resulting in elevated POD concentrations.