Accumulation of Atmospheric PAHs in White Mustard - Can the Seeds Be Affected?

Traffic-related particulate matter emissions have been considerably reduced due to stringent regulations in Europe. However, emission of diesel-powered vehicles still poses a significant environmental threat, affecting rural ecosystems and agriculture. Several studies have reported that polycyclic aromatic hydrocarbons (PAHs), a group of potentially toxic organic compounds, can accumulate in crops and vegetables. In our study, white mustard (Sinapis alba L.) plants were experimentally treated with an extract of diesel exhaust. PAH concentrations were measured in the different plant compartments (stems, leaves and seeds), bioconcentration factors (BCFs) were also calculated. Significant accumulation was measured in the leaves and seeds, stems showed lower accumulation potential. All plant matrices showed high tendency to accumulate higher molecular weight PAHs, BCF was the highest in the 6-ring group. The fact that considerable accumulation was experienced in the seeds might show the risk of cultivating crops nearby roads highly impacted by traffic-related emissions.

Ecotoxicity of PM10 emissions generated during controlled burning of waste PET.

Domestic waste is often burned either as fuel for winter heating or in open areas, simply to get rid of waste. Polyethylene terephthalate (PET) represents an important component of plastics usage as well as of plastic waste produced. While most studies attempt to characterize environmental risk of open burning of mixed household waste, present work evaluates chemical and ecotoxicological parameters of particulate matter (PM) produced during controlled burning of PET samples. In the PM10 samples, polycyclic aromatic hydrocarbon and heavy metal concentrations were measured, ecotoxicity was evaluated using the kinetic Vibrio fischeri bioassay. Both chemical composition and ecotoxicity of the 4 samples showed significant correlation, regardless of the colored or colorless nature of the original PET sample. Antimony was found in considerable concentrations, in the range of 6.93-16.9 mg/kg. PAHs profiles of the samples were very similar, showing the dominance of 4-and 5-ring PAHs, including carcinogenic benzo(a)pyrene.

Pot study using Chlorophytum comosum plants to biomonitor PAH levels in domestic kitchens.

In indoor environments, cooking is a major contributor to indoor air pollution releasing potentially harmful toxic compounds such as polycyclic aromatic hydrocarbons. In our study, Chlorophytum comosum 'Variegata' plants were applied to monitor PAH emission rates and patterns in previously selected rural Hungarian kitchens. Concentration and profile of accumulated PAHs could be well explained by cooking methods and materials used in each kitchen. Accumulation of 6-ring PAHs was characteristic in the only kitchen which frequently used deep frying. It also should be emphasized that applicability of C. comosum as indoor biomonitor was assessed. The plant has proven a good monitor organism as it accumulated both LMW and HMW PAHs.

Characteristics of particle-bound polycyclic aromatic hydrocarbons (PAHs) in indoor PM2.5 of households in the Southwest part of Ulaanbaatar capital, Mongolia.

Air pollution, including PM2.5 concentration in Ulaanbaatar (capital of Mongolia) is a serious matter of concern. As the majority of households use coal in large areas of the city, indoor air quality is also posing a serious risk to human health. This study investigated the concentration of polycyclic aromatic compounds (PAHs) in indoor particulate matter (PM2.5) in 10 non-smoker households. Sampling was conducted in winter of 2018, between 27 January and 09 February. Concentrations of PM2.5 in the indoor air of households ranged between 62.8 and 324.8 µg m-3. Total concentration of PAHs also varied in a relatively wide range, between 46.2 and 175.7 ng m-3. Five-ring PAHs represented a considerably high fraction of total PAHs between 25 and 53%, benzo[b]fluoranthene (BbF) and benzo[a]pyrene (BaP) were the two predominant compounds within five-ring PAHs. Significant correlation was found between indoor and outdoor particulate matter levels in wintertime. Considering individual characteristic PAHs, heavier PAHs homologues (4- to 5-ring and 6-ring PAHs) were detected in all households, which suggested the influence of coal combustion and traffic exhaust. Health risk of children attributed to PAHs inhalation was assessed by taking into account the lifetime-average daily dose (LADD) and corresponding lifetime cancer risk. Lifetime average daily dose for children in only one household were slightly higher than health-based guideline level (1.0 × 10-5), defined by WHO, whereas LADD for adults and children of other households were within acceptable limit. The cancer risks from the exposure of children to air pollutants in all households except HH-3 were found high. In the Vibrio fischeri bioluminescence inhibition assay, according to the toxic unit (TU) values of indoor PM2.5 from ten households, all samples were classified as toxic.

Phytotoxicity of particulate matter from controlled burning of different plastic waste types.

According to careful estimations, open burning of plastic waste affects app. 2 billion people worldwide. While human health risks have become more and more obvious, much less information is available on the phytotoxicity of these emissions. In our study phytotoxicity of particulate matter samples generated during controlled combustion of different plastic waste types such as polyvinyl chloride (PVC), polyurethane (PUR), polypropylene (PP), polystyrene (PS) and polyethylene (PE) was evaluated based on peroxidase levels. While different samples showed different concentration-effect relationship patterns, higher concentration(s) caused decreased peroxidase activities in each sample indicating serious damage.

Ecotoxic emissions generated by illegal burning of household waste.

The practice of burning household waste including different types of plastic is illegal in Hungary, still an existing problem. As environmental consequences are hardly known, this study attempts to give an initial estimation of the ecotoxicity generated during controlled combustion of different waste types. These samples included polystyrene (PS), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyurethane (PU), oriented strand board (OSB) and rag (RAG). Ecotoxicological profiling was completed using the following test battery: Vibrio fischeri bioluminescence inhibition assay, Daphnia magna immobility test and the seedling emergence assay. Also, genotoxicity of plastic waste samples was assessed using the SOS Chromotest. Concerning main pollutants in the samples, the samples could be distinguished as 'PAH-type' and 'heavy metal-type' samples. PVC, PU and PS samples showed the highest toxicity in the Vibrio and Daphnia assays. The PVC sample was characterized by an extremely high cadmium concentration (22.4 µg/L), PS, PP and PU samples on the contrary had high total PAH content. While Vibrio and Daphnia showed comparable sensitivity, the phytotoxicity assay had no response for any of the samples tested. Samples originating from the controlled burning of different plastic types such as PU, PVC, PS and PP were classified as genotoxic, PS sample showed extremely high genotoxicity. Genotoxicity expressed as SOSIF showed strong correlation with most of the PAHs detected.

Accumulation pattern of polycyclic aromatic hydrocarbons using Plantago lanceolata L. as passive biomonitor.

Biomonitors are considered a cheap alternative of active air samplers, especially where spatial pattern of air quality is to be monitored, requiring numerous parallel measurements. Of higher plants, Plantago lanceolata L. has been proven a good monitor species with proper accumulation capacity. While biomonitoring studies are difficult to compare due to inherent errors such as the diverse plant material used in different studies, the No. 227 OECD GUIDELINE FOR THE TESTING OF CHEMICALS: Terrestrial Plant Test: Vegetative Vigour Test provides a tool to test extract of aerosol samples under controlled laboratory conditions. In our study, this guideline was followed to experimentally treat Plantago with the aqueous extract of a diesel exhaust sample. Accumulation pattern of polyaromatic hydrocarbons (PAHs) was assessed and compared to samples collected in the field. Unlike most studies reported in the literature, both in the experimentally treated and field Plantago samples, high ratio of high molecular weight PAHs was experienced. Distribution pattern of accumulated PAHs showed strong correlation between the experimentally treated sample and most of the field plantain samples, underlying the usefulness of laboratory treatments for bioaccumulation studies.

Ecotoxicity testing of airborne particulate matter-comparison of sample preparation techniques for the Vibrio fischeri assay.

The bioassay based on the bioluminescence inhibition of the marine bacterium Vibrio fischeri has been the most widely used test for the assessment of airborne particulate matter ecotoxicity. Most studies available use an extract of the solid sample, either made with water or organic solvents. As an alternative, a whole-aerosol test is also available where test bacteria are in actual contact with contaminated particles. In our study, different extraction procedures were compared to this direct contact test based on the V. fischeri assay and analytical measurements. The lowest PAH content and the highest EC50 were determined in water extract, while the highest PAH amount and lowest EC50 were measured in dichloromethane, hexane, and dimethyl-sulphoxide extracts. EC50 of the direct contact test was comparable to that of the methanol extract. Our results suggest that the sensitivity of the direct contact test equals to that of extraction procedures using organic solvents, moreover, it is mimicking an environmentally realistic exposure route.

Assessment of Foliar Uptake and Accumulation of Airborne Polyaromatic Hydrocarbons Under Laboratory Conditions.

Urban horticulture and community gardening have become more and more popular in the past years, however, the risk of bioaccumulation of atmospheric polyaromatic hydrocarbons (PAHs) in vegetables grown in polluted areas cannot be neglected. In our study, the No. 227 OECD GUIDELINE FOR THE TESTING OF CHEMICALS: Terrestrial Plant Test: Vegetative Vigour Test was followed to assess foliar uptake of PAHs from aqueous extract of an urban aerosol. Using lettuce (Lactuca sativa) as a test organism, significant accumulation was experienced. The highest bioconcentration factors (BCFs) were experienced for naphthalene and for anthracene, pyrene and fluoranthene showed the lowest bioaccumulation potential. BCF of each PAH showed strong correlation with molecular weight. The standard protocol defined by the Guideline made it possible to assess bioaccumulation pattern under controlled laboratory conditions.