Effects of compost and digestate on environment and plant production – results of two research projects

A yearly amount of 9.3x106t compost and digestate derived from separately collected organic waste is produced in the 25 European Union member states. The improvement of soil properties is a major benefit of compost application. However, little is known about the occurrence of organic pollutants in compost. In order to estimate the potential of Swiss composts and digestates to influence soil fertility and plant health, one hundred products representative for the different composting systems and qualities available on the Swiss market were analyzed in two research projects. In the first study, polycyclic aromatic hydrocarbons (PAHs), ortho substituted and dioxin-like polychlorinated biphenyls (PCBs, DL PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA), perfluorinated alkyl substances (PFAS), pesticides, chlorinated paraffins (CPs), phthalates and nonylphenol (NP) were analyzed. All compound classes were detected except for NP. PFAS, HBCD, TBBPA, some compounds out of PBDEs and pesticides were found in compost and digestate for the first time. Concentrations of most compounds were in the low ppb range. Contents of PAHs were between 600 and 12473 μg/kg dry weight (dw) and contents of HBCD and CPs between 17 and 384 μg/kg dw. Tests with springtails (Folsomia candida) have been shown to be a versatile tool for ecotoxicological assessment. Within these tests, inhibiting and stimulating effects due to compost application were observed. Except for high PAHs contents, no major problem with regard to contamination of compost and digestate was identified. In the second study, the physical, chemical and biological properties of the composts and digestats, and their influence on soil fertility and plant growth, were characterized. The organic substance and the nutrient content of the composts varied largely between the composts with the feedstock materials as major influencing factors. The respiration rate and enzyme activities exhibited large variations as well, particularly in the youngest composts. These differences decreased when the composts became more mature. Maturity, the degradation stage of the organic matter, depended not only on the age of the compost, but also on the management of the process. The N-mineralization potential of compost added to soil showed that a high proportion of young composts immobilized the nitrogen in the soil. Two compost parameters allowed to predict the risk of nitrogen immobilization in soil: the NO3- and the humic acids contents. The phytotoxicity of the composts varied largely even in mature composts, showing that the storage of the compost plays a decisive role. While the majority of composts protected cucumber plants against Pythium ultimum, only a few composts suppressed Rhizoctonia solani in basil. With respect to disease suppression, the management of the maturation process seems to play a major role. In field experiments, some biologically immature composts immobilized nitrogen in soil and reduced growth of maize. With additional fertilization, however, it was possible to compensate this effect. Digestates and composts increased the pH-value and the biological activity of soil. These effects were observable also one maize season after compost application. In conclusion, the management of the composting process seems to influence the biological quality of the composts and digestats to a higher extent than the feedstock materials or the composting system. More attention should be paid to this biological quality, in order to produce composts with more beneficial effects on crops

Occupational exposure of firefighters to polycyclic aromatic hydrocarbons in non-fire work environments

This work aims to characterize personal exposure of firefighters to polycyclic aromatic hydrocarbons (PAHs) in non-fire work environments (fire stations), and assesses the respective risks. Eighteen PAHs (16 considered by USEPA as priority pollutants, dibenzo[a,l] pyrene and benzo[j] fluoranthene) were monitored in breathing zones of workers at five Portuguese fire stations during a normal shift. The obtained levels of PAHs fulfilled all existent occupational exposure limits as well as air quality guidelines with total concentrations (Sigma PAHs) in range of 46.8-155 ng m(-3). Light compounds (2-3 rings) were the most predominant congeners (74-96% of Sigma PAHs) whereas PAHs with 5-6 rings accounted 3-9% of Sigma PAHs. Fuel and biomass combustions, vehicular traffic emissions, and use of lubricant oils were identified as the main sources of PAHs exposure at the studied fire corporations. Incremental lifetime cancer risks were below the recommend USEPA guideline of 10(-6) and thus negligible for all the studied subjects, but WHO health-based guideline level of 10(-5) was exceeded (9-44 times) at all fire corporations. These results thus show that even during non-fire situations firefighters are exposed to PAHs at levels that may promote some adverse health outcomes; therefore the respective occupational exposures to these compounds should be carefully controlled. (C) 2017This work was supported by European Union (FEDER funds through COMPETE) and National Funds (Fundação para a Ciência e Tecnologia) through projects UID/QUI/50006/2013, POCI/01/0145/FEDER/007265 and UID/EQU/00511/2013-LEPABE, by the FCT/MECwith national funds and co-funded by FEDER in the scope of the P2020 Partnership Agreement. Additional financial support was provided by Fundação para Ciência e Tecnologia through fellowships SFRH/BD/80113/2011 and SFRH/BPD/105100/2014. The authors are thankful to all firefighters involved in the study and to collaborators from Escola Superior de Saúde from Instituto Politécnico de Bragança.info:eu-repo/semantics/publishedVersio

Polycyclic Aromatic Hydrocarbons from the Chattanooga Creek Flood Plain and Their Effects on Endothelial Cells via Group IVC Phospholipase A\u3csub\u3e2\u3c/sub\u3e

Exposure to environmental pollution can be a contributing factor to the development of cardiovascular disease (CVD). Due to contamination produced by long-term discharge of coal tar wastes into the creek, a 2.5-mile section of the Chattanooga Creek in south Chattanooga was designated as a Superfund site by the USEPA in 1994. In order to further investigate the potential health risks posed by creek contamination, 12 PAHs found in high levels in the sediment of the creek as compared to an uncontaminated control site were evaluated for their effects on the human coronary artery endothelial cell (HCAEC) phospholipase A2 (PLA2)/arachidonic acid (AA) cascade, a pathway known to play a significant role in endothelial cell inflammation, apoptosis, and atherosclerosis. Aortic tissue from feral mice trapped at the Superfund site exhibited an increase in markers of inflammation and apoptosis when compared to mouse tissue from the control site, suggesting that natural exposure to contaminants in the creek results in similar findings as in the in vitro studies. Six of the compounds studied (acenaphthylene, benz [e] acephenanthrylene, benzo [k] fluoranthene, fluoranthene, naphthalene, and phenanthrene) activated the AA cascade by targeting the isoform of PLA2, Group IVC PLA2. Upregulation of the enzyme was associated with an increase in apoptosis of HCAECs, as measured by 3H-AA release and histone fragmentation, as well as Western blot analysis for PARP cleavage. Transfection with siRNA specific for Group IVC decreased the amount of histone fragmentation induced by the six compounds. Two compounds (anthracene and benz [a] anthracene) were inactive. Four compounds (benzo [g,h,i] perylene, chrysene, indeno [1,2,3-c,d] pyrene, and pyrene) fluoresced independently of reagents used to measure histone fragmentation and were not able to be evaluated accurately in respect to this. However, these four compounds induced PARP cleavage and three of the four (chrysene, indeno [1,2,3-c,d] pyrene, and pyrene) produced significant 3H-AA release from HCAECs. These data suggest that PAHs present in Chattanooga Creek have potential toxic effects on the cardiovascular system both in vivo and in vitro, and confirm the need for further studies

Evaluating genotoxic effects of plants exposed to heavy metals and polycyclic aromatic hydrocarbons at dumpsite, mechanic workshop and metal scrap site in Lagos

Soil contamination from heavy metals and polycyclic aromatic hydrocarbons (PAHs) from dumpsite, automobile mechanic workshop and metal scrap sites pose human and ecological health risks. This study assesses the levels of heavy metals and PAHs in soils from these sites and their effects on the DNA yield and fragmentation of native plants around there. The DNA yield and fragmentation were compared to those obtained from non-polluted sites (control). DNA of the plants species, Musa acuminata (banana), Jatropha curcas (Barbados nut), Carica papaya (pawpaw), Axonopus compressus (carpet grass), Sida acuta (wireweed), and Eleucine indica (crabgrass grass) for polluted sites and control were analyzed using Gel electrophoresis. Soil heavy metals; copper (Cu), zinc (Zn), lead (Pb) and chromium (Cr) were evaluated from dumpsite, metal area and mechanic workshop using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Polycyclic aromatic hydrocarbons were also determined from soils of the polluted sites using the GC/MS spectrophotometry. The result obtained from the DNA analysis showed that DNA yield and fragmentation of the polluted plants had higher indices than the controls which shows that heavy metals and polycyclic aromatic hydrocarbons affect the DNA of the plants. The effects of the pollutants on DNA of polluted plants had more smearing in their tissue than non-polluted plants. Heavy metals evaluation showed that zinc level was the highest in all the study sites; dumpsite, metal area and mechanic workshop (5.146 mg/kg, 2.709 mg/kg and 1.990 mg/kg respectively) than the control (p<0.05). Chromium was the least present (0.022 mg/kg, 0.018 mg/kg and 0.002 mg/kg respectively). The results of this study indicate that dumpsite, mechanic workshop and metal scrap sites are potential sources of PAH and toxic metal, which can pose serious human health and ecological risks.Keywords: DNA fragmentation, heavy metals, Gel electrophoresis, polycyclic aromatic hydrocarbo

Dietary Exposure Among Adults in Selangor, Malaysia, to Heterocyclic Amines and Polycyclic Aromatic Hydrocarbons in Cooked Meat and Fish

Heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) are possible human carcinogens and potent mutagens which increase the incidence of colon, mammary, prostate, breast and other cancers in rodents. Food containing meat and fish are the most important source of exposure to HCAs and PAHs in the diet and heat-treated foods, especially those which are fried, broiled and grilled. The intake of HCAs and PAHs are influenced by the amount and type of meat and fish ingested, frequency of consumption, cooking methods, cooking temperature and duration of cooking. The aim of the present study was to determine the level of HCAs and PAHs in the most consumed foods in Selangor, Malaysia in order to estimate their exposure to these toxic compounds. The dietary intake of HCAs and PAHs in foods consumed by people in Selangor, Malaysia was determined. Levels of six HCAs, namely: 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3-4-dimethylimidazo[4,5-f] quinoline (MeIQ), 2-amino-3-8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4, 8-DiMeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,7,8-trimethylimidazo[4,5f] quinoxaline (7,8-DiMeIQx) and three PAHs, fluoranthene, benzo[b]fluoranthene and benzo[a]pyrene were measured. Forty-two samples of meat and fish were included in the study. High-performance liquid chromatography with photodiode array detector and fluorescence detector was used to analyze HCAs and PAHs, respectively. Dietary food consumption data (g/day), including meat type and cooking method were obtained using food frequency questionnaires, which were completed by 600 randomly selected subjects aged above 18 years. Results of the study showed that the level of total HCAs in food samples studied ranged from 0 to 38.7 ng/g whereas the level of total PAHs was, 0 to 66.28 ng/g. Among the analyzed HCAs and PAHs, PhIP (30.6 ng/g) and fluoranthene (50.96 ng/g) showed the highest level, respectively. The highest level of total HCAs was found in grilled chicken satay (38.7 ng/g) and for PAHs it was in grilled beef satay (66.28 ng/g). The most abundant HCAs such as PhIP and MeIQx, and for PAHs such as fluoranthene were detected in the food products studied. The 4,8-DiMeIQx, 7,8-DiMeIQx (HCAs) for HCAs and benzo[a]pyrene for PAHs were found in 12 and 22% of the meat and fish dishes. The average daily intake level of HCAs was 553.7 ng/capita/day and for PAHs of 297.58 ng/capita/day. The intake of PhIP was the highest, followed by MeIQx and MeIQ, whereas intake of fluoranthene was the highest, followed by benzo[b]fluoranthene and benzo[a]pyrene. The results reveal that grilled and fried meat and fish products were the major contributors to the exposure of HCAs and PAH

Photodegradation of polycyclic aromatic hydrocarbons in soils under a climate change base scenario

The photodegradation of polycyclic aromatic hydrocarbons (PAHs) in two typical Mediterranean soils, either coarse- or fine-textured, was here investigated. Soil samples, spiked with the 16 US EPA priority PAHs, were incubated in a climate chamber at stable conditions of temperature (20 degrees C) and light (9.6 W m(-2)) for 28 days, simulating a climate change base scenario. PAH concentrations in soils were analyzed throughout the experiment, and correlated with data obtained by means of Microtox (R) ecotoxicity test. Photodegradation was found to be dependent on exposure time, molecular weight of each hydrocarbon, and soil texture. Fine-textured soil was able to enhance sorption, being PAHs more photodegraded than in coarse-textured soil. According to the EC50 values reported by Microtox (R), a higher detoxification was observed in fine-textured soil, being correlated with the outcomes of the analytical study. Significant photodegradation rates were detected for a number of PAHs, namely phenanthrene, anthracene, benzo(a)pyrene, and indeno(123-cd)pyrene. Benzo(a)pyrene, commonly used as an indicator for PAH pollution, was completely removed after 7 days of light exposure. In addition to the PAH chemical analysis and the ecotoxicity tests, a hydrogen isotope analysis of benzo(a)pyrene was also carried out. The degradation of this specific compound was associated to a high enrichment in H-2, obtaining a maximum delta H-2 isotopic shift of +232 parts per thousand. This strong isotopic effect observed in benzo(a) pyrene suggests that compound-specific isotope analysis (CSIA) may be a powerful tool to monitor in situ degradation of PAHs. Moreover, hydrogen isotopes of benzo(a)pyrene evidenced a degradation process of unknown origin occurring in the darkness. (C) 2016 Elsevier Ltd. All rights reserved