The fate of organic chemicals and their metabolites in soils is often investigated in model matrices having undergone various pre-treatment steps that may qualitatively or quantitatively interfere with the results. Presently, effects associated with soil sterilization by γ-irradiation and soil spiking using an organic solvent were studied in one freshly spiked soil (sterilization prior to contamination) and its field-contaminated (sterilization after contamination) counterpart for the model organic compound 1,1-Dichloro-2,2-bis(4-chlorophenyl)ethene (p,p'-DDE). Changes in the sorption and potential bioavailability of spiked and native p,p'-DDE were measured by supercritical fluid extraction (SFE), XAD-assisted extraction (XAD), and solid-phase microextraction (SPME) and linked to qualitative changes in soil organic matter (SOM) chemistry measured by diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy. Reduced sorption of p,p´-DDE detected with XAD and SPME was associated more clearly with spiking than with sterilization, but SFE showed a negligible impact. Spiking resulted in an increase of the DRIFT-derived hydrophobicity index, but irradiation did not. Spectral peak height ratio descriptors indicated increasing hydrophobicity and hydrophilicity in pristine soil following sterilization, and a greater reduction of hydrophobic over hydrophilic groups as a consequence of spiking. In parallel, reduced sorption of p,p´-DDE upon spiking was observed. Based on the present samples, γ-irradiation appears to alter soil sorptive properties to a lesser extent when compared to common laboratory processes such as spiking with organic solvents.
The subject of this study is the assessment of the influence of climate and land use change on the potential re-emission of organochlorine pesticides (OCPs) from background and agricultural soils. A deterministic spatially and temporally explicit model of the air-surface exchange was created, fed with distributed data of soil and atmospheric concentrations from real measurements, and run under various scenarios of temperature and land use change for a case study area representative of central European conditions. To describe land use influence, some important features were implemented including effect of plowing, influence of land cover, temperature of soil, and seasonal changes of air layer stability. Results show that volatilization of pesticides from soil largely exceeded dry gas deposition in most of the area. Agricultural soils accounted for more than 90% of the total re-emissions both because of the generally higher soil fugacities (higher loads of chemicals and relatively low organic carbon content), but also due to physical characteristics and land management practices enhancing the dynamics of the exchange. An increase of 1 °C in air temperature produced an increase of 8% in the averaged total volatilization flux, however this effect can be neutralized by a change of land use of 10% of the arable lands to grassland or forest, which is consistent with projected land use change in Europe. This suggests that future assessment of climate impact on POP fate and distribution should take into consideration land use aspects.
- MeSH
- dichlordifenyldichlorethylen analýza chemie MeSH
- hexachlorbenzen analýza chemie MeSH
- látky znečišťující půdu analýza chemie MeSH
- látky znečišťující vzduch analýza chemie MeSH
- monitorování životního prostředí MeSH
- podnebí MeSH
- teoretické modely * MeSH
- teplota MeSH
- volatilizace MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
