Time filter

Source Type

Frouz J.,Charles University | Frouz J.,Institute of Soil Biology | Hrckova K.,Institute of Soil Biology | Hrckova K.,University of South Bohemia | And 6 more authors.
Applied Soil Ecology | Year: 2011

The responses of soil algae, vascular plants, and invertebrates to soils collected along a toxicity gradient of post-mining sites were measured in laboratory toxicity tests, and the responses were compared with field pattern of communities of these organisms along this gradient. The study was performed in the Sokolov coal mining district (Czech Republic) where three types of soil materials were sampled: highly acidic coal-rich clays (pH 2.8 ± 0.4), slightly acidic tertiary volcanic ashes (4.6 ± 1.6), and alkaline tertiary clays (8.2 ± 0.1). Laboratory tests with eight species of algae, two species of invertebrates (Enchytraeus crypticus and Folsomia candida), and one plant species (Sinapis alba) gave similar results and showed that besides low pH and the associated solubility of Al, As content and high conductivity were the major factors correlated with toxicity of post-mining substrates. Communities consisting of 69 species of soil algae, 21 species of vascular plants, and 44 morphospecies of soil macrofauna were found during field survey of post mining sites. The toxicity tests explained about 21% of the data variability for the algal community in the field but did not explain any of the data variability for the plant or invertebrate community in the field. The poor ability of laboratory tests to predict the data obtained from surveys of natural communities may result from environmental factors and biotic interactions that have strong effects in the field but not in the laboratory. The study shows that understanding the effects of toxic agents in a complex environmental gradient may require more research on the interaction between toxicity and environmental factors. © 2011 Elsevier B.V.

Pomati F.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Nizzetto L.,Norwegian Institute for Water Research | Nizzetto L.,Research Center for Toxic Compounds in the Environment
Ecotoxicology | Year: 2013

We exposed replicated phytoplankton communities confined in semi-permeable membrane-based mesocosms to 0, 0.1, 1 and 10 μg L-1 triclosan (TCS) and placed them back in their original environment to investigate the occurrence of trans-generational responses at individual, population and community levels. TCS diffused out of mesocosms with a half-life of less than 8 h, so that only the parental generation was directly stressed. At the beginning of the experiment and after 7 days (approximately 2 generations) we analysed responses in the phytoplankton using scanning flow-cytometry. We acquired information on several individually expressed phenotypic traits, such as size, biovolume, pigment fluorescence and packaging, for thousands of individuals per replicated population and derived population and community aggregated traits. We found significant changes in community functioning (increased productivity in terms of biovolume and total fluorescence), with maximal effects at 1 μg L-1 TCS. We detected significant and dose-dependent responses on population traits, such as changes in abundance for several populations, increased average size and fluorescence of cells, and strong changes in within-population trait mean and variance (suggesting micro-evolutionary effects). We applied the Price equation approach to partition community effects (changes in biovolume or fluorescence) in their physiological and ecological components, and quantified the residual component (including also evolutionary responses). Our results suggested that evolutionary or inheritable phenotypic plasticity responses may represent a significant component of the total observed change following exposure and over relatively small temporal scales. © 2013 Springer Science+Business Media New York.

Schneider S.C.,Norwegian Institute for Water Research | Nizzetto L.,Norwegian Institute for Water Research | Nizzetto L.,Research Center for Toxic Compounds in the Environment
Environmental Science and Technology | Year: 2012

It has been hypothesized that highly hydrophobic substances (LogK OW > 5) including many persistent organic pollutants cannot overtake protective tissues and diffuse inside the body of plants due to steric hindrance or very slow diffusion. We investigated the bioaccumulation of hexachlorobenzene (HCB, LogKOW = 5.5) in a benthic charophycean macro-alga: Chara rudis. Chara species are a group of common freshwater algae with a complex body structure encompassing a protective layer of cortex cells surrounding large internode cells. The charophyte cell wall has many features in common with that of higher plants; therefore, they are useful models to investigate bioaccumulation mechanisms in general. We found that HCB diffused through the cortex and reached the cytoplam of internode cells. More than 90% of the HCB mass found in the organism was in the cortex and 10% in the internode cell cytoplasm. The cortex reached a pseudoequilibrium partitioning with water, and the bioconcentration factor was in the same range as that of lower aquatic organisms such as phytoplankton. Charophytes are therefore very efficient accumulators of hydrophobic compounds. Based on the structural and ecological features of charophytes, we speculated on their possible use as biomonitors and bioremediation tools. © 2012 American Chemical Society.

Zheng Q.,CAS Guangzhou Institute of Geochemistry | Zheng Q.,University of Chinese Academy of Sciences | Nizzetto L.,Norwegian Institute for Water Research | Nizzetto L.,Research Center for Toxic Compounds in the Environment | And 9 more authors.
Environmental Science and Technology | Year: 2015

Semivolatile persistent organic pollutants (POP) are bioaccumulative and toxic contaminants. Their global distribution depends on source distribution, atmospheric transport, degradation, and the exchange with ocean and land surfaces. Forests are crucial terrestrial reservoirs due to the commonly envisaged high capacity of their surface soils to store and immobilize airborne contaminants bound to soil organic matter. Our results show that POPs can be unexpectedly mobile in the soil of a tropical rainforest due to fast litter turnover (leading to rapid POP transfer to the subsoil) and leaching rates exceeding degradation rates especially for more hydrophobic congeners. Co-transport in association with leaching fine particulate and dissolved organic matter appears as a relevant driver of this PCB export. A markedly different distribution pattern is displayed in this soil in comparison to soils of colder environments with lower overall storage capacity. These findings show that biogeochemistry of organic matter degradation and weathering can influence POP soil fate. Because tropical forests represent 60% of the global terrestrial productivity, the highlighted dynamics might have an implication for the general distribution of these contaminants. © 2015 American Chemical Society.

Komprda J.,Research Center for Toxic Compounds in the Environment | Komprdova K.,Research Center for Toxic Compounds in the Environment | Sanka M.,Research Center for Toxic Compounds in the Environment | Mozny M.,Czech Hydrometeorological Institute | And 2 more authors.
Environmental Science and Technology | Year: 2013

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. © 2013 American Chemical Society.

Discover hidden collaborations