Ecological Science

Abstract. The fate of the fungicide carbendazim (applied in the formulation Derosal) in soil was deter-mined in Terrestrial Model Ecosystem (TME) tests and corresponding field-validation studies, which were performed in four different countries (United Kingdom, Germany, ...

The effect of the fungicide carbendazim (applied in the formulation Derosal Ò ) on nutrient cycling in soil was determined in Terrestrial Model Ecosystem (TME) tests and corresponding field-validation studies, which were performed in four different countries (United Kingdom, Germany, Portugal, and The Netherlands). The tests used different soil types, and lasted for 16 weeks. On three of the four sites, grassland soils were used while the fourth site had an arable soil. TMEs consisted of intact soil columns (diameter 17.5 cm; length 40 cm) and were taken from the site where the field study was performed. In the first series of TME tests, carbendazim applied at dosages unto 77.8 kg a.i./ha did not affect sulfate and phosphate concentrations in the top 15 cm soil layers. These nutrients were therefore no longer included in the second series of TME tests and the field-validation studies. Ammonium concentrations in the top soil layers of TMEs and field plots, and in the leachates of the TME columns did not show any effect of carbendazim treatment. Nitrate concentrations in soils and leachates did show some reduction at the highest treatment levels (77.8 kg a.i./ha in the first TME tests, 87.5 kg a.i/ha in the second TME tests and the field-validation studies). Since nitrate concentrations in both soils and leachates were correlated with soil moisture content, these effects could however, mainly be attributed to variations in soil moisture contents, and in some cases also indirectly to effects on earthworm activity. It is concluded that carbendazim, even at dosages as high as 87.5 kg a.i./ha, does not have a significant impact on soil nutrient cycling processes. Nutrient levels in TME tests and the field-validation studies generally showed similar patterns, thus confirming the predictive value of the TME test system.

Cerium oxide nanoparticles (CeO2 NPs) are used as diesel fuel additives to catalyze oxidation. Phenanthrene is a major component of diesel exhaust particles and one of the most common pollutants in the environment. This study aimed at determining the effect of CeO2 NPs on the toxicity of phenanthrene in Lufa 2.2 standard soil for the isopod Porcellionides pruinosus and the springtail Folsomia candida. Toxicity tests were performed in the presence of CeO2 concentrations of 10, 100 or 1000mg Ce/kg dry soil and compared with results in the absence of CeO2 NPs. CeO2 NPs had no adverse effects on isopod survival and growth or springtail survival and reproduction. For the isopods, LC50s for the effect of phenanthrene ranged from 110 to 143mg/kg dry soil, and EC50s from 17.6 to 31.6mg/kg dry soil. For the springtails, LC50s ranged between 61.5 and 88.3mg/kg dry soil and EC50s from 52.2 to 76.7mg/kg dry soil. From this study it may be concluded that CeO2 NPs have a low toxicity and do not a...

Chlorantraniliprole (CAP) is a newly developed, widely applied insecticide. In the aquatic environment, several transformation products are formed under natural conditions, one by dehydration and others by photoinduced degradation. Data on aquatic ecotoxicity of CAP can mainly be found in registration and regulatory evaluation reports. Moreover, the toxicity of its transformation products and especially effects upon chronic exposure remain completely unknown. Hence, our aim was to investigate the acute and chronic toxicity of CAP and its transformation products to the daphnid Daphnia magna. The results showed that CAP is extremely toxic to D. magna, with an acute and chronic LC 50 of 9.4 and 3.7 μg/L, respectively. No effects on daphnid reproduction were observed, but the impact on daphnid survival also affected population growth rate, with an EC 50 of 3.5 μg/L. In contrast, no negative effects of the two main degradation products were observed. The present study demonstrated a high sensitivity of nontarget microcrustaceans to CAP. However, the actual risk of CAP in water diminishes with its spontaneous or light-induced degradation into two transformation products, showing no toxicity to the daphnids in the present study.

Diclofenac is widely used as nonsteroidal anti-inflammatory drug leaving residues in the environment. To investigate effects on terrestrial ecosystems, we measured dissipation rate in soil and investigated ecotoxicological and transcriptome-wide responses in Folsomia candida. Exposure for 4 weeks to diclofenac reduced both survival and reproduction of F. candida in a dose-dependent manner. At concentrations ≥200 mg/kg soil diclofenac remained stable in the soil during a 21-day incubation period. Microarrays examined transcriptional changes at low and high diclofenac exposure concentrations. The results indicated that development and growth were severely hampered and immunity-related genes, mainly directed against bacteria and fungi, were significantly up-regulated. Furthermore, neural metabolic processes were significantly affected only at the high concentration. We conclude that diclofenac is toxic to non-target soil invertebrates, although its mode of action is different from the ...

The effects of Ag-NPs and AgNO3 on the isopod Porcellionides pruinosus were determined upon soil and dietary exposures. Isopods avoided Ag in soil, with EC50 values of ∼16.0 and 14.0 mg Ag/kg for Ag-NPs and AgNO3, respectively. Feeding inhibition tests in soil showed EC50s for effects on consumption ratio of 127 and 56.7 mg Ag/kg, respectively. Although similar EC50s for effects on biomass were observed for nanoparticulate and ionic Ag (114 and 120 mg Ag/kg dry soil, respectively), at higher concentrations greater biomass loss was found for AgNO3. Upon dietary exposure, AgNO3 was more toxic, with EC50 for effects on biomass change being >1500 and 233 mg Ag/kg for Ag-NPs and AgNO3, respectively. The difference in toxicity between Ag-NPs and AgNO3 could not be explained from Ag body concentrations. This suggests that the relation between toxicity and bioavailability of Ag-NPs differs from that of ionic Ag in soils.

A river ecosystem in East Java, Indonesia, fed by a volcanic lake with high concentrations of dissolved metals and a low pH, was found to support only few macroinvertebrates. To unravel the causes of toxicity and to determine the level of dilution necessary to obtain non-toxic water, a bioassay was conducted with the fairy shrimp Thamnocephalus platyurus. A partial toxicity identification evaluation (TIE) approach was used with EDTA as a chelating agent to relate toxicity to pH and metal concentrations. Three water samples were tested, with pHs ranging from 0.72 to 4.5, and diluted with water from a neutral river to different degrees. The dilution factor necessary to achieve no more than 50% mortality in the Thamnotox test (Ldf 50 ) varied from N 300 at the most acidic site, to 7 for water of pH 2.6 and 1.5 for water of pH 4.5. Toxicity was best explained from both low pH and high concentrations of metals, especially Al and Fe. The key role of Al and Fe in the toxicity was confirmed by relating concentrations of the different compounds in the river water to toxicity data from the literature. EDTA addition did not significantly influence Ldf 50 or the lethal pH 50% (LpH 50 ), suggesting a large effect, besides cationic components and pH, of anions (F, SO 4 and Cl).