Transformation of organoarsenical species by the microflora of freshwater crayfish

A study of the transformation of arsenic species by the microflora of the freshwater crayfish Procambarus clarkii was carried out. The study of the degradation of AB (arsenobetaine) was performed in aerobic conditions in two culture media (tryptic soy broth and saline medium) at two temperatures (30 and 8 degrees C). The microflora transformed AB into TMAO (trimethylarsine oxide), DMA (dimethylarsinate), MA (methylarsonate), and an unidentified compound (U1). The quickest transformations were carried out by microflora from hepatopancreas incubated in saline medium at 30 degrees C. The individualized study of other arsenic species [AC (arsenocholine), TETRA (tetramethylarsonium ion), TMAO, DMA, and MA] was also performed in saline medium. The only transformation observed was of AC into AB. The bacteria possibly responsible for AB degradation were isolated, identified by phenotypic and genotypic methods, and individually assayed for AB transformation. Only isolates allocated to the species Pseudomonas putida were able to metabolize AB.     

The Importance of Precedent Hydro-climatological Conditions for the Mass Transfer of Pollutants in Separated Sewer Systems and Corresponding Tributaries During Storm Events

Runoff events were analysed in separated sewer systems in the town of Luxembourg. The relationships between Event Mean Concentrations of different pollutants and runoff patterns were evaluated. In addition, the inter-storm and intra-storm variability of the material transport were determined. Primarily, the variations in pollutant concentrations and loads are determined by the antecedent weather conditions. The presence of illicit sanitary inputs in one of the sewers produced a significant first flush effect as well as higher Event Mean Concentrations for pollutants. Furthermore, near the town of Trier 40 storms were analyzed in a small natural basin mainly influenced by runoff from a separated sewer system. Natural and artificial storm events were investigated in order to estimate the relationship between the pollutant sources in the channel and from the separated sewer system. Just like in the canalization of Luxembourg City the pollutant dynamics during natural storms are strongly influenced by pre-event hydrological conditions. The artificial storms behave differently. Despite little pre-rain, the maximum concentrations of toxic substances are comparatively low. A resuspension of sediment only occurs in the natural channel system, without the introduction of fines from the sewer system.     

Potential of Borago officinalis, Sinapis alba L. and Phacelia boratus for Phytoextraction of Cd and Pb from Soil

Heavy metal phytoextraction is a soil remediation technique, which makes use of plants in removing contamination from soil. The plants must thus be tolerant to heavy metals, adaptable to soil and climate characteristics, and able to take up large amounts of heavy metals. Most of the high biomass productive plants such as, maize, oat and sunflower are plants, which do not grow in cold climates or need intensive care. In this study three “weed” plants, Borago officinalis; Sinapis alba L. and Phacelia boratus were investigated for their ability to tolerate and accumulate high amounts of Cd and Pb. Pot experiments were performed with soil containing Cd and Pb at concentrations of up to 180 mg kg^?1 and 2,400 mg kg^?1 respectively. All three plants showed high levels of tolerance. Borago officinalis; and Sinapis alba L. accumulated 109 mg kg^?1 and 123 mg kg^?1 Cd, respectively at the highest Cd spiked soil concentration. Phacelia boratus reached a Cd concentration of 42 mg kg^?1 at a Cd soil concentration of 100 mg kg^?1. In the case of Pb, B. officinalis and S. alba L. displayed Pb concentrations of 25 mg kg^?1 and 29 mg kg^?1, respectively at the highest Pb spiked soil concentration. Although the Pb uptake in P. boratus reached up to 57 mg kg^?1 at a Pb spiked soil concentration of 1,200 mg kg^?1, it is not suitable for phytoextraction because of its too low biomass.     

Ozone Biomonitoring with Bel-W3 Tobacco Plants in the City of Valencia (Spain)

A biomonitoring study using the ozone-sensitive bioindicator plant Nicotiana tabacum cv. Bel-W3 was conducted in the city of Valencia (eastern Spain) and surrounding areas in 2002. Plants were exposed to ambient air at seven sites, including four traffic-exposed urban sites, a large urban garden and a suburban and a rural station, for six consecutive 2-week periods using highly standardised methods. Foliar injury was registered at all stations in at least one of the exposure periods. The urban stations submitted to intense traffic showed lower ozone injury than the less traffic-exposed stations. Strong changes in the intensity of ozone injury were observed for the different exposure periods. Leaf injury was significantly related to both mean ozone values (24 and 12 h means) and cumulative exposure indices (AOT20, AOT40). However, correlation strength was moderate (r _s?=?0.39 to 0.58), suggesting that the plant response to ozone was modified by environmental factors. The use of sensitive bioindicators like tobacco Bel-W3 in cities provides complementary information to that of continuously operating air quality monitors, as the impact of ambient ozone levels is directly measured.     

Repeated monitoring of organic carbon stocks after eight years reveals carbon losses from intensively managed agricultural soils in Western Germany

Past land‐use changes, intensive cropping with large proportions of root crops, and preferred use of mineral fertilizer have been made responsible for proceeding losses of soil organic C (SOC) in the plough layer. We hypothesized that in intensive agriculturally managed regions changes in SOC stocks would be detectable within a decade. To test this hypothesis, we tracked the temporal development of the concentrations and stocks of SOC in 268 arable sites, sampled by horizon down to 60 cm in the Cologne‐Bonn region, W Germany, in 2005 and in 2013. We then related these changes to soil management data and humus balances obtained from farmers' surveys. As we expected that changes in SOC concentrations might at least in part be minor, we fractionated soils from 38 representative sites according to particle size in order to obtain C pools of different stability. We found that SOC concentrations had increased significantly in the topsoil (from 9.4 g kg^?1 in 2005 to 9.8 g kg^?1 in 2013), but had decreased significantly in the subsoil (from 4.1 g kg^?1 in 2005 to 3.5 g kg^?­1 in 2013). Intriguingly, these changes were due to changes in mineral‐bound SOC rather than to changes in sand‐sized organic matter pools. As bulk density decreased, the overall SOC stocks in the upper 60 cm exhibited a SOC loss of nearly 0.6 t C (ha · y)^?1 after correction by the equivalent soil mass method. This loss was most pronounced for sandy soils [?0.73 t SOC (ha · y)^?1], and less pronounced for loamy soils [?0.64 t SOC (ha · y)^?1]; silty soils revealed the smallest reduction in SOC [?0.3 t SOC (ha · y)^?1]. Losses of SOC occurred even with the overall humus balances having increased positively from about 20 kg C (ha · y)^?1 (2003–2005) to about 133 kg C (ha · y)^?1 (2005–2013) due to an improved organic fertilization and intercropping. We conclude that current management may fail to raise overall SOC stocks. In our study area SOC stocks even continued to decline, despite humus conservation practice, likely because past land use conversions (before 2005) still affect SOC dynamics.     

Leaching of carbon and nitrogen from a sandy soil substrate: A comparison between suction plates and ion exchange resins

To determine boundary effects on leaching, we investigated (1) how filter materials affect the concentrations of dissolved organic carbon (DOC) and nitrate (NO₃‐N) in soil percolates and (2) whether ion exchange resins and suction plates are equally suited to capture NO₃‐N. DOC leaching was higher with PE suction plates and plate material did not affect NO₃‐N leachate concentrations. Cumulative NO₃‐N leaching was similar for glass suction plates and ion exchange resins.     

Shooting range contamination: mobility and transport of lead (Pb), copper (Cu) and antimony (Sb) in contaminated peatland

Purpose

Small arm shooting ranges located in peatland areas are gathering increased attention due to severe metal and antimony (Sb) contamination and challenging conditions for remediation. The goal of the present study was to gain further understanding of the distribution, binding and transport of lead (Pb), copper (Cu) and Sb in peatland contaminated by small arm shooting range activities.

Materials and methods

A field experiment was carried out at a recently closed shooting range facility in Norway, including (i) peat soil sampling for various selective extractions (water, chemical extractions, extractions by diffusive gradients in thin films, DGT), (ii) establishing groundwater wells for groundwater sampling and monitoring of groundwater level and (iii) sampling of water and sediments in surface water. The results from groundwater monitoring were used to carry out hydrogeological numerical simulations using Seep/W and CTran/W. These models were used to evaluate the residence time of the contaminants in the peatland.

Results and discussion

Increased metal concentrations were observed in the top layer of the peatland, indicating low vertical transport. Groundwater revealed high concentrations of Pb (22 ± 5 μg/L), Cu (16 ± 6 μg/L) and Sb (11 ± 2 μg/L), the dominating contaminant source to the downstream surface water. Hydrogeological modelling indicated that transport mainly happened in the upper peat layer, as a result of a higher hydraulic conductivity close to the surface and a high groundwater table. Pb (6.9 ± 0.1 μg/L), Cu (24.0 ± 0.0 μg/L) and Sb (7.4 ± 0.1 μg/L) concentrations in the stream samples confirmed the spreading of contaminants at levels toxic to aquatic organisms. Pb and Cu were most likely associated with dissolved organic carbon (DOC), whereas Sb showed no correlation with DOC.

Conclusions

The elements contaminating the peatland may leak to the nearby water course over a long-term period. Copper showed the highest concentration in the stream water despite considerably higher levels of Pb in the peat soil. Strong complexation of Cu to dissolved organic matter might explain this observation. Only a little fraction of the contaminants is transported in a particulate form, and therefore are increased sedimentation measures not considered as viable remediation option.

     

Effects of nitrogen fertilization and irrigation on N2O emissions from a sandy soil in Germany

The aim of this study was to investigate the effect of supplemental irrigation on the amount of N₂O emissions on a sandy soil in north-east Germany. N₂O flux measurements were carried out over two vegetation periods from the emergence of plants to harvest. The level of N₂O emissions was low, which is typical for sandy soils in north-east Germany. In both periods, irrigation had no increasing effect on N₂O emissions. Relevant factors were the soil temperature and the soil water-filled pore space (WFPS), which were mainly influenced by weather conditions. This may indicate that nitrification was the main source of N₂O emissions. In conclusion, this study has confirmed that sandy soils under weather conditions of north-east Germany generally have a very low potential for N₂O emissions.     

Effects on Motile Factors and Cell Growth of Euglena gracilis After Exposure to Wood Ash Solution; Assessment of Toxicity, Nutrient Availability and pH-Dependency

Wood ash application (WAA) to the forest has been suggested as a resource of nutrients for trees and for restoration of acidified soils and surface waters. However, studies of the effects of WAA on aquatic systems are few. This study investigated the effects of wood ash (1–25 g L^?1) on the unicellular flagellate Euglena gracilis, which has been proved to be a sensitive test organism for assessing environmental change. Long-term (7 days) growth studies and short-term (direct, 24 and 48 h) studies of different motile factors, using the automatic biological test system Ecotox, were conducted. The results show no indication of biotoxic effects due to wood ash (adjusted to neutral) treatments. However, when no adjustments of pH in wood ash solutions were made, inhibitory effects on motile factors and cell growth were observed at higher concentrations of wood ash (10–25 g L^?1) due to high pH (> 8). In tests with pH adjusted to neutral, enhanced motility was observed. These results indicate that high concentration of WAA could affect freshwater environments.     

LC-MS/MS quantification of bioactive angiotensin I-converting enzyme inhibitory peptides in rye malt sourdoughs

This study quantified antiotensin I-converting enzyme (ACE) inhibitory peptides in rye malt sourdoughs supplemented with gluten proteins and fermented with six strains of Lactobacillus spp. Bioinformatic analysis of prolamins from barley, rye, and wheat demonstrated that the ACE inhibitory peptides LQP, LLP, VPP, and IPP are frequently encrypted in their primary sequence. These tripeptides were quantified by liquid chromatography-tandem mass spectrometry. Tripeptide levels in sourdoughs were generally higher as compared to the chemically acidified controls. Sourdoughs fermented with different strains showed different concentrations of LQP and LLP. These differences corresponded to strain-specific differences in PepO and PepN activities. The highest levels of peptides VPP, IPP, LQP, and LLP, 0.23, 0.71, 1.09, and 0.09 mmol (kg DM)(-1), respectively, were observed in rye malt: gluten sourdoughs fermented with Lactobacillus reuteri TMW 1.106 and added protease. These concentrations were 6-7 times higher as compared to sourdough without fungal protease and exceed the IC(50) by 100-1000-fold.