Dietary exposure to technical hexabromocyclododecane (HBCD) alters courtship, incubation and parental behaviors in American kestrels (Falco sparverius)

Hexabromocyclododecane (HBCD) is a high production volume brominated flame retardant that has been detected in the environment and wildlife at increasing concentrations. This study was designed to determine potential effects of dietary exposure to environmentally relevant levels of HBCD on behavior during reproduction in captive American kestrels. Twenty kestrel pairs were exposed to 0.51 μg technical HBCD g⁻¹ kestrel d⁻¹ from 4 weeks prior to pairing until chicks hatched (∼75 d). Ten pairs of controls received the safflower oil vehicle only and were used for comparison. During the courtship period the chitter-calls were reduced in both sexes (p = 0.038) and females performed fewer bonding displays (p = 0.053). Both sexes showed a propensity to be less active than controls during courtship. The reduction in male courtship behavior was correlated with reduced courtship behaviors of females (p ? 0.008) as well as reduced egg mass (p = 0.019). During incubation, nest temperatures of treatment pairs were lower at mid-incubation (p = 0.038). HBCD-exposed males performed fewer key parental behaviors when rearing nestlings, including entering the nest-box, pair-bonding displays and food-retrievals. HBCD-exposed females appeared to compensate for the reduced parental behavior of their mates by performing these same behaviors more frequently than controls (p = 0.004, p = 0.027, p = 0.025, respectively). This study demonstrates that HBCD affects breeding behavior in American kestrels throughout the reproductive season and behavioral alterations were linked to reproductive changes (egg size). This is the first study to report HBCD effects on reproductive behavior in any animal model.     

Echoes from the Past: A Healthy Baltic Sea Requires More Effort

Integrated sediment multiproxy studies and modeling were used to reconstruct past changes in the Baltic Sea ecosystem. Results of natural changes over the past 6000 years in the Baltic Sea ecosystem suggest that forecasted climate warming might enhance environmental problems of the Baltic Sea. Integrated modeling and sediment proxy studies reveal increased sea surface temperatures and expanded seafloor anoxia (in deep basins) during earlier natural warm climate phases, such as the Medieval Climate Anomaly. Under future IPCC scenarios of global warming, there is likely no improvement of bottom water conditions in the Baltic Sea. Thus, the measures already designed to produce a healthier Baltic Sea are insufficient in the long term. The interactions between climate change and anthropogenic impacts on the Baltic Sea should be considered in management, implementation of policy strategies in the Baltic Sea environmental issues, and adaptation to future climate change.     

Fate of atrazine in switchgrass–soil column system

Atrazine, a broad-leaf herbicide, has been used widely to control weeds in corn and other crops for several decades and its extensive used has led to widespread contamination of soils and water bodies. Phytoremediation with switchgrass and other native prairie grasses is one strategy that has been suggested to lessen the impact of atrazine in the environment. The goal of this study is to characterize: (1) the uptake of atrazine into above-ground switchgrass biomass; and (2) the degradation and transformation of atrazine over time. A fate study was performed using mature switchgrass columns treated with an artificially-created agricultural runoff containing 16 ppm atrazine. Soil samples and above-ground biomass samples were taken from each column and analyzed for the presence of atrazine and its chlorinated metabolites. Levels of atrazine in both soil and plant material were detectable through the first 2 weeks of the experiment but were below the limit of detection by Day 21. Levels of deethylatrazine (DEA) and didealkylatrazine (DDA) were detected in soil and plant tissue intermittently over the course of the study, deisopropylatrazine (DIA) was not detected at any time point. A radiolabel study using [¹⁴C]atrazine was undertaken to observe uptake and degradation of atrazine with more sensitivity. Switchgrass columns were treated with a 4 ppm atrazine solution, and above-ground biomass samples were collected and analyzed using HPLC and liquid scintillation counting. Atrazine, DEA, and DIA were detected as soon as 1 d following treatment. Two other metabolites, DDA and cyanuric acid, were detected at later time points, while hydroxyatrazine was not detected at all. The percentage of atrazine was observed to decrease over the course of the study while the percentages of the metabolites increased. Switchgrass plants appeared to exhibit a threshold in regard to the amount of atrazine taken up by the plants; levels of atrazine in leaf material peaked between Days 3 and 4 in both studies.     

Effect of modified montmorillonites on the biodegradation and adsorption of biomarkers such as hopanes, steranes and diasteranes

The effect of modified montmorillonites on the biodegradation and adsorption of selected steranes, diasteranes and hopanes was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The unmodified montmorillonite was treated with didecyldimethylammonium bromide, hydrochloric acid and the relevant metallic chloride to produce organomontmorillonite, acid activated montmorillonite and homoionic montmorillonite respectively which were used in this study. The study indicated that organomontmorillonite, acid activated montmorillonite and potassium montmorillonite did not support the biodegradation of the selected steranes, diasteranes and hopanes as alteration of the biomarkers via biodegradation varied from a paltry 2–6 %. The adsorption of the selected biomarkers on acid activated montmorillonite and organomontmorillonite was also poor. However, adsorption of the biomarkers on potassium montmorillonite was relatively high. Sodium montmorillonite and unmodified montmorillonite appear to stimulate the biodegradation of the selected biomarkers moderately (30–35 %) with adsorption occurring at low level. Calcium montmorillonite and ferric montmorillonite effected significant biodegradation (51–60 %) of the selected biomarkers.     

Laboratory Investigation of a New Trommel Model

Abstract

Rotary screens, or trommels, are an important unit operation in material and fuel processing. A computer model has been developed based upon fundamental mechanics. The coefficients and variables employed in the model thus have real physical meaning; adjusting them based upon laboratory data allows the model user to draw conclusions about the behavior of the trommel that can be applied to design and operational changes. The laboratory testing program was specifically designed to test the model described in this paper.

The model proved able to track the laboratory data. Important phenomena that were validated or revealed included the significance of particle layering, changes in bed sliding with rotational velocity, and the pre-eminence of residence time.     

Rural southeast Texas air quality measurements during the 2006 Texas Air Quality Study

The authors conducted air quality measurements of the criteria pollutants carbon monoxide, nitrogen oxides, and ozone together with meteorological measurements at a park site southeast of College Station, TX, during the 2006 Texas Air Quality Study II (TexAQS). Ozone, a primary focus of the measurements, was above 80 ppb during 3 days and above 75 ppb during additional 8 days in summer 2006, suggestive of possible violations of the ozone National Ambient Air Quality Standard (NAAQS) in this area. In concordance with other air quality measurements during the TexAQS II, elevated ozone mixing ratios coincided with northerly flows during days after cold front passages. Ozone background during these days was as high as 80 ppb, whereas southerly air flows generally provided for an ozone background lower than 40 ppb. Back trajectory analysis shows that local ozone mixing ratios can also be strongly affected by the Houston urban pollution plume, leading to late afternoon ozone increases of as high as 50 ppb above background under favorable transport conditions. The trajectory analysis also shows that ozone background increases steadily the longer a southern air mass resides over Texas after entering from the Gulf of Mexico. In light of these and other TexAQS findings, it appears that ozone air quality is affected throughout east Texas by both long-range and regional ozone transport, and that improvements therefore will require at least a regionally oriented instead of the current locally oriented ozone precursor reduction policies.     

Sensitivity of potential natural vegetation in China to projected changes in temperature,precipitation and atmospheric CO2

A sensitivity study was performed to investigate the responses of potential natural vegetation distribution in China to the separate and combined effects of temperature, precipitation and [CO₂], using the process-based equilibrium terrestrial biosphere model BIOME4. The model shows a generally good agreement with a map of the potential natural vegetation distribution based on a numerical comparison using the ΔV statistic (ΔV = 0.25). Mean temperature of each month was increased uniformly by 0–5 K, in 0.5- or 1-K intervals. Mean precipitation of each month was increased and decreased uniformly by 0–30%, in 10% intervals. The analyses were run at fixed CO₂ concentrations of 360 and 720 ppm. Temperature increases shifted most forest boundaries northward and westward, expanded the distribution of xeric biomes, and confined the tundra to progressively higher elevations. Precipitation increases led to a greater area occupied by mesic biomes at the expense of xeric biomes. Most vegetation types in the temperate regions, and on the Tibetan Plateau, expanded westward into the dry continental interior with increasing precipitation. Precipitation decreases had opposite effects. The modelled effect of CO₂ doubling was to partially compensate for the negative effect of drought on the mesic biomes and to increase potential ecosystem carbon storage by about 40%. Warming tended to counteract this effect, by reducing soil carbon storage. Forest biomes showed substantial resilience to climate change, especially when the effects of increasing [CO₂] were taken into account. Savannas, dry woodland and tundra biomes proved sensitive to temperature increases. The transition region of grassland and forest, and the Tibetan plateau, was the most vulnerable region.     

To duckweeds (Landoltia punctata), nanoparticulate copper oxide is more inhibitory than the soluble copper in the bulk solution

CuO nanoparticles (CuO-NP) were synthesized in a hydrogen diffusion flame. Particle size and morphology were characterized using scanning mobility particle sizing, Brunauer-Emmett-Teller analysis, dynamic light scattering, and transmission electron microscopy. The solubility of CuO-NP varied with both pH and presence of other ions. CuO-NP and comparable doses of soluble Cu were applied to duckweeds, Landoltia punctata. Growth was inhibited 50% by either 0.6 mg L⁻¹ soluble copper or by 1.0 mg L⁻¹ CuO-NP that released only 0.16 mg L⁻¹ soluble Cu into growth medium. A significant decrease of chlorophyll was observed in plants stressed by 1.0 mg L⁻¹ CuO-NP, but not in the comparable 0.2 mg L⁻¹ soluble Cu treatment. The Cu content of fronds exposed to CuO-NP is four times higher than in fronds exposed to an equivalent dose of soluble copper, and this is enough to explain the inhibitory effects on growth and chlorophyll content.     

The dynamics of mercury around an artisanal and small-scale gold mining area,Camarines Norte,Philippines

Environmental Science and Pollution Research - To elucidate the dynamics of mercury emitted and released by artisanal and small-scale gold mining (ASGM) activity and to estimate its impact on the...