Energy-dispersive X-ray fluorescence systems as analytical tool for assessment of contaminated soils

To determine the heavy metal content in soil samples at contaminated locations, a static and time consuming procedure is used in most cases. Soil samples are collected and analyzed in the laboratory at high quality and high analytical costs. The demand by government and consultants for a more dynamic approach and by customers requiring performances in which analyses are performed in the field with immediate feedback of the analytical results, is growing. Especially during the follow-up of remediation projects or during the determination of the sampling strategy, field analyses are advisable. For this purpose four types of ED-XRF systems, ranging from portable up to high performance laboratory systems, have been evaluated. The evaluation criteria are based on the performance characteristics for all the ED-XRF systems such as limit of detection, accuracy and the measurement uncertainty on one hand, and also the influence of the sample pretreatment on the obtained results on the other hand. The study proved that the field portable system and the bench top system, placed in a mobile van, can be applied as field techniques, resulting in semi-quantitative analytical results. A limited homogenization of the analyzed sample significantly increases the representativeness of the soil sample. The ED-XRF systems can be differentiated by their limits of detection which are a factor of 10 to 20 higher for the portable system. The accuracy of the results and the measurement uncertainty also improved using the bench top system. Therefore, the selection criteria for applicability of both field systems are based on the required detection level and also the required accuracy of the results.     

Rapid modification in the olfactory signal of ants following a change in reproductive status

In insect societies, the presence and condition of egg-layers can be assessed with pheromones. Exocrine secretions are expected to vary in time in order to give up-to-date information on an individuals reproductive physiology. In the queenless monogynous ant Streblognathus peetersi, we allowed a previously infertile high-ranking worker to accede to the alpha rank, thus triggering the onset of her oogenesis (15 replicates). We then studied her interactions with an established egg-layer from the same colony after different durations, ranging from 20 h to several days. Even though her eggs are only ready to be laid after 30 days, the new alpha was recognised within 1–2 days. Detection occurred at a distance of a few millimetres, suggesting the involvement of a pheromone with low volatility, such as cuticular hydrocarbons. When the new alpha had differentiated for >48 h, she was attacked by the established egg-layer. In all cases, low-ranking workers eventually immobilised one of the two alphas: the new alpha was the target if she had differentiated only recently, suggesting that police workers select the dominant worker with the less fertile odour. Using the behaviour of ants as our measure, we demonstrate that a dominants olfactory signal changes rapidly with a modification in her social status, and it occurs well before the onset of egg-laying.     

Prenatal sonographic diagnosis of intracranial haemorrhage: Report of a case with a sinusoidal fetal heart rate tracing,and review of the literature

The sinusoidal fetal heart rate pattern has been described in association with severe fetal anaemia, with fetal hypoxaemia, and with the administration of parenteral narcotics. Here, we report a case of decreased fetal movement in which a sinusoidal tracing was recorded. The sonographic diagnosis of a massive fetal intracranial haemorrhage was made. A non-interventive approach was taken and the fetus died soon after in utero. We review 28 previous cases in which the prenatal sonographic diagnosis of fetal intracranial haemorrhage was made, including the underlying maternal and fetal factors and neonatal outcomes. We propose that the sinusoidal tracing in this case was due to the intracranial bleed and suggest that fetal intracranial haemorrhage be considered in the sonographic evaluation of the fetus with a sinusoidal pattern.     

Potentially toxic elements in bottom ash from hazardous waste incinerators: an integrated approach to assess the potential release in relation to solid-phase characteristics

Journal of Material Cycles and Waste Management - Understanding the chemical and mineralogical characteristics of bottom ash (BA) containing Potentially Toxic Elements (PTEs, e.g., As, Cd, Co, Cu,...     

Human milk contamination by nine organochlorine pesticide residues (OCPs)

Abstract

Organochlorine pesticides (OCPs) are widely used around the world as insecticides, herbicides, fungicides, nematicides, and rodenticides. Despite banned in Brazil, the usage remains occurring in many countries. The persistence and extreme mobility of OCPs contribute to the contamination of the environment and the human body. The OCPs bioaccumulation in adipose tissue triggers the excretion into human milk during breastfeeding. Hence, the present study determined eighteen OCPs residues in the breast milk of mothers from the Western Region of Bahia State, Brazil. Nine different residue species were found, including beta-Hexachlorocyclohexane (9.24?±?0.00?ng g^?1 fat), delta- Hexachlorocyclohexane (22.15?±?10.48?ng g^?1 fat), Heptachlor (58.08?±?74.13?ng g^?1 fat), Aldrin (142.65?±?50.65?ng g^?1 fat), Dieldrin (774.62?±?472.68?ng g^?1 fat), Endosulfan I (408.44?±?245.51?ng g^?1 fat), Dichloro-diphenyl-dichloro-ethylene (29.17?±?22.42?ng g^?1 fat), Dichloro-diphenyl-trichloro-ethane (28.87?±?0.00?ng g^?1 fat) and Methoxychlor (1699.67?±?797.43?ng g^?1 fat). The Methoxychlor presence in all samples may reveal a recent exposure, while Dieldrin and Endosulfan I analyses can point to distant past exposure.     

Soil C and N models that integrate microbial diversity

Industrial agriculture is yearly responsible for the loss of 55–100 Pg of historical soil carbon and 9.9 Tg of reactive nitrogen worldwide. Therefore, management practices should be adapted to preserve ecological processes and reduce inputs and environmental impacts. In particular, the management of soil organic matter (SOM) is a key factor influencing C and N cycles. Soil microorganisms play a central role in SOM dynamics. For instance, microbial diversity may explain up to 77 % of carbon mineralisation activities. However, soil microbial diversity is actually rarely taken into account in models of C and N dynamics. Here, we review the influence of microbial diversity on C and N dynamics, and the integration of microbial diversity in soil C and N models. We found that a gain of microbial richness and evenness enhances soil C and N dynamics on the average, though the improvement of C and N dynamics depends on the composition of microbial community. We reviewed 50 models integrating soil microbial diversity. More than 90 % of models integrate microbial diversity with discrete compartments representing conceptual functional groups (64 %) or identified taxonomic groups interacting in a food web (28 %). Half of the models have not been tested against an empirical dataset while the other half mainly consider fixed parameters. This is due to the difficulty to link taxonomic and functional diversity.     

Using ecological memory as an indicator to monitor the ecological restoration of four forest plantations in subtropical China

A large area of plantations has been established worldwide and especially in China. Evaluating the restoration status of these plantations is essential for their long-term management. Based on our previous work, we used an ecological memory (EM) approach to evaluate four 26-year-old plantations that represent four common kinds of plantations in subtropical China, i.e., mixed broad-leaved plantation (MBP), mixed coniferous plantation (MCP), eucalyptus plantation (EP), and mixed legume plantation (MLP). Comparing them with the regional climax community, i.e., monsoon evergreen broad-leaved forest (BF), all four plantations accumulated nearly the same pattern of EM during succession. EM was >50 % for soil minerals, light conditions, soil age, soil animals, and soil microbes. EM was about 25 % for soil pollen and 10 % for birds, soil seed bank, and plant species. The total EM value of the four plantations ranged from 50.96 to 52.54, which indicated that all four plantations were in the regional, natural trajectory of succession and between the early and medium successional stages. The results indicated that natural succession processes are unlikely to be accelerated by planting late-stage tree species without sufficient EM. The results also demonstrated that all four plantations were in positive successional trajectories, and the positive succession dynamics were greater in the MLP and MCP. We suggest that the entire natural succession trajectory be used to evaluate the restoration of a site and that the ultimate restoration target be divided into several milestones along the reference trajectory to monitor progress. Forest restoration may be accelerated by starting with a minimum dynamic unit supporting sufficient EM.     

Ecological literacy and beyond: Problem-based learning for future professionals

Ecological science contributes to solving a broad range of environmental problems. However, lack of ecological literacy in practice often limits application of this knowledge. In this paper, we highlight a critical but often overlooked demand on ecological literacy: to enable professionals of various careers to apply scientific knowledge when faced with environmental problems. Current university courses on ecology often fail to persuade students that ecological science provides important tools for environmental problem solving. We propose problem-based learning to improve the understanding of ecological science and its usefulness for real-world environmental issues that professionals in careers as diverse as engineering, public health, architecture, social sciences, or management will address. Courses should set clear learning objectives for cognitive skills they expect students to acquire. Thus, professionals in different fields will be enabled to improve environmental decision-making processes and to participate effectively in multidisciplinary work groups charged with tackling environmental issues.     

Water pressure head and temperature impact on isoxaflutole degradation in crop residues and loamy surface soil under conventional and conservation tillage management

Laboratory incubations were performed in order to evaluate the dissipation of the proherbicide isoxaflutole in seedbed layer soil samples from conventional and conservation tillage systems and in maize and oat residues left at the soil surface under conservation tillage. The effects of temperature and water pressure head on radiolabelled isoxaflutole degradation were studied for each sample for 21 d. Mineralisation of isoxaflutole was low for all samples and ranged from 0.0% to 0.9% of applied ¹⁴C in soil samples and from 0.0% to 2.4% of applied ¹⁴C in residue samples. In soil samples, degradation half-life of isoxaflutole ranged from 9 to 26 h, with significantly higher values under conservation tillage. In residue samples, degradation half-life ranged from 3 to 31 h, with significantly higher values in maize residues, despite a higher mineralisation and bound residue formation than in oat residues. Whatever the sample, most of the applied ¹⁴C remained extractable during the experiment and, after 21 d, less than 15% of applied ¹⁴C were unextractable. This extractable fraction was composed of diketonitrile, benzoic acid derivative and several unidentified metabolites, with one of them accounting for more than 17% of applied ¹⁴C. This study showed that tillage system design, including crop residues management, could help reducing the environmental impacts of isoxaflutole.     

Airborne molds and mycotoxins associated with handling of corn silage and oilseed cakes in agricultural environment

In agricultural areas, the contamination of feedstuffs with molds and mycotoxins presents major environmental and health concerns. During cattle feeding, fungi and mycotoxins were monitored in corn silage, oilseed cakes and bioaerosols collected in Normandy. Most of the corn silages were found to be contaminated by deoxynivalenol (mean concentration: 1883 μg kg^?1) while a few of oilseed cakes were contaminated by alternariol, fumonisin B₁ or gliotoxin. In ambient bioaerosols, the values for fungi per cubic meter of air varied from 4.3 × 10² to 6.2 × 10⁵ cfu m^?3. Seasonal variations were observed with some species like Aspergillus fumigatus which significantly decreased between the 2 seasons (P = 0.0186) while the Penicillium roqueforti group significantly increased during the second season (P = 0.0156). In the personal bioaerosols, the values for fungi per cubic meter of air varied from 3.3 10³ to 1.7 10⁶ cfu m^?3 and the number of A. fumigatus spores significantly decreased between the 2 seasons (P = 0.0488). Gliotoxin, an immunosuppressive mycotoxin, was quantified in 3 personal filters at 3.73 μg m^?3, 1.09 μg m^?3 and 2.97 μg m^?3.