Influence of complexation on lead(II) and cadmium(II) percolation through a clay liner

Wastes are usually stocked in waste disposals without any pre-treatment. Runoff waters lead to the formation of leachates containing mineral and organic pollutants. In order to prevent groundwater contamination, a double barrier is placed on the landfill bottom. The first one is an active barrier made up of a draining system and a geomembrane, and the second one, consisting of a clay liner allowing pollutant retention, is considered as a passive system. The aim of this work is to evaluate the complexation impact on the organic and inorganic retention. Percolations on columns filled with clay are performed, which allow a better knowledge of the transfer of metallic pollutants, complexed or not, through a model porous media, considering charge and conditional stability of complexes.     

Respiratory irritation due to carpet shampoo: Two outbreaks

Dried detergent residue left in carpets after they were shampooed with underdiluted carpet shampoo caused respiratory irritation among most employees in an office building and among all staff members and most children in a day-care center. Symptoms included cough, dry throat, difficulty in breathing, nasal congestion, and headache. Eye irritation was also noted by day-care center staff members. Symptoms persisted for many weeks until the carpets were wet extracted. The major ingredient of the three shampoo products implicated in these two outbreaks and in a third similar report in sodium dodecyl sulfate, a respiratory irritant in mice. Unpublished occupational investigations suggest that soap dust exposure may be associated pulmonary function abnormalities in some exposed workers. Detergent dust is a newly recognized example of indoor air pollution and should be considered when patients or employees complain of building-specific respiratory or eye irritation.     

Assessing cypermethrin-contaminated soil with three di erent earthworm test methods

A series of tests (lethal, sublethal, and behavioral) on earthworms were conducted as an eco-assessment of pesticides. In this study, the toxicity of cypermethrin-contaminating soil on adult and juvenile earthworms was assessed. Beside the acute and chronic tests, an avoidance response test was carried out. It was shown that the all-round toxicity from cypermethrin was weak on adult earthworms. Compared with adult earthworms, the toxicity of juvenile earthworms from cypermethrin especially chronic toxicity increased significantly. Growth and reproduction of earthworms appeared to be more severely a ected by cypermethrin at juvenile stage than at adult stage. Applied at 10 mg/kg, cypermethrin had obvious adverse impact on the growth of juvenile earthworms, while 20 mg/kg, cypermethrin caused significant toxic e ects in reproduction. The results also indicated that ecotoxicological risk assessment using only adult specimens may underestimate the e ects of cypermethrin on soil invertebrate populations.     

Assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans in sludges according to the European environmental policy

The amount of sewage sludge generated in Europe is expected to surpass the 10 million tons/year in 2006 as a result of the waste water treatment process according to the Water Policy in European Union. Sewage sludge is what is left behind after water is cleaned in waste treatment plants and is characterized for this high content in nitrogen and phosphorous that could be of great importance in agriculture as fertilizer or soil conditioner. On the other hand, pollutants like metals and organic contaminants are usually removed from water and are accumulated in the sewage sludge, reaching the food chain if their concentrations are not below the safe limits established by the European legislation. The latter issue is of great concern nowadays and in this sense, different works alert against the use of the sewage sludge in agriculture arguing that serious illnesses, even resulting in death as well as adverse environmental impacts are associated to the application of sewage sludge. This work is a continuation of a former comprehensive survey on of priority organic pollutant in sludges for agricultural purposes carried out by our group in Catalonia and this time is focused on the polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), one of the most toxic group of organic compounds listed in the Work Document on Sludge which is the reference tool in this field in Europe and is also included in the Stockholm Convention. Eighty eight samples were collected from the end of 2003 to April 2006 and the concentrations detected were lower than the 100 ng/kg I-TEQ limit recommended by the European legislation (EC, 2000). Thus, sewage sludges generated in Catalonia do not represent a threat to human health if they are used as fertilizers in agriculture.     

Effects of human footprint and biophysical factors on the body-size structure of fished marine species

Marine fisheries in coastal ecosystems in many areas of the world have historically removed large-bodied individuals, potentially impairing ecosystem functioning and the long-term sustainability of fish populations. Reporting on size-based indicators that link to food-web structure can contribute to ecosystem-based management, but the application of these indicators over large (cross-ecosystem) geographical scales has been limited to either fisheries-dependent catch data or diver-based methods restricted to shallow waters (<20 m) that can misrepresent the abundance of large-bodied fished species. We obtained data on the body-size structure of 82 recreationally or commercially targeted marine demersal teleosts from 2904 deployments of baited remote underwater stereo-video (stereo-BRUV). Sampling was at up to 50 m depth and covered approximately 10,000 km of the continental shelf of Australia. Seascape relief, water depth, and human gravity (i.e., a proxy of human impacts) were the strongest predictors of the probability of occurrence of large fishes and the abundance of fishes above the minimum legal size of capture. No-take marine reserves had a positive effect on the abundance of fishes above legal size, although the effect varied across species groups. In contrast, sublegal fishes were best predicted by gradients in sea surface temperature (mean and variance). In areas of low human impact, large fishes were about three times more likely to be encountered and fishes of legal size were approximately five times more abundant. For conspicuous species groups with contrasting habitat, environmental, and biogeographic affinities, abundance of legal-size fishes typically declined as human impact increased. Our large-scale quantitative analyses highlight the combined importance of seascape complexity, regions with low human footprint, and no-take marine reserves in protecting large-bodied fishes across a broad range of species and ecosystem configurations.     

2种杀菌制剂对微生物和大型无脊椎动物降解落叶的影响

水生真菌对于河流中的落叶降解这一重要的生态系统服务有着重要的作用。然而,杀真菌剂对于参与落叶降解的水生真菌和大型无脊椎动物的影响却鲜有了解。本实验将美国红枫（Acer rubrum）的叶片在河流中进行处理（处理组）以获得微生物（细菌与真菌）,或是在自来水下进行淋洗（未处理组）以模拟杀真菌剂可能带来的微生物生物量减少的情况。将处理组叶片分别置于绿钩虾属动物Hyalella azteca（端足类动物,在暴露开始时7日龄,是一种落叶分解物种）存在或不存在的环境中,在23 ℃条件下暴露于复合杀真菌剂QUILT（嘧菌酯和丙环唑）或是PRISTINE（啶酰菌胺和唑菌胺酯）培养14天。QUILT（~ 0.3 μg?L^-1, 1.8 μg?L^-1, 8 μg?L^-1）有加速端足类动物分解落叶的趋势（不显著）,却没有促进端足类动物本身生物量的同时增长,表明端足类动物对于落叶消费量的上升应该主要由于落叶营养成分的减少。PRISTINE（~ 33 μg?L^-1）显著地抑制了端足类动物的生长,降低其生物量（P<0.05）,在未处理组中也观察到类似结果。PRISTINE对于端足类动物生长显著的抑制作用以及随QUILT浓度升高而加快的落叶降解的趋势表明受到杀真菌剂影响的河流中落叶降解这一过程很可能被改变。在河流生态系统相关的条件下,如温度的变化和与杀虫剂混合后脉冲式的暴露,杀真菌剂对于落叶降解的影响需要进一步的研究。
精选自Adria A. Elskus, Kelly L. Smalling, Michelle L. Hladik, Kathryn M. Kuivila. Effects of 2 fungicide formulations on microbial and macroinvertebrate leaf decomposition under laboratory conditions. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2834–2844, November 2016. DOI: 10.1002/etc.3465
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3465/full
     

Environmental fate of pesticides used in Australian viticulture IV. Aqueous stability of dithianon

Dithianon formulations are unstable in slightly basic aqueous solutions (pH 9, 20°C, t _½ = 5.6 h) but relatively stable in neutral or acidic solution (pH 4,20°C, t _½ = 6443 h). To ensure the efficacy of this fungicide it is important to prepare the spray mix fresh with neutral or slightly acidic water. Dithianon is unstable towards natural sunlight in the solid and aqueous phase, with half‐lives of approximately 68 and 42 days, respectively. Thermal hydrolysis does not seem to be the preferred degradation pathway when aqueous solutions are heated by the South Australian summer sun. The major aqueous phase photodegradation product has been identified as 2,3‐dihydro‐1,4‐dithiaanthraquinone. These results strongly suggest that should dithianon be accidentally released into basic Australian waters then it is likely to be rapidly chemically hydrolysed and pose little long term environmental threat. However, dithianon is only slowly chemically and photo‐lytically hydrolysed in neutral and acidic waters, and in this case accidentally release may pose a significant short term environmental threat.     

Evaluating the impacts of multiple generalist fungal pathogens on temperate tree seedling survival

Host-specific mortality driven by natural enemies is a widely discussed mechanism for explaining plant diversity. In principle, populations of plant species can be regulated by distinct host-specific natural enemies that have weak or nonexistent effects on heterospecific competitors, preventing any single species from becoming dominant and thus promoting diversity. Two of the first steps in exploring the role of natural enemies in diversity regulation are to (1) identify potential enemies and (2) evaluate their levels of host specificity by determining if interactions between any one host and its enemy have equivalent survival impacts on co-occurring host species. We developed a bioinformatics framework to evaluate impacts of potential pathogens on seedling survival, for both single and multiple infections. Importantly, we consider scenarios not only if there are specialist pathogens for each plant, but also when generalist pathogens have differential effects on multiple host species, and when co-infection has species-specific effects. We then applied this analytical framework to a field experiment using molecular techniques to detect potential fungal pathogens on co-occurring tree seedling hosts. Combinatorial complexity created by 160 plant-fungus interactions was reduced to eight combinations that affect seedling survival. Potential fungal pathogens had broad host ranges, but seedling species were each regulated by different combinations of fungi or by generalist fungi that had differential effects on multiple plant species. Soil moisture can have the potential to shift the nature of the interactions in some plant-fungal combinations from neutral to detrimental. Reassessing the assumption of single-enemy-single-host interactions broadens the mechanisms through which natural enemies can influence plant diversity.     

A process-based population dynamics model to explore target and non-target impacts of a biological control agent

The risks and benefits associated with efforts to control invasive alien species using classical biological control are being subjected to increasing scrutiny. A process-based population dynamics model was developed to explore the interactions between a folivorous biological control agent, Cleopus japonicus, and its plant host Buddleja davidii. The model revealed that climate could have a significant impact upon the interactions between B. davidii and C. japonicus. At the coolest sites, the impact of C. japonicus on B. davidii was slowed, but it was still eventually capable of controlling populations of B. davidii. At the warmer sites where both B. davidii and C. japonicus grew faster, B. davidii succumbed rapidly to weevil damage. We hypothesise that barring an encounter with a natural enemy, C. japonicus will eventually be able to provide sustained control B. davidii throughout the North Island of New Zealand. The model scenarios illustrate the potential for the C. japonicus population to attain high densities rapidly, and to defoliate patches of B. davidii, creating the potential for spill-over feeding on non-target plants. The potential magnitude of this threat will depend partly on the climate suitability for C. japonicus, the pattern by which it migrates in response to a reduction in the available leaf resource, and the suitability of non-target plants as hosts. In all migration scenarios considered, the pattern of population growth and resource consumption by C. japonicus was exponential, with a strong tendency toward complete utilisation of resource patches more quickly at the warmer compared to colder sites. In addition to providing some useful hypotheses about the effects of climate on the biological control system, and the non-target risks, it also provides some insight into the mechanisms by which climate affects the system.