Evaluation of simplifying assumptions on pesticide degradation in soil

There is evidence that degradation of pesticides in simple laboratory systems may differ from that in the field, but it is not clear which of the simplifications inherent in laboratory studies present serious shortcomings. Laboratory experiments evaluated several simplifying assumptions for a clay loam soil and contrasting pesticides. Degradation of cyanazine [2-(4-chloro-6-ethylamino-1,3,5-triazin-2-ylamino)-2-methylpropiononitrile] and bentazone [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] at fluctuating temperature and moisture was predicted reasonably well based on parameters derived from degradation under constant conditions. There was a tendency for slower degradation of cyanazine and bentazone in soil aggregates of 3 to 5 mm in diameter (DT50 at 15 degrees C and 40% maximum water holding capacity of 25.1 and 58.2 d, where DT50 is the time for 50% decline of the initial pesticide concentration) than in soil sieved to <3 mm (DT50 of 19.1 and 37.6 d), but the differences were not significant for most datasets. Degradation of cyanazine, isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea], and chlorotoluron [3-(3-chloro-p-tolyl)-1,1-dimethylurea] was measured in soil amended with different amounts of lignin. The effect of lignin on degradation was small despite considerable differences in sorption. The DT50 values of cyanazine, isoproturon, and chlorotoluron were 16.2, 18.6, and 33.0 d, respectively, in soil without lignin and 19.0, 23.4, and 34.6 d, respectively, in soil amended with 2% lignin. Degradation of bentazone and cyanazine in repacked soil columns was similar under static and flow conditions with 50.1 and 47.2% of applied bentazone and 74.7 and 73.6% of applied cyanazine, respectively, degraded within 20 d of application. Thus, the assumptions underpinning laboratory to field extrapolation tested here were considered to hold for our experimental system. Additional work is required before general conclusions can be drawn.     

Vertical migration of radionuclides in undisturbed grassland soils

Literature data on numerical values obtained for the parameters of the two most popular models for simulating the migration of radionuclides in undisturbed soils have been compiled and evaluated statistically. Due to restrictions on the applicability of compartmental models, the convection–dispersion equation and its parameter values should be preferred. For radiocaesium, recommended values are derived for its effective convection velocity and dispersion coefficient. Data deficiencies still exist for radionuclides other than caesium and for soils of non-temperate environments.     

Liquid household hazardous wastes in the United States: Identification,disposal, and management plan

Present methods of disposal of today's hazardous household chemicals in the United States are frequently not acceptable because of pathways to groundwater, surface water, and the atmosphere. This report identifies potentially hazardous liquid waste in the household, notes current disposal practices, and recommends an improved management plan that utilizes consumer education, manufacturer cooperation, and governmental intervention. Laws requiring uniform disposal labeling on packaging are critical. Local, county, and state governments must be encouraged to coordinate the necessary infrastructure. Managing hazardous household wastes now will mitigate potential disposal problems.     

Simulating urban waste compost effects on carbon and nitrogen dynamics using a biochemical index

Composting has emerged as a valuable route for the disposal of urban waste, with the prospect of applying composts on arable fields as organic amendments. Proper management of urban waste composts (UWCs) requires a capacity to predict their effects on carbon and nitrogen dynamics in the field, an issue in which simulation models are expected to play a prominent role. However, the parameterization of soil organic amendments within such models generally requires laboratory incubation data. Here, we evaluated the benefit of using a biochemical index based on Van Soest organic matter fractions to parameterize a deterministic model of soil C and N dynamics, NCSOIL, as compared with a standard alternative based on laboratory incubation data. The data included C mineralization and inorganic N dynamics in samples of a silt loam soil (Typic Hapludalf) mixed with various types of UWC and farmyard manure. NCSOIL successfully predicted the various nitrogen mineralization-immobilization patterns observed, but underestimated CO(2) release by 10 to 30% with the less stable amendments. The parameterization based on the biochemical index achieved a prediction error significantly larger than the standard parameterization in only 10% of the tested cases, and provided an acceptable fit to experimental data. The decomposition rates and C to N ratios of compost organic matter varied chiefly according to the type of waste processed. However, 62 to 66% of their variance could be explained by the biochemical index. We thus suggest using the latter to parameterize organic amendments in C and N models as a substitute for time-consuming laboratory incubations.     

Preliminary ecotoxicological characterization of a new energetic substance, CL-20

A new energetic substance hexanitrohexaazaisowurtzitane (or CL-20) was tested for its toxicities to various ecological receptors. CL-20 (epsilon-polymorph) was amended to soil or deionized water to construct concentration gradients. Results of Microtox (15-min contact) and 96-h algae growth inhibition tests indicate that CL-20 showed no adverse effects on the bioluminescence of marine bacteria Vibrio fischeri and the cell density of freshwater green algae Selenastrum capricornutum respectively, up to its water solubility (ca. 3.6 mg l(-1)). CL-20 and its possible biotransformation products did not inhibit seed germination and early seedling (16-19 d) growth of alfalfa (Medicago sativa) and perennial ryegrass (Lolium perenne) up to 10,000 mg kg(-1) in a Sassafras sandy loam soil (SSL). Indigenous soil microorganisms in SSL and a garden soil were exposed to CL-20 for one or two weeks before dehydrogenase activity (DHA) or potential nitrification activity (PNA) were assayed. Results indicate that up to 10,000 mg kg(-1) soil of CL-20 had no statistically significant effects on microbial communities measured as DHA or on the ammonium oxidizing bacteria determined as PNA in both soils. Data indicates that CL-20 was not acutely toxic to the species or microbial communities tested and that further studies are required to address the potential long-term environmental impact of CL-20 and its possible degradation products.     

Importance of colloids in the transport within the dissolved phase (<450 nm) of artificial radionuclides from the Rhône river towards the Gulf of Lions (Mediterranean Sea)

The significance of colloidal fractions regarding the transport of artificial radionuclides in natural water systems is underlined by using sequential ultrafiltration both in the Rh?ne freshwater and the marine area under and outside the influence of the river outflow. Indeed, the Rhodanian aquatic system represents an interesting test site as various artificial radionuclides are released into the Rh?ne river by several nuclear installations. We focused our study on (137)Cs, (106)Ru, (60)Co, (238)Pu and (239+240)Pu. Our results show that Fe, Al and Organic carbon (OC) are the main components of colloidal matter. Colloids represent about 15% of dissolved (<450 nm) OC and 25% of dissolved Fe and Al exported towards the sea. Within the dissolved (< 450 nm) phase, these colloidal compounds are shown to account for the transport of 40% for both Co and Ru, 60% for (238)Pu and (239+240)Pu and have no significance on (137)Cs flux.     

New and versatile optical-immunoassay instrumentation for water monitoring

This article is a review of new and versatile optical-immunoassay instrumentation for water monitoring developed through two European Union projects, RIver ANAlyser (RIANA) and Automated Water Analyser Computer Supported System (AWACSS). Both projects utilise immunoassay techniques to isolate the analytes and Total Internal Reflection Fluorescence (TIRF) to quantify them. Completed in 1999, the RIANA project developed a sensitive and cost-effective analytical system capable of simultaneous detection of multiple-analytes in real-world water samples. The AWACSS project has been in progress since 2001 and is developing rugged-but-sensitive instrumentation that will detect up to 30 analytes simultaneously, will operate unattended, and will have networking capability.     

为不确定的未来实施洪水风险管理战略:荷兰,与莱茵河洪水共生存

无论从经济还是从自然保护角度,冲积平原和三角洲的社会压力都很大.随着经济的发展及大坝增高,由于预期的损失上升和更深的洪水,洪水风险在逐渐增加.全球变化,社会需求变化了,人们的观念也变化了,需要修订长期的洪水风险管理战略.而修订洪水风险管理战略应以柔性战略替代过去以加高大坝为主的刚性战略.柔性战略为主的洪水风险管理就意味着允许洪水临时性大面积泛滥,通过改变土地利用方式减少洪水灾害损失.这样的战略是基于风险管理和"与洪水共生存"的理念提出的,完全替代了过去的灾害控制观念.荷兰三角洲地区是世界人口密度最大区域之一,在这里,灵活的柔性洪水风险管理战略水文功能和"可持续的标准"被详细阐述和评估.     

Perceived prosocial impact,perceived situational constraints,and proactive work behavior: Looking at two distinct affective pathways

This paper examines the role of affect as a linking mechanism between experiences at work (perceived prosocial impact and situational constraints) and two distinct components of proactive work behavior (issue identification and implementation). Based on a dual‐tuning perspective, we argue that both positive affect and negative affect can be beneficial for proactive work behavior. Multi‐level path analysis using daily‐survey data from 153 employees showed that perceived prosocial impact predicted positive affect and that situational constraints as a typical hindrance stressor predicted negative affect. Negative affect, in turn, predicted issue identification, and positive affect predicted implementation. Overall, our study suggests that both positive and negative affects can be valuable in the organizational context by contributing to distinct components of proactive behavior. Copyright © 2015 John Wiley & Sons, Ltd.