Photocatalytic degradation of the diuron pesticide

The occurrence of chlorinated pesticides in wellwaters is a major problem of public health in Ivory Coast and other African countries. Here, we studied the photocatalytic degradation of the pesticide diuron in aqueous solution in presence of two commercial TiO₂ catalysts, P25 and PC500. The capacity of diuron adsorption at the TiO₂ surface is lower for both photocatalysts. The efficiency of photocatalytic degradation of diuron, it is higher using P25 Degussa than PC500 Millenium TiO₂ catalyst.     

First approach of the selective treatment of water by heterogeneous photocatalysis

Photocatalytic reactions using titanium dioxide are of great interest due to their possible applications to solar energy storage and detoxification of wastewater. However, TiO₂ has usually given a very poor selectivity. Here we show that, using binary mixtures, it is possible to selectively degrade one molecular substance without any concentration change of another substance. We have studied the influence of the pH and TiO₂ concentration on the selectivity of the degradation of benzamide and 4-hydroxybenzoic acid. With appropriate modifications of both parameters, the selectivity can be improved.     

Landscape and Agricultural Patterns in Rural Areas: a Case Study in the Brionne Basin, Normandy, France

Landscape changes over a period of 25 years were assessed for a catchment basin in Normandy, France. Landscape attributes, i.e. land use, land cover and natural habitat, were obtained from aerial photographs (1964, 1989) and soil maps, to define a landscape typology. Data were aggregated on a 500 m×500 m grid system and treated by multivariate analysis. Results of these analysis show that this rural landscape has undergone changes in landcover (mainly grassland receding to crop) as well as changes in spatial structure (mainly increase of plot size and uniformisation). These changes were related to a typology of farms (realised by multivariate analysis of a field survey on the 38 registered farms of the site). Results suggest that (i) farms with a narrow range of production, i.e. specialised farms, are located on a narrow range of environmental conditions and are associated with stable landscapes, while (ii) farms with a broader range of production (i.e. polyculture) are distributed more widely throughout the landscape, and are mostly associated with the landscape changes.     

How to uncoil your partner—“mating songs” in giant pill-millipedes (Diplopoda: Sphaerotheriida)

The stridulation of the giant pill-millipede genus Sphaerotherium from South Africa, one of only three groups of millipedes that produce sounds, was studied. One hundred one stridulation series of a total of nine different species (Sphaerotherium dorsaloide, Sphaerotherium hanstroemi, Sphaerotherium mahaium, Sphaerotherium similare, Sphaerotherium punctulatum, Sphaerotherium convexitarsum, Sphaerotherium dorsale, Sphaerotherium rotundatum, and Sphaerotherium perbrincki) were analyzed. Stridulation sounds are produced only with a special field of ribs on the posterior surface of the posterior telopod, which is actively moved over a field of sclerotized nubs on the inner margin of the anal shield. The Sphaerotherium male usually stridulates only when in contact with a female to initiate mating. This seems to prevent the female from volvating into a ball or stimulate the female to uncoil when already rolled in. The sound analyzes revealed a broad frequency spectrum in all stridulation sounds produced, without obvious differences in frequency distribution among species. However, the temporal pattern of the stridulation varies greatly between species and seems to be species-specific, arguing for a species recognition function of the stridulation during courtship behavior. A single species (S. punctulatum) was found to stridulate during mating while three species also show postcopulatory stridulation. Apparently, pill-millipedes are not capable of acoustic perception, as no hearing organs are known, indicating that the communication is mainly based on perception of temporal vibration patterns, and not of the acoustic signal itself. The need to overcome the rolling-in reflex of the female is developed as a hypothesis why stridulation exists only in millipedes able to coil into a ball, and apparently evolved four times independently in the superorder Oniscomorpha.     

Exposure to four chemical UV filters through contaminated sediment: impact on survival,hatching success,cardiac frequency,and aerobic metabolic scope in embryo-larval stage of zebrafish

Environmental Science and Pollution Research - UV filters are widely used in many pharmaceutical and personal care products such as sunscreen and cosmetics to protect from UV irradiation. Due to...     

磷石膏对麦田CO2排放和小麦产量的影响及其经济环境效益分析

磷石膏是一种可以利用的磷化工废渣,本文以磷石膏为麦田温室气体减排剂,研究磷石膏对小麦生长、麦田温室气体二氧化碳(CO2)排放的影响,并分析磷石膏资源化利用的经济环境效益.结果表明,在常规施肥条件下,增施磷石膏2 100kg·hm-2能显著促进小麦生长,增产达37.71%.磷石膏对麦田CO2的减排作用在小麦生长的各个时期有所不同:施用磷石膏1 050 kg·hm-2处理,在小麦生长拔节期、抽穗期和灌浆期对麦田CO2的减排效果较为明显,相比对照分别减少8%、10%和6%;在整个小麦生长季累计减少CO2排放3%;施用磷石膏2 100 kg·hm-2处理,在小麦越冬返青期、拔节期和抽穗期,相比对照减少CO2排放11%、4%和12%,在小麦生长季累计减少CO2排放7%.磷石膏施用量较大的处理对CO2的抑制和减排效果较好.研究还表明在施用磷石膏的情况下,一定范围内,CO2的排放强度(单位鲜重CO2排放与单位产量CO2排放)与小麦穗长、鲜重和产量呈现显著负相关:即穗长越长,鲜重和产量越大,CO2的排放效率越低.在碳交易背景下,磷石膏资源化利用具有较高的经济和环境效益,主要体现在:与对照相比,投入/产出从1∶8.3变为1∶10.7,即在相同投入的情况下可提高28.92%的产出;每吨磷石膏作为麦田温室气体减排剂,可节省治理环境的费用与增产总额合计约290元.废渣磷石膏资源化利用,不仅可以减少环境污染、促进小麦生长,而且可以减少CO2排放,对发展低碳农业、生态农业以及可持续发展农业具有重要应用价值.     

How application of agricultural waste can enhance soil health in soils acidified by tea cultivation: a review

Environmental Chemistry Letters - Tea is one of the world’s most consumed beverages and an important crop of many developing countries. Intensive tea cultivation has negative impacts on soil...