On the sedimentary occurrence of chlorophyllone a

The 13(2),17(3)-cyclopheophorbide a enol (CPP) is shown to convert mainly to a approximately 1:1 mixture of (13(2)R/S) chlorophyllones a (Chlone), when chromatographed over silica gel or alumina supports. 15(1)-hydroxychlorophyllonelactone a and some other chlorophyll a related compounds are also tentatively identified as minor transformation products of CPP. This raises the possibility that the chlorophyllones reported in recent sediments may be analytical artifacts from CPP. However, data for the surface sediments from Lake Motte as well as literature data for other contemporary sediments show that, (i) they are not artifacts, (ii) considering that CPP is the intermediate compound in the formation of chlorophyllones from chlorophyll a, the hydroxylation of CPP in the sedimentary environment involves an enzymatic process leading preferentially to 13(2)S chlorophyllone a.     

Persistence of atrazine impact on aneuploidy in Pacific oysters,<Emphasis Type="Italic"> Crassostrea gigas</Emphasis>

Widespread use of the herbicide atrazine has incited much research on its toxicity in aquatic systems, where it is routinely detected due to runoff from cultivated fields. Moreover, the determination of the genotoxic effect of such pollutants in the marine environment has become a major requirement for ecosystem protection. In the Pacific oyster, Crassostrea gigas, hypodiploid aneuploid cells have regularly been reported. There is a negative correlation between this phenomenon and growth, as well as evidence for a genetic basis. A positive relationship between atrazine and aneuploidy has previously been demonstrated in C. gigas adults and juveniles. To evaluate the persistence of this impact, our study examined the offspring of the same adult population previously treated with different atrazine doses (10 µg l^–1, representing a peak value found in a polluted environment and 100 µg l^–1), and a seawater control. We observed that these offspring exhibited significantly higher aneuploidy levels when their parents had been exposed to atrazine (14.9–16.9% in comparison with the control where the levels ranged from 11.4% to 12.8%). In addition, the present study examined the aneuploidy level of a sample of juveniles, previously exposed for 3.5 months to the same doses of atrazine, then transferred to non-polluted conditions for an additional period of 2.5 months; this aneuploidy level remained significantly different between the treatments applied. These results demonstrate the persistence of an atrazine impact on Pacific oyster aneuploidy in time, within and between generations, indicating that this widely used compound may represent an important factor causing at least medium-term damage to genetic material.Communicated by S.A. Poulet, Roscoff     

Cadmium behavior in a karst environment hydrological cycle

Environmental Science and Pollution Research - Karst regions are important water providers, supplying approximately 25% of the world population. These areas present higher vulnerability to...     

Molecular receptive ranges of olfactory receptor neurones responding selectively to terpenoids, aliphatic green leaf volatiles and aromatic compounds, in the strawberry blossom weevil Anthonomus rubi

Summary. An important question in insect-plant interactions is which of the numerous plant compounds contribute to the perception of odour qualities in herbivorous insects and are likely to be used as cues in host-searching behaviour. In order to identify which plant-produced volatiles the strawberry blossom weevil Anthonomus rubi detects, we have used electrophysiological recordings from single olfactory neurones linked to gas chromatography and mass spectrometry. We here present 15 receptor neurone types specialised for naturally produced compounds present in the host and nonhost plants and two types for two aggregation pheromone components. The active compounds were terpenoids, aromatic and aliphatic esters, alcohols and aldehydes, some of which are induced by feeding activity of the weevils. The neurones were characterised by a strong response to one or two primary odorants and weaker responses to a few others having similar chemical structure. With one exception, the molecular receptive range of each neurone type was within one chemical group. Enantiomers of linalool separated on a chiral column activated two neurone types with different enantioselectivity. Inhibition by linalool of another neurone type, excited by α-pinene, indicated an additional mechanism for coding the information about this compound. Altogether, detection of 54 compounds by olfactory receptor neurones is shown, of which 40 have been chemically identified in this study. Thus A. rubi has the ability to detect a large number of odorants that may be used in host selection behaviour.     

Development,larvicide activity,and toxicity in nontarget species of the Croton linearis Jacq essential oil nanoemulsion

Environmental Science and Pollution Research - In this study, the essential oil (EO) from leaves of Croton linearis Jacq was extracted and characterized by GC/MS. The EO hydrophilic-lipophilic...     

The combination of chemical,structural, and functional indicators to evaluate the anthropogenic impacts on agricultural stream ecosystems

Environmental Science and Pollution Research - Freshwater contamination by pesticides in agricultural landscapes is of increasing concern worldwide, with strong pesticide impacts on biodiversity,...     

Effects of medium-pressure UV lamps radiation on water quality in a chlorinated indoor swimming pool

The aim of our study was to determine the impact of medium-pressure UV lamps radiation on water quality in a chlorinated indoor swimming pool. An indoor swimming pool was equipped with two medium-pressure UV lamps. We collected eight samples of water daily over a four-weeks period and measured total and free chlorine, pH, water temperature, bacteriological parameters, total organic carbon and trihalomethanes. During the first week, which served as control, medium-pressure UV lamps were turned off. During the next three weeks, medium-pressure UV lamps were kept on 24 h per day. The third week, we reduced the level of the injected chlorine into water, and the last week we also reduced the water renewal volume by 27%. Our results showed that bacteriological parameters remained within allowable french limits. When medium-pressure UV lamps were kept on, total, free and active chlorine levels were significantly increased (P<0.001), whereas combined chlorine level were significantly decreased (P<0.001 and P<0.05, respectively). The levels of chloroform and bromodichloromethane were significantly increased when medium-pressure UV lamps were kept on (P<0.001), whereas chlorodibromomethane and bromoform levels significantly decreased (P<0.05 and P<0.001, respectively). The additional formation of chloroform and bromodichloromethane may be explained by the increase in active chlorine and by radicalizing mechanisms initiated by UV radiation.     

Design of water quality monitoring networks with two information scenarios in tropical Andean basins

Design and redesign of water quality monitoring networks were evaluated for two similarly sized watersheds in the tropical Andes via optimization techniques using geographic information system technology (GIS) and a matter-element analysis of 5-day biological oxygen demand (BOD₅) and total suspended solids (TSS). This resulted in a flexible, objectively based design for a 1128-km² watershed without prior water quality data (La Miel River), and a network redesign of a 1052-km² watershed with historical water quality monitoring (Chinchiná River). Monitoring design for the undocumented basin incorporated mathematical expressions for physical, anthropological, and historical factors—and was based on clear objectives for diagnosis and intervention of water pollution. Network redesign identified network redundancy, which resulted in a 64% reduction in the number of water quality monitoring stations along the channel, and a 78% reduction of stations throughout the basin. Most tropical drainage basins throughout the world have little to no prior water quality data. But even in well-studied drainage basins like the Chinchiná River, which is among the most thoroughly studied basins in Colombia, redesign of historical and existing monitoring networks will become a standard tool to advance the restoration of polluted surface waters, not only in Colombia, but also throughout the world.     

Effects of two herbicidal wastewaters on Chlorella sp. and Phaeodactylum tricornutum

The effects on Chlorella sp. and Phaeodactylum tricornutum of two industrial wastewaters known to contain the herbicide residues of Trifluralin and Propanil have been determined by monitoring the number of cells, the chlorophyll fluorescence and the carbon dioxide assimilation simultaneously for a period of 14 days. The growth of the diatom, Phaeodactylum tricornutum, was inhibited by concentrations of herbicidal waste of the order of 0.1-0.5%, apparently because the rate of reproduction was reduced. Chlorella sp. cells, on the other hand, whilst dramatically inhibited by 1% concentrations of herbicidal waste, were able to recover over a period of 14 days. If discharged at concentrations below 0.01%, the industrial wastes appeared not to affect phytoplankton.