Carbon dioxide emissions from transport and anemia influence on under-five mortality in Benin

Environmental Science and Pollution Research - This work is the first study about the joint effect (influence) of carbon dioxide emissions (CO2) from transport and anemia influence on under-five...     

Temporal variations in the level of chlordecone in seawater and marine organisms in Martinique Island (Lesser Antilles)

Environmental Science and Pollution Research - The present study, conducted in the Galion Bay in Martinique, aims to highlight the temporal and seasonal variations of chlordecone contamination (an...     

Seasonal variations of heavy metals in central Greenland snow deposited from 1991 to 1995

To better assess the seasonality in the fallout of heavy metals to central Greenland, a continuous series of 68 snow samples has been collected at a remote site in the Summit area from a 2.7 m pit using ultraclean sampling procedures. This covers a continuous four year time period from spring 1991 to spring 1995. Co, Cu, Zn, Mo, Rh, Pd, Ag, Cd, Sb, Pt, Pb, Bi and U were determined using ultrasensitive inductively coupled plasma sector field mass spectrometry under clean room conditions. In addition we also determined Al by graphite furnace atomic absorption spectrometry and Na+, Ca2+, SO4(2-), MSA and oxalate by ion chromatography, species that will assist in the interpretation of the trace metal data. The data show pronounced inter- and intra-annual variations, with large differences in the amplitude of these variations for the element studied, with few clear seasonality patterns. Generally, high concentrations are observed in the spring snow layers, while much lower concentrations are typical of summer snow layers. Significant correlations are observed between Co, Cu, Zn, Ag and Sb, while Pt, Pd and Rh show no correlation with the other metals. Crustal enrichment factors show that while the crustal dust contribution is probably important for some metals for part of the year (spring), anthropogenic inputs are as important in many instances. Pronounced intra-annual variations are observed for some metals, in particular Pt. The variations observed for this metal parallel fairly closely changes in Russian Pt production, which points to emissions from smelters in the Russian Arctic as likely sources for Pt.     

Influence of climatic conditions and soil type on 99TcO4- uptake by rye grass

Climatic changes over the long term will modify significantly the biosphere, with glaciation events probably taking place in the next 100 000 years. This is important to safety assessments of nuclear waste disposal facilities that contain high-level and long-lived waste.The soils will evolve toward new situations, and their properties will be consequently modified (e.g. an increase of soil organic matter may be expected in a cooler climate). These changes in soil properties would affect the mobility and the soil-to-plant transfer of radionuclides such as (99)Tc. This study aimed at simulating the cooling of climatic conditions for soils representative of a Jurassic limestone plateau, and the effect on transfer parameters of (99)TcO(4)(-) in the soil-plant systems was investigated. The cooler conditions were simulated by increasing elevation, a surrogate for climate change. Soils were sampled in similar geological background and topography at different elevations in the north east of France (Lorraine and Jura). Soil/solution distribution coefficients (K(d)) of (99)TcO(4)(-) were measured on soil samples in short-term batch experiments with 1:10 soil:solution ratio. Rye grass was grown on the soils spiked with (99)TcO(4)(-) at temperature regimes adapted to each soil. Also, two different temperature regimes (cold and temperate) were applied to one soil to test the effect of plant physiology and evapotranspiration on (99)TcO(4)(-) uptake. K(d) values did not show significant differences among soils in aerobic conditions, and were not significantly different from 0. During plant culture, reduction of (99)Tc was never totally achieved in soils, including in a peaty OM soil. Concentration ratios (CR) were calculated on a dry weight basis and ranged from 20 to 370. CR were always higher in high temperature regimes than in cold temperatures. They were also inversely correlated with soil organic matter (OM) content. A decrease of CR values from 5 to 10-fold was observed with increasing soil OM. Results suggested that the water holding capacity, in which (99)Tc is diluted, the nitrification potential of the soils and the evapotranspiration of plants (efficiency of uptake of soluble (99)TcO(4)(-)) were strongly involved in these differences.     

Hydraulic characteristics of an anaerobic ba ed reactor as onsite wastewater treatment system

The feasibility of using anaerobic ba ed reactor (ABR) as onsite wastewater treatment system was discussed. The ABR consisted of one sedimentation chamber and three up-flow chambers in series was experimented under di erent peak flow factors (PFF of 1 to 6), superficial gas velocities (between 0.6 and 3.1 cm/hr) and hydraulic retention times (HRT) (24, 36 and 48 hr). Residence time distribution (RTD) analyses were carried out to investigate the hydraulic characteristics of the ABR. It was found that the PFF resulted in hydraulic dead space. The dead space did not exceed 13% at PFF of 1, 2 and 4 while there was 2-fold increase (26%) at PFF of 6. Superficial gas velocities did not result in more (biological) dead space. The mixing pattern of ABR tended to be a completelymixed reactor when PFF increased. Superficial gas velocities did not a ect mixing pattern. The e ects of PFF on mixing pattern could be minimized by higher HRT (48 hr). The tank-in-series (TIS) model (N = 4) was suitable to describe the hydraulic behaviour of the studied system. The HRT of 48 hr was able to maintain the mixing pattern under di erent flow patterns, introducing satisfactory hydraulic e ciency. Chemical oxygen demand (COD) and total suspended solids (TSS) removals under all flow patterns were achieved more than 85% and 90%, respectively. The standard deviation of e uent COD and TSS concentration did not exceed 15 mg/L.     

桑沟湾和胶州湾夏季的沉积物-水界面营养盐通量研究

1999年8月通过原样培养研究了黄海的桑沟湾和胶州湾潮下带沉积物-海水界面的营养盐通量.结果表明,两个湾的沉积物均向水层释放NH4-N,通量为0.76(桑沟湾)和0.67 mmol/m2·d(胶州湾),对水层初级生产所需无机氮的贡献为14%(桑沟湾)和12%(胶州湾);桑沟湾的沉积物对PO4-P有净吸收,通量为-1.17mmol/m2·d,而胶州湾的沉积物释放PO4-P,通量为0.01 mmol/m2·d.与其他近岸浅海环境相比,桑沟湾和胶州湾的沉积物-水界面营养盐通量及对水层初级生产的贡献率均处于较低水平.回归统计分析表明,桑沟湾和胶州湾沉积物-水界面的NH4-N通量与沉积物表层的C、N含量正相关,PO4-P通量与沉积物耗氧率和上覆水PO4-P浓度相关.     

Vectorization of agrochemicals: amino acid carriers are more efficient than sugar carriers to translocate phenylpyrrole conjugates in the <Emphasis Type="Italic">Ricinus</Emphasis> system

Producing quality food in sufficient quantity while using less agrochemical inputs will be one of the great challenges of the twenty-first century. One way of achieving this goal is to greatly reduce the doses of plant protection compounds by improving the targeting of pests to eradicate. Therefore, we developed a vectorization strategy to confer phloem mobility to fenpiclonil, a contact fungicide from the phenylpyrrole family used as a model molecule. It consists in coupling the antifungal compound to an amino acid or a sugar, so that the resulting conjugates are handled by active nutrient transport systems. The method of click chemistry was used to synthesize three conjugates combining fenpiclonil to glucose or glutamic acid with a spacer containing a triazole ring. Systemicity tests with the Ricinus model have shown that the amino acid promoiety was clearly more favorable to phloem mobility than that of glucose. In addition, the transport of the amino acid conjugate is carrier mediated since the derivative of the L series was about five times more concentrated in the phloem sap than its counterpart of the D series. The systemicity of the L-derivative is pH dependent and almost completely inhibited by the protonophore carbonyl cyanide 3-chlorophenylhydrazone (CCCP). These data suggest that the phloem transport of the L-derivative is governed by a stereospecific amino acid carrier system energized by the proton motive force.