Photochemical oxidation of p-chlorophenol by UV/H2O2 and photo-Fenton process. A comparative study

In this study, photochemical advanced oxidation processes (AOPs) utilizing the combinations of UV/H2O2 and the photo-Fenton reaction (UV + classical Fenton reaction) were investigated in lab-scale experiments for the degradation of p-chlorophenol. The study showed that the photo-Fenton process, (a mixture of hydrogen peroxide and ferrous or ferric ion), was the most effective treatment process under acidic conditions and produced a higher rate of degradation of p-chlorophenol at a very short radiation time. It accelerated the oxidation rate by 5-9 times the rate for the UV/H2O2 process. The reaction was found to follow the first order, the reaction was influenced by the pH, the input concentration of H2O2 and the amount of the iron catalyst and the type of iron salt. The experimental results showed that the optimum conditions were obtained at a pH value of 3, with 0.03 mol/l H2O2, and 1 mmol/l Fe(II) for the UV/H2O2/Fe(II) system and 0.01 mol/l H2O2 and, 0.4 mmol/l Fe(III) for the UV/H2O2/Fe(III) system. The reactions were accompanied by the generation of Cl- which reached its maximum value at a short reaction time when using the photo-Fenton process. Finally a rough comparison of the specific energy consumption shows that photo-Fenton process reduced the energy consumption by at least 73 to 83% compared with the UV/H2O2 process.     

Contribution of particulate phosphorus to runoff phosphorus bioavailability

Runoff P associated with eroded soil is partly solubilized in receiving waters and contributes to eutrophication, but the significance of particulate phosphorus (PP) in the eutrophying P load is debatable. We assessed losses of bioavailable P fractions in field runoff from fine-textured soils (Cryaquepts). Surface runoff at four sites and drain-flow at two of them was sampled. In addition to dissolved molybdate-reactive phosphorus (DRP) losses, two estimates of bioavailable PP losses were made: (i) desorbable PP, assessed by anion exchange resin-extraction (AER-PP) and (ii) redox-sensitive PP, assessed by extraction with bicarbonate and dithionite (BD-PP). Annual losses of BD-PP and AER-PP were derived from the relationships (R2 = 0.77-0.96) between PP and these P forms. Losses of BD-PP in surface runoff (94-1340 g ha(-1)) were typically threefold to fivefold those of DRP (29-510 kg ha(-1)) or AER-PP (13-270 g ha(-1)). Where monitored, drainflow P losses were substantial, at one of the sites even far greater than those via the surface pathway. Typical runoff DRP concentration at the site with the highest Olsen-P status (69-82 mg kg(-1)) was about 10-fold that at the site with the lowest Olsen P (31-45 mg kg(-1)), whereas the difference in AER-PP per mass unit of sediment was only threefold, and that of BD-PP 2.5-fold. Bioavailable P losses were greatly influenced by PP runoff, especially so on soils with a moderate P status that produced runoff with a relatively low DRP concentration.     

On the value of large predators in Sweden: a regional stratified contingent valuation analysis

This paper contributes with an applied policy analysis of the predator preservation policy in Sweden. We estimate the overall mean willingness to pay (WTP) for preserving the four large predators in the Swedish fauna by applying the contingent valuation method. Using survey data from 2004 we find that 50 percent of the Swedish population is willing to contribute financially toward implementation of the predator policy package, and that the estimated overall mean WTP is approximately SEK 290. Further, we test for spatial differences in attitudes and WTP and find that respondents in Stockholm have the highest overall mean WTP, while respondents living in wolf-territories have the lowest. Our mean WTP measure is flawed with upward bias, since we cannot estimate the willingness to accept for those with clearly negative preferences regarding the predator policy package (e.g. hunters). In this paper, we set their WTP equal to zero. Thus, we cannot rule out the possibility that the mean willingness to pay is, in fact, negative, i.e. the social-value of implementing the predator policy is negative. Finally, the estimates of the overall WTP are sensitive to response-uncertainty. When the respondents indicate uncertainty about their valuation, they tend to state higher values.     

Determinants of paternity success in the spider Pholcus phalangioides (Pholcidae: Araneae): the role of male and female mating behaviour

In double mating experiments, we examined whether and to what extent various male and female behavioural traits influence the course of mating and fertilization success in the cellar spider. In males, we focussed on pre-copulatory behaviour and on the rhythmic twisting movements that the male performs with his pedipalps during copulation. In females, we investigated remating decisions and the effect of female termination of copulation. Second males fertilized a high proportion of the eggs (P ₂: median 89%) despite much shorter second matings, with high variation in relative paternity success. The number of pedipalp movements (PPMs) of either male was a better predictor of paternity than copulation duration. Our results suggest that in second matings, PPMs help to remove sperm from previous males, whereas in first matings a high number of PPMs enhances fertilization success, either due to numerical sperm competition or cryptic female choice. Furthermore, we found a negative male age effect on paternity in second matings, implying that age-related deterioration of spermatozoa may promote variation in fertilization success. Female receptivity decreased significantly in second matings; only 70% of the females remated. Females that accepted a second copulation were found to terminate these much earlier and with higher probability than first matings. This suggests that the intensity of conflict between the sexes is higher in second matings. Increased intensity of sexual conflict may be responsible for stronger selection on male traits, as pre-copulatory behaviour and age only affected male copulatory performance and paternity in second matings. Electronic Publication     

Response patterns in adult forest trees to chronic ozone stress: identification of variations and consistencies

The responsiveness of adult beech and spruce trees to chronic O(3) stress was studied at a free-air O(3) exposure experiment in Freising/Germany. Over three growing seasons, gas exchange characteristics, biochemical parameters, macroscopic O(3) injury and the phenology of leaf organs were investigated, along with assessments of branch and stem growth as indications of tree performance. To assess response pattern to chronic O(3) stress in adult forest trees, we introduce a new evaluation approach, which provides a comprehensive, readily accomplishable overview across several tree-internal scaling levels, different canopy regions and growing seasons. This new approach, based on a three-grade colour coding, combines statistical analysis and the proficient ability of the "human eye" in pattern recognition.     

Performance of some growth variables

European beech (Fagus sylvatica L.), Norway spruce (Picea abies L. Karst.) and Silver fir (Abies alba Mill.) were exposed to low concentrations of ozone (O(3)) and sulfur dioxide (SO(2)), alone and combined, and simulated acid rain (pH 4.0) in sheltered open-top chambers in Hohenheim (Southwest Germany) for almost five years. The concentrations of O(3) and SO(2) used were related to annual ambient average found in southern West Germany. Two control chambers were ventilated with charcoal filtered air and rainfall was simulated at pH 4.0 and 5.0. Because of large dense plant growth in the chambers it was only possible to measure uncompleted growth of shoots in the upper canopy. Therefore, growth analysis was restricted to this area. The treatment with acidic precipitation decreased the annual shoot growth of beech and reduced leaf surface area of those trees. Exposure to SO(2), O(3) alone and in combination resulted in further reduction of shoot length and leaf surface area. Fumigation with SO(2) and O(3) + SO(2) caused insignificant decreases of shoot length, total dry weight and needle surface area of spruce. The lateral leader shoot growth of spruce exposed to O(3) was significantly reduced only in the last year of the experiment. Growth rates of the spruce exposed to charcoal filtered air and non-acidic precipitation were reduced more than those of beech and fir. Growth variables determined for fir reflected different rates of incremental change. Exposure to O(3) resulted in the largest dry matter production of all fir groups but those exposed to charcoal filtered air and non-acidic precipitation responded with the best lateral leader shoot growth, lowest specific leaf area (SLA) and leaf area ratio (LAR) respectively indicating best metabolic efficiency. At the conclusion of this study a classification of sensitivity was developed for the tree species.     

An empirically tested overlap between indigenous and scientific knowledge of a changing climate in Bolivian Amazonia

Regional Environmental Change - Existing climate data for Bolivian Amazonia rely on observations from a few sparse weather stations, interpolated on coarse-resolution grids. At the same time, the...     

Effects of the 2008 flood on economic performance and food security in Yemen: a simulation analysis

Extreme weather events such as floods and droughts can have devastating consequences for individual well being and economic development, in particular in poor societies with limited availability of coping mechanisms. Combining a dynamic computable general equilibrium model of the Yemeni economy with a household‐level calorie consumption simulation model, this paper assesses the economy‐wide, agricultural and food security effects of the 2008 tropical storm and flash flood that hit the Hadramout and Al‐Mahrah governorates. The estimation results suggest that agricultural value added, farm household incomes and rural food security deteriorated long term in the flood‐affected areas. Due to economic spillover effects, significant income losses and increases in food insecurity also occurred in areas that were unaffected by flooding. This finding suggests that while most relief efforts are typically concentrated in directly affected areas, future efforts should also consider surrounding areas and indirectly affected people.