Sorption and photodegradation of chlorpyrifos on riparian and aquatic macrophytes

Surface water bodies may become contaminated via spray drift following pesticide application. In this investigation, the photodegradation and sorption of chlorpyrifos was studied in four riparian macrophytes representative of Mediterranean flora (Phragmites australis, Iris pseudacorus, Equisetum pratense and Typha latifolia). The results of experiments with both the active ingredient and the formulation DURSBAN 48® EC confirm the ability of these species to interact with chemicals such as chlorpyrifos. The maximum sorption of chlorpyrifos at equilibrium was observed in Phragmites australis (22%). And, the maximum instantaneous sorption of chlorpyrifos was observed in the dried biomass of Phragmites australis (49%). The epicuticular waxes present on leaves influence photodegradation processes, resulting in a decrease in chlorpyrifos persistence depending on the nature of the extract. The half-life of chlorpyrifos residues in leaf waxes decreased from 34 to 99 minutes when irradiated.     

Rheological Studies of Microfibrillar Cellulose Water Dispersions

The rheological behaviour of microfibrillar cellulose (MFC) water dispersions has been investigated. For the first time a detailed study of shear dependent viscosity at low and high shear rate is presented. A peculiar time dependent behaviour measured in the area between 0 and 1000 s⁻¹ was identified. The study shows a hysteresis loop in the shear rate–viscosity relationship at low shear rate. Additional time dependent shear rate measurements were performed, and a hypothesis for a mechanism of interaction and formation of a fibrils network was suggested. Higher temperature caused lower viscosity values, and this difference was increased at higher shear rate values. Oscillatory measurements showed how the closeness of the fibrils helps network creations. Data obtained from high shear measurements showed that 1% MFC water dispersions had a dilatant behaviour at ultra high shear rates with values increasing from 120 to 300 Pa s in the area between 180,000 and 330,000 s⁻¹ .     

Preliminary evaluation of insecticide resistance in a strain of Musca domestica (Diptera: Muscidae) from an intensive chicken farm of Northern Italy

The house fly, Musca domestica L., a relevant sanitary pest, is mainly controlled by insecticides. However, an inappropriate use of chemicals may induce resistance, treatment efficacy decline and environmental damages. We evaluated toxicity of some organophosphates, pyrethroids, spinosad and neonicotinoids by topical applications on adults of a M. domestica strain (OcRo) collected from an intensive chicken farm in Northern Italy, in comparison to a susceptible strain (s-DBF). The OcRo strain exhibited higher levels of resistance (RR??) to four pesticides in comparison to s-DBF. Spinosad and imidacloprid had very low RR??, thus were still efficient in OcRo control. We also tested resistance to pesticides in OcRo after topical applications of synergistic compounds. Hydrolases were involved in phosphorganic detoxification and cytochrome P450 monoxygenases in that of pyrethroids. These results indicate that OcRo strain is now multiresistant to organophosphates and pyrethroids, and this should be considered for an environmentally safe pest management.     

A microcosm system to evaluate the toxicity of the triazine herbicide simazine on aquatic macrophytes

This study evaluates the effects of the triazine herbicide simazine in an outdoor pond microcosm test system that contained two submerged rooted species (Myriophyllum spicatum and Elodea canadensis) and two emergent rooted species (Persicaria amphibia and Glyceria maxima) over a period of 84 days. Simazine was applied to the microcosms at nominal concentrations of 0.05, 0.5 and 5 mg/L. General biological endpoints and physiological endpoints were used to evaluate herbicide toxicity on macrophytes and the algae developing naturally in the system.Concentration-related responses of macrophytes and algae were obtained for the endpoints selected, resulting in a no observed ecologically adverse effect concentration (NOEAEC) at simazine concentrations of 0.05 mg active ingredient/L after 84 days. E. canadensis was the most negatively affected species based on length increase, which was consistently a very sensitive parameter for all macrophytes. The experimental design presented might constitute a suitable alternative to conventional laboratory single-species testing.     

Life cycle assessment of Italian citrus-based products. Sensitivity analysis and improvement scenarios

Though many studies concern the agro-food sector in the EU and Italy, and its environmental impacts, literature is quite lacking in works regarding LCA application on citrus products. This paper represents one of the first studies on the environmental impacts of citrus products in order to suggest feasible strategies and actions to improve their environmental performance. In particular, it is part of a research aimed to estimate environmental burdens associated with the production of the following citrus-based products: essential oil, natural juice and concentrated juice from oranges and lemons. The life cycle assessment of these products, published in a previous paper, had highlighted significant environmental issues in terms of energy consumption, associated CO₂ emissions, and water consumption. Starting from such results the authors carry out an improvement analysis of the assessed production system, whereby sustainable scenarios for saving water and energy are proposed to reduce environmental burdens of the examined production system. In addition, a sensitivity analysis to estimate the effects of the chosen methods will be performed, giving data on the outcome of the study. Uncertainty related to allocation methods, secondary data sources, and initial assumptions on cultivation, transport modes, and waste management is analysed. The results of the performed analyses allow stating that every assessed eco-profile is differently influenced by the uncertainty study. Different assumptions on initial data and methods showed very sensible variations in the energy and environmental performances of the final products. Besides, the results show energy and environmental benefits that clearly state the improvement of the products eco-profile, by reusing purified water use for irrigation, using the railway mode for the delivery of final products, when possible, and adopting efficient technologies, as the mechanical vapour recompression, in the pasteurisation and concentration of juice.     

Variability of ozone concentration in a montane environment,northern Italy

To evaluate the spatial variability of ozone concentrations, two studies were undertaken in the montane environment of Trentino region, northern Italy, in 2007. In the first study, a 225 km² area was considered. Here, a randomized design was used to evaluate the variability of ozone concentration at 1 and 225 km² scale. Measurements were carried out by passive samplers between May and June 2007. In a second study, the whole 6207 km² area of Trentino was considered. The area is covered by five grid cells of the European Monitoring and Evaluation Programme (EMEP). A systematic 15 × 15 km grid was used to allocate 15 passive samplers over the entire province, resulting into 1–4 samplers for each of the 5 EMEP grid cells (2500 km² each) overlapping the study area. Measurements were carried out between June and September 2007. Accuracy of passive samplers was checked by direct comparison with conventional ozone analysers. Significant differences (P = 0.034) were found in ozone concentration among 1 × 1 km quadrates within the 225 km² study area, while variability within the 1 × 1 km grid cells (coefficient of variation, CV′ = 0.12) slightly exceed the measurement error (CV′ = 0.08). At larger scales (225, 2500 and 6207 km²), ozone concentration shows much higher variability (CV′ from 0.18 to 0.28, with peak values at 0.40). Reported differences lead to very different AOT40 estimates even within the same EMEP grid cell. These findings suggest that 1 × 1 km resolution seems appropriate for ozone concentration modelling. On the other hand, significant sub-grid variation may exist at the resolution adopted by the EMEP model. Coupled with the likely variability of other important meteorological, soil and vegetation variables, our findings suggest that ozone risk assessment for vegetation based on large-scale modelled AOT40 and flux needs to be considered with great caution. The evidence reported in this paper asks for more detailed national-scale modelling, and the development of methods to incorporate local scale variations into large-scale models.     

Comparison of different probe molecules for the quantification of hydroxyl radicals in aqueous solution

We show that the transformation of benzene into phenol is a more selective probe for the hydroxyl radical than the transformation of nitrobenzene or the generation of 4-hydroxybenzoic acid from benzoic acid. The benzene to phenol system showed adequate performance as a probe upon irradiation of lake water samples and humic acids. We show that the use of nitrobenzene and benzoic acid as hydroxyl probes should be avoided because of poor selectivity. Moreover, all the tested probe molecules underwent important interference by irradiated antraquinone-2-sulphonate, and considerably overestimated the formation of the hydroxyl radicals.     

Sorption and desorption of sulfentrazone in Brazilian soils

This study was undertaken to obtain information about the behavior of sulfentrazone in soil by evaluating the sorption and desorption of the herbicide in different Brazilian soils. Batch equilibrium method was used and the samples were analyzed by high performance liquid chromatography. Based on the results obtained from the values of Freundlich constants (Kf), we determined the order of sorption (Haplic Planosol < Red-Yellow Latosol < Red Argisol < Humic Cambisol < Regolitic Neosol) and desorption (Regolitic Neosol < Red Argisol < Humic Cambisol < Haplic Planosol < Red-Yellow Latosol) of sulfentrazone in the soils. The process of pesticide sorption in soils was dependent on the levels of organic matter and clay, while desorption was influenced by the organic matter content and soil pH. Thus, the use of sulfentrazone in soils with low clay content and organic matter (low sorption) increases the probability of contaminating future crops.     

Insecticidal activity and fungitoxicity of plant extracts and components of horseradish (Armoracia rusticana) and garlic (Allium sativum)

To avoid environmental pollution and health problems caused by the use of traditional synthetic pesticides, there is a trend to search for naturally occurring toxicants from plants. Among the compounds discussed for anti-fungal and insecticidal activity, the natural extracts from garlic and horseradish have attracted considerable attention. The objective of this study is to determine the insecticidal and anti-fungal activity of Armoracia rusticana and Allium sativum L. extracts against larvae of Aedes albopictus (Skuse) and some pathogenic fungi. For the insecticidal test, horseradish and garlic extracts were prepared from fresh plants (cultivated in Emilia Romagna region) in a solution of ethanol 80 % and the two different solutions were used at different concentrations (for the determination of the lethal dose) against the fourth instar mosquito's larvae. The fungicidal test was carried out by the agar plates technique using garlic and horseradish extracts in a 10 % ethanol solution against the following organisms: Sclerotium rolfsii Sacc., Trichoderma longibrachiatum, Botrytis cinerea Pers., Fusarium oxysporum Schlecht. and Fusarium culmorum (Wm. G. Sm.) Sacc. The first results demonstrated that the horseradish ethanol extracts present only a fungistatic activity against Sclerotium rolfsii Sacc., Fusarium oxysporum Schlecht. and F. culmorum (Wm.G. Sm) Sacc. while garlic extracts at the same concentration provided a good fungicidal activity above all against Botrytis cinerea Pers. and S. rolfsii. A. rusticana and A. sativum preparations showed also an interesting and significant insecticidal activity against larvae of A. albopictus, even if horseradish presented a higher efficacy (LC?? value of 2.34 g/L), approximately two times higher than garlic one (LC?? value of 4.48 g/L).