Improving the knowledge of pesticide and nitrate transfer processes using age-dating tools (CFC, SF6, H) in a volcanic island (Martinique, French West Indies)

Numerous successful examples of CFC and SF₆ groundwater dating applications were recently published. However the proposed CFC/SF₆ method needs various hydrodynamic parameters that are not always available. In order to predict groundwater-quality trends in areas where the hydrogeological context is poorly known, a dating method using tritium, CFC and SF₆ was successfully implemented in Martinique. Hydrogeological understanding is limited in this volcanic island where groundwater contamination by pesticides and nitrate has been recently proven in various areas. A negative correlation was observed between nitrate concentrations and groundwater ages while pesticide contamination showed a more complex schema. Consequently the presence of old groundwater clearly explained the absence or low pesticide and nitrate concentrations in some areas. However a possible degradation of the water quality is to be feared in the future. In view of the relatively long transfer times and the complexity of the remobilization processes of solutes, the expected effects of any modifications in the use of fertilizers, or of changes in pesticide-use legislation, would take a long time to become apparent.     

UV-C as a means to combat biofilm proliferation on prehistoric paintings: evidence from laboratory experiments

A laboratory investigation of UV-C effects was conducted over a 62-h period: a much higher dose than in classic UV-C treatment was applied to five pigments and two painting binders used by prehistoric humans. Colorimetric parameters were compared to a control to see if UV-C can change pigment and binder color. Infrared spectroscopy, scanning electron microscopy, inductively coupled plasma and X-ray crystallography were also carried out to confirm colorimetric measurement. In order to understand how microorganism may physically deteriorate paintings, limestone blocks were painted and monitored until their complete colonization by algae, cyanobacteria, fungi and/or mosses. The results show that UV-C has no effect on mineral compounds. Conversely, it is noteworthy that binder color changed under both UV-C light conditions as well as in visible light. Concerning painted blocks, a fast proliferation has been observed with deterioration of the paintings. These results show the high importance of treating biofilm as soon as possible. Moreover, these findings may be a promising avenue inducing cave managers to use friendly UV-C light to treat contaminated cave paintings and also in the prevention of biodeterioration by lampenflora.     

UV-C as an efficient means to combat biofilm formation in show caves: evidence from the La Glacière Cave (France) and laboratory experiments

Environmental Science and Pollution Research - Ultra-violet C (UV-C) treatment is commonly used in sterilization processes in industry, laboratories, and hospitals, showing its efficacy against...     

Effects of thermal desorption on the composition of two coking plant soils: impact on solvent extractable organic compounds and metal bioavailability

To evaluate the efficiency and the influence of thermal desorption on the soil organic compartment, contaminated soils from coking plant sites (NM and H) were compared to their counterparts treated with thermodesorption. The extractable organic matter, and the metal content and distribution with soil compartments were studied.In both thermodesorbed soils, PAH (polycyclic aromatic hydrocarbon) degradation exceeded 90%. However, the thermal desorption led not only to a volatilization of the organic compounds but also to the condensation of extractable organic matter.The treatments only affected the Fe and Zn distribution within the more stable fractions, whereas the organic compound degradation did not affect their mobility and availability.     

Acute aquatic toxicity of western juniper (Juniperus occidentalis) foliage and Port Orford cedar (Chamaecyparis lawsoniana) heartwood oils

Recently, interest has developed for using essential oils from Western juniper (Juniperus occidentalis) foliage and Port Orford cedar (Chamaecyparis lawsoniana) heartwood in commercial products such as pest repellents and cosmetics. In order to gauge the relative toxicological risk that these oils pose to freshwater and marine organisms, the acute aquatic toxicity of these oils was evaluated using OPPTS guidelines to the cladoceran Daphnia magna, the rainbow trout Oncorhynchus mykiss and the green alga Selenastrum capricornutum. For western juniper foliage oil, no toxicity was exhibited toward D. magna or O. mykiss, even at 5.0 mg/L (the highest concentration tested and limit of solubility). For toxicity to S. capricornutum using algal cell density, the 72 and 96 h EC₅₀ value was 1.7 mg/L and the no observable effect concentration (NOEC) was 0.63 mg/L. For Port Orford cedar heartwood oil, no toxicity was exhibited toward O. mykiss or S. capricornutum, even at 5.0 mg/L (the highest concentration tested and limit of solubility). The 48-h D. magna EC₅₀ value was 1.9 mg/L; the NOEC values for algal cell density were 1.25 mg/L (72 h) and 0.63 mg/L (96 h). In summary, this study shows that western juniper foliage and Port Orford cedar heartwood oils demonstrate little to no risk to aquatic organisms.     

Spatial Validation of Land Use Change Models Using Multiple Assessment Techniques: A Case Study of Transition Potential Models

Using land use and cover change (LUCC) models for the urban growth planning, environmental assessment, and decision-making needs the establishment of an appropriate level of confidence in their performance. The objective of this research is to explore the importance of using multiple assessment techniques in order to fairly evaluate the performance of land use models. An application is conducted by using the Land Change Modeler for Ecological Sustainability (LCM) which is an empirical and transition potential model. LCM is applied to model the agricultural to developed areas transition in Rennes metropolitan area (France). The land demand is estimated using the Markov Chain model; whereas, the transition potential map is implemented using the Multi-Layer Perceptron Neural Network (MLP) method based on historical changes and driving variables. The model performance is assessed based on a variety of the most commonly used validation techniques. At the study area level, the correctness and disagreement analysis shows that LCM performs better at predicting the amount than the allocation of developed areas. Additionally, landscape metrics reveal that LCM tends to predict a fragmented urban form, which seems evident because of the large number of the individual urban patches. At the municipality level, the error budget analysis shows that the model performance, which varies highly between different subareas, needs to be improved. Moreover, the cross-tabulation between the transition potential map and both the observed and the predicted agricultural to developed areas transitions reveals that the order of the transition potential values does not perfectly fit the observed change; whereas, the predicted change is not solely limited to areas with high potential.     

Characteristics of dwellings contaminated by moulds

Dwellings showing a presence of moulds are considered to be unhealthy both by the inhabitants and by sanitary authorities. Although the thresholds of pathogenicity have not yet been established, the toxic, allergic and infectious risk of indoor moulds is better understood today. A study on indoor fungi contamination for 128 dwellings was done between October and May in France. It concerned 69 dwellings, the occupants of which either complained to the sanitary authorities about problems of moulds and humidity or consulted a doctor who related their symptoms to housing conditions. Fifty-nine other dwellings, the occupants of which were healthy, constituted the control group. We present the statistical analysis of questionnaires, which aimed to clarify characteristics of dwellings associated with high concentrations of airborne moulds. Air samples were taken with an impactor in 500 rooms. On visiting dwellings, investigators obtained answers to 25 questions concerning characteristics of inhabitants and living space, as well as the presence of mould indicators. Indoor and outdoor temperature and indoor relative humidity of air measurements were taken. The total concentration of fungi in the air was significantly higher in ground floor apartments versus those on other floors (p = 0.047), in small and highly occupied dwellings (p = 0.03 and 0.003), in dwellings with electric heating (p = 0.04), without a ventilation system (p = 0.003), with water damage (p = 0.003), and finally, in those where the investigator noted an odour of moisture or visible moulds (p < 0.001). The efficacy of the latter criteria in the evaluation of insalubrity is discussed.     

A prospective study of amniotic fluid cholinesterases: Comparison of quantitative and qualitative methods for the detection of open neural tube defects

The value of quantitative and qualitative methods of cholinesterase (ChE) analysis in the detection of open neural tube defect (NTD) has been assessed in a prospective survey of 1495 mid-trimester amniotic fluids. Using a quantitative method the mean ChE values were much lower in fluids from pregnancies of normal outcome but it was not possible to discriminate these fluids completely from those associated with NTD pregnancies. particularly when the specimens were contaminated with blood. Similarly, measurement of acetylcholinesterase (AChE) activity alone by three different methods also failed to eliminate the overlap between the two groups. In contrast, polyacrylamide gel electrophoresis revealed only a single band of ChE activity in 1408 out of 1410 fluids from pregnancies with a normal outcome whilst amniotic fluids from all 60 cases of open NTD. 6 out of 7 cases of exomphalos and 3 out of 4 cases of intra-uterine death gave the characteristic second faster-running AChE band. A qualitative gel method which requires the same amount of ChE activity to be loaded from each amniotic fluid is an effective method for pre-natal diagnosis of NTDs.     

Chronic ozone exposure alters the growth of leaves, stems and roots of hybrid Populus

Rooted cuttings of hybrid Populus (DN34, Populus deltoides x nigra) were grown outdoors in pots in open-top chambers at Ithaca, NY (74.5 degrees W, 42.5 degrees N), during 1988 and 1989 (experiment 1) and during 1989 and 1990 (experiment 2). Ambient air was passed through charcoal filters to produce a 0.5 times ambient ozone treatment, and ozone generated from oxygen was added to produce one and two times ambient ozone treatments. In experiment 1, treatments were applied for 8-12 h each day for 112 days of the 1988 growing season, then the plants were grown outdoors with ambient ozone in 1989. In experiment 2, treatments were applied for 9 h each day for 98 days of the 1989 growing season, then the plants were grown outdoors with ambient ozone in 1990. Chronic exposure to ozone caused the following changes (statistically significant in one or both experiments at p<0.05): (1) earlier leaf abscission, (2) decreased stem basal diameter, (3) decreased stem mass, (4) decreased internode length, (5) decreased shoot height p=0.005, and (6) decreased leaf size in the growing season following ozone treatment. There was also strong evidence that ozone increased the number of leaves produced p=0.055. Finally, there was some evidence that ozone increased the ratio of shoot mass to root mass p=0.093.