Mejora de sensores vítreos sol-gel para la conservación preventiva de materiales históricos frente a la acidez

[ES] Los sensores a base de recubrimientos vítreos sol-gel dopados con ácido 2[4-(dimetil-amino) fenilazo] benzoico son capaces de cambiar su absorción óptica cuando se someten a distintas concentraciones de iones H3O+ y OH-. La respuesta de los sensores en ensayos de campo se estudió en Cracovia (Polonia) variando el procedimiento normal de uso, con el fin de mejorar su respuesta. Se midieron tanto los parámetros ópticos de los sensores como las condiciones ambientales (temperatura, humedad, presión y concentraciones de SO2 y de NOx). La respuesta de los sensores se analizó en términos de los cambios de su absorción visible. Dichos cambios se deben a reacciones locales de neutralización que tienen lugar en la superficie de los sensores, debido al efecto conjunto de los contaminantes de carácter ácido y a la humedad ambiental. Se establecieron correlaciones entre la concentración del contaminante principal (SO2) y la respuesta de los sensores para elaborar una calibración directa entre la absorción óptica y el pH ambiental. Los sensores pueden detectar y evaluar la acidez ambiental, así como alertar sobre la concentración de contaminantes ácidos que pueden dañar a la mayoría de los materiales históricos.[EN] Sensors based on sol-gel glassy coatings doped with 2[4-(dimethyl-amino) phenylazo] benzoic acid are able to change their optical absorption when they are submitted to different concentration of H3O+ and OH-. The sensors behaviour in field tests was studied in Cracow (Poland), varying the normal procedure of operation to improve their response. Both the sensors optical parameters and the environmental conditions (temperature, humidity, pressure, SO2 and NOx concentrations) were measured. The sensors response was analysed in terms of their visible absorbance changes, which are due to local neutralisation reactions in the sensors surface by the join effect of acid pollutants and humidity. Correlations between the main acid pollutant (SO2) concentration and the sensors response are established to provide a relation between the optical absorption and the environmental pH. The sensors are able to detect and monitorise environmental acidity, as well as to alert on the pollutant concentration that may damage most of the historical materials.The authors wish to acknowledge bilateral Polish-Spanish project Ref. PAN-CSIC 2003PL0011, European Marie Curie project Ref. MERG-CT-2004-516436 and Spanish project Ref. CICYT-MAT-2003-03231 for financing support. N.C. acknowledges CSIC-ESF for an I3P postdoctoral contract.Peer reviewe

Assessing the risks of pesticides to soil communities using terrestrial model ecosystems

The Environmental Risk Assessment (ERA) of pesticides in soil is based on a tiered approach that uses surrogate indicators of risk spanning from single species in the laboratory to soil organism communities in the field. This thesis aims to bridge the gap between laboratory approaches and field studies using a Terrestrial Model Ecosystem (TME). Chapter I provides a systematic approach that is applied in this thesis. The effects to soil communities and the corresponding detection limits depend largely on the intrinsic variability and the sensitivity of the systems. Since TME are meant to provide a high degree of realism comparable to field studies, the first chapter gives an overview on the characteristics of soil ecosystems and the ecology of the soil organisms. Chapter II gives an overview of the experimental approaches, the test compound lindane (gamma-hexachlorocyclohexane) and the assessment endpoints measured in both TME and field studies. The complex community-level data of different soil organism groups requires a variety of uni- and multivariate statistical methods. Chapter III involves the description and interpretation of effects of the persistent and toxic pesticide lindane on soil microarthropod communities that were detected in a one-year range-finding study in TME. The open, intact soil cores (diameter 300 mm, height 400 mm) included indigenous soil organisms of undisturbed grassland. Forty units were placed outdoors in an experimental facility. The key objective was at first to evaluate the dynamics and stability of microarthropod communities on grassland over a period that is relevant for assessing the intrinsic recovery potential of the TME communities following toxic stress. Sufficient numbers of organisms and replicates of the experimental units ensured that a statistical evaluation could be performed to estimate the sensitivity and the natural dynamics and the variability of the populations upon application of lindane applied at high rates of 7.5 and 75 kg active ingredient (a.i.)/ha. The results showed that TME soil cores maintained communities of soil organisms marked by typical diversity of improved grassland. Lindane applied at excessive rates caused clear dose-related and long-lasting effects on the communities of microarthropods. On the contrary, lumbricids, the total feeding activity and the growth of plant biomass were not affected by both treatments. Based on the results of the first effect study, a modified ‘dose-response study’ with the same compound lindane was designed (Chapter IV). Further organism groups were included, so that the effects on collembolans, oribatid mites, nematodes, soil fungi and plant biomass could be determined in forty-two TME. Lindane was applied in five concentrations between 0.032 mg a.i./kg dry soil and 3.2 mg a.i./kg dry weight soil, six-fold replicated each. Twelve TME served as untreated controls. Abundance and community structures of oribatids, collembolans, enchytraeids, nematodes and fungi were recorded. Oribatid mites’ community responded three months after treatment, although they were not significantly affected by the overall treatment regime. Collembolans in total and species-specific abundance as well as the community endpoints were adversely affected by moderate dosages of lindane. Effects were transient between three and five months after treatment with a recovery within one year. No significant effects have been detected for enchytraeids, nematodes and fungi. The study design and the obtained results allow for calculations of no observed effect concentrations below the highest treatment level for populations and for soil communities as defined entities, as well as effective concentrations as indicators of dose related responses. In Chapter V the ecology of the coring area is described by means of floristic and faunistic surveys. The distribution of collembolans is analysed by geostatistical methods and categorized as patchy or gradiental. These findings lead to conclusions on optimized soil coring strategies, which are proposed as small-scaled as possible to avoid excess variability. The temporal stability of TME is investigated under the propositions of the criteria ‘no tendency towards altered abundances and diversity structures’ and ‘similarity of communities compared to the original state’. The issue ‘for which kind of habitat is the particular TME representative’ is raised. It has been concluded that a high degree of similarity between field and TME samples remains manifest over time and the pattern persists the large seasonal variation of community structures. Prospective power analyses led to an estimation of the limits of effect detection. On average, the detectable differences of abundances of treatment groups compared to control level (MDD) was between five percent for nematodes and about fifty percent for enchytraeids, collembolans and oribatids, markedly varying between sampling dates

Assessing the risks of pesticides to soil communities using terrestrial model ecosystems

The Environmental Risk Assessment (ERA) of pesticides in soil is based on a tiered approach that uses surrogate indicators of risk spanning from single species in the laboratory to soil organism communities in the field. This thesis aims to bridge the gap between laboratory approaches and field studies using a Terrestrial Model Ecosystem (TME). Chapter I provides a systematic approach that is applied in this thesis. The effects to soil communities and the corresponding detection limits depend largely on the intrinsic variability and the sensitivity of the systems. Since TME are meant to provide a high degree of realism comparable to field studies, the first chapter gives an overview on the characteristics of soil ecosystems and the ecology of the soil organisms. Chapter II gives an overview of the experimental approaches, the test compound lindane (gamma-hexachlorocyclohexane) and the assessment endpoints measured in both TME and field studies. The complex community-level data of different soil organism groups requires a variety of uni- and multivariate statistical methods. Chapter III involves the description and interpretation of effects of the persistent and toxic pesticide lindane on soil microarthropod communities that were detected in a one-year range-finding study in TME. The open, intact soil cores (diameter 300 mm, height 400 mm) included indigenous soil organisms of undisturbed grassland. Forty units were placed outdoors in an experimental facility. The key objective was at first to evaluate the dynamics and stability of microarthropod communities on grassland over a period that is relevant for assessing the intrinsic recovery potential of the TME communities following toxic stress. Sufficient numbers of organisms and replicates of the experimental units ensured that a statistical evaluation could be performed to estimate the sensitivity and the natural dynamics and the variability of the populations upon application of lindane applied at high rates of 7.5 and 75 kg active ingredient (a.i.)/ha. The results showed that TME soil cores maintained communities of soil organisms marked by typical diversity of improved grassland. Lindane applied at excessive rates caused clear dose-related and long-lasting effects on the communities of microarthropods. On the contrary, lumbricids, the total feeding activity and the growth of plant biomass were not affected by both treatments. Based on the results of the first effect study, a modified ‘dose-response study’ with the same compound lindane was designed (Chapter IV). Further organism groups were included, so that the effects on collembolans, oribatid mites, nematodes, soil fungi and plant biomass could be determined in forty-two TME. Lindane was applied in five concentrations between 0.032 mg a.i./kg dry soil and 3.2 mg a.i./kg dry weight soil, six-fold replicated each. Twelve TME served as untreated controls. Abundance and community structures of oribatids, collembolans, enchytraeids, nematodes and fungi were recorded. Oribatid mites’ community responded three months after treatment, although they were not significantly affected by the overall treatment regime. Collembolans in total and species-specific abundance as well as the community endpoints were adversely affected by moderate dosages of lindane. Effects were transient between three and five months after treatment with a recovery within one year. No significant effects have been detected for enchytraeids, nematodes and fungi. The study design and the obtained results allow for calculations of no observed effect concentrations below the highest treatment level for populations and for soil communities as defined entities, as well as effective concentrations as indicators of dose related responses. In Chapter V the ecology of the coring area is described by means of floristic and faunistic surveys. The distribution of collembolans is analysed by geostatistical methods and categorized as patchy or gradiental. These findings lead to conclusions on optimized soil coring strategies, which are proposed as small-scaled as possible to avoid excess variability. The temporal stability of TME is investigated under the propositions of the criteria ‘no tendency towards altered abundances and diversity structures’ and ‘similarity of communities compared to the original state’. The issue ‘for which kind of habitat is the particular TME representative’ is raised. It has been concluded that a high degree of similarity between field and TME samples remains manifest over time and the pattern persists the large seasonal variation of community structures. Prospective power analyses led to an estimation of the limits of effect detection. On average, the detectable differences of abundances of treatment groups compared to control level (MDD) was between five percent for nematodes and about fifty percent for enchytraeids, collembolans and oribatids, markedly varying between sampling dates

Application of the Closure Principle Computational Approach Test to Assess Ecotoxicological Field Studies: Comparative Analysis Using Earthworm Field Test Abundance Data

Field studies to determine the effects of chemicals on earthworm communities are generally conducted according to International Organization for Standardization standard 11268‐3 (and later comments). However, statistical test procedures suggested in the guideline are frequently criticized, mainly for 2 reasons: 1) Earthworm abundances are count data and often do not fulfill requirements for multiple t tests (normal distribution and homogeneity of variance), and 2) the resulting toxicity metrics of multiple testing procedures (no/lowest‐observed‐effect concentrations [NOEC/LOEC]) fail to adequately detect the actual level of effects. Recently, a new method to overcome these shortcomings was presented by the introduction of the closure principle computational approach test (CPCAT). We applied this statistical method to assess chemical effects on abundance in a large dataset of 26 earthworm field studies (with up to 3 test chemical application rates) and an additional extended study with 6 application rates. A comparative analysis was provided considering results of well‐established multiple testing approaches (Dunnett's test) with particular consideration of the degree of overdispersion found in these data. It was shown that the CPCAT detects substantially more effects in earthworm field tests as statistically significant than standard t test approaches. This lowered the LOEC/NOEC for many chemical treatments to control comparisons. As a consequence, the statistically detected NOECs/LOECs were often set at lower percentage deviations between control and chemical treatment. This is the first time the performance of the CPCAT has been assessed within a comprehensive analysis of earthworm field study data. Environ Toxicol Chem 2021;40:1750–1760. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.Umweltbundesamt http://dx.doi.org/10.13039/50110001080