Determination of indicator polychlorinated biphenyls (PCBs) by gas chromatography–electron capture detector

An effective method for determination of indicator polychlorinated biphenyls (PCBs) has been validated using gas chromatography (GC) equipped with electron capture detector (ECD). The GC–ECD method was validated by determining the linear range (working range) for determination of the compounds, minimum detectable quantities (MDQ), the precision and accuracy of the method for the analysis of the compounds. MDQ obtained for the compounds ranges from 0.0005 to 0.002 ng. Indeed the method was found to be more sensitive as the number of chlorine atoms attached to the biphenyl increases. The precision and accuracy of the GC method validated ranges from 2.4% to 14.5% and −7.0% to 14.6% respectively. Coefficient of variation associated with the repeatability of the retention times and corresponding peak areas was found to be 0.0001–0.0007 for the retention times and 0.0014–0.059 for the peak areas. Percentage recoveries for the compounds were in the range of 95.7–101.0%. The validated method was then applied to determine levels of indicator PCBs in sediments sampled from eleven sampling points along the Lake Bosuntwi in Ghana and the highest PCB load of 19.17 ng g⁻¹ was recorded at Pipie No. 2. PCB 52 and PCB 101 were found to be the most ubiquitous indicator PCBs in the study area, both with 90.91% occurrence.     

Chemical and morphological characterization of aerosol particles at Mt. Krvavec, Slovenia, during the Eyjafjallajökull Icelandic volcanic eruption

Objective

In this work, continuous and size-segregated aerosol measurements at Mt. Krvavec, Slovenia, during the Eyjafjallajökull volcanic eruption were performed. Based on chemical and morphological characteristics of size-segregated particles, the presence of the volcanic aerosols after long-range transport to Slovenia was to be confirmed.

Results and conclusions

Continuous measurements with the aethalometer and SMPS indicated the suspected volcanic ash plume passing over the sampling site. The aerosols collected by discrete sampling showed a chemical signature similar to the known elemental signature of the Icelandic volcanic ash. Coarse particles showed a composition typical for silicates rich in metals; in many cases also S was present. Morphological analysis showed particles with features indicative of an explosive volcanic eruption, e.g., pumice and pumice shards, glass shards, minerals, evidence of steam condensation, etc. The high sulfate concentration associated with the fine particles resulted in sulfate crystallization within the cascade impactor leading to the formation of large structures resembling a “fern”. Mass size distributions for Fe, Ti, Mn, Ca, Na, and Mg showed one primary peak (for Fe, Mn, and Ti at 2.8 μm; for Ca, Na, and Mg at ca. 4 μm), which supports the fact that most of the particles in the coarse sizes were silicates rich in metals. The size distribution of the water-soluble SO ₄ ^2? showed a maximum peak at 0.75 μm, which also confirms the high sulfate concentration in the fine particles. Chemical and morphological characterization of aerosols collected at Mt. Krvavec indeed confirmed that volcanic ash plume passed over Slovenia.     

Application of nanoscale zero valent iron (NZVI) for groundwater remediation in Europe

Purpose  

Nanoscale zero valent iron (NZVI) is emerging as a new option for the treatment of contaminated soil and groundwater targeting mainly chlorinated organic contaminants (e.g., solvents, pesticides) and inorganic anions or metals. The purpose of this article is to give a short overview of the practical experience with NZVI applications in Europe and to present a comparison to the situation in the USA. Furthermore, the reasons for the difference in technology use are discussed.     

Resilience of the poorest: coping strategies and indigenous knowledge of living with the floods in Northern Namibia

In Northern Namibia, the climate is highly polarised between dry and wet seasons, and local communities have lived with these varying weather extremes for centuries. However, the recent changes in socio-environmental dynamics—associated with urbanisation, inappropriate spatial planning, and population growth—have disturbed the river system in the area. These changes, together with torrential seasonal rains, have aggravated the social impacts of the flood events. By using various qualitative and quantitative data sources, and comparative analyses between the flood dynamics in urban and rural environments, this research studies local residents’ coping strategies to endure the irregular flood events from the perspective of socio-ecological resilience. Particular interest is placed on the learning processes that enhance the residents’ capability to cope and the role of indigenous knowledge. Indigenous knowledge (IK) has been emphasised as a source of resilience in both theory and practice, as it is built upon learning from past experiences of natural hazards. The findings reveal that the floods are a result of complex and relational development without the necessary linear relationship between the causes and effects. The abrupt socio-ecological changes, together with the multiple stressors related to poverty, have made residents more vulnerable to the flood events and attenuated the communities’ coping strategies based on IK. Instead of focusing on the communities’ capacity to self-organise, the focus of resilience building needs to be directed to emphasising the broader socio-political processes, which are making the communities vulnerable in the first place.     

Lagrangian Dispersion Modeling of Vehicular Emissions from a Highway in Complex Terrain

Abstract

Transit traffic through the Austrian Alps is of major concern in government policy. Pollutant burdens resulting from such traffic are discussed widely in Austrian politics and have already led to measures to restrict traffic on transit routes. In the course of an environmental assessment study, comprehensive measurements were performed. These included air quality observations using passive samplers, a differential optical absorption spectroscopy system, a mobile and a fixed air quality monitoring station, and meteorological observations. As was evident from several previous studies, dispersion modeling in such areas of complex terrain and, moreover, with frequent calm wind conditions, is difficult to handle. Further, in the case presented here, different pollutant sources had to be treated simultaneously (e.g., road networks, exhaust chimneys from road tunnels, and road tunnel portals). No appropriate system for modeling all these factors has so far appeared in the literature. A prognostic wind field model coupled with a Lagrangian dispersion model is thus presented here and is designed to treat all these factors. A comparison of the modeling system with results from passive samplers and from a fixed air quality monitoring station proved the ability of the model to provide reasonable figures for concentration distributions along the A10.     

Application of a computational model for Michael addition reactivity in the prediction of toxicity to Tetrahymena pyriformis

A computational model to predict acute aquatic toxicity to the ciliate Tetrahymena pyriformis has been developed. A general prediction of toxicity can be based on three consecutive steps: 1. Identification of a potential reactive mechanism via structural alerts; 2. Confirmation and quantification of (bio)chemical reactivity; 3. Establishing a relationship between calculated reactivity and toxicity. The method described herein uses a combination of a reactive toxicity (RT) model, including computed kinetic rate constants for adduct formation (log k) via a Michael acceptor mechanism of action, and baseline toxicity (BT), modelled by hydrophobicity (octanol-water partition coefficient). The maximum of the RT and BT values defines acute toxicity for a particular compound. The reactive toxicity model is based on site-specific steric and quantum chemical ground state electronic properties. The performance of the model was examined in terms of predicting the toxicity of 106 potential Michael acceptor compounds covering several classes of compounds (aldehydes, ketones, esters, heterocycles). The advantages of the computational method are described. The method allows for a closer and more transparent mechanistic insight into the molecular initiating events of toxicological endpoints.     

Report on EU guidance on groundwater monitoring developed under the common implementation strategy of the water framework directive

The establishment of high quality long-term monitoring programmes is essential if the implementation of the Water Framework Directive (WFD) is to be effective. It is recognised that monitoring can be very expensive and so guidance is needed to establish cost-effective, risk-based and targeted groundwater monitoring across Europe that enables WFD objectives to be met. In this context, the Groundwater Working Group (WGC) of the Common Implementation Strategy (CIS) of the WFD has developed recommendations aiming to implement consistent groundwater monitoring across Europe. This has been published on the internet in the form of a non-legally binding guidance document, which provides useful elements for the development and maintenance of networks at high standards and thereby provide the necessary information to assess (ground)water status, identify trends in pollutant concentrations, support establishment and assessment of programmes of measures and the effective targeting of economic resources. This paper presents this guidance document.     

Effective monitoring of agriculture: a response

The development of effective agricultural monitoring networks is essential to track, anticipate and manage changes in the social, economic and environmental aspects of agriculture. We welcome the perspective of Lindenmayer and Likens (J. Environ. Monit., 2011, 13, 1559) as published in the Journal of Environmental Monitoring on our earlier paper, "Monitoring the World's Agriculture" (Sachs et al., Nature, 2010, 466, 558-560). In this response, we address their three main critiques labeled as 'the passive approach', 'the problem with uniform metrics' and 'the problem with composite metrics'. We expand on specific research questions at the core of the network design, on the distinction between key universal and site-specific metrics to detect change over time and across scales, and on the need for composite metrics in decision-making. We believe that simultaneously measuring indicators of the three pillars of sustainability (environmentally sound, social responsible and economically viable) in an effectively integrated monitoring system will ultimately allow scientists and land managers alike to find solutions to the most pressing problems facing global food security.     

Perinatal dioxin exposure, cytochrome P-450 activity, liver functions and thyroid hormones at follow-up after 7-12 years

OBJECTIVES: Prenatal and lactational exposure to Dutch "background" dioxin levels may cause health effects spanning many years. In addition, perinatal studies have shown a relationship between dioxin exposure and thyroid disturbance. To assess the later health effects of prenatal and lactational dioxin exposure on liver function we measured plasma ALAT and ASAT levels amongst our longitudinal cohort, as was done perinatally and at 2(1/2) years. The children underwent a caffeine loading test to determine CYP1A2 activity. To assess the later effects on thyroid function we measured plasma TSH and FT4. STUDY DESIGN: A longitudinal cohort of 37 healthy children (age 7-12, mean 8.2 years), with documented prenatal and lactational dioxin exposure, ingested 3mg caffeine/kg BW 6h prior to blood withdrawal. Paraxanthine/caffeine molar ratio, ALAT, ASAT, TSH and FT4 were determined in venous blood. RESULTS: Linear regression of ASAT and ALAT revealed no relation with prenatal and lactational dioxin exposure. No correlation was found between the paraxanthine/caffeine molar ratio and prenatal and lactational dioxin exposure. Linear regression of TSH and FT4 revealed no relation with prenatal and lactational dioxin exposure. CONCLUSION: This follow-up has shown a normalisation of previously abnormal ALAT and ASAT levels, indicating a transient effect. CYP1A2 activity, measured by means of a caffeine-loading test, revealed no correlation with the prenatal and lactational exposures. A normalisation of previously abnormal thyroid hormone homeostasis was seen, also possibly indicating a transient effect. This study provides new data on long-term follow-up after perinatal dioxin exposure to background levels of dioxins.     

Risk assessment of biocides in roof paint

BACKGROUND, AIM AND SCOPE: Many surface coatings, including roof paints, contain biocides. It is generally not known to what extent roof paint biocides leach from the paint, and consequently, what concentration the biocide may attain in a rainwater collection system. To this end the leaching of specific biocides from a variety of German roof paints was investigated and the resulting concentrations in collected rain water were estimated. MATERIALS AND METHODS: A laboratory simulation was used to determine the time dependant leaching rate of the biocide from the paint into synthetic rainwater. The concentrations of biocide in the leachate were quantified using HPLC. The course of the leachate concentrations over time was fitted using a simple mathematical model. This was then used to estimate concentrations of biocides in a typical household rainwater collection system over time. RESULTS: Surprisingly, the biocides found in the paints did not always concur with the declared biocides. Concerning the modelling of runoff concentrations, it was found that--under the model assumptions--the rain intensity and cumulative raining time after application are the dominant factors influencing the concentration of the biocide. At the highest modelled rain intensity of 40 mm/hour it only takes about 2 hours to reach peak concentrations lower than 0.1 mg/L, at 0.3 mm/hour it takes about 10 hours to reach peak concentrations of 1.3, 0.9, 5.2 and 1.1 mg/L for terbutryn from Emalux paint, terbutryn from Südwest paint, carbendazim from Emalux paint, and carbendazim from MIPA paint, respectively. DISCUSSION: The results confirm that biocides leached from roof paint will be present in roof runoff. The highest estimated peak concentrations are close to the water solubility of the respective biocides. This indicates that the model assumption of a concentration independent leaching rate will tendentially lead to an overestimation of the leached concentrations under these circumstances. However, under most circumstances such as higher rain intensities, and longer time after peak concentrations have been reached, the runoff concentrations are far from the solubility limit, and therefore it is proposed that the model assumptions are tenable. CONCLUSIONS: The leaching of biocides from roof paints can be roughly assessed using a relatively simple approach. The declaration of biocidal ingredients in roof paints should be improved and information on their biocide leaching behaviour should be made available. Furthermore, the estimations should be evaluated by a field study. RECOMMENDATIONS AND PERSPECTIVES: The leaching study indicated that the concentrations of selected biocides can reach significant levels, especially after low intensity rainfall. Taking into account the inherent biological activity of the substances under scrutiny, it can already be concluded that it is not advisable to use runoff water from roofs freshly painted with biocide containing roof paints. These results have been complemented by a literature search of biological effects of the investigated biocides, ecotoxicological tests with several species and a risk analysis for organisms exposed to runoff water. This will be presented in Part 2 of this contribution.