Reply to the comment by D. Guyonnet,on “Comparison on percolation to batch and sequential leaching tests: Theory and data”

Reply to the comment by D. Guyonnet, on “Comparison on percolation to batch and sequential leaching tests: Theory and data”.     

Critical Loads – Is There A Need For A New Concept?

The concept of critical loads has been an important andsuccessful tool for the development of control strategiesfor transboundary air pollution in Europe. The use of theconcept has led us to a situation where very few areas inEurope will have an exceedance of critical loads foracidification in 2010, indicating that the benefits offurther control acidifying substances will be lessuseful. The critical loads concept does not, however,take into account the large benefits of further controlin damaged systems but where critical loads are nolonger exceeded. In this paper we discuss the importanceof widening the critical loads concept to include thesebenefits and we propose an additional effect-relatedmeasure, Dynamic Impact Analysis, to be included infurther control strategies and assessments. With such aconcept the actual situation and its further developmentwill be included in assessments and control strategies.     

Regional or global WEEE recycling. Where to go?

If we consider Waste Electrical and Electronic Equipment (WEEE) management, we can see the development of different positions in developed and developing countries. This development started with the movement of WEEE from developed countries to the developing countries. However, when the consequences for health and the environment were observed, some developing countries introduced a ban on the import of this kind of waste under the umbrella of the Basel Convention, while some developed countries have been considering a regional or global WEEE recycling approach. This paper explores the current movements between Source and Destination countries, or the importers and exporters, and examines whether it is legal and why illegal traffic is still rife; how global initiatives could support a global WEEE management scheme; the recycling characteristics of the source an destination countries and also to ascertain whether the principle of Extended Producer Responsibility (EPR) has been established between the different stakeholders involved in WEEE management.Ultimately, the Full Extended Producer Responsibility is presented as a possible solution because the compensation of the environmental capacity for WEEE recycling or treatment could be made by the contribution of extra responsibility; and also generating an uniform standard for processing WEEE in an environmentally sound manner could support the regional or international solution of WEEE and also improve the performance of the informal sector.     

Composting toilets as a sustainable alternative to urban sanitation – A review

In today’s flush based urban sanitation systems, toilets are connected to both the centralized water and wastewater infrastructures. This approach is not a sustainable use of our water and energy resources. In addition, in the U.S., there is a shortfall in funding for maintenance and upgrade of the water and wastewater infrastructures. The goal of this paper was to review the current knowledge on composting toilets since this technology is decentralized, requires no water, creates a value product (fertilizer) and can possibly reduce the burden on the current infrastructure as a sustainable sanitation approach. We found a large variety of composting toilet designs and categorized the different types of toilets as being self contained or central; single or multi chamber; waterless or with water/foam flush, electric or non-electric, and no-mix or combined collection. Factors reported as affecting the composting process and their optimum values were identified as; aeration, moisture content (50–60%), temperature (40–65 °C), carbon to nitrogen ratio (25–35), pH (5.5–8.0), and porosity (35–50%). Mass and energy balance models have been created for the composting process. However there is a literature gap in the use of this knowledge in design and operation of composting toilets. To evaluate the stability and safety of compost for use as fertilizer, various methods are available and the temperature–time criterion approach is the most common one used. There are many barriers to the use of composting toilets in urban settings including public acceptance, regulations, and lack of knowledge and experience in composting toilet design and operation and program operation.     

A review on calcium-rich industrial wastes: a sustainable source of raw materials in India for civil infrastructure—opportunities and challenges to bond circular economy

Journal of Material Cycles and Waste Management - This study provides an overview of calcium rich industrial wastes usage in construction materials, their properties and different applications...     

The Probability of a Horizontal Gene Transfer from Roundup Ready® Soybean to Root Symbiotic Bacteria: A Risk Assessment Study on the GSF Lysimeter Station

The gene transfer from glyphosate tolerant soybean to Bradyrhizobium japonicum was evaluated in a free-air lysimeter experiment under natural conditions and increasing selection pressure, to monitor for the probability of horizontal gene transfer (HGT). A large volume lysimeter study that offers conditions comparable to normal farming was conducted in 2004 and 2005 with Roundup Ready® (RR) soybean and Roundup® application according to agricultural practice. Analysis of nodules showed, as expected, the presence of the transgenic 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). However, in bacteroids that were isolated from nodules and then cultivated for several rounds in the presence of high levels of glyphosate, the EPSPS gene could no longer be detected. This indicates no stable HGT transfer of the whole EPSPS gene under field conditions.     

A Methodology to Identify the Releasing of the Amide-Containing β-Glucan from the Usnea Lichen: A Spectroscopic Study

Journal of Polymers and the Environment - Polymer fractions from a biological matrix have been well-characterized by vibrational spectroscopy, XPS, CP/MAS 13C NMR, MALDI-TOF mass...     

Do remediation experts have what it takes to explain empirical uncertainty?

Words matter in risk communication, and experts’ choice of words is critical when remediation risks are being explained to nonexperts. In risk communication studies, communication gaps between experts and nonexperts are investigated but there is lack of primary research. An Australian project addresses this shortcoming through research into communication about the risks of contaminated land remediation, and this paper provides some of its findings. Seventeen experts completed a questionnaire about the meaning of some scientific terms, and analysis found that they have capacity to improve communication through their selection and use of language. When experts undertake risk communication, the language they use may increase or reduce communication gaps. When the topic is uncertainty about health risks, communication gaps about the extent of uncertainty may reduce the effectiveness of social engagement, leading to unintended consequences such as cost overruns. This situation makes for a good case study since remediation is about benefit as well as risk, and communication about benefit, while desirable, may not always be achievable. The study suggests how to improve risk communication by exploring the accuracy, clarity, and depth of expert language. It identifies attributes of language that can bridge gaps in knowledge and understanding and characterizes them as integration mechanisms. These are defined as knowledge forms and mental processes that support cooperation between different epistemic communities to achieve mutually agreed outcomes. Two integration mechanisms are suggested. Bridging content addresses communication gaps through the selection of content (what knowledge is selected). Bridging process addresses communication gaps through the use of language (how knowledge is explained). Bridging content and bridging process can be expressed through cognitive and experiential platforms, or a blending of both, so whether words are positioned in the science‐based or mental model of risk communication, a utility value can be found in their quality, whether reflected by accuracy or the power to communicate meaning.     

Cancer incidence in people with residential exposure to a municipal waste incinerator: An ecological study in Modena (Italy), 1991–2005

We conducted a retrospective ecological study to assess cancer incidence during the period 1991–2005 in proximity of a municipal waste incinerator (MWI) in Modena (Italy). We identified three bands of increasing distance from the MWI, up to a radius of 5 km and used the residence as surrogate marker of the exposure. Residential history for Modena’s population was reconstructed and residents were associated to the most appropriate census unit. Age-standardized incidence ratios (ASR) and standardized incidence ratios (SIR) were estimated for all cancers and selected sites. Variations in cancer incidence were investigated using space and space–time scan statistic. Deprivation index was taken into account as potential confounding factor. During the 15-year study period, 16,443 new cases of cancer were diagnosed among residents in Modena. The space–time clustering test identified three significant clusters but their shapes were not associable to the MWI exposition. The purely spatial analysis not showed statistically significant clusters. The SIR computed for all cancers and selected sites did not show any excess of risk in the area closest to the plant. Higher SIR for leukaemia was found in the second band from MWI (2–3.5 km) for females (SIR, age and DI adjusted: 1.35, 95%CI: 1.01–1.79) and for both sexes (SIR, age and DI adjusted: 1.28, 95%CI: 1.03–1.57), but not a spatial trend was observed, thus excluding a possible link with MWI. In conclusion, bearing in mind the intrinsic limits of the study, the results suggest that there is no detectable increase of cancer risk for people living in proximity to the Modena MWI.     

CHEMIFOG_V – A Model to Simulate Radiation Fogs and their Interaction with Vegetation and Chemistry

Radiation fog is an important modifier of atmosphericcompounds in the planetary boundary layer. In vegetated areas effects are especially pronounced due to the enlarged surface area. Besides affectingthe lower boundary of atmospheric models fog acts as amulti-phase reaction chamber leading to acid deposition. Here we present the 1-dimensional radiation fog modelCHEMIFOG_V to simulate regional radiation fogevents. The key feature of the fog model is thedetailed microphysics, where the aerosol/dropletspectrum is describedwith a joint 2-dimensional distribution, but also thedynamics, thermodynamics, and radiative transfer are calculated. Toinvestigate the interaction between fog and the biosphere amulti-layer vegetation module, including a soil module as well as a drydeposition module were coupled. Vegetation influences thedynamics, thermodynamics, and the radiation field of the lowestatmospheric layers. With CHEMIFOG_V, numerical case studieson dry and moist deposition processes on vegetation surfaces wereperformed. Hereby multi-phase chemistry and the processing of aerosolswere considered. The results show that the chemical composition of thedeposited fog droplets is mainly determined by the aerosol composition. Dry deposition fluxes are dependent on the incoming radiation and the leaves' surface conditions with respect to water coverage.Due to chemical aerosol processing and deposition, the aerosol spectrumis significantly modified in the planetary boundary layer.     

A survey on municipal solid waste and residents’ awareness in Da Nang city, Vietnam

A survey on solid waste generation and residents’ awareness was conducted in Da Nang city, Vietnam in 2010. We took samples from residents, hotels, restaurants, and city markets. Data reveals that each resident generates on average 0.71 kg/capita/day (3 kg/household/day). Regarding the composition, organic waste (food, flowers, leaves, grass) accounts for about 70 % of residents’ waste followed by plastics. Likewise, about 14 % of residents’ waste can be recycled. Furthermore, we find that middle income households in the suburbs have the largest waste generation with 4.9 kg/household/day. We consider that this finding is explained by their dedication to agricultural activities, such as planting fruit trees and vegetables, and gardening. Finally, we find that only about 60 % of interviewees have knowledge of how to segregate waste, however more than 90 % of them are willing to cooperate with the introduction of a waste segregation program in the city.     

Developing environmental legislation to promote recycling of industrial by-products – An endless story?

In Finland during the last few decades, mineral industrial residues (by-products) have been used in earthworks, but only to a limited extent relative to their total volume. The most important barrier to efficient recycling of by-products has been the need for a site-specific environmental permit, since the permit process tends to be time-consuming and laborious. In 2000 a working group was set up to prepare national legislation, i.e., a Government decree, in order to promote the use of by-products in earth construction. The aim was to exempt certain residues from the environmental permit obligation. At the first stage, the working group determined specific decision criteria for the selection of the by-products to be included. For the selected residues, the acceptable construction applications and material-specific environmental standards were defined. Various difficulties were encountered during the preparation of the decree. These were mainly caused by the lack of data and by some ongoing changes in environmental regulations. Furthermore, the draft decree received several critical and partly contradictory comments and proposals for amendments. This resulted in considerable delay in implementation.     

Criteria selection for landfills: do we need a limitation on inorganic total content?

The chemistry of the landfill environment is complex and dissolution rates may be higher than in natural systems. As will be shown in this paper, there are often great uncertainties in terms of leaching kinetics and long-term emissions of landfills in general. Leaching tests used in the laboratory may reflect a leaching behaviour not consistent with real landfill scenarios. Geochemical calculations for model systems provide an impression of the possible long-term behaviour of buffered, inorganic landfills. For a buffered carbonate-containing system (this system may be a mono-landfill of slag and/or ash after a few decades and/or centuries), maximums for the solubility of the elements Zn, Cd, Pb and Cu can be calculated while taking into account the presence of gypsum, the complexation in water ("speciation") and other factors influencing solubility. We have made these calculations using the recent version of the geochemical code PHREEQC-2. Finally, we conclude that under most circumstances the total elemental content, or the so-called "total availability," is a valuable assessment tool when combined with other criteria, such as leachable amounts and leachate test results. Exceptions may be carbonate-buffered monofill scenarios (e.g. monofill or quasi-monofill of MSWI residues), where setting limits on some elemental contents (Cu, Zn, Fe and Mn) does not seem to be very useful.     

Chemical Recycling of PLA: A Great Opportunity Towards the Sustainable Development?

This work aims at analyzing the energy efficiency of the chemical recycling process of polylactic acid (PLA) and its sustainability from an environmental point of view. The results show that the production of lactic acid from chemical depolymerization of PLA is preferable, from an energy point of view, to the production of lactic acid by glucose fermentation. The study also shows that the environmental footprint of the analyzed process is larger than that of the PLA mechanical recycling.     

Can Nutrient Spiralling be Used to Detect Seasonal Nutrient Uptake in a Forested Stream?

Nutrient spiralling measurements were conducted in Lyrebird Creek, a forested stream in the Dandenong Ranges, Victoria, Australia. Spiralling indices from several nutrient (, ) enrichment experiments were correlated with seasonal variation in factors thought to control nutrient uptake, i.e., temperature, light and algal biomass. It was hypothesized that nutrient uptake would be higher in summer as increased temperatures would promote both biotic and abiotic processes and higher light levels in summer would stimulate photosynthesis. However, results did not support this hypothesis. Uptake length for and and uptake velocity were not correlated with chlorophyll-a, light or temperature (r ² < 0.30, P > 0.1) despite the seasonality of these biophysical factors (r ² > 0.42, P < 0.02). Lyrebird Creek might had no seasonal trend in nutrient uptake and/or nutrient spiraling measurements only appears suitable for contrasting streams with large differences in biophysical factors that supports biotic and abiotic nutrient processing. In addition, small errors in measuring a nutrient concentration can result in a large range in the estimated S _w and increased difficulty in determining significant differences in nutrient spiralling indices.