Mass balance to assess the efficiency of a mechanical-biological treatment

Using mechanical-biological treatment of residual municipal solid waste, it is possible to significantly lower landfill volume and gas and leachate emissions. Moreover, the landfill characteristics are improved. The performance of the Mende (France) mechanical-biological treatment plant is assessed via mass balances coupled with manual sorting according to the MODECOMtrade mark methodology and biochemical methane potential after 90 days of incubation. The site includes mechanical sorting operations, a rotary sequential bioreactor, controlled aerobic stabilisation corridors, maturation platforms, and a sanitary landfill site for waste disposal in separated cells. Results showed that several steps could be improved: after a first sieving step, about 12% of the potentially biodegradable matter is landfilled directly without any treatment; mechanical disintegration of papers and cardboards in the rotary sequential bioreactor is insufficient and leads to a high proportion of papers and cardboards being landfilled without further treatment. Two fine fractions go through stabilisation and maturation steps. At the end of the maturation step, about 54% of the potentially biodegradable matter is degraded. The biochemical methane potential after 90 days of incubation is reduced by 81% for one of the two fine fractions and reduced by 88% for the other one. Considering the whole plant, there is a reduction of nearly 20% DM of the entering residual municipal solid waste.     

Genotoxicity of leachates from highly polluted lowland river sediments destined for disposal in landfill

The Matanza-Riachuelo is one of the most polluted rivers of Latin America. The complex chemical mixture of pollutants discharged into the river is accumulated in the river sediments. In this paper, Matanza-Riachuelo river sediment composition and genotoxicity were tested in order to develop a cost-effective, environmentally sound option for disposal and management of contaminated dredged materials. Sampling was performed in a rural area, in a solid waste dumpsite and also in an urban and industrial area. The concentrations of total heavy metals increased from the upper basin to the lower basin. The Ames Salmonella typhimurium test and the Saccharomyces cerevisiae D7 test were performed using toxicity characteristic leachate procedure (TCLP) leachates. The concentrations of copper, lead, and chromium in the leachates exceeded the guide levels for the protection of aquatic life. Low concentrations of organic chlorinated compounds were detected in the leachates. Genotoxic profiles were obtained by testing TCLP leachates from polluted sediment samples with Salmonella typhimurium, Saccharomyces cerevisiae D7, and water sediment suspension with Allium cepa test. No mutagenicity effects on Ames test were observed. Gene conversion and mitotic reversion in Saccharomyces cerevisiae D7 and chromosome aberration in Allium cepa were induced by the sediment samples. Results obtained suggest that dredged sediments could be classified as genotoxic hazardous waste.     

Assessment of the potential of ecolabels to promote agrobiodiversity

We conducted a study to assess to what extent current ecolabels contain standards that stimulate conservation and sustainable use of on-farm biodiversity of agricultural landscapes (agrobiodiversity). First, we developed an agrobiodiversity management yardstick to assess and compare the labeling schemes of ecolabels for arable farming. Key characteristics of the yardstick are the five levels linking the abstract notion of agrobiodiversity management to concrete measures on a farm and its foundation upon expert judgment regarding the effect of farming practices on agrobiodiversity. Several environmental themes, among them agrobiodiversity management, are regulated through the standards of labeling schemes of ecolabels. With the aid of this yardstick, the labeling schemes were scrutinized and the number, average efficacy, and compulsory nature of relevant standards was determined for 10 categories of farm management. The results show that all examined ecolabels contain at least some standards that stimulate conservation and sustainable use of agrobiodiversity, but there are large differences between the labels. We consider the results of the five ecolabels to be insufficient to warrant their usefulness as a governance strategy that the Dutch government could refer to and depend on as part of a national agrobiodiversity policy to stimulate agrobiodiversity.     

Arsenic speciation of atmospheric particulate matter (PM10) in an industrialised urban site in southwestern Spain

An arsenic speciation study has been performed in PM10 samples collected on a fortnight basis in the city of Huelva (SW Spain) during 2001 and 2002. The arsenic species were extracted from the PM10 filters using a NH2OH x HCl solution and sonication, and determined by HPLC-HG-AFS. The mean bulk As concentration of the samples analyzed during 2001 and 2002 slightly exceed the mean annual 6 ng m(-3) target value proposed by the European Commission for 2013, arsenate [As(V)] being responsible for the high level of arsenic. The speciation analyses showed that As(V) was the main arsenic species found, followed by arsenite [As(III)] (mean 6.5 and 7.8 ng m(-3) for As(V), mean 1.2 and 2.1 ng m(-3) for As(III), in 2001 and 2002, respectively). The high levels of arsenic species found in PM10 in Huelva have a predominant industrial origin, such as the one from a nearby copper smelter, and do not present a seasonal pattern. The highest daily levels of arsenic species correspond to synoptic conditions in which the winds with S and SW components transport the contaminants from the main emission source. The frequent African dust outbreaks over Huelva may result in an increment of mass levels of PM10, but do not represent a significant input of arsenic in comparison to the anthropogenic source. The rural background levels of arsenic around Huelva are rather high, in comparison to other rural or urban areas in Spain, showing a relatively high atmosphere residence time of arsenic. This work shows the importance of arsenic speciation in studies of aerosol chemistry, due to the presence of arsenic species [As(III) and As(V)] with distinct toxicity.     

Persistent organic pollutants in atmospheric deposition and biomonitoring with Tillandsia Usneoides (L.) in an industrialized area in Rio de Janeiro state, south east Brazil--Part I: PCDD and PCDF

Monitoring of immission of persistent organic pollutants in the industrialized area of Volta Redonda (V.R.) and in the National Park of Itatiaia (PNI) in southeast Brazil was performed using an endemic Bromeliad species as biomonitor and measuring total deposition rates on funnels covered with polyurethane foams. Samples were collected during 78 days in V.R. and 95 days in PNI in winter (dry season, June-August 2003) and during 114 days in both areas in summer (rainy season, December 2003-February 2004). The PCDD/PCDF deposition rates ranged from 0.10 to 1.9 pg WHO-TEQ/(m2 day) in winter and from 0.11 to 2.2 pg WHO-TEQ/(m2 day) in summer. Deposition rates found in V.R. in summer were four- to ninefold higher than those measured in PNI, while in winter deposition rates in both regions were in the same range. Deposition rates in V.R. in summer were about five fold lower than those measured in 1996. PCDD/PCDF levels in biomonitor samples were between 0.95 and 14.6 ng WHO-TEQ/kg d.m. in winter and between 2.2 and 5.2 ng WHO-TEQ/kg d.m. in summer. In winter, concentrations found in V.R. were up to 11 times higher than those found in PNI, while in summer the levels measured in both areas were comparable. The homologue and isomer profiles found in the deposition as well as in the biomonitor samples from V.R. indicate that steel production is the main source of contamination in the region, whereas in PNI, the long range transport of these pollutants is the predominant contamination pathway.     

Ground laser remote sensing measurements of a Saharan dust outbreak in Central Spain. Influence on PM10 concentrations in the lower and upper Spanish plateaus

This paper presents the hourly evolution of a severe Saharan dust outbreak, (SDO), affecting Central Spain over July 23-24, 2004 measured with a laser remote sensing device at a location close to the Guadarrama mountain range foothills and its impact on PM10 levels (particles with an aerodynamic diameter below 10 microm) recorded at four contrasting monitoring stations located in the upper and lower Spanish plateau, some 170km apart. During the period of study the Saharan dust layer, (SDL), presented significant hourly variability in height (3600-1500m), depth (1500-700m) and aerosol dust loading (extinction coefficient, EC, 0.22-1.28km(-1)). Overnight layering was generally observed whereas a well mixed layer prevailed in the afternoon. The (SDO) impact on the lower levels took place approximately 12h after the (SDL) was initially observed and triggered by a descending dust enriched, evidencing the important role of subsidence over the presence of dust in lower altitudes. During the event, PM10 levels at all the stations exceeded EU air quality daily mean standards, 50 microgm(-3), on 2-4days. The maximum values ranged from 185 to 245 microgm(-3) depending on the monitoring station. The impact on PM10 spread from 2days in the upper plateau to 3-4 in the lower plateau, in agreement with the geographical location of the monitoring stations with respect to the southwest origin of the intrusion. The impact was even more dramatic on PM10 hourly concentrations, leading to maximum hourly peaks ranging from 322 to 598 microgm(-3) again depending on the monitoring station. Correlations between EC vertical profiles and PM10 hourly concentrations at the monitoring stations showed the great influence of the (SDO) on surface concentrations. The best linear fits corresponded to the extinction coefficients in the lower altitudes (close to the lower range of the device 500-650m), EC2, yielding satisfactory correlation coefficients ranging from 0.68 to 0.71. The low variability of the slope of each individual linear fit, 19.2%, shows the similar impact of (SDO) on the PM10 hourly concentrations recorded in the area under study.     

Evaluation of genotoxicity and toxicity of water and sediment samples from a Brazilian stream influenced by tannery industries

This paper reports results of genotoxicity and toxicity studies of water and sediment samples collected from the Estancia Velha stream of southern Brazil, a stream transporting both domestic sewage and effluents from regional factories working in the leather industry. Three sites were selected: in the stream headwaters (Site 1), located downstream of an urban area (Site 2), and near the basin outfall (Site 3). Results obtained with Allium cepa showed no evidence of chromosomal mutation, either in water or in sediment, during winter or summer seasons, but samples collected below Site 1 showed high toxicity. Physical and chemical analyses showed high concentrations of pollutants at these sites. Ecotoxicity tests with Daphnia magna and Ceriodaphnia dubia measured toxicity in water from Sites 2 and 3 in summer 2004. A toxic effect on Hyalella azteca was only found in sediment from Site 3 during winter 2003 and summer 2004. The results suggest that the synergy among different compounds in domestic and industrial sewage discharges can make it difficult to maintain system stability.     

Assessment of the pollution impact on biomarkers of effect of a freshwater fish

Changes in biomarkers of fish captured from stressed environments may represent a reliable tool in revealing sublethal effects of the pollutants found in aquatic ecosystems. The response patterns of selected biochemical and morphological variables biomarkers of effect were assessed in adult females of an indigenous teleost Cnesterodon decemmaculatus, caught at a polluted site (San Francisco) of the Reconquista river (Buenos Aires, Argentina). Combined field-caging experiments with controlled laboratory exposure to clean media were performed. The biochemical parameters measured were specific activities of gill (Na+ + K+)-ATPase, liver AlaAT and AspAT, and brain AChE; LSI and CF were also calculated. The changes in gill (Na+ + K+)-ATPase and liver AlaAT activities of fish captured in the field in most cases were reversible after transfer to clean media. The results were interpreted in association with the physicochemical profile of the water samples taken simultaneously with the capture of the fish. Results suggested the suitability of the test species used as tools in environmental monitoring programs of risk assessment.     

Spatial variance in multimedia mass balance models: comparison of LOTOS-EUROS and SimpleBox for PCB-153

The aim of this study was to determine whether nested generic box models can be used to predict spatial variance. An inter-comparison study was performed for the nested box model SimpleBox, and the spatially resolved model LOTOS-EUROS, using PCB-153 emissions in Europe as an example. We compared the two models concerning (1) average environmental concentrations, (2) spatial concentration variances, (3) spatial concentration patterns (maps), and (4) agreement with measured concentrations for the air and soil compartments. In SimpleBox, the spatial concentration variances and patterns were calculated subsequently for each separate grid cell surrounded by a regional and a continental shell with homogeneous, averaged circumstances. Average European PCB-153 concentrations calculated by LOTOS-EUROS and SimpleBox for the period 1981-2000 agree well for the air and soil compartments. Moreover, the predicted concentrations of both models are in line with the measured PCB-153 concentrations in Europe during that period. For PCB-153, the prediction of spatial concentration variances with the nested multimedia fate model SimpleBox performs adequately in most cases, except for the lower concentration boundary in the air compartment. It is concluded that SimpleBox can be used to predict the spatial maximum and average concentrations of PCB-153 in the air and soil compartments. The proposed method has to be tested systematically for different types of compounds, emission scenarios, environmental compartments and spatial scales in order to allow conclusions about the general applicability of the method.     

Comparison of different stomatal conductance algorithms for ozone flux modelling

A multiplicative and a semi-mechanistic, BWB-type [Ball, J.T., Woodrow, I.E., Berry, J.A., 1987. A model predicting stomatal conductance and its contribution to the control of photosynthesis under different environmental conditions. In: Biggens, J. (Ed.), Progress in Photosynthesis Research, vol. IV. Martinus Nijhoff, Dordrecht, pp. 221-224.] algorithm for calculating stomatal conductance (g(s)) at the leaf level have been parameterised for two crop and two tree species to test their use in regional scale ozone deposition modelling. The algorithms were tested against measured, site-specific data for durum wheat, grapevine, beech and birch of different European provenances. A direct comparison of both algorithms showed a similar performance in predicting hourly means and daily time-courses of g(s), whereas the multiplicative algorithm outperformed the BWB-type algorithm in modelling seasonal time-courses due to the inclusion of a phenology function. The re-parameterisation of the algorithms for local conditions in order to validate ozone deposition modelling on a European scale reveals the higher input requirements of the BWB-type algorithm as compared to the multiplicative algorithm because of the need of the former to model net photosynthesis (A(n)).