Comparative overview of indoor air quality in Antwerp, Belgium

This comprehensive study, a first in Belgium, aimed at characterizing the residential and school indoor air quality of subgroups that took part in the European Community Respiratory Health Survey and the International Study of Asthma and Allergy in Childhood [Masoli M, Fabian D, Holt S, Beasley R. Global Burden of Asthma, Medical Research Institute of New Zealand, University of Southampton; 2004.] questionnaire-based asthma and related illnesses studies. The principal aim was to perform a base-line study to assess the indoor air quality in Antwerp in terms of various gaseous and particulate pollutants. Secondly, it aimed to establish correlations between these pollutants investigated, the pollutant levels in the indoor and outdoor micro-environments, findings of the previous questionnaire-based studies and an epidemiological study which ran in conjunction with this study. Lastly, these results were compared and evaluated with current indoor and ambient guidelines in various countries This paper presents selected results on PM1, PM2.5 and PM10 mass concentrations and elemental C estimates as black smoke, as well as gaseous NO(2), SO(2), O(3) and BTEX concentrations of 18 residences and 27 schools. These are related to current guidelines of Flanders, Germany, Norway, China and Canada and evaluated with reference to selected similar studies. It was found that indoor sources such as tobacco smoking and carpets, the latter causing re-suspension of dust, are responsible for elevated indoor respirable particulate matter and place school children and residents at risk. Both PM2.5 and PM10 equalled or exceeded the current guidelines adopted by Flanders, noting that 12-h and 24-h PM2.5 were compared with an annual limit value. Indoor and ambient NO(2) concentrations in the school campaign were higher than the annual EU ambient norm. The other studied pollutant levels were below the current guidelines.     

Elemental composition of bottom-sediments from Pangani river basin,Tanzania: lithogenic and anthropogenic sources

River-bed sediments from the Pangani basin, Tanzania, were characterized for elemental compositions, following contamination risks from rapid expansions of human activities in the area. Samples were collected during two individual seasons and analyzed by high-polarizing beam energy dispersive X-ray fluorescence (EDXRF) for eight major and 14 trace elements. Evaluation of enrichment factors (EFs) was used to investigate the elemental flux and assess the contributions of natural and anthropogenic influences. The abundances of the major elements followed the order Si?>?Al?>?Fe?>?Ca?>?K?>?Ti?>?Mn?>?P, similar to that of the upper earth's crust, and were generally from the weathering of the bed-rock. The high concentrations of typical anthropogenic trace-elements (Cr??1, V??1, Ni??1, Cu??1, La??1) coupled with high EFs (>2) in some locations indicated contamination associated with agricultural and industrial activities. Factor analysis extracted five principal components that contributed to 96.0% of the total observed variance. The results indicated that river-bed sediments of the Pangani basin were influenced to a larger extent by lithogenic sources than anthropogenic impacts.     

Distribution and fractionation of heavy metals in the Tisa (Tisza) River sediments

Introduction In this work, sediments of the River Tisa (Tisza) are studied to assess their environmental pollution levels for some major heavy metals, as well as to predict the investigated elements’ mobility on the basis of their association type with the substrate. The Tisa River catchments area is a subbasin of the River Danube. Part of this river, 166 km long, belongs to the Serbian province of Vojvodina, before it flows into the Danube. It has been chosen for our investigation, because it has been exposed to intense pollution in the last decades. Materials and Methods The river sediment samples were collected at 32 locations. The proportions of sand, silt and clay fractions were determined. The sequential extraction procedure following a modified Tessier method was applied for speciation of the metal forms in the collected samples. The metal concentrations of Zn, Cd, Pb, Ni, Cu, Cr, Fe and Mn in extracts were determined by atomic absorption spectroscopy. Results and Discussion Granulometric analysis showed that some 50% of the Tisa River sediments were silt and clay, while the rest was sand with quartz, as the main constituent. The average metal content of the surface river sediment samples for every fraction of sequential extraction was presented and discussed in relation to pH, Eh and metal fractionation. The average metal content from the Tisa River sediments, obtained as an average of the metal’s concentration released in all five sequential extraction fractions was compared with: average metal contents of the Tisa River sediments in Hungary, metal content in soils formed on the Tisa River alluvium of Vojvodina, average metal content in soils of Vojvodina, and average metal content in soils of Hungary. An assessment of metal pollution levels in Tisa River sediments was made by comparing mean values for obtained results for the Tisa River sediments with the freshwater sediment’s Quality Guidelines as published by US EPA, Environment Canada and soil standards for Serbia. Conclusion According to US EPA and Canadian Quality Guidelines for freshwater sediments, the concentration of heavy metals in Tisa sediments were: (a) much higher than defined concentrations below which harmful effects on river biota are unlikely to be observed, (b) below defined concentrations above which harmful effects on river biota are likely to be observed. The concentration levels of Pb, Ni, Cu and Cr in Tisa River sediments are safe when compared with Serbian MAQ (Maximum Allowed Quantity) standards for soils, but they are unsafe in the case of Zn and Cd. Recommendations and Outlook The quality of sediments in the Tisa River was on the border line between potentially polluted and polluted. This line could very easily be exceeded since the quality of sediments in the Tisa River in Hungary was already worse than in Serbia. These results indicated the need for further monitoring of heavy metals in that locality.     

Partitioning of selected environmental pollutants into organic matter as determined by solid-phase microextraction

Partitioning/sorption of selected environmental pollutants (PCBs, organochlorine insecticides, triazine and amide herbicides) into dissolved humic acids (HA), soil and mineral substances was evaluated by measuring their free concentrations by solid-phase microextraction (SPME). Compounds were chosen to cover a wide range of logK(ow) (2.2-7.6). Two different types of partitioning behaviour for dissolved HA were observed. Compounds with logK(ow)>5 partitioned almost instantly into HA fraction and the remaining free fraction remained rather constant. LogK(HA) and logK(DOC) were calculated and found to be similar for commercial HA, HA standard and isolated HA. The behaviour of these compounds in soil suspension was similar, but strong sorption on CaCO3 and Florisil was also noticed. For compounds with logK(ow)<5, we have not noticed significant changes in free concentrations in HA solutions over time. In soil suspension, however, some sorption/partitioning was observed over time for some compounds, but it was matching the sorption on CaCO3 and Florisil.     

Removal of anthelmintic drugs and their photodegradation products from water with RO/NF membranes

Photolytic reactions are often complex, involving various competing or parallel pathways and leading to multiple reaction products. Removal of anthelmintic drugs (AD) – levamisole (LEV), albendazole (ABZ), praziquantel (PZQ), febantel (FEBA) from water and their photodegradation products with reverse osmosis (RO) and nanofiltration (NF) membranes were investigated in this work. Simulation of photodegradation of ADs was carried out under laboratory conditions with UV lamp at a wavelength of 254 nm for 4 h.Reverse osmosis (LFC–1 and XLE) and tight nanofiltration (NF90) membranes showed good removal (>83%) of anthelmintic drugs in binary solutions and in mixture. Other nanofiltration (NF270, NF and DK) membranes had rejection between 22 and 45% for smaller drugs (LEV and ALB) and >90% for PZQ and FEBA. These results show that main rejection mechanism in binary solutions was size exclusion and in mixture additional physico-chemical interactions had influence.After the UV treatment anthelmintic drugs were degraded into several photodegradation products (5 for LEV, 2 for ABZ, 1 for PZQ and 8 for FEBA). Reverse osmosis and NF90 membranes removed >95% of all photodegradation products (except FEBA₁ around 70%) and other nanofiltration membranes between 33 and 99.99%.