PAH mass concentrations measured in PM10 particle fraction

This paper presents daily, monthly and yearly variations of PAH mass concentrations measured in PM(10) particle fraction, collected at one measuring site in Zagreb air between 2001 and 2004, and seasonal differences in PAH mass concentrations in PM(10) samples collected from 21 March 2003 to 20 March 2004. Twenty-four hour samples were taken in the northern residential part of Zagreb using a low-volume (50 m(3)) sampler and glass or quartz filters. The analysis was performed using a high-performance liquid chromatograph (HPLC) and fluorescence detector with changeable excitation and emission wavelength. The annual average mass concentrations over the four-year measuring period for BaP ranged from 1.17 ng/m(3) in 2004 to 1.87 ng/m(3) in 2003 and were below the limit value (2 ng/m(3)) set by the Ordinance on Recommended and Limit Air Quality Values in Croatia. The highest concentrations of all PAHs measured in PM(10) samples collected from 21 March 2003 to 20 March 2004 were found in the winter and the lowest in the summer. Winter average of BaP was 2.94 ng/m(3) and summer average 0.12 ng/m(3). Autumn average was 2.76 ng/m(3) and was very similar to winter concentrations. Spring average of 0.58 ng/m(3) was higher than the summer average (0.12 ng/m(3)). Mass concentrations of all measured PAHs were much higher in the autumn than in the spring. Although annual averages for BaP did not exceed the limit value, autumn and winter BaP mass concentrations did, which calls for measures for reducing PAH emissions in the autumn and winter.     

The Adsorption of Formaldehyde on Suspended Particles investigated on model systems

Our laboratory investigation aimed at assessing to what extent suspended particles could adsorb formaldehyde, allowing it, when inhaled, to penetrate deeper into the lung. We used two types of pure soot, N-220 and N-660 (the former being a highly active oil furnace soot with smaller particles and a larger surface area than the latter), because of their chemical inactivity and the adsorptive properties. The results obtained in experimental conditions showed that soot particles could bind 2.3 to 50.2% of formaldehyde, depending on the particle size, relative humidity, amount of particles and the duration of the contact. The recovery of formaldehyde from the particles was also tested. Further investigation is planned under realistic conditions.     

Comparison of mass concentrations of SO2 determined in air by two different methods

Mass concentrations of sulphur dioxide were determined in parallel 24-hour samples of ambient air at a measuring site in Zagreb during a period of eight years. The methods used were the West-Gaeke's tetrachloromercurate-pararosaniline method (TCM) and the Standard British Method (SBM). Total results for the annual intervals of measuring were analyzed statistically and also discussed separately for winter and summer periods, in order to see whether they are influenced by seasonal rhythm.     

The effect of metals and ammonia on SO2 oxidation to sulphates in the ambient air

The effect of metals and ammonia on the relationship between mass concentrations of sulphur dioxide and sulphate in the air was studied near an aluminium plant over a 1-year period. Sulphur dioxide, sulphates and ammonia in the air as well as metals (Pb, Fe, Mn, Zn, Cu, Cd and Al) in the deposit were measured at four measuring sites.The levels of mass concentrations of SO₂ were low at all measuring sites while the levels of mass concentrations of sulphates in the air and concentrations of metals in the deposit were high. The levels of ammonia were found to decrease in relationship to the distance from the source of pollution.The relationship between the mass concentrations of sulphate and SO₂ can be described by the equation y=ax ^b ;where y is the percentage of sulphate sulphur in the total sulphur (sulphate and SO₂) and x is the mass concentration of the total sulphur in the air. The values of the coefficients a and b are characteristic of individual areas.As the results show the coefficients a and b obtained at a measuring site close to the plant and outside the urban area are characteristic of an industrial area. At control sites in the urban area the coefficients are characteristic of an urban area. At the measuring site close to the industrial zone and the centre of the urban area the interaction of the effects occurs. Therefore, the coefficient a is characteristic of an urban area and b of an industrial one.     

PAH Levels and Profiles in the Suspended Particulate Matter in Zagreb through Four Seasons

This paper presents the analysis of polycyclic aromatic hydrocarbons (PAHs) measured in all four seasons in suspendedparticulate matter (SPM) collected with a high-volume sampler on one measuring site in the northern part of Zagreb. About 30 samples of SPM were analysed for each season, including workdays and weekends and there were no differences amongst them. The concentrations of all PAHs were highest in winter andlowest in summer. The spring PAH concentrations were lower thanthe autumn ones, as the spring had more sunny and warm days. Theprofiles of PAH/BaP at the measurement sites showed that the mainsource of PAHs in spring and summer was traffic while asubstantial amount of autumn and winter PAHs, besides traffic,came from heating.     

Soil Contamination by Pb, Zn and Cn from a Lead Smeltery

In the environment of a lead smeltery contamination with lead, zinc and cadmium was measured over a 15-year period. Efficient bag filters were installed in order to remove dust from the flue gases. This measure of improvement resulted in a drastic reduction of lead, zinc and cadmium content in suspended particles (by 92, 94 and 89%), to a lesser extent in depositions (by 79, 75 and 68%), whereas in household dust the reduction was considerably lower (by 53, 55 and 70%). It can be assumed that household dust contains also redispersed soil particles on which the dust from the smeltery flue gases has deposited over years. To determine to what extent contaminated soil continues to cause increased population exposure directly or through plants or pastures, in the period 1981–1985 the content of metallic ions in the soil was measured at three depths. Selective solubility of soil metallic compounds was analysed in water, in 1 mol ammoniumacetate solution and in 0.05 mol ethylenediaminetetra-acetic acid (EDTA) solution in relation to their solubility in suspended particles, depositions and household dust. A considerably low portion of soluble metallic compounds was found in the soil and physico-chemical characteristics of the soil and portion of metallic ions bound to fulvice and humic acids were determined. The behaviour of metallic ions in contact with soil samples was studied in laboratory and it was found that approximately 50% of lead, 70% of zinc and 7% of cadmium ions change into non-soluble or poorly soluble compounds. By qualitative phase analysis in the non-soluble fraction PbO₂, Pb₃P₄O₁₃, Zn(OH)₂, ZnO, Fe₂O₃ and Cd(OH)₂ were identified.     

The effects of subchronic exposure to NeemAzal T/S on zebrafish (Danio rerio)

The objective of the study was to investigate the subchronic effects of the insecticidal preparation NeemAzal T/S at concentrations of 3, 10 and 30?mg/L on the mortality, growth and histopathology of juvenile zebrafish (Danio rerio), as well as its related effects on selected indices of oxidative stress during a 28-day toxicity test. The juvenile growth toxicity test was performed according to OECD Guidelines 215 (Fish, Juvenile Growth Test). The results of this study indicate that these tested concentrations of NeemAzal T/S (containing 1% of the active ingredient azadirachtin A) affect fish growth and have a negative influence on the indices of oxidative stress in the juvenile stage of zebrafish, as well as cause mild histopathological changes in liver tissue.