Henri Wortham

Chemical composition of rainwater in Eastern France

Abstract Rainwater sampled weekly at nine sites in eastern France from October 1991 to March 1992 has been analysed for major ions (Cl − , NO 3 − , SO s 2− , NH 4 + , Na + , K + , Mg 2+ and Ca 2+ ), pH and conductivity. The major elements are SO 4 2− and Cl − for the anions and NH 4 + and Ca 2+ for the cations. The major ion concentrations are higher in urban areas, especially at Colmar (no.2), where rainfall amounts are low. Surprisingly, the acidity is higher at the sites in rural areas [i.e. mean pH of 4.4 for Ban sur Meurthe (no. 7)] and lower in the urban areas [mean pH of 5.0 for Strasbourg (no. 1) and pH of 5.7 for Colmar (no. 2)]. This is probably due to the presence of CaCO 3 in the “loess”, which is the major constituent of soils in the upper Rhine valley. The relationship between the chemical composition of rain andair-mass trajectories for four humid weeks which presented only one rain event are also examined.

Comparison of atmospheric pesticide concentrations measured at three sampling sites: local, regional and long-range transport

We present the comparison of atmospheric concentrations of eleven currently used pesticides (HCB, alpha-HCH, gamma-HCH, trifluraline, mecoprop, phosalone, atrazine, carbofuran, carbaryl, diuron and isoproturon) measured in remote (Aubure), rural (Colmar) and urban (Strasbourg) areas of Alsace and Vosges regions (cast France). Pesticides samples were collected simultaneously on two of the three sites during the summer season of 1993 and 1994, using a Hi-Vol sampler with Whatman filter paper and XAD-2 resin. The particle and gas phases were collected separately during 24 h. The relative importance of local emissions and local, regional and long distance transport on the contamination of the atmosphere in the three environments (remote, rural and urban) were investigated. To facilitate the interpretation of the results, the alpha/gamma-HCH ratio was used as a tracer of pesticide emissions.

Atmospheric contamination by pesticides: Determination in the liquid, gaseous and particulate phases

Between 1991 and 1993, 18 fogwater samples, 31 rainwater samples and 17 atmosphere (gas and particles) samples were analysed for 13 pesticides (pp’DDT,pp’DDD,pp’DDE, aldrin, dieldrin, lindane, hexachlorobenzene, fenpropathrin, mecoprop, methyl-parathion, atrazine, isoproturon and aldicarb). The samples were collected in a rural area where some of the compounds are in use (experimental INRA farm, “Institut National de la Recherche Agronomique” in Colmar, Eastern France, 80,000 inhabitants). This paper briefly presents the analytical methodology used and, in detail, the contamination level of the different atmospheric phases. The contamination levels are roughly constant throughout the year in all the atmospheric phases and the most abundant pesticides are those commonly used on the experimental INRA farm and other surrounding farms. Nevertheless, some pesticides not used since the 1970s such as 1,1-Bis(4-chlorophenyl)-2,2,2-trichloroethane (pp’DDT) and 2,2-Bis(4-chlorophenyl)-1,1-dichloroethane (pp ’DDD) are also detected in the atmosphere of Colmar. A small increase in the pesticide concentrations in the atmosphere (gas and particles) was observed during treatments.

Analytical method using gas chromatography and ion trap tandem mass spectrometry for the determination of S-triazines and their metabolites in the atmosphere.

Gas chromatography-ion trap detector (GC-ITD) was used to detect atmospheric triazines and their degradation products in the gaseous and particulate phases. Because triazines and their metabolites are expected to be present at very low concentrations and enclosed in the complex atmospheric matrix, the analytical method used was both highly selective and sensitive. These two properties were obtained by associating chromatography with ion trap tandem mass spectrometry (GC-ITD (MS/MS)). To develop this method, a comparison between the two ionization modes (electron impact and positive-chemical-ionisation) in single-MS was first conducted to choose the parent ions of the five target analytes, i.e. atrazine, desethylatrazine, deisopropylatrazine, terbuthylazine and desethylterbuthylazine. Then, a MS/MS method was optimised by parameters such as the radio frequency storage level and the collision-induced dissociation excitation voltage. Finally, a last step enabled the development of a calibrating program based on the quantification of daughter ions. With this analytical procedure, the detection limits varied between 0.8 and 15 pg m(-3) depending on the compounds under study. This method was tested with success for four atmospheric samples collected in Strasbourg (France) in which four of the five target compounds were detected.

Cloud water deposition at a high-elevation site in the Vosges Mountains (France)

The importance of cloud water deposition fluxes to a high-elevation site in the Vosges Mountains (France) has been studied. An existing one-dimensional cloud water deposition model has been adapted to site conditions. The adaptation of the main parameters has been tested and is discussed. These tests illustrate the small influence of the surface area index (SAI) and the roughness length on cloud water deposition and the negligible contribution of sedimentation compared to impaction of cloud droplets. Model input data, including cloud water composition, liquid water content (LWC) and wind speed, have been collected over a 1-year period and are used to evaluate annual cloud deposition fluxes of major ions and trace metals. The calculations indicate that the hydrologic input by cloud water (55.5 mm year(-1)) is negligible compared to the input by rainwater (1265 mm year(-1)). However, due to the higher concentrations in cloud water, the deposition fluxes of cloud water represent 10-28% of the total wet deposition (rain + cloud deposition) for major ions and 50% or higher for trace elements.

Solubility of polyvalent cations in fogwater at an urban site in Strasbourg (France)

Abstract The concentrations in the soluble and total (soluble + insoluble) fractions of Mg, Ca, Fe, Mn, Zn, Al, Cd and Pb have been analysed by “inductively coupled plasma (ICP)” in 14 fog events collected in 1992 at an urban site in France (Strasbourg). For each fog event, two droplet size categories (2–6 μm and 5–8 μm) have been collected separately. For the analysis of the polyvalent cations in the soluble and total fractions, an analytical procedure using ICP and filtration on cellulose/PVC filters has been developed. The study of the solubility of some polyvalent cations has shown that two of the most important factors controlling the partitioning between the soluble and insoluble fraction are the nature of the particles and the pH of the fogwater. The influence of pH depended on the element. The solubility of Pb, Cd, Al, Fe, Mg, and Ca were pH dependent whereas, Zn and Mn solubility varied but no relationship with pH existed, ranging between 25 and 100% and 10 and 100%, respectively. On the other hand, Mg, Pb and Ca were predominantly present in the soluble phase, whereas Al was prevalent in the insoluble fraction. In the case of Cd and Fe., the presence in the soluble or insoluble phase depended largely on the fogwater pH.

Low molecular weight organic acids in fogwater in an urban area: Strasbourg (France)

Abstract This work presents the chemical analysis of low weight carboxylic acids: formate and acetate in two droplet-size categories (2–6 and 5–8 μm) of fogwater collected in Strasbourg (eastern France) between 1991 and 1994. For each sample, the ratio between acetate and formate was calculated, in many cases, this ratio was typically higher than one. This calculation indicates that the origin of acetate and formate can be attributed to automobile exhaust. Maximum contribution of these acids to the total free acidity of fogwater was also checked and the results show that the contribution is very low in regard to the strong mineral acids from anthropogenic origin.

Evolution of the fogwater composition in Strasbourg (France) from 1990 to 1999

Abstract The chemical composition of fogwater has been studied in the city of Strasbourg (France) from 1990 to 1999. During these years, fogwater samples have been collected and analysed for major ions and trace metals. This paper reports on the analysis of the collected dataset. The analysis revealed a significant decrease in acidity of approximately one pH unit over the course of the study. This decrease in acidity appears to be linked to a decrease in SO 2(g) and the resulting SO 4 2− . Trace metal concentrations have also strongly decreased over the 10-year period. Pb concentrations, following the elimination of leaded gasoline, decreased by more than one order of magnitude.

Comparison of annual dry and wet deposition fluxes of selected pesticides in Strasbourg, France

This work summarizes the results of a study of atmospheric wet and dry deposition fluxes of Deisopropyl-atrazine (DEA), Desethyl-atrazine (DET), Atrazine, Terbuthylazine, Alachlor, Metolachlor, Diflufenican, Fenoxaprop-p-ethyl, Iprodione, Isoproturon and Cymoxanil pesticides conducted in Strasbourg, France, from August 2000 through August 2001. The primary objective of this work was to calculate the total atmospheric pesticide deposition fluxes induced by atmospheric particles. To do this, a modified one-dimensional cloud water deposition model was used. All precipitation and deposition samples were collected at an urban forested park environment setting away from any direct point pesticide sources. The obtained deposition fluxes induced by atmospheric particles over a forested area showed that the dry deposition flux strongly contributes to the total deposition flux. The dry particle deposition fluxes are shown to contribute from 4% (DET) to 60% (cymoxanil) to the total deposition flux (wet+dry).

Precursor ion scanning-mass spectrometry for the determination of nitro functional groups in atmospheric particulate organic matter.

An analytical method for the quantitative determination of the total nitro functional group (R-NO2) content in atmospheric particulate organic matter is developed. The method is based on the selectivity of NO2(-) (m/z 46) precursor ion scanning (PAR 46) by atmospheric pressure chemical ionization-tandem mass spectrometry (APCI-MS/MS). PAR 46 was experimented on 16 nitro compounds of different molecular structures and was compared with a neutral loss of NO (30 amu) technique in terms of sensitivity and efficiency to characterize the nitro functional groups. Covering a wider range of compounds, PAR 46 was preferred and applied to reference mixtures containing all the 16 compounds under study. Repeatability carried out using an original statistical approach, and calibration experiments were performed on the reference mixtures proven the suitability of the technique for quantitative measurements of nitro functional groups in samples of environmental interest with good accuracy. A linear range was obtained for concentrations ranging between 0.005 and 0.25 mM with a detection limit of 0.001 mM of nitro functional groups. Finally, the analytical error based on an original statistical approach applied to numerous reference mixtures was below 20%. Despite of potential artifacts related to nitro-alkanes and organonitrates, this new methodology offers a promising alternative to FT-IR measurements. The relevance of the method and its potentialities are demonstrated through its application to aerosols collected in the EUPHORE simulation chamber during o-xylene photooxidation experiments and in a suburban area of a French alpine valley during summer.