Analysis of 3-year observations of CFC-11, CFC-12 and CFC-113 from a semi-rural site in China

In-situ measurements of atmospheric chlorofluorocarbons (CFCs) can be used to the assess their global and regional emissions and to check for compliance with phase-out schedules under Montreal protocol and its amendments. The atmospheric mixing ratios of CFC-11 (CCl₃F), CFC-12 (CCl₂F₂) and CFC-113 (CCl₂F–CClF₂) have been measured by an automated in-situ GC-ECDs system at the regional Chinese Global Atmosphere Watch (GAW) station Shangdianzi (SDZ), from November 2006 to October 2009. The time series for these three principal CFCs showed large episodic events and background conditions occurred for approximately 30% (CFC-11), 52% (CFC-12) and 56% (CFC-113) of the measurements. The mean background mixing ratios for CFC-11, CFC-12 and CFC-113 were 244.8 ppt (parts per trillion, 10^?12, molar) 539.6 ppt and 76.8 ppt, respectively, for 2006–2009. The enhanced CFC mixing ratios compared to AGAGE sites such as Trinidad Head (THD), US and Mace Head (MHD), Ireland suggest regional influences even during background conditions at SDZ, which is much closer to highly-populated areas. Between 2006 and 2009 background CFCs exhibited downward trends at rates of ?2.0 ppt yr^?1 for CFC-11, ?2.5 ppt yr^?1 for CFC-12 and ?0.7 ppt yr^?1 for CFC-113. De-trended 3-year average background seasonal cycles displayed small fluctuations with peak-to-trough amplitudes of 1.0 ± 0.02 ppt (0.4%) for background CFC-11, 1.3 ± 2.1 ppt (0.3%) for CFC-12 and 0.2 ± 0.4 ppt (0.3%) for CFC-113. On the other hand, during pollution periods these CFCs showed much larger seasonal cycles of 11.2 ± 10.7 ppt (5%) for CFC-11, 7.5 ± 6.5 ppt (2%) for CFC-12 and 1.0 ± 1.2 ppt (1.2%) for CFC-113, with apparent winter minima and early summer maxima. This enhancement was attributed to prevailing wind directions from urban regions in summer and to enhanced anthropogenic sources during the warm season. In general, horizontal winds from northeast showed negative contribution to atmospheric CFCs loading, whereas South Western advection (urban sector: Beijing) had positive contributions.     

Critical remarks on the use of terrestrial moss (Hylocomium splendens and Pleurozium schreberi) for monitoring of airborne pollution

Duplicate samples of the two terrestrial moss species Hylocomium splendens and Pleurozium schreberi, which are widely used to monitor airborne heavy metal pollution, have been collected from eight catchments spread over a 1,500,000 km2 area in northern Europe. These were analysed for a total of 38 elements by inductively coupled plasma-mass spectrometry, inductively coupled plasma-atomic emission spectrometry and cold vapour-atomic absorption spectometry techniques. Results show that the moss species can be combined without interspecies calibration for regional mapping purposes. For the majority of elements the observed within-catchment variation is large--big composite samples over a large area should thus be collected when moss is to be used for monitoring purposes. For the majority of elements the input of dust governs moss chemistry. For a reliable 'contamination' signal over a sizeable area a major source is needed. Some elements show a dependence on climate/vegetation zone. In coastal areas the input of marine aerosols will alter the chemical signal obtained from moss samples.     

Topsoil (0-5 cm) composition in eight arctic catchments in northern Europe (Finland, Norway and Russia)

Frozen topsoil samples (0-5 cm) were collected during March/April 1994 in eight Arctic catchments in northern Europe (four in Russia, three in Finland, one in Norway), at different distances and in different wind directions from the emissions of the Russian mining, roasting and smelting industry on the Kola Peninsula. Between 14 and 25 sites were sampled in each of the eight catchments ranging in size from 12 to 35 km2. Results show that close to the smelters in Monchegorsk and Nikel, topsoil is clearly enriched in Ag, As, Bi, Cd, Co, Cr, Cu, Fe, Ni, Pb, Sb, Se, Te and V. Cu and Ni median contents in topsoils collected close to Monchegorsk are about 600 times higher than in the Finnish catchments. The effect of open-cast mining and waste dumps of alkaline rocks from the nephelinite industry near Kirovsk can be seen in the elevated contents of Al, Ba, K, La, Mn, Na, Sr, Ti, Y and Zn in topsoil collected in a nearby catchment. For many elements, however, variations observed in single catchments are as great as the total regional variation. Several elements (e.g. Cd, Hg, Cu, Ni, Pb, S, Zn) show strong positive correlation between the organic content of the sample and the element content observed. Thus it is necessary to determine the organic content of the samples and correct the element levels when using depth-related soil samples (here, the 0-5 cm topsoil layer) for regional mapping.     

Seasonal variability of total and easily leachable element contents in topsoils (0-5 cm) from eight catchments in the European Arctic (Finland, Norway and Russia)

Frozen topsoil samples (0-5 cm) were collected during March/April 1994 in eight Arctic catchments in northern Europe (4 in Russia, 3 in Finland, 1 in Norway) at varying distances and wind directions from the emissions of the Russian nickel ore mining, roasting and smelting industry on the Kola Peninsula. Between 14 and 25 sites were sampled in catchment basins ranging in size from 12 to 35 km(2). Sampling was repeated in spring immediately after the snow melted, in summer and in autumn to study seasonal variability and the fate of elements when the snow melts. The <2 mm fraction of air-dried topsoils was analysed for total (aqua regia extraction) and easily leachable (in 1 m ammonium acetate, buffered at pH 4.5) element concentrations using ICP-AES and GFAAS for up to 35 elements. Results for selected elements are presented here. Soil organic matter can be shown to be the controlling factor determining element contents and fate. In catchments close to the Russian nickel industry, the topsoils have low carbon and nitrogen contents. Using both extraction methods most elements reach maximum concentrations in winter; lowest concentrations are observed in midsummer. Soil organic matter and elements associated with it are thus leached out of the soils together with soluble elements when the snow melts. This process continues in summer. Elements will enrich surface waters, the lower layers of podzol profiles, or reach the groundwater. The use of the two extractions described provides a simple method to study the mobilities and pathways of elements in the topsoils during the arctic year. Using the proportions of easily leachable to total concentration, a good estimation of the status of the topsoil in the study area can be given.     

Emissions from the copper–nickel industry on the Kola Peninsula and at Noril'sk,Russia

Published estimates for base metal emissions from the copper–nickel industry on the Kola Peninsula are re-examined in the light of (a) chemical data on the composition of the ores; (b) official emission figures for 1994; and (c) modelled emissions based on dry and wet deposition estimates derived from data for snow and rain samples collected in 1994. The modelled emissions, official emission figures and chemical data are mutually compatible for Ni, Cu and Co and show that previously published figures underestimated the emissions of the major elements, Ni and Cu (though within the same order of magnitude) and overestimated the emissions of As, Pb, Sb and Zn by up to several orders of magnitude, in some cases exceeding the calculated total input to the plants. Published estimates have neglected information on the nature and chemistry of the ores processed in metallurgical industries in the Noril'sk area of Siberia and the Urals. Revised emission estimates for 1994, using knowledge of the chemistry of the ores, are proposed: taken with published information on total emissions up to 2000 these data give an indication of emission levels in more recent years.     

Publicly available datasets on thallium (Tl) in the environment—a comment on <Emphasis Type="Italic">“Presence of thallium in the environment: sources of contaminations,distribution and monitoring methods”</Emphasis> by Bozena Karbowska,Environ Monit Assess (2016) 188:640 (DOI 10.1007/s10661-016-5647-y)

This comment highlights a whole series of datasets on thallium concentrations in the environment that were overlooked in the recent review by Karbowska, Environmental Monitoring and Assessment, 188, 640, 2016 in this journal. Geochemical surveys carried out over the last few decades all over the world at various scales and using different sampling media have reported the concentration of thallium (and dozens more elements) in tens of thousands of samples. These datasets provide a ‘real-world’ foundation upon which source apportionment investigations can be based, monitoring programs devised and modelling studies designed. Furthermore, this comment also draws attention to two global geochemical mapping initiatives that should be of interest to environmental scientists.