Physicochemical variations in atmospheric aerosols recorded at sea onboard the Atlantic–Mediterranean 2008 Scholar Ship cruise (Part II): Natural versus anthropogenic influences revealed by PM10 trace element geochemistry

The geochemistry of PM₁₀ filter samples collected at sea during the Scholar Ship Atlantic–Mediterranean 2008 research cruise reveals a constantly changing compositional mix of pollutants into the marine atmosphere. Source apportionment modelling using Positive Matrix Factorization identifies North African desert dust, sea spray, secondary inorganic aerosols, metalliferous carbon, and V–Ni-bearing combustion particles as the main PM₁₀ factors/sources. The least contaminated samples show an upper continental crust composition (UCC)-normalised geochemistry influenced by seawater chemistry, with marked depletions in Rb, Th and the lighter lanthanoid elements, whereas the arrival of desert dust intrusions imposes a more upper crustal signature enriched in “geological” elements such as Si, Al, Ti, Rb, Li and Sc. Superimposed on these natural background aerosol loadings are anthropogenic metal aerosols (e.g. Cu, Zn, Pb, V, and Mn) which allow identification of pollution sources such as fossil fuel combustion, biomass burning, metalliferous industries, and urban–industrial ports. A particularly sensitive tracer is La/Ce, which rises in response to contamination from coastal FCC oil refineries. The Scholar Ship database allows us to recognise seaborne pollution sourced from NW Africa, the Cape Verde and Canary islands, and European cities and industrial complexes, plumes which in extreme cases can produce a downwind deterioration in marine air quality comparable to that seen in many cities, and can persist hundreds of kilometres from land.     

Evolving Pb isotope signatures of London airborne particulate matter (PM 10)-constraints from on-filter and solution-mode MC-ICP-MS

Pb isotope compositions of biologically significant PM(10) atmospheric particulates from a busy roadside location in London UK were measured using solution- and laser ablation-mode MC-ICP-MS. The solution-mode data for PM(10) sampled between 1998-2001 document a dramatic shift to increasingly radiogenic compositions as leaded petrol was phased out. LA-MC-ICP-MS isotope analysis, piloted on a subset of the available samples, is shown to be a potential reconnaissance analytical technique. PM(10) particles trapped on quartz filters were liberated from the filter surface, without ablating the filter substrate, using a 266 nm UV laser and a dynamic, large diameter, low-fluence ablation protocol. The Pb isotope evolution noted in the London data set obtained by both analytical protocols is similar to that observed elsewhere in Western Europe following leaded petrol elimination. The data therefore provide important baseline isotope composition information useful for continued UK atmospheric monitoring through the early 21(st) century.     

Salt enrichment of municipal sewage: New prevention approaches in Israel

Wastewater irrigation is an environmentally sound wastewater disposal practice, but sewage is more saline than the supplied fresh water and the salts are recycled together with the water. Salts have negative environmental effects on crops, soils, and groundwater. There are no inexpensive ways to remove the salts once they enter sewage, and the prevention of sewage salt enrichment is the most immediately available solution. The body of initiatives presently structured by the Ministry of the Environment of Israel are herein described, with the aim to contribute to the search for a long-term solution of salinity problems in arid countries. The new initiatives are based on: (1) search for new technologies to reduce salt consumption and discharge into sewage; (2) different technologies to cope with different situations; (3) raising the awareness of the public and industry on the environmental implications of salinity pollution; and (4) an elastic legal approach expressed through new state-of-the-art regulations. The main contributor to the salinity of sewage in Israel is the watersoftening process followed by the meat koshering process. Some of the adopted technical solutions are: the discharge of the brine into the sea, the substitution of sodium by potassium salts in the ion-exchangers, the construction of centralized systems for the supply of soft water in industrial areas, the precipitation of Ca and Mg in the effluents from ion-exchangers and recycling of the NaCI solution, a reduction of the discharge of salts by the meat koshering process, and new membrane technology for salt recovery.