Multiyear variability of ecological-hygienic condition of the land: metals in soils of surroundings of the Astrakhan gas complex

Abstract

There are presented the results of a 21-year-old (1991-2012) monitoring of Hg concentrations and amounts of metals, including heavy and toxic, Zc(MnCrVNiCoCuAgZnPbSnMo) in soils of the zone of the exposure to emissions from Astrakhan gas complex (AGK), working from 1987 within a radius of 50 km. On those criteria for the period over 1997-2012 there was revealed a steady deterioration of ecological-hygienic conditions of the lands in the control zone. The spatial variability of this condition is largely controlled by the dispersion of the emissions by the prevailing easterly and southeasterly winds. The content of Hg in 2007, remote from AGK by 15 km, increased by 6-8 times on the leeward north-west territories, where the accumulation of the toxicant was 2.5 times more pronounced than in the windward Eastern and North-Eastern side. The significant role in the deterioration of sanitary-ecological state of the territory of the sanitary protection zone when dealing with Hg-containing (70-100 mkg/kg) commodity grey belongs to reblowing of particles and their eolian spread from places of storage, loading and transportation. In separate halos the content of Hg in the soil has reached 285 mkg/kg and become closer to the "target" safe level (300 mkg/ kg), adopted in Western Europe (zone AGK-30 km). The total amount of metals as in the near (up to 5 km of sanitary protection), so far (5-50 km) zones as in background sites has increased steadily. By 2012 in some places, remoted up to 30 km from AGK there were fixed already hygienically dangerous levels of total metals accumulation (up to Zc =34)