Forecasting heavy metal pollution of soils in an administrative district of Belarus

We tested the dynamical model of migration based on balance equations, for a predictive assessment of soil pollution by heavy metals: lead, cadmium, zinc and copper, at the level of an administrative district. As the main input components of the balance, we took into account the flows of metals caused by atmospheric depositions, weathering of parent materials and input with fertilizers (on agricultural lands); the expenditure part of the balance is described by flows of metals with the infiltration subsurface flow and consumption for buildup of the vegetation biomass or the removal with the harvest. It is found that given the continuation of the existing level of loads (scenario 1), for the calculated period (40 years) in the soils of natural ecosystems the concentrations of the four elements can decrease substantially or remain at the previous level. Changes will make up 0.2–0.8% for lead, 0.5–5 for cadmium, 0.8–4 for copper, and 0.3–1.5% for zinc of their total content levels in the soil. In the soils of agricultural lands, provided that the aforementioned conditions are observed, the total content of lead will increase by 5–6.5%, cadmium by 1–1.2%, copper by 2.1–3, and zinc by 12.5–16.5%. It is determined that with an increase in the flow of atmospheric deposition (scenario 2), for 40 years the soils of natural ecosystems will retain a minor negative balance of cadmium (0.001–0.004 mg/kg of the soil); for lead the negative balance in forest ecosystems will change to a minor positive balance (0.09–0.18 mg/kg of the soil), and the removal of zinc and copper will retain its previous level. In the soils of agricultural lands, with a simultaneous increase of the rates of application of organic fertilizers by 20%, the total concentrations of lead for the calculated period can increase by 7.1–9.6%, cadmium by 7–8.5, copper by 5.2–7.8, and zinc by 18.2–24.2%.     

Comparative toxicity of drilling muds: role of chromium and petroleum hydrocarbons

Samples of used drilling muds collected during the course of a single well drilling operation exhibited different degrees of acute toxicity to sheepshead minnows and grass shrimp. For moulting grass shrimp, Palaemonetes pugio, the 96-h LC₅₀'s were 360 to 14 560 ppm (μl/litre); many of these values were considerably lower than those reported from previous drilling mud assays. However, when some of the muds used in this study were tested on sheepshead minnows, Cyprinodon variegatus, the resulting 96-h LC₅₀'s (6300 to 100 000ppm) were well within the range of previously reported values.Although a number of the drilling mud samples had relatively high amounts of chromium due to the addition of sodium chromate, there was a low correlation between chromium concentration and toxicity. In only three drilling muds could chromium content alone account for the observed toxicities. Furthermore, chemical analyses revealed the presence of No. 2 fuel oil like petroleum hydrocarbons in the mud samples. Based on the results of toxicity tests with No. 2 fuel oil and the concentrations of oil present in the muds, the toxicity of the mud samples to grass shrimp appears to be largely attributable to the petroleum hydrocarbon content.     

Assessing total atmospheric air pollution

Assessment techniques for total (integral) atmospheric air pollution are presented. An account is given of the principles forming the basis for calculating the atmospheric pollution index that has been used for nearly 30 years in assessing atmospheric air pollution in Belarus and in other CIS countries. The advisability of improving the system for integral assessment of the atmospheric air quality in Belarus is substantiated, drawing on international experience, with the purpose of enhancing its potentialities as regards a real-time monitoring of the state of urban air environment.