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HEAVY METALS IN DUST EMISSIONS FROM CIVIL ENGINEERING AND METALLURGIC ENTERPRISES: EXPERIENCE IN QUALITATIVE AND QUANTITATIVE DETERMINATION

May Irina, S. Yu. Zagorodnov

Abstract

Technological processes that are applied at civil engineering and metallurgic enterprises involve intense emissions of solid particles into ambient air. Adverse impacts exerted by particulate matter on human health have been confirmed by multiple research works, both domestic and foreign ones. At the same time, an extent to which technogenic dust emissions are hazardous is determined by contents of various chemical components in them including heavy metals. The research goal was to quantitatively and qualitatively analyze heavy metals contents in dust emissions from civil engineering and metallurgic enterprises in order to correctly and adequately assess an existing ecological situation and population health risks. Metallurgic and civil engineering enterprises were selected as research objects. Priority sources of dust emissions that were typical for such production were established during the research. Dusts concentrations in samples were determined via gravimetry and with a laser analyzer. Particles morphology and component structures were determined via electronic microscopy performed with S3400N HITACHI high performance scanning electronic microscope (magnification from x5 to x300000) with an x-ray fluorescent device. Chemical structure was identified via X-ray diffraction phase analysis performed on samples with XRD-700 Shimadzu X-ray diffractometer. Dust and gas emissions from different technological processes were examined; it allowed revealing that the components structure of emissions was quite stable with high heavy metals contents in them. Thus, emissions from electrical steel furnaces installed at a metallurgic enterprise contained a high fraction of iron trioxide (up to 63.1±5.290%) together with persistent contents of silicon oxide (15.1±3.66%), magnesium oxide (4.35±0.98%), aluminum and manganese oxides (3.72±0.88% and 3.33±0.89% accordingly). Other admixtures occurred in smaller quantities with their fractions being lower than 2.0±0.7%. Basic components in solid emissions remained the same as well as their average mass ratio. Vanadium iron smelting is accompanied with iron trioxide emissions (up to 65.73 ±5.36%) and vanadium oxide ones (up to 15.23 ±3.25%) etc. The research results revealed there was a discrepancy between inventory lists of standardized chemicals and actual structure of emissions; the existing procedures for emission assessments concentrate only on overall metallic dusts without any adjustments as per specific chemicals. Specified data on components structure of dust emissions from enterprises allow reliable estimation of contribution made by a specific enterprise into ambient air contamination on an adjourning territory and assessment of health risks for exposed population. As per research results the examined enterprises were recommended to adjust their programs for industrial control.

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