Graphic Yearbook 2015
IV.6 HEAVY METALS
IV.6.1 Air pollution caused by heavy metals in the year 2014
Lead
In 2015 the annual ambient limit value for lead (0.5 μg.m-3) was not exceeded at any of the 55 localities with sufficient data for the calculation of the valid annual average. The highest annual average was measured at the locality Ostrava-Radvanice ZÚ (Table XIII.14). With the exception of the year 2011, when the highest concentration was recorded at the locality Příbram I-nemocnice, the highest lead concentrations are repeatedly measured in the O/K/F-M agglomeration.
Long-term lead concentrations are very low in the whole territory of the Czech Republic, barely reaching half of the limit value, i.e. the lower assessment threshold of 0.25 μg.m-3 (Fig. IV.6.5). In comparison with the year 2014, lead concentrations decreased at 83 % of localities (43 of the total number of 52 stations, which measured lead concentrations in both 2014 and 2015).
Cadmium
In 2015 the annual limit value for cadmium (5 ng.m--3) was exceeded only at one locality (Tanvald-školka, 6.9 ng.m-3) out of the total number of 55 localities with a valid annual average (Table. XIII.15). The highest annual average concentrations were measured mostly at localities in the districts of Jablonec nad Nisou and Ostrava-město (Fig IV.6.1). For example, at the station Souš (Jablonec nad Nisou region), which is classified as a rural background station, long-term concentrations of cadmium are an order higher than those measured at other rural localities (Fig. IV.6.9).
In the long term, airborne cadmium concentrations are within their limit in most of the Czech Republic (Fig. IV.6.3, Fig. IV.6.6). In comparison with the year 2014, at almost 59 % of localities (29 of the total number of 49 stations which measured cadmium concentrations in both 2014 and 2015), the average annual concentrations decreased.
Arsenic
In 2015 the annual limit value of arsenic (6 ng.m-3) was not exceeded at any locality (in 2014 the highest average annual concentration, exactly equalling the limit value of 6.0 ng.m-3, was recorded at the station Kladno-Švermov) out of the total number of 55 localities with a valid annual average (Table XIII.16, Fig. IV.6.2). The limit value for arsenic was exceeded every year at least at one station since the beginning of measurements in 1986 with the exception of the year 2012, when the limit value was met at all measuring stations (Fig. IV.6.7). In comparison with the year 2014, the annual average concentration for 2015 decreased at 56 % of localities (29 out of the total number of 52 stations, which measured arsenic concentrations in both 2014 and 2015). Conversely, concentrations of arsenic increased at 31 % of localities (16 out of the total number of 52 stations that measured As concentrations in both 2014 and 2015). The districts of Kladno and Prague are exposed to the heaviest long-term loads of arsenic (Fig. IV.6.4).
Nickel
In 2015 the annual limit value for nickel (20 ng.m-3) was not exceeded at any of the 55 localities with sufficient data for the calculation of the valid annual average. The highest concentration, 2.6 ng.m-3, was measured at the locality Ostrava-Mariánské Hory (Table XIII.17). A decrease of the annual average concentration in comparison with the previous year was recorded at 62 % of localities (32 out of the total number of 52 stations which measured Ni concentrations in both 2014 and 2015). Conversely, concentrations of Ni increased at only 6 % of localities (3 out of the total number of 52 stations that measured concentrations of Ni in both 2014 and 2015). In the long term, concentrations of nickel are very low throughout the Czech republic and barely reach half of the allowed ambient limit, i.e. the 10 μg.m-3 lower assessment threshold value (Fig. IV.6.8).
IV.6.2 The development of heavy metals concentrations
Annual average concentrations of all monitored heavy metals have been slightly decreasing in the past years, except for two surges in the years 2010 and 2013 (Fig. IV.6.9). These surges are as yet not sufficiently explained, but the one in 2010 could have been caused by poor dispersion and meteorological conditions.
The area around the town of Tanvald (in the Liberec region) is characterized by a strong presence of the glass industry (ASKPCR 2014), which used to be the significant source of cadmium emissions from dying and fluxing substances, used primarily in the past (Beranová 2013).
Since 2004 the measures set by the Integrated regional programme to improve ambient air quality in the Liberec region, aimed at the reduction of cadmium emissions from glassworks, were implemented (Rada Libereckého kraje 2004). The implementation of modern technologies resulted in a marked decrease of cadmium concentrations from upgraded plants in the next few years (ATEM 2006). Despite this decrease, limit-exceeding cadmium concentrations are still being recorded.
In areas not influenced by industrial production, average annual concentrations of all heavy metals are usually higher in cities (Fig. IV.6.9). This is caused primarily by the concentration of industrial plants in cities and by higher intensity of traffic. Urban localities are also characterized by a more marked decrease of heavy metals concentrations during the evaluated period in comparison with rural localities. Since 2006–2007, when heavy metals concentrations decreased slightly at rural localities, their levels tend to be stagnating.
IV.6.3 Emissions of heavy metals
Heavy metal pollutants comprise metals with specific weights of over 4.5 g.cm-3 and their compounds. Compounds of heavy metals are a natural component of fossil fuels, and their content in these fuels varies according to the mining locality. The amount of emissions of heavy metals during the combustion of fossil fuels depends primarily on the type of fuel, the type of the combustion plant and on the combustion temperature influencing the volatility of heavy metals. Emissions of heavy metals are formed also during certain technological processes because they are contained in raw materials. Heavy metals are present in iron ore, scrap iron, glass batch or cullet, dyes, glass shards, etc. In addition, there are many sources of fugitive emissions containing heavy metals such as tyre and brake wear or emissions of heavy metals connected with old ecological burdens from mining and metallurgical activities.
Combustion processes are the main sources of especially of arsenic and nickel. One of the most important sectors on the country-wide scale is sector 1A1a-Public electricity and heat production; its share in arsenic and nickel emissions in 2014 was 54.0 % and 62.1 %, respectively (Figs. IV.6.10 and IV.6.12). This sector also contributed significantly to cadmium (34.9 %; Fig. V.6.14) and lead emissions (22.1 %; IV.6.16). The share of the sectors of iron and steel production (1A2a and 2C1) prevailed in 2014 mainly in emissions of lead (34.6 %). The influence of sector 1A4bi-Local household heating was apparent especially in emissions of arsenic (13.3 %). Emissions of heavy metals from sector 1A3bvi-Road transport: tyre and break wear, which have newly been included in the emissions inventory, are significant especially in the case of lead, where this sector contributes 16.9 % of the total emissions of this pollutant. The decreasing trend of heavy metals emissions in the period of 2007–2013 is related to the development of emissions of suspended particles (Chapter IV.1.3), to which these substances bind. This trend can in some years be influenced by changing content of heavy metals in coal or feed-stocks of technological processes. In the last years, the volume of secondary production of non-iron metals, especially aluminium and lead, is growing. Emissions of heavy metals from these sources are highly variable depending on the quality of the scrap metal being processed.
Due to the prevailing share of the sector of public electricity and heat production and the sector of iron and steel production, the spatial distribution of heavy metals emissions is given primarily by the location of the plants belonging to the above sectors. Significant emissions of arsenic and nickel are concentrated in areas with coal-burning thermal power plants and heating plants (Figs. IV.6.18 and IV.6.19). This mainly concerns enterprises operating in the Ústí nad Labem region. Large amounts of nickel are emitted into the atmosphere also in the Pardubice region from the Chvaletice power plant and in the Plzeň region from the Teplárny ELÚ III heating plant. Emissions of arsenic are emitted, besides the Ústí nad Labem region, also in the Central Bohemia region from the Mělník I power plant and in the Pardubice region from the Opatovice power plant. Emissions of lead and cadmium prevail in the O/K/F-M agglomeration due to the high concentration of plants producing iron and steel. In the Central Bohemia region, a significant amount of lead is emitted into the atmosphere by secondary lead production at the Kovohutě Příbram metallurgical plant (Fig. IV.6.20 and IV.6.21).
Fig. IV.6.1 Field of annual average concentration of cadmium
in the ambient air, 2015
Fig. IV.6.2 Field of annual average concentration of arsenic in
the ambient air, 2015
Fig. IV.6.3 Five-year average of annual average concentrations
of cadmium, 2011–2015
Fig. IV.6.4 Five-year average of annual average concentrations
of arsenic, 2011–2015
Fig. IV.6.5 Annual average concentrations of lead in the ambient
air at selected stations, 2005–2015
Fig. IV.6.6 Annual average concentrations of cadmium in the
ambient air at selected stations, 2005–2015
Fig. IV.6.7 Annual average concentrations of arsenic in the
ambient air at selected stations, 2005–2015
Fig. IV.6.8 Annual average concentrations of nickel in the
ambient air at selected stations, 2005–2015
Fig. IV.6.9 Trends of heavy metals annual characteristics in the
Czech Republic, 2006–2015
Fig. IV.6.10 Total emissions of arsenic sorted out by NFR
sectors, 2014
Fig. IV.6.11 The development of arsenic total emissions,
2007–2014
Fig. IV.6.12 Total emissions of nickel sorted out by NFR sectors,
2014
Fig. IV.6.13 The development of nickel total emissions,
2007–2014
Fig. IV.6.14 Total emissions of cadmium sorted out by NFR
sectors, 2014
Fig. IV.6.15 The development of cadmium total emissions,
2007–2014
Fig. IV.6.16 Total emissions of lead sorted out by NFR sectors,
2014
Fig. IV.6.17 The development of lead total emissions, 2007–2014
Fig. IV.6.18 Arsenic emission density from 5x5 km squares, 2014
Fig. IV.6.19 Nickel emission density from 5x5 km squares, 2014
Fig. IV.6.20 Cadmium emission density from 5x5 km squares, 2014
Fig. IV.6.21 Lead emission density from 5x5 km squares, 2014
