This paper elaborates soil, water, and lettuce contamination status with respect to selenium, sulphur, trace metals, and BTEX (benzene, toluene, ethylbenzene, and xylenes) in a coal-based area (Raša Bay, Adriatic Sea, Croatia). A local coal-fired power plant polluted soil with S, Se, Cd, and PAHs due to the combustion of domestic superhigh-organic-sulphur coal. The locality is dotted with waste from coal mining/separation, coal combustion, former metal factories, untreated municipal and coal mine effluents, along with various harbour activities, which contribute to environmental contamination. The methodology involved ICP-MS and GC-MS for the measurement of trace elements and BTEX, respectively, while soil sulphur was determined with Eschka’s mixture. The max values of the analysed trace elements in soil (mg/kg) are reported: Hg 1.14, Cd 3.29, V 624, Se 10.3, Pb 872, Cr 1860, Zn 6580, Cu 1850, and U 25.2. According to ecological indices, these values fall into the category of an extremely high level of soil pollution. Elevated total Se values in surface water are ascribed to leaching of seleniferous coal, ash, and coal-polluted soil. Levels of BTEX in water samples were very low (0–0.83 µg/L). The data provide basic information on the inorganic and organic contamination status of the Raša Bay area.

The Istrian coal mines, located in the eastern part of the Istrian Peninsula (Northern Adriatic Sea, Croatia) had by far the most important and economically the most valuable deposits of the anthracite coal reserves in Croatia since the 18th century until the year 1999, when their excavation and use in the coal-fired power plant Plomin ceased. The coal is found within the Palaeocene Kozina limestone beds. Four coal basins, Karojba, Sveti Martin, Pićan, and the Labin basin, hosted seven coal mines, e.g. Tupljak, Potpićan, Kozljak, Štrmac, Raša, Ripenda, and Krapan. The coal has been generally known under the name of Raša coal. It is exceptional in world terms due to its high content of organic sulphur, which can be up to 14%. Herewithin, this paper reviews Croatian scientific publications devoted to various aspects of Raša coal, along with the most important publications on either similar coals or relevant subjects worldwide. A brief introduction deals with the role of coal in electricity production, and the history of coal mining in Istria. The following chapter summarises current knowledge of the coal sulphur geochemistry, with several examples of high-sulphur coals from India and China. It is followed by the geological, geochemical, and physical characterisation of Raša coal. Since perturbations to ecosystems caused by coal combustion have been documented in numerous papers from a number of countries, Croatian studies carried out to determine the impact of Raša coal combustion on the local environment are also presented.

Coal mining and coal combustion release environmental contaminants which stay at emission sites for many decades. This paper reports total Se and other potentially toxic elements (As, Cd, Cu, Cr, Hg, Pb, Sr, U, V, and Zn) in lettuce, potato, and tissues (liver, kidney, heart, and muscle) of three non-migratory bird species (pigeon, jay, and black coot) from the Raša Bay area (North Adriatic, Croatia). They have presumably been exposed to elevated levels of the mentioned elements in garden soil, surface water, and aquatic sediment contaminated with superhigh-organic-sulphur (SHOS) Raša coal, highly enriched in S, Se, V, and U. Results point at selenium contamination of stream water (up to 78 g/L total Se in a non-ltered sample), which is well above the Croatian regulatory threshold of 10 g/L total Se. The stream drains a site of the former coal-separation unit, and an associated bottom sediment contains up to 10.8 mg/kg total Se, which is also above the safe level of 0.60 mg/kg total Se. Moreover, values of Mo, U, V, and Sr, elements commonly elevated in SHOS coal varieties, were also increased in the majority of water samples as well as in analysed vegetables, soil, and aquatic sediments. Although Cu, Zn, Pb, and V were slightly increased in liver samples of birds, more in black coot than the other two birds, selenium values were found to be adequate for their normal growth. The fact that Se can be environmentally hazardous and toxic to life, even in small doses, warrants further research on this topic.

Raša coal, mined on the Istrian Peninsula (NW Croatia) for nearly 400 years up to 1999, is notable for having superhigh organic sulfur, and high levels of selenium, uranium, vanadium, and molybdenum. Selenium is the poison responsible for the widespread loss of cattle and sheep. It is essential to human health in trace amounts, but higher concentrations can be harmful. An estimated 4.4Mt. of coal remains underground within marine carbonate rocks. The study area belongs to the coastal karst of the Adriatic Sea. Several abandoned coal-mine discharges (CMDs) were released into local streams and the Raša Bay for decades. Therefore, the water quality of a natural karst spring (Fonte Gaja), the Raša Bay seawater, municipal wastewater, and the Raša CMDs were investigated, focusing on sulfur, selected metal(loid)s (major, minor, and trace), radioactivity, and cytotoxicity. The Fonte Gaja spring water, unrelated to the Raša CMD, served as a reference. Its values of Se, U, V, and Mo (µg/L) were as follows: 1.09, 0.75, 1.37, and 2.04, respectively. However, the respective levels (µg/L) were increased in the rest of the water samples as follows: 10.9, 10.8, 4.60, and 33.1. Water sulfate levels were low though. Total beta activities of the CMDs and Raša Bay water were 235 and 1320 Bq/m 3 , respectively, below the guideline level of 2000 Bq/m 3 . The cytotoxicity of water samples on the RTG-2 fish cells was not statistically significant. The large volumes of water involved mean the transport of rather large amounts of Se and U, and their deposition in the Adriatic Sea. Due to the complexity of the karst hydrogeology, knowledge of Se and U circulation patterns is highly needed.