Sulfur, Metal(loid)s, Radioactivity, and Cytotoxicity in Abandoned Karstic Raša Coal-Mine Discharges (The North Adriatic Sea)

Abstract

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.

Scaling in a Geothermal Heat Exchanger at Soultz-Sous-Forêts (Upper Rhine Graben, France): A XRD and SEM-EDS Characterization of Sulfide Precipitates

“…Galena is studied in ore deposits for scientific and economical purposes [38][39][40], and because of its toxicity in mining environments [41][42][43]. Galena is also well known in the industry, in particular for its semi-conductor properties and is thus thoroughly studied [44][45][46].…”

Soil pollution of the Labin city area with polycyclic aromatic hydrocarbons derived from Raša coal mining and associated industries

“…In Croatia, the surrounding area of the Labin and Raša towns, renowned for its stunning karstic coastline, attracts hundreds of thousands of visitors and tourists per year (see Figure 1). Beyond a narrow scientific community, local residents are far less aware of the scale of the pollution of their immediate environment (Medunić et al, 2020a(Medunić et al, , b, 2021. Istrian coal mines are located in the Labin region, in the eastern part of Istria, more precisely the area between the river Raša, Čepićko polje, Plomin Bay, the southern part of the Učka massif and the Kvarner Bay (Matijašić, 2005).…”

Potentially Toxic Elements in Water, Sediments and Fish from the Karstic River (Raša River, Croatia) Located in the Former Coal-Mining Area

“…Istria, the largest Croatian peninsula, known for the unique beauty of both its shoreline and hinterland, natural attractions [ 1 ], diversity of habitats and great plant and animal biodiversity [ 2 , 3 ], attracts over 20 million tourists and visitors every year [ 4 ]. Although Istria’s landscape is usually perceived as pristine, with clean and unspoiled nature, until recently the entire region had been subjected to ecological changes [ 5 , 6 , 7 , 8 , 9 ] driven by centuries-long coal mining and utilization [ 10 ]. In the Labin basin, which was the most important and biggest coal mining district in Istria, approximately 40 million tons of coal had been excavated by 1999, when coal mining and coal combustion activities ceased.…”

“…Considering the history of coal mining in Istria, the anthropogenic impact on the eastern part of the Raša River drainage area, encompassing five mining towns (Labin, Štrmac, Vinež, Krapan, Raša), the Krapan valley, the Krapan brook, the estuary (i.e., the lowest course of the Raša River) and Raša Bay, has been extensively studied addressing a range of contamination issues resulting from former mining activities. Several of these studies have investigated the occurrence and distribution of potentially toxic elements in natural spring waters, seawater, wastewater and coal-mine discharge [ 7 , 8 ], contaminated soils [ 8 , 13 ], vegetables [ 8 , 13 ], birds [ 13 ], wild boar [ 9 ], contaminated aquatic [ 13 , 14 ] and marine sediment [ 9 ], marine fish [ 9 ] and marine mussels [ 9 ]. Some also investigated the presence of volatile organic compounds (BTEX) in water samples [ 8 ] and polycyclic aromatic hydrocarbons (PAHs) in the soil [ 6 ] or evaluated potential radioactivity and cytotoxicity in abandoned coal mine discharge [ 7 ].…”

“…Several of these studies have investigated the occurrence and distribution of potentially toxic elements in natural spring waters, seawater, wastewater and coal-mine discharge [ 7 , 8 ], contaminated soils [ 8 , 13 ], vegetables [ 8 , 13 ], birds [ 13 ], wild boar [ 9 ], contaminated aquatic [ 13 , 14 ] and marine sediment [ 9 ], marine fish [ 9 ] and marine mussels [ 9 ]. Some also investigated the presence of volatile organic compounds (BTEX) in water samples [ 8 ] and polycyclic aromatic hydrocarbons (PAHs) in the soil [ 6 ] or evaluated potential radioactivity and cytotoxicity in abandoned coal mine discharge [ 7 ]. However, except for the pioneering work of Frančišković-Bilinski et al [ 15 ], the impact of former long-term mining activities and potential impact of two thermal power plants (TPP Vlaška and TPP Plomin) on the western part of the Raša River drainage area, encompassing the upper and central course of the Raša River before confluence with the Krapan brook, has never been systematically investigated.…”