Maps from mapy.mk.cvut.cz/index_e.html, thumbnail pseudo mosaic prepared here. Click to enlarge.
Pollution spills at Baia Mare travel along the Sasar, Lapus, Somes, Tisza, and Danube before reaching the Black Sea. A map extending farther west than the above would show that Ukraine is the second country after Hungary that a Baia Mare spill reaches. Pollution spills at Baia Borsa travel along the Cisla, Viseu, Tisza, and Danube before reaching the Black Sea.
The map above shows how Ukraine is the first country that a Baia Borsa spill reaches. Thus, spills from both Baia Mare and Baia Borsa impact Ukraine both at the beginning and at the Danube Delta end of their circuitous, counter-clockwise journey through Central Europe to the Black Sea.
