Evaluation of Water Resources in Dalmatia for Human Health

Abstract

The purpose of this study was to monitor and evaluate the specific characteristics and properties of the most important water resources in Dalmatia, located in Southern Croatia, for a period of five years (1999–2003). The paper presents a detailed account of the water's chemical content, classification and concentration of salts. The bacteriological pollution levels are indicated by the total coliform bacterial levels (MPN coli/100 ml). The water characteristics are expressed by coefficients which represent the ratios between water ingredients. The Ca/Mg eq ratio, SO₄/Cl eq ratio and K₁, K₂ for bicarbonate hardness were calculated. The hygienic characteristics of the water samples were expressed by the total coliform bacteria estimation (MPN coli/100 ml), the permanganate consumption (KMnO₄) and biological oxygen demand (BOD₅). Karst waters, i.e. rain waters, in Dalmatia are moderately hard, the SO₄/Cl ratio is 0.38-1.6, non corrosive (K₁ lower than 0.2) and not significantly mineralised (<500 mg/L minerals). Sulfate waters are generally hard, the SO₄/Cl ratio is higher than 1.6, K₁ is 0.2-0.65. Marine waters are quite hard or hard, particularly at the river estuaries, the SO₄/Cl ratio is lower than 0.38, and K₁ is higher than 0.65. Rain water direction equation, marine direction equation and sulfate direction equation are calculated on the base of SO₄/Cl ratio. The groundwater and springs in Dalmatia are less polluted than surface waters. A majority of the water observed, 24 of 42 locations, have geometric average values of MPN coli<150/100 ml of water. This group includes the majority of springs in Dalmatia, as well as some sections of rivers studied. The highest bacteriological pollution was found at nine locations where MPN coli>1000/100 ml. Moderate pollution was found at nine locations where MPN coli is between 150–1000/100 ml of water. The water in Dalmatia is quite safe and mainly preserves its natural properties.

Keywords:

• spring waters
• groundwater
• surface waters
• water quality
• water classification
• rainwater
• marine water
• sulfate water
• Dalmatia