Spatio-temporal monitoring of mercury and other stable metal(loid)s and radionuclides in a Croatian terrestrial ecosystem around a natural gas treatment plant.

The natural gas industry bears a certain contamination risk to human and biota due to, among others, mercury, arsenic, and naturally occurring radioactive material content in gas. We tracked multiple stabile metal(loid)s and radionuclides within the natural gas treatment plant Molve, Croatia, ecosystem during the last decade through a comprehensive monitoring of soil, earthworms, moss, livestock (blood, milk, hair, urine, and feces from cows), and wildlife animals (brain, muscle, liver, and kidney of European hare and pheasant). The level of mercury and other stable metal(loid)s has shown temporal variation, but without an obvious trend. The found spatial differences in soil and earthworms were based on the differing soil characteristics of the sampled locations and exceeded the maximal allowable concentration of arsenic and zinc for agricultural soil. The status of essential copper, selenium, and zinc in cows, hares, and pheasants inclined towards deficiency. The measured stable metal(loid) levels in soil and animal samples were generally in the same range of values reported in earlier decades from the same area or non-polluted areas across Europe. The consumption of local cow and game products (e.g., milk, meat) can be considered safe for human health, although game offal is advised to be avoided as a food item due to the low risk of lead and cadmium's adverse effects. Although the activity concentrations of some radionuclides in moss were higher than reported for pristine areas, transfer from soil to moss was assessed as average (except for lead-210). Radiological risk to human and biota around the gas treatment plant Molve was estimated as negligible.

Temporal impacts of pile burning on vegetation regrowth and soil properties in a Mediterranean environment (Croatia).

Burning slash piles is common in the Mediterranean regions to manage the unwanted biomass. This work aims to study the effect of two experimental pile burns ((moderate (MS) and high severity (HS)) conducted in Croatia on vegetation and soil compared to an unburned treatment (UB). We studied vegetation cover (VC), soil water repellency (SWR), mean weight diameter (MWD), water-stable aggregates (WSA), pH, electrical conductivity (EC), soil organic matter (SOM), the total content of calcium (Ca), aluminium (Al), silicon (Si), and iron (Fe), available phosphorus (P2O5) and potassium (K2O). The impacts of the burn were studied 5 days after burning (DAB), 3, 8, 12, and 15 months after burn (MAB). The results showed that VC was significantly higher in UB than in MS 5 DAB-15MAB. SWR was significantly higher in the smallest soil fractions (<0.25 mm) in burn treatments than in the UB on 5 DAB and 3 MAB. Also, 3 MAB, MWD and WSA were significantly lower in the burned treatments than in UB. pH was significantly higher in HS than in UB 3, 12 and 15 MAB, while EC was significantly higher in HS than in UB, 5 DAB, 3 and 15 MAB. MS and HS did not significantly affect SOM content. Total Ca was significantly higher in burn treatments than in UB 5 DAB-12 MAB. Total Al and Si were significantly higher in UB than in HS (5 DAB-15MAB), while total Fe was significantly higher in UB than in HS 5 DAB, and 8-15 MAB. P2O5 was significantly higher in HS than in UB from 3 to 15 MAB, while K2O was significantly higher in MS and HS than in UB 5 DAB. Soils need more time to recover from pile burning disturbance, likely due to the soil poor natural conditions, therefore this type of management is detrimental.