Natural attenuation potential of selected hydrokarst systems in the Carpathian Mountains (Romania)

Abstract

We examined the potential for natural attenuation of ten hydrokarst systems (HKS) in three mountain units in the Carpathian Mountains. We sampled in places where water enters below ground and where water emerges back to the surface in springs and is used as drinking water by the local communities. Water samples were used to assess the degree of chemical and microbiological pollution. Although the water in the ten HKS was rather clean, a general decrease in the concentration of most chemical compounds was observed along the flow path, regardless of the number of tributaries the underground stream receives. Dilution caused by tributaries could not account for the decrease in the concentration of most compounds. The contribution of other chemical immobilization processes, such as retention of pollution in the subsurface or sorption to sediment particles was suggested, in combination with the activity of microorganisms. The bacteria diversity is complex and decreases from upstream to downstream locations due to dilution with water provided by tributaries or retention of bacteria in the subsurface by adhesion to substrates. We suggest that karst can have a significant potential for natural attenuation by retaining the pollution underground, in combination with biodegradation performed by microorganisms.

Water Quality Survey of Streams from Retezat Mountains (Romania)

“…311 from June 28, 2004" (Romanian Government 2004) are given in Table 3 for comparison with the analyzed samples. As can be seen, except for a somewhat increased iron content in sample 1 (probably due to the humus-iron-illuvial podzols, which are present in the area), the studied streams are within the limits specified for drinking water (Brad et al, 2015) by all specified standards. The metal contents are generally low and there is no observable trend downstream on any of the elements.…”

Bacterial isolation and genome analysis of a novel Klebsiella quasipneumoniae phage in southwest China’s karst area

“…and Salmonella spp ., as well as Pseudomonas aeruginosa were distributed in karst ecosystem [ 12 ]. Conditional pathogenic bacteria in karst water system, such as Bacteroides and Aureobacterium , were found and the detection rate is different from the upstream and downstream of karst river [ 13 ]. Due to the spatial difference and hydrological complexity of karst systems, the understanding of microbes in karst systems is still limited.…”