Exploitation of lignite within the area of Muskau Arch, carried out from the mid-nineteenth century, contributed to the transformation of the natural environment and changes in water regime. In the post-mining subsidences pit lakes were formed. The chemical composition of waters is a consequence of the intensive weathering of pyrite (FeS2), which is present in Miocene lignite-bearing rock forming the embankments of the lakes. This process leads to the formation of Acid Mine Drainage (AMD) and finally acidification of lake waters.

This paper presents results of the identification of hydrogeochemical processes affecting the chemistry of waters from these reservoirs carried out using the speciation and statistical (cluster and factor) analyses. Cluster analysis allowed to separate from the analyzed group of anthropogenic reservoirs 7 subgroups characterized by a similar chemical composition of waters. The major processes affecting the chemistry of waters were identified and interpreted with help of factor and speciation analysis of two major parameters (iron and sulfur).

The study was carried out in Polish goat population to estimate the prevalence of the nasal cavity infection with various staphylococcal species including methicillin-resistant Staphylococcus aureus (MRSA), investigate the potential permissive role of small ruminant lentivirus (SRLV) infection and determine the level of clonality of S. aureus nasal isolates. Nasal swabs and blood samples were collected from 1300 clinically healthy adult goats from 21 Polish goat herds. Blood samples were serologically screened for SRLV. Staphylococci were isolated from nasal swabs and identified using classical microbiological methods, MALDI-TOF, multiplex-PCR, and their clonality was assessed using PFGE. Antimicrobial resistance was determined on the basis of minimum inhibitory concentration and by demonstration of the presence of the mecA gene encoding the multiplex-PCR PBP2a protein and of the five main types of staphylococcal cassette chromosome mec. The apparent prevalence of staphylococcal and S. aureus infection of the nasal cavity was 29.1% (CI 95%: 26.9%, 31.5%) and 7.3% (CI 95%: 6.1%, 8.8%), respectively. No relationship was found between the SRLV-infection and the presence of any staphylococcal species including S. aureus (p=0.143). Only 9.8% of S. aureus isolates were resistant to amoxicillin/clavulanic acid and 5.9% to chloramphenicol and ciprofloxacin. All tested isolates proved to be phenotypically and genotypically sensitive to methicillin, which yielded the apparent prevalence of MRSA of 0% (CI 95%: 0%, 7.0%). S. aureus isolates show high genetic similarity within goat herds, however vary considerably between herds. Goats do not appear to be an important source of S. aureus for humans in Poland.