In polar regions, apart from tundra and glaciers, geothermally active areas

with elevated temperatures are important elements of ecosystems. One such geothermally

active region characterized by mosaic ecosystems and vast areas covered by recent lava

fields is Iceland. The aim of our study was to explore the diversity of invertebrates

inhabiting geothermally active lava fields in the Krafla area (Iceland). Eight bryophyte

samples were collected from a warm surface, mainly from the steaming areas. We have

found Nematoda, Rotifera, Tardigrada and Oribatida in the samples. Habitat analysis

demonstrated there to be 12 bryophyte species (five liverworts and seven mosses).

The diversity of bryophytes in a single sample ranged from one to six species. The

most common bryophyte was Racomitrium lanuginosum (Hedw.) Brid. Four species

of tardigrades were found, including one that was new. Pilatobius islandicus sp. nov.

is described herein by morphological, morphometric and molecular approaches (COI,

28S rRNA, 18S rRNA). Oribatida mites were identified as two species (Malaconothrus

monodactylus (Michael, 1888) and Camisia foveolata Hammer, 1955). The average density

of invertebrates was 13.1 ind./g with a maximum of 40.8 ind./g calculated per dry

material. The tardigrades found in our study belonged to herbivores, microbivores and

omnivores, whereas the mites belonged to saprophages, which indicates complex trophic

networks in geothermally active lava fields.

This paper presents the concentrations of the polycyclic aromatic hydrocarbons (PAH) and heavy metals in leachates from the autothermal thermophilic aerobic digestion (ATAD). The leachates from ATAD installations (Dąbrowa Białostocka, Hajnówka, Pisz, Olecko, Giżycko, Wysokie Mazowieckie) located in Poland were tested. The concentrations of PAHs in samples from Pisz, Giżycko, Wysokie Mazowieckie and Hajnówka were similar to those in industrial wastewater. The cluster analysis confirmed that in sites with a higher polyethylene (p.e.) input from the industrial sector, the leachates were more contaminated with PAH compounds. In samples from Dąbrowa Białostocka, Olecko, Pisz and Hajnówka, the heavy fraction of PAHs compounds prevailed over the light fraction. Concentrations of heavy metals in leachates from ATAD varied. The Ward’s method isolated the wastewater treatment plant in Giżycko. The p.e. from the industrial sector was the highest for this facility. Also, the samples from ATAD had the highest total concentration of heavy metals (5.87 mg/l). The leachates from ATAD are returned to biological systems of municipal sewage treatment plants, where they can be combined into more toxic compounds. Biological wastewater treatment processes do not ensure the removal of PAHs and heavy metals from the wastewater. As a result, harmful compounds can get into the water or ground, polluting the environment.