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Phytoremediation has proven to be a suitable method for removing heavy metals from the soil with the help of plants. To examine the phytoremediation potential, the experimental study monitored the influence of high and low concentrations of heavy metals (Pb, Cd, and Zn) on Helianthus annuus L., as well as their accumulation in seeds, roots, stems and leaves. The experiment was carried out during one growing season in outdoor conditions, in pots with a volume of 5L in which Helianthus annuus L. was planted, and the soil was contaminated with these heavy metals in concentrations below and above the maximum allowable concentration prescribed by the Rulebook on Determining Permissible Quantities of Harmful and Dangerous Substances in Soil and Methods of Their Testing. After growth and development of the plant, the experimental research examined the accumulation potential of the plant, the growth of the plant itself and its ability to survive depending on different concentrations of heavy metals. By processing the obtained results, statistically significant differences of heavy metals were determined in individual parts of the plants, depending on the applied concentration. The highest concentration of Zn was recorded in the leaves of the plant in the amount of 18.21 mg/kg, and the lowest concentration in the stem, 3.92 mg/kg. The measured values of heavy metals Cd and Pb differ from the above because the lowest concentrations of these heavy metals were recorded in the seed, and were 12.02 mg/kg for Pb and 9.20 mg/kg for Cd, which is a statistically significantly lower determined value relative to other parts of the plant.

Heavy metal pollution is a significant environmental problem and has a negative impact on human health and agriculture. Phytoremediation has recently emerged as an efficient heavy metal remediation technology. To examine the phytoremediation potential, an experiment was conducted, where the influence of high and low concentrations of heavy metals, lead, cadmium and zinc (Pb, Cd and Zn) on the phenological characteristics of corn (Zea mays), as well as their accumulation in the underground and aboveground part was monitored. The experiment was carried out in outdoor conditions in pots in which corn was planted and the soil was contaminated with heavy metals in concentrations below and above the maximum allowable concentration prescribed by the Ordinance. The experiment lasted 45 days. By processing the results, statistically significant differences in plant development were determined.The highest concentration of Zn was recorded in the aboveground part of the plant, the stem in the amount of 24.443 mg/kg, and the lowest concentration in the leaf 0.216 mg/kg. The highest concentrations of Cd and Pb were recorded in the root, for lead 26.610 mg/kg and in the stem for cadmium 30.490 mg/kg, which is a statistically significantly higher established value compared to other parts of the plant.

The accumulation of organochlorines (OCs) in mussel tissue depends on the physiological and biochemical status of the organism and its interaction with the environment. Mytilus galloprovincialis, 2- and 1-year-old mussels, sampled from Mali Ston Bay, a reference area, and transplanted to Ka&scaron, tela Bay in cages, were used for the assessment of OC levels and influence of biological parameters on accumulation. Results of bimonthly exposures during one year highlighted that OC accumulation decreases with increasing mussel age. Polychlorinated biphenyls (PCBs) and p,p&rsquo, dichlorodiphenyltrichloroethane (p,p&prime, DDTs) increased, while organochlorine pesticide (OCP, i.e., HCB, lindane, heptachlor, and aldrin) variations were very low. Statistical analysis generally did not confirm the significant effect of lipid content on the accumulation of OCs in mussel tissue. OC levels in mussels were below the maximum permitted levels for human consumption (European Commission).

Constructed wetlands, as an alternative to conventional methods, are systems designed on the basis of the application of natural purification processes that take place in watery and swampy overgrown habitats, with certain microbiological groups. In the wastewater treatment process various types of constructed wetlands can be combined to achieve a higher efficiency of the purification. In this study, the removal effectiveness of the organic substances from municipal wastewater was monitored, using a horizontal pilot - scale constructed wetland utilizing Typha latifolia and Phragmites australis. In addition to the measurement of organic substances content through COD, BOD and KMnO4 consumption, and total dissolved substances (TDS) in influent and effluent, microbiological sample analysis was performed, monitored by total number of coliform bacteria. The aim of this study was to calculate the effectiveness of removing organic substances from municipal wastewater, depending on the season, as well as the effectiveness of eliminating total coliform bacteria. The results of one-year research have shown that the removal effectiveness of the organic substances from municipal wastewater, expressed as the chemical oxygen demand (COD), was the highest in summer - 87.82% ± 2.83%, and the lowest in the winter - 64.51% ± 5.89%. During the study, effectiveness of elimination of total coliform bacteria was 97.88 ± 0.80% and total dissolved substances 71.27% .

Environmental care, higher requirements for quality of effluent, high cost of conventional wastewater treatment, and increased energy costs required for their work, have led scientists to more comprehensive research on a possibility of using a constructed wetland in wastewater treatment technology. Constructed wetlands are artifi-cially shaped swamps with the aim of creating conditions conducive to the purification of wastewaters flowing through them. They are used for treatment of municipal wastewater from small settlements and a small industrial facility, as well as other types of wastewater. The educational pilot - scale constructed wetland on which the research was conducted is located in the area of Bihać municipality, on a plot used by the Biotechnical Faculty in Bihać. The pilot - scale constructed wet-land for wastewater treatment covers an area of 20 m2 and is dimensioned for 10 equivalents of population. In this research we have examined the effectiveness of domestic wastewater treatment in the "Grmeč" Teaching Center using pilot - scale constructed wetland. Plants planted in the constructed wetland were Typha latifolia and Phragmites australis, and the sub-strate was made of sand and pebbles of different granulations. The recipient of purified wastewater is the Drob-nica stream, which is about 10 m away from the site. The research was conducted in May, with the flow varied depending on a weekly student workload. Efficiency of purification using constructed wetland depended on flow rate and organic wastewater load, ranging from 37.15% at a minimum flow of 9.89x10-6 m3/s and HPK values of 35 mgO2/L, up to 89.48% at the highest flow value of 2.51x10-5 m3/s, and HPK values of 189 mgO2/L. The highest concentration of ammonia in the influent was 145.62 mg N/L, and the lowest concentration of ammonia in the effluent was 6.31. mg N/L.

Tehnikom obogaćivanja mikrobne kulture priređene su dvije mješovite mikrobne kulture, MKN i MKK. Istražena je razgradnja otpadne vode deponija pomoću MKN provedbom procesa nitrifikacije i denitrifikacije uz organske sastojke iz otpadne vode i uz natrijev-acetat kao izvore ugljika. Istražena je razgradnja odabranog spoja koji ima ksenobiotička svojstva, 6-aminonaftalen-2-sulfonske kiseline (6AN2SK). U otpadnoj vodi deponija obitavaju mikroorganizmi koji imaju potencijal uklanjanja sastojaka s dušikom i spojeva koji su biološki teško razgradivi.

Tlo predstavlja tanki (maksimalno do 50-cm) rahli sloj smješten na površini planeta Zemlje, između litosfere i atmosfere. Nastaje izuzetno složenim i dugotrajnim djelovanjem podnebl¬ja, vegetacije i živih makro i mikro organizama na litosferu. Među brojnim procesima oštećenja tla, sve veći značaj ima onečišćenje tla. Pod tim pojmom podrazumijeva se nazočnost problematičnih tvari u tlu u količini u kojoj uzrokuje vidljiv ili mjerljiv poremećaj neke od uloga tla. Ako želimo definirati što je to onečišćeno tlo, možemo reći da je to tlo u kojemu je ljudskom djelatnošću povećan sadržaj štetnih (organskih i anorganskih) tvari kojima koncentracija može biti opasna za ljudsku aktivnost, odnosno za uzgoj biljaka ili životinja. Iz tih razloga zadnjih desetljeća sve se više govori o remedijaciji onečišćenih tala. Tehnologije sanacije/remedijacije onečišćenog tla mogu se provesti biološko, kemijskom, fizikalnom odnosno termalnom remedijacijom (Kisić, I: Sanacija onečišćenog tla – Sveučilišni udžbenik, izdavač Agronomski fakultet, 2012). Ciljevi sanaciju su: - smanjenja koncentracije ukupnog onečišćenja na prihvatljivu razinu u skladu s budućim načinom korištenja tla, - fizikalna/kemijska/biološka/mehanička izolacija onečišćenja radi sprječavanja daljnje reakcije tla s okolišem, - smanjenjem biološke dostupnosti (biopristupačnosti) organskih i anorganskih onečišćenja. Odabir navedenih tehnologija najviše ovisi o: • tipu i vrsti onečišćenja, • prostornoj zahvaćenosti onečišćenja (površini, volumenu i mjestu onečišćenja – blizina površinskih/podzemnih voda), • tipu tla (reakcija, sadržaj organske tvari, teksturi, osobito postotnom udjelu i tipu gline), • vremenskom razdoblju izlaganja potencijalnom onečišćenju, • budućem načinu korištenja tla, • definiranom zakonskom okviru pojedine države o potrebnom stupnju remedijacije. Biološke metode sanacije pripadaju u skupini okolišno prihvatljivih zelenih tehnologija sanacije tla. Kao način sanacije koriste se mikroorganizmi ili biljke. Bioremedijacija (biostimulacija ili bioaugmentacija) je proces u kome se koriste mikrorganizmi. Sanacija pomoću biljaka – fitoremedijacija može se provesti kao fitoekstrakcija, rizofiltracija, fitostabilizacija, fitovolatizacija itd. Riječ je o metodama koje se najčešće koriste in situ (na onečišćenim lokacijama) što je njihova prednost. Uprkos svim prijeporima ta metoda ima budućnost za sanaciju tala onečišćenih organskim i anorganskim onečišćenjima.