Kazimierz Grabas

Assessment of toxicity using dehydrogenases activity and mathematical modeling.

Dehydrogenase activity is frequently used to assess the general condition of microorganisms in soil and activated sludge. Many studies have investigated the inhibition of dehydrogenase activity by various compounds, including heavy metal ions. However, the time after which the measurements are carried out is often chosen arbitrarily. Thus, it can be difficult to estimate how the toxic effects of compounds vary during the reaction and when the maximum of the effect would be reached. Hence, the aim of this study was to create simple and useful mathematical model describing changes in dehydrogenase activity during exposure to substances that inactivate enzymes. Our model is based on the Lagergrens pseudo-first-order equation, the rate of chemical reactions, enzyme activity, and inactivation and was created to describe short-term changes in dehydrogenase activity. The main assumption of our model is that toxic substances cause irreversible inactivation of enzyme units. The model is able to predict the maximum direct toxic effect (MDTE) and the time to reach this maximum (TMDTE). In order to validate our model, we present two examples: inactivation of dehydrogenase in microorganisms in soil and activated sludge. The model was applied successfully for cadmium and copper ions. Our results indicate that the predicted MDTE and TMDTE are more appropriate than EC50 and IC50 for toxicity assessments, except for long exposure times.

Chemical elimination of the harmful properties of asbestos from military facilities

This work presents research on the neutralization of asbestos banned from military use and its conversion to usable products. The studies showed that asbestos can be decomposed by the use of phosphoric acid. The process proved very effective when the phosphoric acid concentration was 30%, the temperature was 90°C and the reaction time 60min. Contrary to the common asbestos treatment method that consists of landfilling, the proposed process ensures elimination of the harmful properties of this waste material and its transformation into inert substances. The obtained products include calcium phosphate, magnesium phosphate and silica. Chemical, microscopic and X-ray analyses proved that the products are free of harmful fibers and can be, in particular, utilized for fertilizers production. The obtained results may contribute to development of an asbestos utilization technique that fits well into the European waste policy, regulated by the EU waste management law.

Impact of military metallurgical plant wastes on the population's health risk.

This paper presents the results of water, soil and air analyses taken in the vicinity of a former ferrochromium metallurgical plant. In the past, the area was used for the disposal of waste materials containing smelter slag, dust and other waste products from the manufacture of ferrochromium alloys for the army. Recently, production was abandoned and a project aimed at the liquidation of the dump has been initiated. The project concentrates on the recovery of chromium remains and the utilization of the leftover material as a road construction aggregate. Based on the analyses of ground water, soil and air, a health risk caused by environmental pollution with chromium, especially with Cr(VI), was determined for residential and occupational scenarios. It was found that the level of chromium emissions to the environment constitutes a potential danger of toxic and carcinogenic cases in humans exposed to the emission in the affected area. An increased level in the hazard quotient has been observed in the case of occupational activities. As far as the mutagenic effects are concerned, the occupational inhalation exposure was found to be very high, which may raise extreme concern about carcinogenic risk.

Mitigation of the Environmental Health Risk on Military Air Bases Polluted with Hydrocarbons

AbstractThis paper presents the environmental and health threats caused by petroleum products as well as the results of remediation work on five air bases where biological cleaning methods developed by the authors were implemented. The aviation fuel leakages endangered the health of people and surface water streams at the sites as well as in distant locations. The aim of the research was to verify remediation techniques developed in laboratory tests. The initial concentration of total petroleum products in the soils reached 2,320–8,770  mg/kg of dry matter, which presented an extremely high risk to the population and the environment. The autochthonous bacterial strains, which included Pseudomonas fluorescens, Acinetobacter calcoaceticus, Pseudomonas putida I, and Pseudomonas putida II, were proven to be very effective in degrading the xenobiotics. The applied microorganisms in conjunction with the authors’ remediation techniques produced very successful results. In the technical ex situ and in situ tests,...

Biological Characteristics of “Wartowice” Post-Flotation Tailings Pond (Lower Silesia, Poland)

Abstract “Wartowice” tailings pond was closed in 1989, resulting in 232,4 ha tailings pile requiring reclamation. The major problem is heavy metals presence and poor nutrient conditions and physicochemical structure of soil which disturbs the plants development. In order to assess the real condition of studied area the complete biological characteristic has been done. The physicochemical conditions were assessed altogether with phytosociological, microbiological and toxicological studies of deposits. We recorded only 27 species of vascular plants belonging to 15 families on the tailings pond of which 5 belong to Rosaceae, 4 to Asteraceae and 3 to Poaceae and Saliceae. Species inhabiting the tailings depended on their dispersal capacity, metal tolerance and rhizome strategy. Microbiological analyses revealed the low number of bacteria and fungi on the tailings pond, apart from the small uplift area where the plants were indentified. Bacteria identified on the tailings pond were classified to 8 genera. The low number of bacteria suggests the lack of nutrients which affects the development of soil microflora. Toxicity tests showed that post-flotation sludge is not toxic to microorganisms because of its high pH. Some plants, such as lucerne could even influence positively the microorganisms development what has been proved in our studies. The tailings toxicity was higher towards producers, where Secale cereale appeared to be the most sensitive species. Amendment with topsoil from adjacent areas can influence positively the phytotoxic properties of tailings and enrich them into native seeds. Streszczenie Osadnik po fl otacji miedzi „Wartowice” został zamknięty w 1989 roku, co skutkowało pozostawieniem 232,4 hektarów osadów, które wciąż wymagają rekultywacji. Podstawowy problem stanowią: niedobór substancji odżywczych, obecność metali ciężkich oraz fi zyczno-chemiczna struktura gleby, który zaburza rozwój roślin. Aby dokonać oceny czynników wpływających na rozwój organizmów żywych przeprowadzono kompleksową biologiczną charakterystykę terenu badań. Badania objęły fi zyczno-chemiczne analizy, badania fi tosocjologiczne, mikrobiologiczne i toksykologiczne. Na obszarze badań zarejestrowano tylko 27 gatunków roślin naczyniowych (obszar niewielkiego wzniesienia) należących do 15 rodzin, 5 z nich należało do rodziny Rosaceae, 4 do Asteraceae i po 3 do Poaceae i Saliceae. Obecność gatunków zależała od ich potencjału kolonizacji, tolerancji na metale oraz morfologii (strategia kłącza). Analizy mikrobiologiczne wykazały niską liczbę bakterii i grzybów na obszarze osadnika za wyjątkiem małej wysepki (wzniesienie) gdzie wcześniej stwierdzono obecność roślin. Bakterie obecne na obszarze badań zostały zaklasyfi kowane do 8 rodzajów. Niska liczba bakterii sugeruje brak substancji odżywczych, który z kolei upośledza rozwój mikrofl ory glebowej. Badania toksykologiczne wykazały niską toksyczność osadu w stosunku do mikroorganizmów, co wynika z jego zasadowego pH. Pewne gatunki, jak na przykład lucerna, mogą wpływać korzystnie na rozwój mikroorganizmów glebowych, co zademonstrowano w prezentowanych badaniach. Toksyczność odpadów po fl otacji miedzi była wyższa w stosunku do producentów. Żyto zwyczajne (Secale cereale) okazało się być najwrażliwszym gatunkiem. Zastosowanie wierzchniej warstwy gleby z obszarów przyległych mogłoby znacznie obniżyć fi totoksyczne własności odpadów i jednocześnie wzbogacić je w rodzime nasiona, które dałyby początek roślinom odpornym na niekorzystne warunki siedliskowe.

Effect of Surfactants on the Biodegradation of Petroleum Hydrocarbons

This paper focuses on the influence of Rokafenol N9-surfactant on the degree of biodegradation of diesel oil fraction (295–310°C). The diesel oil was a product of atmospheric distillation of Russian crude oil from the “Ural” oil field. It contained hydrocarbons characteristically hardly susceptible to biodegradation and of high toxicity. Bioindication tests carried out by the Ames test showed that it contained compounds of potential mutagenic and carcinogenic properties. The effectiveness of the diesel oil biodegradation was analyzed both for the individual native strain and their consortium. Biodegradation of diesel oil was most effective in the culture of bacteria mixture. It was confirmed that introducing a 0.5g/dm3 concentration of the surfactant Rokafenol N9 increased the effectiveness of biodegradation from 36 to 81 %mas.