In 1979- 1981 at the King George Island samples of adipose tissue of 5 pinniped species (L. carcinophagus, L. weddelli, H. leptonyx, M. leonina and A. gazella) were collected and the contents of chlorinated hydrocarbons (CHs) were determined with the gas chromatography method. The highest values were recorded in the leopard seal (432.3 -614.7 ppb DDT), the second highest values in the mature elephant seal (73.4 ppb DDT) and the third in the Weddell seal (54.4 — 69.1 ppb DDT). In the Weddell seal the highest level of HCH content (23.3 — 32.1 ppb) was recorded. A decrease in the content of pp'DDE in the adipose tissue of crabeater seal in successive years was recorded, the values being 36.8 ppb in 1979, 24.4 ppb in 1980 and 15.3 ppb in 1981, as well as an increase in the concentration of HCH (15.3 ppb in 1980 and 27.4 ppb in 1981). The contents of CHs in the adipose tissue of Antarctic pinnipeds are 100—1000 times lower than those in the Arctic seals.

The objective of the paper is to use life cycle assessment to compare environmental impact of different technologies used in the process of water disinfection. Two scenarios are developed for water disinfection life cycle at ZUW Raba water treatment plant: (1) historical, in which gaseous chlorine is used as a disinfectant and (2) actual, in which UV radiation and electrolytically generated sodium hypochlorite are used for that purpose. Primary data is supplemented with ecoinvent 3 database records. Environmental impact is assessed by IMPACT2002+ method and its midpoint and endpoint indicators that are calculated with the use of SimaPro 8.4 software. The focus of the assessment is on selected life cycle phases: disinfection process itself and the water distribution process that follows. The assessment uses the data on flows and emissions streams as observed in the Raba plant. As the results of primal analysis show, a change of disinfectant results in quantitative changes in THMs and free chlorine in water supplied to the water supply network. The results of analysis confirm the higher potential of THMs formation and higher environmental impact of the combined method of UV/NaClO disinfection in distribution phase and in whole life cycle, mainly due to the increase of human toxicity factors. However, during the disinfection phase, gaseous chlorine use is more harmful for environment. But the final conclusion states that water quality indicators are not significant in the context of LCA, while both disinfection and distribution phases are concerned.

Water supply of Riga City uses water from the river Daugava, lakes Baltezers as well as deep well groundwater as drinking water. Due to chlorination of drinking water before use, inhabitants health may be at risk due to trihalornethanes and some organic pollutants. The objective of this study was to determine the level of pollution of drinking water and possible health risk. Pollutants were determined with previous solid phase microextraction (on fibre coated with polidirnethylsilox ane) or pentane extraction of chemical substances by use of gas chromatography and for benzo(a)pyrene by spectrofluorimetry The summary concentration of thrihalornethanes (bromoform, chloroform, bromodichlorornethane, dibromochloromethane) ranged from 3.4 ug/drn' to 304.4 etg/dm3 (maximum allowable concentration - MAC 100 μg/dm-' according to water standards in Latvia), summary lrichloroethene and tetrachloroethene occurred in the concentration from I .O ug/drn' to 13.4 ug/dm' (MAC = I O ug/drri') The level of aromatic hydrocarbons benzene and toluene was below 0.2 ug/drrr' (MAC = I μg/dm'). The concentration of benzo(a)pyrenc was below 0.002 ug/drrr' (MAC= O.Ol ug/drrr'). Fluctuations of concentration were found to depend on the season and place of sampling. The results confirmed an occurrence of risk due lo the impact of trihalomethanes to health. Therefore, water ozonation has been planed to replace chlorination with ozonation in Riga City.

In the region of Bransfield Strait and southern part of Drake Passage the highest amounts of chlorinated hydrocarbons (CHs — compounds of the DDT group, HCH isomers and PCBs) were found in the samples taken at the sampling station where the CHs bottom deposits were released to the upper layers due to the special hydrological situation at this station. Increased amounts of CHs were observed also in phytoplankton sampled close to the melting ice of glacier origin which was considered as a source of pollution. However, phytoplankton sampled from the waters covered with pack-ice exhibited the lowest rate of CHs accumulation. Slightly elevated CHs accumulation was found in sea ice diatoms. All the samples exhibited elevated amount of polichlorinated biphenyls, markedly higher than that of chloroorganic insecticides.

TCE artificially contaminated soil was cleaned under anaerobic, reductive conditions. A laboratory scale treatability studies were carried out to determine optimal physico-chcmical and microbiological parameters for biorcmcdiation process. Upon treatability studies results a sewage sludge mixture was chosen as a microorganism's source. The chlorinated solvents contaminated soil bioreactor (CSCS bioreactor) was designed and built. It consists of a 6 m3 reactor vessel, a gas recirculation system, a leachate recirculation system and a data acquisition system. The bioreactor vessel was designed as a continuous gas flow packed bed reactor. During 210 days 4 Mg of soil containing approximately 350 mg TCE/kg of soil has been completely remediated under anaerobic conditions. The obtained results indicate that the stepwise dechlorination of TCE to ETH occurs in the bioreactor. Increasing amounts of chloride in the leachate were correlated with dechlorination.

Pathways of PCDTs and PCTAs in the environment are discussed. Data on levels of these compounds in various pan of the environment and their possible sources are presented. Finally, the data on biological effects of PCDTs and PCT As based on some preliminary toxicological investigations are given.

Polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its metabolite, dichlorodiphenyldichloroethylene (DDE) can disturb the secretory function of the ovary and both contractions and secretory function of the uterus during the estrus cycle and pregnancy. Additionally, PCBs can pass through the placental barrier into allantoic and amniotic fluid. The presence of PCBs in these fluids is associated with higher frequency of spontaneous abortions and premature births in humans and animals. Therefore, the effect of PCBs, DDT and DDE on the connexins (Cx26, Cx32 and Cx43) and keratin 8 (KRT8) expression in bovine placentomes was investigated. The placentome slices from the second trimester of pregnancy were incubated with PCB153, 126, 77, DDT and DDE (each at doses of 1, 10 or 100 ng/ml) for 48 h. Then, the slices were stained using immunohistochemistry. The density of Cxs staining was measured with Axio- Vision Rel. 4.8 software in fetal-maternal connections and binuclear cells (BNC). None of the tested xenobiotics (XBs) affected the localization of Cxs and KRT8 in the fetal-maternal connection area, but the XBs affected the density of Cxs in fetal-maternal connections and binuclear cells (BNCs). Depend on the doses, in fetal-maternal connections all used PCBs changed the protein expression of different Cxs, while in BNCs, all tested XBs except DDT increased the expression of Cxs. None of investigated XBs affected on KRT8 expression. In summary, used XBs affect the expression of Cxs and change the quantitative relationships between them. Therefore, XBs can unfavorably influence function of the utero-placental barrier in cows.

Influence exerted by various concentrations (0.01 to 50 ppm) of some chlorinated hydrocarbons (Aroclor 1254, Aroclor 1242, pp'DDE, pp'DDT and Lindane (ɣ НСН)) upon the photosynthetic assimilation of 14C02 in Antarctic marine diatom assemblage dominated by Corethron criophilum and some species of Nitzschia (Fragilariopsis group) has been investigated. The photosynthesis was fully inhibited by Lindane (ɣ HCH) in all applied concentrations To smaller extent the photosynthetic process was inhibited in turn by Aroclor 1242, pp'DDE and pp'DDT successively. Aroclor 1254 proved to be the least toxic. The possibility of the decrease of the primary production of the Antarctic diatoms caused by the chlorinated hydrocarbons was discussed.

The present study aims at investigating and simulating the hydrogen cycle production at low temperatures using thermochemical reactions. The cycle used in this work is based on the dissociation of water molecules depending on a copper chlorine couple. Furthermore, the proposed method uses mainly thermal energy provided by a solar thermal field. This proposed cycle differs from what is found in the literature. However, most of the thermochemical cycles for hydrogen production work at quite high temperatures which is a technical challenge. Therefore, the maximum temperature used in the present cycle is limited to 500°C. A thermodynamic analysis based on both the first and second laws is performed to evaluate the energy, exergy and efficiency of each reaction as well as the overall exergetic efficiency of the system. Furthermore, a parametric study is conducted to figure out the impact of the surrounding temperatures on the overall exergetic efficiency using commercial energy simulation software. The results show that the cycle can achieve an exergy efficiency of 30.5%.

Our scientific research is based on oxidation reactions and monitoring of chemical reaction kinetics in the Velekinca groundwaters plant in Gjilan municipality, Kosovo. The GW of this plant contains high concentration of manganese so we need to use potassium permanganate (KMnO4) as one of the most power oxidants in the water treatment plant. In our re-search the high concentration of Mn in groundwaters is 0.22–0.28 mg∙dm–3 and this concentration is not in accordance with the WHO. Chlorine is one of the most common disinfectants used in the water treatment industry because it has a low cost and immediate effect on the destruction of microorganisms, the concentration of chlorine (Cl2) in our research is 0.1–0.32 mg∙dm–3. The speed of chemical reactions in the technology of GW is extremely important because sometimes in the elimi-nation of chemical pollutants using oxidizing agents often form intermediate species. The speed of reactions indicates how fast chemical bonds are formed in the creation of a product, and this depends on the rate of reaction (XA). The focus for the research is to study the potassium permanganate and chlorine gas reactions in water if it forms intermediate products (in-termediate species) due to the high speed of reactions. Scientific research conclusion, intermediate species in the oxidation reactions of Mn and water disinfection with Cl2(g) it is impossible to cause a high rate of chemical reactions from the reac-tion rate (XA = 1%) to the reaction rate (XA = 99%). The maximum speed at the highest XA Cl2 is from 4.405∙10–11 to 8.87∙10–10 mol∙dm–3∙s–1, while at Mn is (2.030–4.034)∙10–7 mol∙dm–3∙s–1.

The aim of the research was to study the temporal and spatial dynamics of a set of agronomic criteria for irrigation water in the process of transporting it from the Southern Buh River intake site to the lands of the Southern Buh and Kamianska irrigation systems situated in southern Ukraine. Six stationary research sites for monitoring the quality of irrigation water were established along the route of irrigation water transportation. Determination of agronomic criteria for irrigation water quality was carried out in two terms: at the beginning of the irrigation season, in May, and at the end, in September. The content of cations of sodium, magnesium, calcium, and anions of chlorine, sulphates, carbonates, and bicarbonates was determined. In the field, the pH and electrical conductivity of water, the total salt content, and the total amount of dissolved solids were determined. It is determined that waters have an average level of danger from the point of view of salinisation of soils. This fact leads to a decrease in yield of sensitive to salinity crops (corn, alfalfa and most vegetables). The high content of sodium cations along with the low content of calcium and magnesium cations indicates the danger of degradation of the physical properties of the southern chernozems and the need to use the meliorants containing calcium. There is a high probability of toxic effects on crops caused by sodium cations. At the same time, it is stated that there is no negative effect of chlorine anions on plants.

Most of the existing toxic gas mitigation techniques have difficulty in practical implementation. More effective mitigation methods are required for handling hazardous gas releases in Chemical Process Industries (CPIs). One of the most hazardous chemicals is chlorine, an integral part of almost all chemical industries, especially chlor-alkali. This study examined a possible accidental spill of liquid chlorine from a chlorine storage area. Computational Fluid Dynamics, Process Hazard Analysis Software Tool (PHAST), and Probit analysis were combined to develop the overall effect and vulnerability models. The dispersion of chlorine vapors at wind speeds of 2, 3, and 4 m/s was analyzed, and the corresponding threat zones were plotted. Many public establishments of extreme vulnerability were located inside the threat zones. Offsite emergency planning guidelines are necessary for such conditions. Based on the results of the consequence analysis, a practical and cost-efficient IoT (Internet of Things) based mitigation system using physical barriers is proposed. The proposed mitigation system accounts for entrapment, continuous removal, and safe handling of the chlorine vapor from the release area. The proposed mitigation system can be implemented in all CPIs dealing with the production and storage of toxic gases. The outcome of this study can contribute to the development of Emergency Response Planning (ERP) guidelines for chlorine release.

The seawater desalination process is emerging as a substantial source of fresh water by removing salt and minerals from an infinite supply of seawater effectively. The first stage in a desalination plant is the use of chlorine gas to sterilize the microorganisms in the water. During excess chlorine leakage, an alert is activated, employees are relocated away from the site for a specific period, and dampers will be manually opened. This will cause unsafe working conditions and a waste of time. To overcome this problem, this paper proposes a coefficient diagram method based proportional integral derivative (CDM-PID) control strategy for the tune the control parameter with the distributed control system (DCS) interfaced conical tank. During operation, a 10% NaOH solution is injected into the top of the scrubber column using an ethylene-ter-polymer (ETA) designed distributor to ensure that the solution is evenly distributed across the packing surface. The three control strategies are compared to tune the control parameter with the DCS interfaced conical tank. Instead of the sodium hydroxide tank in the chlorine scrubber system, this work presents the pilot plant of DCS interfaced with two conical tank interacting systems with different liquid level heights. Here, the proposed CDM-PID controller is compared with the standard Ziegler-Nichols (ZN)-ultimate cycling method, and the internal model control (IMC) method. The results demonstrated that the proposed CDM-PID approach is superior to existing approaches in terms of low oscillation, settling period, and high robustness.