The ability of six types of granular activated carbon (GAC) to quench H2O2 was evaluated by bench-scale H2O2 decomposition kinetics tests and pilot-scale H2O2 breakthrough tests. Bench-scale studies showed that carbon ageing significantly reduced the performance of H2O2 quenching by the GAC, but that the greatest impacts occurred within the first 25 000 bed volumes of water treated, with performance tending to stabilize afterwards. Pilot-scale studies suggested that both H2O2 exposure and exposure to natural organic matter were important factors in GAC ageing, with exposure to oxygen also suspected of being important. A continuously stirred tank reactor (CSTR)-in-series model was proposed for the prediction of H2O2 breakthrough in a GAC column.

Pasiūlytas mangano nustatymo metodas geriamajame vandenyje inversinės voltamperometrijos metodu naudojant gyvsidabrio plėvelinį elektrodą. Manganui nustatyti vandens mėginio nereikia chemiškai apdoroti. Optimalios nustatymo sąlygos: kaupimo potencialas –1,75 V, kaupimo trukmė 5–30 s, anodinis tirpinimas atliekamas naudojant kvadratinės bangos voltamperometriją. Mangano aptikimo riba kaupiant jį 30 s yra apie 0,4 μg l–1, o santykiniai standartiniai nuokrypiai darbiniame koncentracijų intervale ne didesni kaip 0,10. Realios kalcio, magnio ir geležies jonų koncentracijos geriamojo vandens mėginiuose netrukdo nustatyti manganą. Metodo palyginimas su standartiniu fotometriniu metodu parodė, kad jie yra ekvivalentiški, tačiau elektrocheminis metodas gali būti taikomas labai mažoms mangano koncentracijoms nustatyti, be to, jam netrukdo geriamajame vandenyje esantys geležies jonai. Chromo nustatymui cemente gali būti naudojamas katalitinės adsorbcinės voltamperometrijos metodas naudojant kabančio gyvsidabrio lašo elektrodą. Terpės sudėtis Cr(VI) nustatyti: 0,15 mol l-1 CH3COONa, 5 mmol l-1 dietilentriaminpentaacto rūgšties (DTPA), 0.7 mol l-1 NaNO3, pH = 6. Optimalios votamperometrijos sąlygos: kaupimo potencialas –0.9 V, kaupimo trukmė 5-10 s, kvadratinės bangos voltamperometrijos režimas. Cr(VI) aptikimo riba yra apie 0,05 µg l 1, santykinis standartinis nuokrypis neviršija 3%. Iš cemento mėginių chromas išekstrahuojamas vandeniu arba azoto rūgštimi. Bendras chromo kiekis... [toliau žr. visą tekstą] / There was proposed method for the determination of manganese in drinking water by inverse voltammetry using a mercury film electrode. The determination of manganese in drinking water does not need chemical treatment of a sample. Optimal detection conditions: accumulation potential of -1.75 V, accumulation time 5-30 s, anodic dissolution is performed using square wave voltammetry. Manganese accumulation by the detection limit of 30 seconds is about 0.4 mg l-1, and the relative standard deviations of the working range of concentrations do not exceed 0.10. Actual calcium, magnesium and iron ion concentration in samples of drinking water does not influence the manganese determination. Method comparison with a standard photometric method showed that they are equivalent, but the electrochemical method can be applied in very small concentrations of the manganese, in addition, it does not influence the iron ions in the drinking water. Determination of chromium in cement can be performed by catalytic adsorption voltammetry method using a hanging mercury drop electrode. The medium composition for Cr (VI) determination: 0.15 mol L-1 CH3COONa, 5 mmol l-1 diethylenetriaminepentaacetic acid (DTPA), 0.7 mol l-1 NaNO3, pH = 6. Optimal voltammetry conditions: accumulation potential of -0.9 V, accumulation time 5-10 s, square wave voltammetry mode. Cr (VI) detection limit is about 0.05 mg l-1, the relative standard deviation does not exceed 3%. Chromium was extracted from the cement samples... [to full text]

There was proposed method for the determination of manganese in drinking water by inverse voltammetry using a mercury film electrode. The determination of manganese in drinking water does not need chemical treatment of a sample. Optimal detection conditions: accumulation potential of -1.75 V, accumulation time 5-30 s, anodic dissolution is performed using square wave voltammetry. Manganese accumulation by the detection limit of 30 seconds is about 0.4 mg l-1, and the relative standard deviations of the working range of concentrations do not exceed 0.10. Actual calcium, magnesium and iron ion concentration in samples of drinking water does not influence the manganese determination. Method comparison with a standard photometric method showed that they are equivalent, but the electrochemical method can be applied in very small concentrations of the manganese, in addition, it does not influence the iron ions in the drinking water. Determination of chromium in cement can be performed by catalytic adsorption voltammetry method using a hanging mercury drop electrode. The medium composition for Cr (VI) determination: 0.15 mol L-1 CH3COONa, 5 mmol l-1 diethylenetriaminepentaacetic acid (DTPA), 0.7 mol l-1 NaNO3, pH = 6. Optimal voltammetry conditions: accumulation potential of -0.9 V, accumulation time 5-10 s, square wave voltammetry mode. Cr (VI) detection limit is about 0.05 mg l-1, the relative standard deviation does not exceed 3%. Chromium was extracted from the cement samples... [to full text] / Pasiūlytas mangano nustatymo metodas geriamajame vandenyje inversinės voltamperometrijos metodu naudojant gyvsidabrio plėvelinį elektrodą. Manganui nustatyti vandens mėginio nereikia chemiškai apdoroti. Optimalios nustatymo sąlygos: kaupimo potencialas –1,75 V, kaupimo trukmė 5–30 s, anodinis tirpinimas atliekamas naudojant kvadratinės bangos voltamperometriją. Mangano aptikimo riba kaupiant jį 30 s yra apie 0,4 μg l–1, o santykiniai standartiniai nuokrypiai darbiniame koncentracijų intervale ne didesni kaip 0,10. Realios kalcio, magnio ir geležies jonų koncentracijos geriamojo vandens mėginiuose netrukdo nustatyti manganą. Metodo palyginimas su standartiniu fotometriniu metodu parodė, kad jie yra ekvivalentiški, tačiau elektrocheminis metodas gali būti taikomas labai mažoms mangano koncentracijoms nustatyti, be to, jam netrukdo geriamajame vandenyje esantys geležies jonai. Chromo nustatymui cemente gali būti naudojamas katalitinės adsorbcinės voltamperometrijos metodas naudojant kabančio gyvsidabrio lašo elektrodą. Terpės sudėtis Cr(VI) nustatyti: 0,15 mol l-1 CH3COONa, 5 mmol l-1 dietilentriaminpentaacto rūgšties (DTPA), 0.7 mol l-1 NaNO3, pH = 6. Optimalios votamperometrijos sąlygos: kaupimo potencialas –0.9 V, kaupimo trukmė 5-10 s, kvadratinės bangos voltamperometrijos režimas. Cr(VI) aptikimo riba yra apie 0,05 µg l 1, santykinis standartinis nuokrypis neviršija 3%. Iš cemento mėginių chromas išekstrahuojamas vandeniu arba azoto rūgštimi. Bendras chromo kiekis... [toliau žr. visą tekstą]

Lead (Pb) is a known toxicant that affects young children. It is believed that old water reticulation systems are prone to lead leaching from the walls of lead pipes and fixtures where water is conveyed to households. Many households in Christchurch city particularly in the Northwestern and Central parts of the city contain old water reticulation systems thereby, putting children at considerable health risks. The purpose of this dissertation is to identify the hazards of lead exposure that comes from old water reticulation system of Northwest (NW) Christchurch water supply to households, characterize the health risks due to such contamination and, finally, to suggest possible ways to minimize the hazards. This is accomplished by conducting a systematic review of literature on the exposure patterns of lead from reticulation systems and a literature review of the possible dose response patterns of health effects of lead contamination from old water reticulation systems on children. Thus, this dissertation involves a literature based risk assessment of lead contamination of drinking water supply in the Northwest Christchurch Zone and particularly, its effects on young children. The selection process of the research studies is based on whether they offer accurate and suitable information on the risk of adverse mental function in infants and young children due to environmental lead exposure; whether the studies have been peer reviewed by qualified scientists; whether the results are confirmed by other studies; and involves only human subjects. Future research may consider whether lead levels in drinking water are seasonal; whether these values are significant to health or, the possible role of the government in tightening product controls when monitoring the availability and health risk of high lead drinking water supply plumbing products available in the New Zealand market.

The Bolivian Altiplano (BA) is a high plateau located in the western part of the country at an altitude of 3,600 to 3,900 meters above sea level and is bordered by the Eastern and Western Cordillera. Within the BA there is a large endorheic hydrologic system linking the Titicaca Lake in the north the Desaguadero River, lakes Uru-Uru and Poopó in the central part; and the Lacajahuira River and Coipasa and Uyuni salt pans in the south. Several mineralized areas, especially in the Eastern Cordillera, have been intensively exploited for centuries for the extraction of silver, gold, and tin from polymetallic sulfide ore deposits. Presently many urban centers are also contributing for an extensive contamination in localized areas; especially the Poopó Lake and some rivers are affected by high loads of wastewater and solid waste, in addition to the release of heavy metals and arsenic (As) due to acid mine drainage. The presence of As in the BA was known to be related to mining only, but recent studies revealed that As of geogenic origin also contributing to the elevated concentration of As in surface and groundwater. The Poopó Lake basin is characterized by a semiarid climate. Geologic formations predominantly are of volcanic origin and groundwater flow is sluggish in nature. These environmental settings have generated substantially elevated concen- trations of geogenic As and other trace elements in surface and groundwater. Both surface and groundwater used for drinking water have high concentrations of As that by far exceed the World Health Organization (WHO) guideline. The overall objective of the present study has been focused on the determination of the sources and principal mechanisms for mobilization of geogenic As into surface and groundwater of the Poopó Lake basin area. More specifically, this study has determined the spatial distribution and the extent of As contamination in surface and groundwater; chemical composition of surface and groundwater, rock and sediment; major geochemical mechanisms for As mobilization from solid phase to aqueous phases. This study also made an assessment of drinking water quality in rural areas within the Poopó Lake basin. Arsenic concentration exceeded the WHO guideline and national regulations for drinking water of 10 µg/L in 85% of the samples collected from the area around the Poopó Lake (n=27) and 90% of the samples from the southern part of the lake basin (n=42). Groundwater samples collected from drinking water wells had As concentrations up to 623 µg/L, while samples collected from piezometers had even higher up to 3,497 µg/L. Highest concentration in river water samples was observed 117 µg/L. Alkaline nature of water (median pH 8.3 for groundwater and 9.0 for surface water), predominance of Na-Cl-HCO3 water type and elevated Eh reflecting oxidized character has been revealed by As(V) as the major species in As speciation. Different rock types were analyzed for their As content and the highest concentration of 27 mg/kg was found in a coral limestone sample. In evaporate it was 13 mg and 11 mg As/kg was measured in calcareous sandstone. Elevated concentration of As was also observed in sediment cores collected from two drilling sites; 51 mg/kg in Condo K and 36 mg/kg in Quillacas. Physical and chemical weathering of volcanic rocks, limestone, carbonates and plagioclase minerals enhance the supply of Na+ and HCO3- into solution and as a consequence pH and alkalinity increase, which in turn, favor As desorption from solid mineral surfaces (especially Fe(III) oxyhydr- oxides) and therefore dissolved As in water is increased. / <p>QC 20150529</p>

Chloramine is a widely used alternative disinfectant for chlorine in potable distribution water. This alternative was investigated and employed to show its effect for suppressing coliforms, trihalomethanes(THMs), disinfection by-products (DBPs), and corrosivity.Coliform analyses were performed with m-Endo(total coliform) and m-T7 agar(injured coliform) by using a standard Membrane Filtration method. Heterotrophic bacteria were monitored with HPC agar(PCA) and R2A agar (nutrient limited agar). EPA methods 502.2, 524.2, and 504 were used to determine levels of Trihalomethanes(THMs) and Disinfection by-products(DBPs).In our study, we observed no significant differences in coliform counts, that could be attributed to the switch in disinfectant. The most common coliform identified was Enterobacter cloacae. We also noted that m-T7 performed better than m-Endo in the detection of coliforms. We also observed a low level of corrosion (0.4-3.8 mils/year) in the distribution system (DS). Higher counts of heterotrophic bacteria were enumerated on R2A when compared to HPC. DBP values decreased two fold when compared with DBP values for the two previous years during which chlorine was used as the disinfectant. / Department of Biology

Recently the EPA placed Aeromonas hydrophila on the Candidate Contaminant List (CCL). It has long been known to be a pathogen of cold blooded animals and now is a suspected human opportunistic pathogen as well. Among the various virulence factors produced by A. hydrophila, the cytolytic enterotoxin (AHCYTOEN) is by far one of the most important contributors to the pathogenicity of the organism. This factor is also produced by other pathogenic Aeromonas spp. In this study, PCR technology was used to detect AHCYTOEN gene from a simulated water distribution system. A set of primers was selected to amplify the unique sequence of a pathogenic island, AHCYTOEN gene. To examine the sensitivity of the PCR, serial dilutions of pure A. hydrophila culture were tested. The PCR technique used was sensitive enough to detect samples containing less than 10.0 cells/ml. Source water, bulk water, and simulated distribution biofilm samples were examined for the gene. Biofilm and bulk water samples exposed to raw source water were collected on 4 occasions during a 24-day period. PCR technology detected the AHCYTOEN gene from 100 % of the bulk water samples and 85% of tightly bound biofilm (TB) samples from a simulated water distribution system while no positive results were observed in loosely bound biofilm samples (LB). After the inlet line of the system was changed to normally treated distribution water, 11 biofilm samples were collected on 3 occasions during 15 day sampling period along with bulk water samples. No positive results were observed from the bulk water and LB samples while 91% of TB samples tested for the presence of the gene. No significant difference was observed in detection by PCR from biofilm samples before and after the switch to chloraminated water. / Department of Biology

This qualitative study described and compared the cognitive apprehensions regarding drinking water quality (DW) in Muncie, Indiana, USA. The comparison was between two different, culturally elite groups using constructive-grounded theory. Eighteen semistructured interviews were conducted with both Arab (n=9) and American (n=9) participants. Five essential themes emerged from the interview data: the sensory properties of drinking water, pollutants, health concerns, information sources, and experience. The data from this study is grounded to the epistemologies regarding drinking water. The epistemologies differ between the Arab and American groups due to social factors, such as ethnicity, culture, and past experiences. The study showed that the two groups in the study perceived knowledge regarding drinking water in different ways. The study showed that the educated Arabs had different cognitive apprehensions regarding drinking water compared to educated Americans due to their previous experiences with drinking water quality in their home countries and their lack of interest in the local media. However, similar findings regarding beliefs about pollutants and diseases in drinking water were shared between the groups. The grounded study found that each group had different behaviors regarding drinking water, and it developed a theory that described how different epistemologies lead to different actions regarding drinking water among different ethnicities. Some recommendations based on the study findings endorse that the government agencies should provide a readily accessible publication about the drinking water quality to the community. It is recommended that the government agencies promote the dissemination of water quality studies’ findings through mass media, social media, and other means of communications with the public. In addition, recommendations should also be provided to enhance the local environmental awareness of international students at universities. / Department of Natural Resources and Environmental Management

Darbo objektas: Marijampolės miesto geriamasis vanduo. Darbo tikslas: įvertinti Marijampolės miesto geriamojo vandens kokybę 2005-2013 metais. Darbo metodai: Tyrimai vykdyti UAB „Sūduvos vandenys“ 2005–2013 metais Marijampolės mieste. Eksperimento metu skirtingais metais tirta dviejų vandenviečių cheminė vandens kokybė. Indikatoriniams ir cheminiams geriamojo vandens kokybės tyrimams Marijampolės vandenvietėse vanduo imamas iš gręžinių. Požeminio vandens mėginiai jo cheminės būklės/kokybės vertinimui imami tiesiogiai iš eksploatacinių gręžinių ir vandens mišinio vieną – du kartus per metus, pavasarį ir rudenį. Požeminio vandens mėginiai imami vadovaujantis nustatyta tvarka (LST ISO 5667-11:2009 „Vandens kokybė. Bandinių ėmimas. 11-oji dalis. Nurodymai, kaip imti gruntinio vandens bandinius“; LST EN ISO 5667-3:2006 „Vandens kokybė. Mėginių ėmimas. 3-oji dalis. Nurodymai, kaip konservuoti ir gabenti mėginius“). Darbo rezultatai: Įvertinus Marijampolės miesto eksploatacinių gręžinių geriamojo vandens kokybę nustayta, kad I-ojoje vandenvietėje amonio jonų ir bendrosios geležies koncentracijos yra didesnės nei II-osios vandenvietės vandens mišinyje iš visų artezinių gręžinių ir viršija nustatytas ribines vertes. Marijampolės miesto I-osios vandenvietės vandenyje 2005-2013 metais prieš nugeležinimą didėjo bendrosios geležies koncentracija, mažėjo permanganato indekso vertė. Po nugeležinimo didėjo chloridų, nitratų koncentracijos, mažėjo permanganato indekso vertė. II-osios... [toliau žr. visą tekstą] / The object: of the two Marijampoles watering places city drinking water. To identify: Marijampoles urban drinking water quality dynamics. Working methods: The study was carried UAB „Sūduvos waters“ in 2005-2013 Marijampoles city. During the experiment, two different years studied waterworks chemical quality of the water. The indicator and chemical quality of drinking water research Marijampoles waterworks water taken from wells. Groundwater samples of the chemical status/quality assessment are taken directly from wells and water one - two times a year, in spring and autumn. Groundwater samples shall be taken in accordance with established procedures (ISO 5667-11:2009 Water quality. Sampling. 11th part. Guidance on sampling of groundwater samples "BS EN ISO 5667-3:2006 Water quality. Sampling. 3rd part. Guidance on the preservation and handling of samples). The results: Assessment Marijampoles city wells for drinking water quality Preset that I th wellfield ammonium ion and total iron concentration is higher than in the II-nd watering of water from the artesian well and exceeds the threshold value. Marijampoles town I th watering water year 2005-2013 against the removal of iron increased total iron concentration decreased permanganate index value. After the removal of iron increased chloride, nitrate concentrations decreased permanganate index value. II th watering water before removal of iron decreased the pH value. After the removal of iron increased chloride, nitrate... [to full text]

Recently some chemicals has been accused of mimicking the female hormone estrogen. The mode of action is termed estrogen-mimicking, because of the effects that is produced by these chemicals. Playing canary in a coal mine, wildlife was the first to indicate that something was wrong. Reproductive abnormalities such as abnormal sperm, reduced sperm production, cryptorchidism (undescended testes). abnormal hormone levels – particularly high estrogen ratios to that of testosterone. infertility, and genital abnormalities were all evidence that something in the environment was affecting the reproductive status of these animals. Also in humans instances like rising cases of infertility, abnormal sperm conditions and cases of breast cancer raised an increased concern about the potential disruptive effects of these substances on the human existence. After investigations were conducted, it was found that substances which enhance the quality of life like some detergents, agricultural products, additives to plastic, dyestuffs, paint components and pharmaceuticals to name but a few, all caused an abnormal reproductive status as seen in animals. The aims of this study were not to focus on the effect of these substances, but rather to identify estrogen and estrogen - mimics in the South African environment and to evaluate their presence in the water environment qualitatively and quantitatively with the most suitable analytical methods. Estrogen - mimics such as nonylphenol. o'p' and p'p' DDE, o'p' DDD, lindane, atrazine and the PCB's : Arochlor 1254 & Arochlor 1260 were found to contaminate the environment. The drinking water tested of the PWV area indicated that the water was free of these substances, and thus indicated a present safe situation. / Thesis (MSc (Farmaseutika))--PU for CHE, 1998