No description available.

Volatile organic compounds are mostly found in the water as contaminants of human origin. Theoretical part of the thesis is focused on characteristic and occurence of volatile compounds. At the same time it also deals with possibilities of their qualification and quantification. Extensive description have been focused to static head-space technique combine with solid phase microextraction. The objection of the experimental part was gaining experience with operating the device/instrument used for measuring. After locality selection could begin sampling and their analysis.

Surfactants are synthetically made surface-active agents contained in washing and cleaning products. They decrease the surface tension and remove dirt. Surfactants can be divided into three basic classes: anionic, cationic and non-ionic. Thanks to the massive use they penetrate into waste water and can disturb the environment. This diploma thesis deals with the occurrence of surfactants in water and their determination by separation methods, especially LC / MS.

<p>Istraživanja u ovom radu su obuhvatila primenu koncepta analize značaja pritisaka i&nbsp;<br />uticaja i metoda za identifikaciju i klasifikaciju&nbsp; izvora pritisaka; karakterizaciju i analizu&nbsp;pritisaka; procenu statusa vodnih tela i procenu uticaja/rizika da se ne dostigne njihov&nbsp;dobar ekolo&scaron;ki status/potencijal. Ukupan broj registrovanih zagađivača na teritoriji AP&nbsp;Vojvodine iznosi 185, trenutno radi njih 130. Najvi&scaron;e zagađivača svoje otpadne vode&nbsp;<br />ispu&scaron;ta u Tisu, DTD Vrbas-Bezdan i Begej, koji su recipijenti 61% od ukupne količine&nbsp;<br />otpadnih voda. Skoro 70% od ukupnog broja zagađivača pripada sektoru prerađivačke&nbsp;<br />industrije, a među njima je najzastupljenija proizvodnja prehrambenih proizvoda i pića.&nbsp;Prosečna dnevna količina ispu&scaron;tenih otpadnih voda iznosi oko 140.000 m³/dan. &nbsp;Ukupno&nbsp;organsko zagađenje koje se emituje u vodotoke na području AP Vojvodine, a &nbsp;potiče &nbsp;od&nbsp;otpadnih voda iznosi 33 tHPK/dan i 15 tBPK/dan. Polovina zagađivača svoje otpadne vode&nbsp;ispu&scaron;taju bez ikakvog tretmana, četvrtina njih poseduje primarni tretman preči&scaron;ćavanja,&nbsp;dok tercijarni tretman primenjuje svega 3% zagađivača. Veoma je mali broj zagađivača kod&nbsp;kojih su emitovane konecentracije usklađene sa propisanim graničnim vrednostima&nbsp;emisije, za nutrijente je to oko 50%, dok je za organske materije samo četvrtina &nbsp;od&nbsp;ukupnog broja zagađivača. Od 37 vodotoka, samo tri se klasifikuju u klasu 2, &scaron;to odgovara&nbsp;dobrom kvalitetu voda. Kvalitet najvećeg broja vodotoka odgovara &nbsp; slabom ili lo&scaron;em&nbsp;statusu/potencijalu (tj. klasama 4 ili 5). Najveća odstupanja od dobrog statusa/ potencijala&nbsp;su u sadržaju nutrijenata i parametara kiseoničnog&nbsp; režima. Rezultati &nbsp;su pokazali da su&nbsp;polutanti visokog rizika najče&scaron;će nutrijenti i parametri kiseoničnog režima, &scaron;to&nbsp;najverovatnije predstavlja negativan uticaj ispu&scaron;tanja otpadnih voda. Ukupno &nbsp;opterećenje&nbsp;zagađujućih materija a time i broj vodotoka na kojima je prema&scaron;eno ciljano opterećenje&nbsp;znatno raste sa porastom emitovanog opterećenja iz&nbsp; koncentrisanih izvora, ali i &nbsp;sa&nbsp;smanjivanjem protoka vode u vodotocima. Najveći broj vodotoka (20) na kojima je&nbsp;prema&scaron;eno ciljano opterećenje je u slučaju HPK i fosfora. U slučaju postizanja graničnih&nbsp;vrednosti emisije kod svakog zagađivača, broj vodotoka na kojima je prema&scaron;eno ciljano&nbsp;opterećenje se smanjuje za 15-50%, zavisno od parametara, pri čemu broj vodotoka na&nbsp;kojima je prema&scaron;eno ciljano opterećenje ne zavisi od veličine emitovanog opterećenja nego&nbsp;samo od protoka vode u kanalima.</p> / <p>Research in this study included the concept of pressure and influence&nbsp;significance analysis as well as the methods for identification and classification of the&nbsp;pressure sources: characterisation and analysis of&nbsp; pressures; assessment of the water&nbsp;bodies&rsquo; status and assessment of impacts/risks thattheir good ecological status/potential&nbsp;is not achieved. Total number of registered polluters in Vojvodina is 185, 130 of them&nbsp;currently working. Most polluters discharge their waste water into the Tisa River, DTD&nbsp;Vrbas-Bezdan and Begej River, who are the recipients of 61% of the total volume of&nbsp;wastewater. Almost 70% of the total number of contaminants belongs to the processing&nbsp;industry, and among them the most common is food and beverage production. The average&nbsp;daily amount of discharged wastewater is approximately 140 000 m³/day. Total organic&nbsp;pollution emitted into the watercourses in the areaof AP Vojvodina originates from the&nbsp;waste water is 33 tCOD/day and 15 tBOD/day. Half of the polluters discharge their waste&nbsp;water without any treatment; a quarter of them haveprimary wastewater treatment, while&nbsp;tertiary treatment is applied by only 3% of polluters. A very small number of polluters&nbsp;have their emitted pollutant concentration compatible with the prescribed emission limit&nbsp;values: for nutrients it is about 50%, while for the organic matter, it is only a quarter of the&nbsp;total number of polluters. From 37 watercourses, only three are classified as class 2, which&nbsp;corresponds to good quality water. Quality of the greatest number of watercourses&nbsp;corresponds to poor or bad status/potential (ie. classes 4 or 5). The biggest deviation from&nbsp;good status/potential is due to nutrients content and oxygen regime parameters. Results&nbsp;showed that high-risk pollutants are commonly nutrients and oxygen regime parameters,&nbsp;which probably represents the negative impact of waste water discharges. The total load of&nbsp;pollutants, and therefore the number of watercourses where the target load it exceeded, &nbsp;significantly increases with the increase of emitted loads from the point sources, but also&nbsp;with the reduction of water flow in rivers. The largest number of watercourses (20) in&nbsp;which the target load is exceeded, is due to COD and phosphorus. In the case of achieving&nbsp;the emission limit values for each polluter, the number of watercourses in which the&nbsp;targeted load is exceeded would be reduced by 15-50%, depending on the parameters,&nbsp;whereby the number of watercourses in which the targeted load it exceeded is not&nbsp;dependent on the load emitted but just on the waterflow in the channels.&nbsp;</p>

Les milieux aquatiques sont les réceptacles finaux des pesticides organiques et inorganiques. Ainsi, des textes réglementaires fixant des objectifs afin de préserver et restaurer l’état des milieux aquatiques ont été établis (ex. Directive Cadre sur l’Eau). Ces textes réglementaires ou les programmes d'actions s'accompagnent de la mise en place de réseaux de suivi de la qualité des eaux. Ces suivis sont effectués via la réalisation de prélèvements ponctuels d'eau, fournissant une donnée souvent sujette à un manque de représentativité temporelle. Pour estimer de façon plus robuste une concentration moyenne dans le temps, des techniques d’échantillonnage passif ont été développées. Celles-ci permettent la pré-concentration in situ des contaminants et disposent d’une capacité intégrative sur plusieurs semaines. Ces travaux de thèse sont axés sur le Polar Organic Chemical Integrative Sampler (POCIS), largement utilisé pour l’échantillonnage des pesticides moyennement polaires et non ionisables (0<log Kow<4).Le premier volet de ces travaux de thèse avait pour objectif de tester la capacité du POCIS à intégrer de brèves variations de concentration en pesticides. Pour ce faire, une expérimentation simulant des pics de contamination d’intensités et de durées variables a été menée dans des conditions contrôlées de laboratoire. Cette expérimentation a démontré que la réactivité du POCIS face à de tels événements était dépendante des propriétés physico-chimiques des pesticides ciblés (notamment du log Kow) et de la durée d’exposition. Des profils d’accumulation différents ont été observés, avec deux phénomènes opposés survenus en début d’exposition, soit le « burst effect » ou le « lag effect ». Malgré ces deux phénomènes, le domaine d’applicabilité du POCIS a été mieux défini puisqu’il a été démontré que pour des pesticides caractérisés par un log Kow entre 2 et 4, les pics de contamination étaient bien pris en compte dans la concentration moyennée obtenue.Le second volet de ces travaux devait définir à large échelle l’apport du POCIS en complément des réseaux de suivi basés sur les prélèvements ponctuels. Dans ce contexte, 51 sites du réseau de contrôle DCE localisés sur les cours d’eau du bassin Adour-Garonne ont été échantillonnés 6 fois en 2016 via ces deux techniques. L’exploitation des données acquises pendant cette année de terrain s’est découpée en deux axes. Le premier avait pour objectif de comparer les informations fournis via les deux techniques. L’apport des caractéristiques intégratives du POCIS y a été démontré. En effet, le POCIS permet d’améliorer significativement le nombre de pesticides quantifiés ainsi que leur fréquence de quantification. De plus, il fournit une meilleure représentativité temporelle des niveaux de contamination mesurés, puisqu’il permet d’avoir une image plus réaliste des variations annuelles des concentrations en lien avec les usages des pesticides ciblés (saisonnalité). Ainsi, la combinaison de ces deux techniques a permis une meilleure caractérisation de la pression « pesticides » subie par le bassin Adour-Garonne.Le second axe visait à proposer une méthodologie d’exploitation automatisée permettant une interprétation visuelle et simple d’un jeu de données conséquent (> 10 000 données). Les données acquises avec les POCIS ont été utilisées pour réaliser des analyses multivariées, type « principal component analysis » et « hierarchical cluster analysis » afin de démontrer des liens entre occupation du sol et pesticides quantifiés. De plus, l’empreinte « pesticides » de chaque site a été établie. Ainsi, ce dernier axe a permis une meilleure caractérisation des zones les plus à risques ainsi qu’une identification rapide des sources potentielles.Ces travaux de thèse ont donc démontré des aspects fondamentaux et appliqués qui confirment l’intérêt du POCIS pour évaluer la qualité des eaux superficielles vis-à-vis des pesticides. / The aquatic environments are considered as the final receptacles of organic or inorganic pesticides. Thus, regulatory texts were established in order to preserve and restore the good status for the aquatic environments (e.g. Water Framework Directive). Currently, the conventional method for freshwater analysis is grab sampling several times per year with a lack of temporal representativeness. To overcome this issue, and in the aim of estimating a robust average concentration over time, passive sampling strategies have been developed. These samplers allow an in situ pre-concentration of contaminants and offer an integrative capacity of several weeks. This thesis focuses on the Polar Organic Chemical Integrative Sampler (POCIS), which is widely used for the sampling of moderately polar or no-ionizable pesticides (0<log Kow<4).The first part of this thesis aimed to test the POCIS capacity to integrate short pesticides contamination peaks. In this way, a laboratory controlled-conditions experiment which included pesticides contamination peaks of variable intensity and duration was performed over 14 days. This experiment proved that POCIS response depends on physico-chemical properties of the studied pesticides and also on the exposure duration. During the first part of the exposure period two different phenomena were observed, which were a “burst effect” or a “lag effect”. Despite these, short contamination peaks were well integrated in the time weighted average concentration, for pesticides with log Kow between 2 and 4.The second part of this thesis was to define, at a large scale, the contribution of POCIS as a complement to the monitoring networks based on grab samples. In this context, 51 monitoring stations located in the Adour-Garonne basin were sampled with these two techniques during 6 periods in 2016. The analysis of the large amount of data collected during this 1-year monitoring was divided into two axes. Firstly, information provided with POCIS and grab samples was compared. The contribution of the integrative capacity of POCIS was demonstrated; this capacity allowed us to obtain additional and complementary information to those of the monitoring networks. Indeed, POCIS improved significantly the number of quantified pesticides as well as their quantification frequency. Moreover, POCIS brought a better temporal representativeness of contamination levels, since it provided a more realistic picture of the annual variations in concentration levels related to the seasonality in the use of some pesticides. Thus, the combination of grab samples and POCIS provided a better assessment of pesticide contamination levels in the Adour-Garonne basin.The second axis aimed to propose an automated methodology allowing a visual and simple interpretation of a large dataset (> 10,000 data). Data acquired with POCIS were used to demonstrate correlations between land use and quantified pesticides. In this context, multivariate analyses, such as hierarchical clustering and principal component analyses, confirmed the relationship between land use in the watershed and the major pesticides quantified. Then, the "pesticide" fingerprint of each site was established. Finally, this last axis has made it possible to better characterize the sites most at risk and to quickly identify potential sources.This thesis work demonstrated fundamental and applied aspects, which confirm the interest of the POCIS in assessing the freshwater quality for pesticides.

No description available.

Thesis (MSc. (Chemistry)) -- University of Limpopo, 2021 / Surface water from the rivers serves as a source of water for many purposes including drinking, irrigation and animal farming. The quality of surface water deteriorates due to human, animals and industrial waste. Amongst these wastes, selenium and other trace elements contaminants are included. Selenium can either be essential or toxic depending on the concentration and oxidation state. The aim of this current study was to determine the concentrations of inorganic selenium [Se(IV) and Se(VI)] in water and sediment samples collected from Blood and Mokolo Rivers in Limpopo Province, South Africa. Water and sediment samples were collected from 10 different sampling sites from down to upstream of each river. Water samples were acidified with 1% ultra-pure HNO3 and analysed directly for total selenium concentration. The accuracy of the method was validated using SRM1643f (trace elements in water reference material). Sediment samples were digested using microwave assisted acid digestion for the determination of total concentration of selenium. The accuracy of the method was evaluated using SRM 8704 (sediment standard reference material). Total concentration of selenium in both water and sediment samples were quantified using ICP-MS. The total concentration of selenium in water samples from Blood and Mokolo River were found to be in the range of 0.0682 to 2.72 μg/L and 0.0851 to 25.4 μg/L respectively. The selenium concentrations in all sediment samples were found to be below instrument detection limit of 0.0571 ng/g in both rivers. An adopted SPE method using Dowex 1 x 2 resin (chloride form) as an adsorbent material to preconcentrate and separate Se(IV) and Se(VI) was used for the speciation in water samples. Both Se(IV) and Se(VI) were retained on the column. The retained Se(IV) and Se(VI) were eluted using 15 mL 1 M HNO3 and 3 M HNO3 respectively at a flow rate of 2 ml/min and diluted to the final volume of 20 mL. The instrument detection limit was 0.192 μg/L and 0.108 μg/L for Se(IV) and Se(VI) respectively. The validation of the method was performed by using SRM 1643f and solutions of known concentrations. The water samples were adjusted to an optimum pH of 6 throughout the speciation analysis. The Se(IV) had higher percentage recoveries of 95 – 114% than Se(VI) with 53%. vi Concentrations of Se(IV) and Se(VI) in Blood River ranged from 0.0411 to 0.820 μg/L and 0.0811 to 1.75 μg/L respectively. Concentrations of Se(IV) and Se(VI) in Mokolo River ranged from 0.135 to 2.79 μg/L and 0.0961 to 14.8 μg/L respectively. The inorganic selenium species in water samples were also determined by using the adopted online mode of HPLC-ICP-MS with Hamilton PRP-X100 column. The separation of the two species was achieved by using isocratic elution of 100 mM NH4NO3 at pH 8.5 in 8 min. The method was successfully validated using SRM 1643f. The LOD of 0.842 μg/L and LOQ of 2.81 μg/L for Se(IV) were achieved. The LOD of 0.690 μg/L and LOQ of 2.30 μg/L for Se(VI) were achieved. The Se(IV) and Se(VI) concentrations determined using HPLC-ICP-MS were found to be in good agreement with Se(IV) and Se(VI) concentrations obtained using SPE in both rivers. The presence of Se(IV) and Se(VI) in water samples in Blood and Mokolo Rivers indicates that industrial and agricultural activities taking place near the rivers have an effect on the quality of the water. The selenium in water may be due to wastes from industrial, municipal and agricultural runoffs. The absence of selenium in sediment samples suggests that the area where the rivers are located is not rich in selenium.

The study investigates and evaluates chemical parameters in handpumped water along Assi, a tributary to Ganga, south of Varanasi, northern India. Assi is polluted from raw sewage, landfill runoff and outlets from industries. To find out if the stream affects the groundwater in its basin, regression analysis of the easily moving ions, nitrite, nitrate and chloride were done during spring and autumn 2008. Significant trends were found for nitrate, most of them in the after monsoon period. No other chemical parameter gave significant trends. Metals as manganese and hexavalent chromium was measured in the spring period. Levels were higher closer to the stream. Significant trends when tested with regression analyses could not be found and the hexavalent chromium do not exceed guideline values in the handpumps measured. Interviews made clear that one quarter of the users of handpumped water have bad water quality during the monsoon period. The mean value of TDS in these pumps were higher than for the pumps that have good water quality and exceeds 500 mg/l. The mean value for turbidity was higher than 5 NTU in these pumps and in pumped water with good quality lower than 5 NTU. High levels of turbidity did not seem to affect the experience of having a good water. Pumps with higher TDS-values shows higher risk for polluted surface runoff together with risk for a broken construction that can allow seepage into the pumped water. Assi gives a severe contribution of raw sewage to Ganga upstream the bathing area in Varanasi and the pollution in the stream seams to affect the groundwater in its basin.

Watershed monitoring programs generally do not have perfect data collection success rates due to a variety of field and laboratory factors. A major source of error in many stream-gaging records is lost or missing data caused by malfunctioning stream-side equipment. Studies estimate that between 5 and 20 percent of stream-gaging data may be marked as missing for one reason or another. Reconstructing or infilling missing data methods generate larger sets of data. These larger data sets generally generate better estimates of the sampled parameter and permit practical applications of the data in hydrologic or water quality calculations. This study utilizes data from a watershed monitoring program operating in the Northern Virginia area to: (1) identify and summarize the major reasons for the occurrence of missing data; (2) provide recommendations for reducing the occurrence of missing data; (3) describe methods for infilling missing chemical data; (4) develop and evaluate methods for infilling values to replace missing chemical data; and (5) recommend different infilling methods for various conditions. An evaluation of different infilling methods for chemical data over a variety of factors (e.g., amount of annual rainfall, whether the missing chemical parameter is strongly correlated with flow, amount of missing data) is performed using Monte Carlo modeling. Using the results of the Monte Carlo modeling, a Decision Support System (DSS) is developed for easy application of the most appropriate infilling method. / Master of Science

South Florida contains one of the largest subtropical wetlands in the world, and yet not much is known about the microbes that live in these surface waters. These microbes play an important role in chemical cycling and maintaining good water quality for both human and ecosystem health. The hydrology of Florida’s surface waters is tightly regulated with the use of canal and levee systems run by the US Army Corps of Engineers and The South Florida Water Management District. These canals run through the Everglades, agriculture, and urban environments to control water levels in Lake Okeechobee, the Water Conservation Areas, and the surrounding farm lands. I hypothesized that there would be noticeable shifts in the microbial communities (also known as “microbiomes”) at the agriculture and urban sites due to anthropogenic influences such as agricultural and sewage runoff. It is also hypothesized that the diversity and stability of these sites will differ from the natural environment Grassy Waters Preserve (GWP), which we studied as a control. The northern section of GWP is a rain-fed Everglades ecosystem with little influence from manmade canal systems, so GWP can represent wetlands before human influences. High-throughput 16s rRNA sequencing was conducted on 112 GWP, canal, and agricultural water samples taken over a one-year period from September 2016 to November 2017. Data were processed in Qiime2 using DADA2 and resulted in 67732 unique taxa. Nineteen metadata factors were measured for 87 of the sampling points to investigate environmental effects. These factors explained 25% (r2=0.25, p=0.002) of the variation between sample locations. Conductivity was found to have the highest effect on microbial diversity (r2=0.078, p=0.002) while latitude and month also significantly influenced the microbial makeup. Urban and agricultural sites were found to have higher stability with lower variation in microbiomes over the course of study. The GWP site was found to have a high seasonality, probably due to its dependence on rain. The most abundant taxa for all sites (urban, agriculture, and control) were; family Spirochaetaceae, phylum Actinobacteria, and family Burkholderiaceae, respectively. Contamination of GWP and canal sites was also investigated using SourceTracker code. Intracoastal waters that receive canal water were found to be heavily influenced in the peak wet season when there is high flow through from the canals. GWP had little influence from farm lands compared to a high influence of agriculture on the urban sites.