Diffuse transfers of pesticides from agricultural land to ground and surface waters can lead to significant drinking water quality issues. This thesis describes the development and application of a parameter-efficient, numerical model to predict pesticide concentrations in raw water sources within an integrated hydrological framework. As such, it fills an unoccupied niche that exists in pesticide fate modelling for a computationally undemanding model that contains enough process complexity to be applicable in a wide range of catchments and hydrogeological settings in the UK and beyond. The model represents the key processes involved in pesticide fate (linear sorption and first-order degradation) and transport (surface runoff, lateral throughflow, drain flow, percolation to the unsaturated zone, calculated using a soil water balance) in the soil at a daily time step. Soil properties are derived from the national soil database for England and Wales and are used to define the boundary conditions at the interface between the subsoil and the unsaturated zone. This is the basis of the integrated hydrological framework which enables the application of the model to both surface water catchments and groundwater resources. The unsaturated zone model accounts for solute transport through two flow domains (accounting for fracture flow and intergranular matrix flow) in three hydrogeological settings (considering the presence and permeability of superficial deposits). The model was first applied to a small headwater sub-catchment in the upper Cherwell. Performance was good for drainflow predictions (Nash Sutcliffe Efficiency > 0.61) and performed better than the MACRO model and as well as the modified MACRO model. Surface water model performance was evaluated for eight pesticides in five different catchments. Performance was generally good for flow prediction (Nash Sutcliffe Efficiency > 0.59 and percentage bias below 10 %, in the validation period for all but two catchments). The 90th percentile measured concentration was captured by the model in 62 % of catchment-pesticide combinations. In theremaining cases predictions were within, at most, a factor of four of measured 90th percentile concentrations. The rank order of the frequency of pesticides detected over 0.1 μg L-1 was also predicted reasonably well (Spearman’s rank coefficient > 0.75; p < 0.05 in three catchments). Pesticide transport in the unsaturated zone model was explored at the point scale in three aquifers (chalk, limestone and sandstone). The results demonstrate that representing the unsaturated zone processes can have a major effect on the timing and magnitude of pesticide transfers to the water table. In comparison with the other catchment scale pesticide fate models that predict pesticide exposure at a daily time-step, the model developed stands out requiring only a small number of parameters for calibration and quick simulation times. The benefit of this is that the model can be used to predict pesticide exposure in multiple surface and groundwater resources relatively quickly which makes it a useful tool for water company risk assessment. The broad-scale approach to pesticide fate and transport modelling presented here can help to identify and prioritise pesticide monitoring strategies, to compare catchments in order to target catchment management and to highlight potential problems that could arise under different future scenarios.

The need of making arsenic contaminated ground water potable is urgent in parts of Burkina Faso. An implementation of a treatment design using Granular Ferric Hydroxide (GFH) is under development. Water from a tube-well in Lilgomdé, Yatenga province, Burkina Faso, has been treated with the adsorbent GFH through column experiments. The water had an arsenic concentration varying between 99 and 215 μg/L and an average pH of 7.9. The study has shown that arsenic, predominantly in the form of arsenate, can be adsorbed to the material in significant amounts despite a high natural pH and the presence of ions competing with arsenic for adsorption sites on the GFH. When run through the column, the pH of the effluent water drastically decreased in the beginning. However, the low pH was soon followed by a slower readjustment towards the pH of the influent water. The adsorption of phosphates and fluorides was also studied. Both competitors exist in higher molar quantities than arsenic in the ground water. Even though arsenic displays a higher affinity for the GFH, an average 44 % of total phosphate and 64 % of the fluoride were adsorbed, making them a factor affecting the results of the study. Hydrogen carbonate is also believed to affect the adsorption process but this could not be confirmed. The empty bed contact time (EBCT), describing the average time of contact between the adsorbent and the water, has shown to be of importance. Increasing the EBCT resulted in notably more arsenic being adsorbed per volume GFH. When increasing the contact time, the study showed that reducing the speed of the flow was more effective than increasing the volume of the adsorbent. The GFH was also found to have a self-regenerating ability to a certain extent. When interrupting the experiment and leaving the column material in the aqueous solution for several days, the arsenic adsorption capacity after the break was shown to be higher than just before it. A 13 % increased capacity was shown in one experiment. Conclusively, the results of this study suggest no hindrances towards developing larger scale columns and prototypes to be applied at tube-well pump stations. Further investigations on the treatment method with GFH, on arsenic contaminated water, are recommended.

Arsenic exposure has been associated with decreased club cell secretory protein (CC16) levels in adults. Further, both arsenic exposure and decreased levels of CC16 in childhood have been associated with decreased adult lung function. Our objective was to determine if urinary CC16 levels in children are associated with arsenic concentrations in environmental media collected from their homes. Yard soil, house dust, and tap water were taken from 34 homes. Urine and toenail samples were collected from 68 children. All concentrations were natural log-transformed prior to data analysis. There were associations between urinary CC16 and arsenic concentration in soil (b = -0.43, p = 0.001, R-2 = 0.08), water (b = -0.22, p = 0.07, R-2 = 0.03), house dust (b = -0.37, p = 0.07, R-2 = 0.04), and dust loading (b = -0.21, p = 0.04, R-2 = 0.04). In multiple analyses, only the concentration of arsenic in soil was associated with urinary CC16 levels (b = -0.42, p = 0.02, R-2 = 0.14 (full model)) after accounting for other factors. The association between urinary CC16 and soil arsenic may suggest that localized arsenic exposure in the lungs could damage the airway epithelium and predispose children for diminished lung function. Future work to assess this possible mechanism should examine potential associations between airborne arsenic exposures, CC16 levels, lung function, and other possible confounders in children in arsenic-impacted communities.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

The main objective of this study was to improve our understanding of biological filtration (biofilm type) treatment for manganese (Mn) removal in drinking water. Biological filtration treatment involves biofilms of Mn(II)-oxidizing microorganisms attached to solid filter material that remove and immobilize dissolved Mn(II) in raw water by conversion to black MnO2(s) precipitates. Mn-biological filtration is an emerging green technology that can serve as an alternative to conventional physicochemical treatments but its full potential is hindered by various factors. These include lack of understanding the: (1) optimal removal conditions for Mn, (2) mechanisms for Mn releases of the accumulated Mn in the biofilter, and (3) effects of recalcitrant natural organic matter (NOM) on biofiltration. Confounding these issues is the unknown identity of the diverse microbial communities which occupy the biofilms attached to the filter media. To investigate these issues, biological Mn removal was studied in laboratory bench scale reactors using a new Mn(II)-oxidizing bacterium isolate, Pseudomonas Putida EC112. The main research hypothesis formulated that the transition metal catalyst, MnO2(s), can increase the bioavailable carbon and energy from recalcitrant NOM (e.g., humic acids (HA)) to biological filters. Mn and HA can be found in most natural waters, including groundwaters, lakes and streams. To test the hypothesis, the potential for strain EC112 growth and Mn(II) oxidation utilizing the organic substrate products from the oxidation reaction between HA and MnO2(s) was assessed. Biological Mn(II)-oxidation kinetics were investigated in batch (suspended cell) and continuous flow (biofilm) bioreactors at optimal pH and temperature conditions for strain EC112. Batch kinetics was successfully characterized with the Monod model. Continuous flow steady-state kinetics was modeled with a single, zero-order kinetic parameter. Enhanced Mn(II) removal capacity was observed for strain EC112 in batch and continuous flow reactors in the presence of HA and MnO2. The effect of MnO2(s) on HA biodegradability was studied and optimal conditions for biodegradation were identified. Biofilter Mn(II) releases were observed during the continuous flow bioreactor experiments. Release conditions were identified and releases modeled using pseudo first-order kinetics. Changes in HA structure induced by MnO2(s) oxidation were studied with Fourier transform infrared (FT-IR) and proton nuclear magnetic spectroscopy (1H-NMR).

<p>A study has been performed that investigates the variation of iron content in groundwater.</p><p>The study was initiated by Midvatten AB, which noticed that the iron content in groundwater samples can vary greatly over small distances. The purpose of this study was to geochemically and geohydrologically determine the factors that influence the content of iron and manganese in groundwater from a selection of eskers in Dalarna, and determine how to best sample groundwater with the method used by Midvatten AB. An evaluation was made of how the vertical variation in soil material, water composition, pumping time and pipe material affects the content of iron in groundwater. Piper diagrams were used to study the relationship between the chemical composition of the groundwater and the content of iron and manganese in groundwater samples from the studied areas. The groundwater from the studied areas was then classified in the Piper diagrams, according to the content of the major ions. Correlations were then studied between the classification and depth below groundwater table, depth below ground surface, pH, iron- and manganese content.</p><p>Field samples were collected from Lennheden in order to investigate the effect of vertical variations of soil material, pumping time and pipe material on the content of iron and manganese. This was also performed to evaluate the best way of sampling groundwater. The groundwater was sampled from a steel pipe and a plastic pipe. Redox potential, pH, dissolved oxygen, iron content, temperature in groundwater, turbidity and conductivity were measured for different depths and pumping times in field.</p><p>Also a groundwater sample from every sampling depth was sent to a laboratory for analysis. Diagrams and correlation tables were used to analyze these results. No correlation between iron and the major ions in groundwater was found in the Piper diagrams, but the content of manganese in groundwater had a tendency to increase with increasing alkalinity. The results from sampling groundwater showed that the average content of iron in groundwater was 0,11 mg/l from the steel pipe and 0,01 mg/l from the plastic pipe. Turbidity has the greatest effect on the analyzed content of iron in groundwater, thus the turbidity needs to be zero while sampling. A suggestion is that while investigating groundwater quality in large areas, iron pipes can be used. When the best place is located, plastic pipes can be used when the iron content needs to be investigated in detail.</p> / <p>Då företaget Midvatten AB har märkt att järnhalten vid provtagning av grundvattnet kan variera stort på små områden har en studie av järnhaltens variation i grundvattnet utförts.</p><p>Syftet var att geokemiskt och geohydrologiskt bestämma de faktorer som påverkar järn- och manganhalten i grundvattnet i ett urval isälvsavlagringar i Dalarna, samt att bestämma hur man bäst ska provta grundvatten med Midvattens AB:s provtagningsmetodik. Studien skulle då utvärdera hur de vertikala variationerna i jordmaterial, vattensammansättning, pumptid och hur rörmaterialet påverkar järn- och manganhalten i uppumpat grundvatten. För att studera sambandet mellan den kemiska sammansättningen i grundvattnet och järn- och manganhalten analyserades flera tidigare insamlade data på grundvattenprov från de studerade lokalerna i Piperdiagram. I Piperdiagrammet klassificerades grundvattenproverna till en hydrokemisk typ med hjälp av sammansättningen av de vanligaste jonerna. Samband söktes mellan klassningen av grundvattenproverna och det uttagna provets djup under grundvattenytan, det uttagna provets djup under markytan, pH, järn- och manganhalt i brunnen.</p><p>Vid undersökning av hur de vertikala variationerna i grundvattnet, pumptiden och rörmaterialet påverkade järnhalten i grundvattnet togs flera grundvattenprover i fält i Lennheden. Detta gjordes även för att utvärdera bästa tillvägagångssätt vid provtagning av grundvattnet. Grundvattnet pumpades upp i vardera ett stålrör och ett plaströr. Redoxpotential, pH, syrgashalt, järnhalt, temperatur i vattnet, turbiditet och konduktivitet mättes vid olika djup och pumptider. Prov för varje provtagningspunkt skickades in till laboratorium för analys. Resultaten av dessa analyser undersöktes därefter i diagram och korrelationstabeller. I Piperdiagrammen märktes inget samband mellan järn och grundvattnets vanligaste joner, men manganhalten tenderade att öka med ökad alkalinitet. När grundvattnet provtogs i fält var medelhalten på järn 0,11 mg/l från ett stålrör och 0,01 mg/l från ett plaströr. Det tyder på att stålröret bidrog till en högre järnhalt i grundvattnet. Den parameter (förutom stålröret) som visade störst påverkan på analysresultatet av järn i laboratorium var turbiditeten. Således behöver turbiditeten i fält vara noll vid provtagning av järn till laboratorium. Förslagsvis kan stålrör användas vid övergripande undersökning av grundvattenkvalité. Plaströr kan sedan användas vid detaljerad undersökning av järnhalten i grundvattnet när bästa plats valts.</p>

<p>Syftet med examensarbetet var att undersöka effekterna av ozonering och filtrering på råvattnet från sjön Mälaren. Studien är utförd i en pilotanläggning på Lovö vattenverk, Stockholm Vatten AB, under våren 2004.</p><p>En negativ effekt med den konventionella reningen är den stora konsumtionen av kemiska koagulanter. Kemikalieanvändningen leder till många transporter och processen producerar också ett slam som för närvarande transporteras till Mälaren. År 2001 byggdes en pilotanläggning på Lovö vattenverk för utveckling av nya processer, en av processerna är ozonering följt av olika filter.</p><p>Ozonering har använts i Europa i många år som desinfektion i slutet av dricksvattenreningsprocessen. Intresset för ozonering har ökat markant sista åren och idag används ozonet också i andra steg i processen. Förutom desinfektion har ozonet andra fördelar, som oxidation av järn och magnesium, mikroflockning, reduktion av lukt och smak samt är bra på att reducera färgen på vattnet. Mikroflockningen leder till att kemikalieanvändningen kan minska och i vissa fall tas bort helt.</p><p>Den här studien startade med en litteraturundersökning följd av försök med ozonering och filtrering i pilotanläggningen. De första undersökningarna sammanfattades med att ozonering följt av filtrering inte gav tillräckligt bra resultat och processen behöver ett komplement för att producera ett högklassigt vatten.</p><p>Undersökningen fortsatte med laboratorieanalyser för att undersöka effekterna av olika kemiska koagulanter. Resultatet visade att järnsulfat tillsammans med kalcium var ett bra alternativ och en lägre kemikaliedos kunde användas.</p><p>Efter implementering av kalcium och järnsulfat till pilotanläggningen testades olika ozondoser och olika järnsulfatdoser. Det bästa resultatet erhölls då man använde sig av en ozondos på 6 mg O3/l och en järnsulfatdos på 50-60 μmol/l. Denna mängd av järnsulfat är ca 60 % lägre än den dos som används vid den konventionella reningen på Lovö vattenverk.</p><p>Olika filter används i pilotanläggningen och för att förbättra resultatet provades även ett Filtralite-filter som biofilter istället för GAC-filtret. Jämförelsen mellan Filtralite-filter och GAC-filter visade på stora skillnader i parametervärden i början av studietiden. När bakteriepopulationen ökade i Filtralite-filtret blev skillnaderna mindre och i slutet av undersökningstiden var parametervärdena likartade. Det slutliga resultatet indikerar att Filtralite-filter kan vara ett bra alternativ som biofilter.</p> / <p>This Master thesis was made to investigate the effects of ozonation and filtration on raw water from Lake Mälaren. The study was performed in lab-scale as well as in a pilot plant at Lovö waterworks, Stockholm Water Company during spring 2004.</p><p>The conventional treatment at Lovö waterworks comes with a few disadvantages, such as large consumption of chemical coagulants. The chemical consumption leads to many transports and the treatment also produces a sludge which is, in present, returned to Lake Mälaren. In 2001 a pilot plant were built at Lovö waterworks for research on new treatment processes, and ozonation followed by filtration is one of them.</p><p>Ozonation has been used in Europe for several years as disinfection at the end of the drinking water treatment process. The interests of ozonation has increased significantly in recent years and today the ozonation is used in other steps in the drinking water treatment process. Except for the disinfection, ozone has other benefits such as oxidation of iron and manganese, microflocculation, reduction of taste and odour and it is also effective to reduce the water colour. The microflocculation leads to the fact that less or no coagulants need to be used in the process.</p><p>This study started with a literature overview followed by experiments on ozonation and filtration in the pilot plant. After the first experiments the conclusions were that the ozonation and filtration did not reach the same results as Lovö waterworks. To continue, jar tests were made to see the effects of different coagulants. The result indicated that ferric sulphate together with calcium addition (pH-adjustment) was a good alternative. Thereby a lower coagulant dose could be used.</p><p>When ferric sulphate and calcium were implemented into the pilot plant, different ozone doses and ferric sulphate doses were tested. The best results occurred when an ozone dose of 6 mg O3/l and a ferric sulphate dose of 50-60 μmol/l were used. This amount of ferric sulphate is approximately 60 % lower than that for the conventional treatment at Lovö waterworks. To produce ozone electrons are needed and energy consumption increases with approximately 66 % compared to the conventional treatment. The decrease in chemical dose and increase in energy demand gives a decrease of the total cost with 10 % compared to the conventional treatment. The results indicate that the treatment with ozonation, calcium addition and ferric sulphate as a coagulant is an alternative to the conventional treatment.</p><p>Different filters were used in the pilot plant and to improve the results a Filtralite-filter was tested instead of the GAC-filter as a bio filter. When comparing Filtralite-filter with the GAC-filter there were large differences between the filters at the beginning of the study. When the bacteria population in the Filtralite-filter had started to increase the differences became less. In the end of the experimental period the filters had similar conditions and Filtralite-filter may be a good alternative as a biofilter.</p>

2 pp. / The greatest management concern with animal wastes is the movement of nitrate into water supplies. Health problems in humans and livestock can result from excessive levels of nitrate in drinking water. This publication outlines the guidelines to minimizing the risk of contaminating your drinking water. It also lists a number of questions to check if your management practices in the collection and storage of animal wastes may pose a risk to your groundwater.

6 pp. / 1. Drinking Water Wells; 2. Private Water Well Components; 3. Do Deeper Wells Mean Better Water; 4. Maintaining Your Private Well Water System; 5. Private Well Protection; 6. Well Water Testing and Understanding the Results; 7. Obtaining a Water Sample for Bacterial Analysis; 8. Microorganisms in Private Water Wells; 9. Lead in Private Water Wells; 10. Nitrate in Private Water Wells; 11.Arsenic in Private Water Wells; 12. Matching Drinking Water Quality Problems to Treatment Methods; 13. Commonly Available Home Water Treatment Systems; 14. Hard Water: To Soften or Not to Soften; 15. Shock Chlorination of Private Water Wells / This fact sheet is one in a series of fifteen for private water well owners. The one- to four-page fact sheets will be assembled into a two-pocket folder entitled Private Well Owners Guide. The titles will also be a part of the Changing Rural Landscapes project whose goal is to educate exurban, small acreage residents. The authors have made every effort to align the fact sheets with the proposed Arizona Cooperative Extension booklet An Arizona Well Owners Guide to Water Sources, Quality, Sources, Testing, Treatment, and Well Maintenance by Artiola and Uhlman. The private well owner project was funded by both the University of Arizonas Water Sustainability Program-Technology and Research Initiative Fund and the USDA-CSREES Region 9 Water Quality Program.

4 pp. / This fact sheet is to be taken from research conducted by Uhlman and Rahman and published on the WRRC web site as: "Predicting Ground Water Vulnerability to Nitrate in Arizona". Funded by TRIF and peer reviewed by ADEQ. It also follows on "Arizona Well Owner's Guide to Water Supply" and also "Arizona Drinking Water Well Contaminants" (part 1 already submitted, part 2 in process). / Arizona's arid environment and aquifer types allow for the persistence of nitrate contamination in ground water. Agricultural practices and the prevalence of septic systems contributes to this water quality concern, resulting in nitrate exceeding the EPA Maximum Contaminant Level (MCL) in several locations across the state. Working with known nitrate concentrations in 6,800 wells across the state, this fact sheet presents maps showing the probability of nitrate contamination of ground water exceeding the MCL. The importance of monitoring your domestic water supply well for nitrate is emphasized.