The growth of fossil fuel production in North Dakota has resulted in numerous releases of brine. Brine releases cause vegetation mortality as well as the deterioration of soil structural and edaphic properties. Little research to date has been dedicated to the germination response of plant species grown in North Dakota to brine-induced salinity. Through the exposure of plant seeds to increasing levels of brine and NaCl-induced salinity, it was determined that the graminoid species Elymus hoffmannii (AC Saltlander) and Pascopyrum smithii (Western Wheatgrass) exhibited the greatest germination at high salinities. Current remediation technologies for brine-impacted lands often produce mixed results, requiring further research and testing. In two laboratory experiments, the ability of materials to wick salts from brine-contaminated soils was tested. The results of these studies show that some materials reduced Na concentrations in sandy loam, loam, and silty clay soils by upwards of 88, 89.5, 38.4% respectively.

Selected public health criteria of pasteurised milk available to the consumer from milk -shops in a selected area of Pretoria compared with a national distributor's milk were evaluated. Pasteurised milk samples were obtained from five randomly selected milk-shops in the northwestern part of Pretoria over a six-week period from June to August 1998. Milk from a wellknown national distributor was also obtained from three supermarkets in the same area during the same time period to act as the control milk. Mean total aerobic bacterial counts, coliform counts and psychrotrophic bacterial counts were determined. The presence of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Salmonella species, staphylococcal enterotoxins, inhibitory substances, alkaline phosphatase and somatic cells in milk were also determined. Of the 135 milk samples purchased from milk-shops, 87% were not fit for human consumption on the basis of the minimum standards prescribed in the Foodstuffs, Cosmetics and Disinfectants Act (Act 54 of 1972). In contrast, 100% of the 79 control milk samples passed all the safety criteria laid down in the Act. x Milk-shop milk quality varied between milk-shops and between sampling days. All milk-shop milk was sold as having been pasteurised, yet 38.5% of milk samples purchased failed the alkaline phosphatase test, indicating that they had not been pasteurised correctly or were contaminated with raw milk. The total aerobic plate counts were generally high for all milkshop milk samples ranging from 1.0 x 102 to 2.7 X 107 CFU/mQ with a median value of 41000 CFU/mQ, whereas for the control milk it ranged from 7.0 x 102 to 8.7 X 103 CFU/mQ, with a median value of 2 200 CFU/mQ. Coliform counts varied from 0 to 3.4 X 104 per mQ in milk-shop milk, with 68% of samples having counts lower than 20 coliforms/mQ, which is the maximum number allowed when the Petrifilm method of counting is used. Coliforms could not be detected in 1 mQ of control milk samples. E. coli was detected in 1 mQ of 17% of milkshop milk, 95% of which originated from milk which was alkaline phosphatase positive. Salmonella spp. could not be detected in 1 mQ in any of the E. coli-positive milk tested. Psychrotrophic bacterial counts done after pre-incubation of milk-shop milk were extremely high, and ranged from 3 x lOS to 2.2 X 108 CFU/mQ, with a median value of 2.4 x 107 CFU/mQ. In Europe the psychrotrophic count may not be greater than 100 000 CFU/mQ. None of the milk-shop milk passed this European standard, whereas 98.7% of the milk obtained from the national distributor fell within the prescribed parameters. S. aureus was isolated from 54 (40%) milk-shop milk samples, and four (7.8%) of 51 isolates tested produced staphylococcal enterotoxins A (SEA), B (SEB), D (SED) or a combination. Control milk did not contain any S. aureus and 15 milk samples tested for the enterotoxin gave a negative result. All control milk was negative for inhibitory substances, but these were detected in 54.1 % of milk-shop milk. Somatic cell counts varied between 1.2 x 104 and 1.6 x 106 cells/mQ in the milk-shop milk, with a median count of 4.2 x 105 cells/mt Only 18.7% of samples had counts above the legal limit of 500 000 cells/mQ. The national distributor's milk always had counts less than 150 000 cells/mQ. xi The results showed that milk-shop milk differed significantly (p < 0.05) from the national distributor's milk, and that the quality of milk purchased from milk-shop outlets was generally of a poor bacteriological quality. The presence of inhibitory substances, and the isolation ofE. coli and S. aureus (some of which were able to produce enterotoxins) indicated potentially unsafe milk and posed a serious public health risk to consumers. / Dissertation (MMed Vet (Hyg))--University of Pretoria, 2000. / Production Animal Studies / unrestricted

The purpose of this investigation is to determine if clothing fabrics act as passive pollen collectors, and to determine if different fabrics vary with regard to the abundance and type of pollen trapped. Five of the most common fabrics in the United States (cotton, wool, polyester, silk and linen) were used to trap pollen. The pollen collecting apparatus was constructed of a 30 cm diameter circular needlepoint hoop, which vertically rotated freely, and was mounted on a dowel that was driven into the soil to chest height. Five pollen collectors, each with one of the five fabrics were placed at a collection site in rural, suburban, and urban habitats in Rhode Island for a 24 h period at weekly or biweekly intervals throughout 2002-2003. Pollen was washed from each of the fabrics and acetolysed. Total pollen per cm2 removed from each of the fabric types was estimated using a haemocytometer. The pollen types were identified, and 200 grains were counted to determine the relative abundance of the various pollen types recovered from the fabrics. Clothing fabrics act as passive pollen collectors and the flora recovered from the fabric represent the qualitative and quantitative components of the pollen rain for that specific day. There are quantitative differences among the relative abundance of pollen types from the three habitats (urban, suburban, and rural). Washing with water and a detergent eliminates a majority of the pollen from the fabrics.

Thesis advisor: Rudolph Hon / Over 10 million tons of deicers are applied on impervious surfaces during winter storms in the United States every year to create safer driving and walking conditions. Road salt, or sodium chloride, is the most common deicer due to its low price and wide availability. Increasing concentrations of sodium chloride (NaCl) over the past decades have been measured in surface waters and groundwater throughout North America and it is projected to continue increasing. As there are no cost effective alternatives available to road salt, its potential role as an environmental and drinking water contaminant needs to be investigated. Field measurements from previous studies reveal the homogenization of NaCl in the subsurface through consistent elevated levels year-round. Through the integration of field and laboratory methods, this thesis aims to investigate the role of subsurface processes in the transport and pathways of deicers from the point of deposition to eventual emergence in surface waters and its potential impact on drinking water supplies. To understand the contamination pathways of NaCl that result in the observed surface water concentrations, experimental simulations were designed that indicate that gravitational/convective processes are the most important initial processes influencing deicer transport, but that other processes such as diffusion, surface tension, and dispersion/advection also play important roles. / Thesis (MS) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

This thesis examines the impact of the physical contamination on optical surfaces of spacecraft by an ABS/GOX thruster. Plume contamination presents a significant operational hazard for spacecraft solar arrays and thermal control surfaces can lead to decreased power production and increased spacecraft temperatures. Historically, due to the lack of a reliable, on-demand, and multiple-use ignition methodology, hybrid rockets have never been previously considered for in-space propulsion. Recent advancements in hybrid rocket technologies, have made hybrid systems feasible for in space propulsion. However, prior to this study no research had ever been performed with regard to plume contamination effects due to hybrid rockets. This paper presents the results from a set of preliminary plume contamination measurements on a prototype small spacecraft hybrid rocket system, collected under both ambient and vacuum chamber conditions.

Flexible packaging is a growing successful market and the majority of flexible package applications are for the food industry. The demand for process optimization and reduced production costs, has led to an increase in flexible packaging. However, fast production lines can result in contamination in the seal area. For flexible food packaging, contamination is considered any food particle or substance trapped in the seal area. Current quality control processes can detect contamination in the seal area, but it is not determined if seal contamination effects seal quality. Oil-based and sodium based snack foods are two common categories that can be packaged on a horizontal flow film and seal (HFFS) flow-wrap machine. The study uses vegetable oil and a salt water solution to simulate the effect of liquid contamination along the T-point of flexible pouches made on an HFFS. The T-point refers to where the fin seal meets the end seal and requires the seal jaw to seal through four layers of film, which is the most difficult point to seal. The study tests a combination of different sealing temperatures and dwell time to determine the optimal sealing condition for a hermetic seal. A quality hermetic seal provides an enclosed seal with no leaks due to successful polymer chain entanglement between the two sealant layers. The different test categories of the study are non-contaminated (control), salt water solution for salt based foods, and vegetable oil for oil-based foods. Given the test parameters of the study, 140⁰C sealing temperature and 0.3 seconds dwell time are considered to be the optimal sealing condition for all three test categories. For Phase 1 of the study, salt water has a lower hermeticity pass rate compared to vegetable oil and non-contaminated seals. In addition, the effect of refrigerated storage temperature and ambient storage temperature did not show to be significant for any of the test categories. However, refrigerated conditions showed a higher hermeticity pass rate, but it was not statistically different. The findings for seal strength indicated no test category had higher or lower seal strength over the 14 day test period. Overall, the study shows there is no effect of liquid contaminant on hermeticity and seal strength for flexible film with LLDPE sealant layer.

Given rising concern over elevated lead in drinking water in the aftermath of the Flint Water Crisis, forthcoming revisions to the U.S. EPA Lead and Copper Rule (LCR), and federal funding designated for replacing lead service lines, lead-tin solder corrosion control will become increasingly important. Lead-tin solder is often a dominant source of lead in drinking water for homes built before 1986 and has been the source of several recent high-profile water lead contamination events. This dissertation advances fundamental understanding of lead-tin solder corrosion by demonstrating that 1) elevated nitrate in water can trigger severe solder corrosion associated with very high LCR action level exceedances, 2) spallation of metallic solder to water is a source of lead contamination, 3) zinc orthophosphate offers superior corrosion control to mitigate nitrate attack, and 4) free chlorine can inhibit solder corrosion by electrochemical reversal. These principles were also applied to an exemplary related problem of lead contamination of food stored in tin cans. The conventional understanding is that lead-tin solder corrosion is worsened by low pH, low alkalinity, and elevated chloride relative to sulfate, but a utility that recently switched to a source water previously classified as non-corrosive suffered severe contamination from lead solder. The incident was characterized by the detachment of large chunks of metallic, lead-bearing solder particles from copper pipe joints that sometimes clogged aerators of consumers' faucets. It also caused a 90th percentile lead level of 131 ppb, which was much higher than reported for the 2001-2004 Washington D.C. lead crisis (79 ppb) or the 2014- 2016 Flint, MI water lead crisis (29 ppb). An exhaustive investigation of possible causes eventually revealed a strong correlation (r2=0.79) between seasonal fluctuations in surface water nitrate levels and the 90th percentile lead. The association of high lead with nitrate was unambiguously proven in bench-scale experiments using both copper coupons with new 50:50 lead-tin solder and harvested pipes with aged solder (extracted from a home with ongoing lead release issues) that replicated the characteristic spallation of solder particles (up to 7-mm in length) to water. Lead levels were occasionally >1,000 ppb in homes and >100,000 ppb in the bench experiments with harvested pipe after exposure to high nitrate above 8 mg/L. This finding is especially concerning given that nitrate is not currently identified as a factor affecting solder corrosion in EPA corrosion control guidance and source water contamination by nitrate is increasingly problematic. It was critically important to identify the mechanism by which nitrate caused solder spallation. Analysis of lead-tin solder surfaces in the bench-scale tests and harvested pipes indicated that nitrate preferentially attacked tin in the solder alloy. Nitrate severely detinned solder alloys > 40% tin by weight, causing cracking and detachment of metallic chunks of lead-tin solder from copper surfaces in a matter of weeks. Pure lead and alloys with less than 30% tin corroded more uniformly in the presence of nitrate and were not subject to spallation. Nitrate is reduced to a combination of ammonia and other nitrogenous compounds via reduction reactions that drove lead-tin solder corrosion at the anode. Nitrate also caused 1.3 times more metal weight loss by corrosion than could be explained by Faraday's law even in short-term 32-hour experiments, consistent with a previously identified "chunk effect" and anomalously high tin anode weight loss in nitrate solutions. This severe solder spallation mechanism has never been reported previously in drinking water environments and seems to be unique to nitrate for high tin-content alloys. This discovery also raises concerns about the possibility of pipe joint failures using lead-free tin-based solders that became more commonplace after the federal ban on lead solder in 1986. Common corrosion control strategies, including the use of phosphate corrosion inhibitors, failed to adequately reduce 90th percentile lead levels at the utility affected by runoff water with high nitrate after 6 months of application. Studies using new lead-tin solder and harvested pipes with aged solder demonstrated that zinc orthophosphate outperformed orthophosphate in controlling corrosion in high nitrate water and reduced lead release by 82-90% compared to phosphate alone or no inhibitor. The benefits of zinc orthophosphate improved with time and the dose of zinc delivered to the pipes. When zinc orthophosphate was applied at the water treatment plant, the 90th percentile lead levels in the affected community fell below the action level within 6 months. Analysis of the pipe scale demonstrated that zinc orthophosphate works by coating the interface usually subject to intense galvanic corrosion between copper and solder. Disinfectants may also play a role in controlling lead contamination from solder. Two water utilities in the Pacific Northwest experienced lead action level exceedances for decades due to solder corrosion while using the same source water with chloramine disinfectant. After one utility switched to a similar water source using free chlorine disinfectant, lead release dropped to low levels within months. This was consistent with laboratory experiments conducted at the second utility more than three decades ago that indicated much lower lead release using free chlorine versus chloramine using the water utility's source water. There was previously no explanation for the benefits from free chlorine, but it was recently demonstrated that chlorine can cause electrochemical reversal of a copper-lead pipe galvanic cell, which dramatically reduced lead release to water. It was hypothesized that a similar reaction could occur for lead-tin solder as well. This was confirmed when lead-tin solder and copper connections exposed to 4 mg/L free chlorine in circulating rigs experienced electrochemical reversal in some waters over a period of weeks. The electrochemical reversal was accompanied by dramatic decreases in lead release, concomitant with the formation of insoluble lead (IV) oxide scale. In some situations where traditional corrosion inhibitors are not effective, it is possible that electrochemical reversal due to free chlorine may control lead solder corrosion, either unintentionally or purposefully. This new understanding of nitrate's ability to exacerbate lead contamination from lead-tin alloys in drinking water was then extended to concerns about lead contamination of food stored in tin-plated cans. Fruits and their juices can contain nitrate, and if lead is present in the tin plating, the resulting corrosion is predicted to cause significant contamination. Twenty-one brands of canned pears from across the U.S. were assessed for lead content, and one brand was found to contain 2-3 times higher lead in the fruit (average=14 ppb, max=38 ppb) and syrup (average=7 ppb, max=15 ppb) than other brands. The brand of cans with higher lead in the fruit also had higher levels of lead in the can materials: surface lead levels in the interior tin-plate was 0.1% by mass on average (max=0.60%) and 7.5% by mass on average (max=29%) in the interior seam, which is up to 146 times the 0.2% value advised in FDA guidelines for lead in food-contact surfaces. Follow-up testing with three brands of canned pears confirmed lead levels in the syrup were also associated with higher levels of ammonia in the juice—ammonia is a reaction product of nitrate corrosion of tin in the can. To confirm that the can material was the source of the lead contamination, the pear cans were emptied and then refilled with a variety of synthetic solutions containing up to 50 mg/L NO3-N. The higher nitrate levels always formed ammonia and were associated with higher lead release in some cases. The use of lead-tin alloys (either lead-bearing tin-plate or solder) in unlined canned goods with solutions known to contain nitrates can create unnecessary lead exposure for consumers. This dissertation provides novel insights into lead-tin solder corrosion with profound implications for water lead contamination, the integrity of potable water infrastructure, and corrosion control strategies in potable water. Rising concerns about nitrate contamination of source waters underscore the importance of understanding these effects on lead and public health. As illustrated by the application of these principles to lead contamination of tin-lined fruit cans, the results may also enhance understanding of corrosion of tin-based materials in electronics, museum artifacts, electrochemical water treatment, and in the automotive and aerospace industries. / Doctor of Philosophy / Given rising concern over elevated lead in drinking water in the aftermath of the Flint Water Crisis, forthcoming revisions to the U.S. EPA Lead and Copper Rule (LCR), and federal funding designated for replacing lead service lines, the issue of lead-tin solder corrosion control will become increasingly important. Lead-tin solder is often a dominant source of lead in drinking water for homes built before 1986 and has been the source of several recent high-profile water lead contamination events. This dissertation advances the fundamental understanding of lead-tin solder corrosion by demonstrating that 1) high source water nitrate levels can trigger severe solder corrosion associated with elevated lead release in drinking water, 2) detachment (i.e., spallation) of metallic solder to water is a source of lead contamination, 3) zinc orthophosphate offers superior corrosion control to mitigate nitrate attack, and 4) free chlorine disinfectant can inhibit solder corrosion by electrochemical reversal. These principles were also applied to an exemplary related problem of lead contamination of food stored in tin cans. It is understood that lead-tin solder corrosion can be affected by water chemistry, but a utility that recently switched to a new source water previously classified as non-corrosive was surprised to discover severe water lead contamination from solder. The contamination was characterized by the detachment of large chunks of lead-bearing solder particles from copper pipe joints that sometimes clogged aerators of consumers' faucets. It also caused a 90th percentile lead level of 131 ppb, a level much higher than reported for the 2001-2004 Washington D.C. lead crisis (79 ppb) or the 2014-2016 Flint, MI water lead crisis (29 ppb). The presence of such large chunks of lead-bearing solder is contrary to the belief that water lead contamination occurs by the dissolution of lead rust from solder. An exhaustive investigation of possible causes eventually revealed that lead release in this community was strongly related to seasonal fluctuations in surface water nitrate levels. The association of high lead with nitrate was unambiguously proven in experiments using both copper coupons with new 50:50 lead-tin solder and harvested pipes with aged solder that had been extracted from a home with ongoing lead release issues, which replicated the characteristic spallation of solder particles (up to 7-mm in length) to water. Lead levels were occasionally >1,000 ppb in homes and >100,000 ppb in the bench experiments with harvested pipe after exposure to high nitrate above 8 mg/L. These levels of water lead contamination are amongst the highest ever recorded. This discovery is especially concerning given that nitrate is not currently identified as a factor affecting solder corrosion in EPA corrosion control guidance and source water contamination by nitrate is increasingly problematic. It was critically important to better understand the mechanism by which nitrate caused solder spallation. Analysis of lead-tin solder surfaces in the bench-scale tests and harvested pipes indicated that nitrate preferentially attacked tin in the solder alloy. Nitrate is reduced to a combination of ammonia and other nitrogenous compounds while contributing to lead-tin solder corrosion at the anode. Nitrate severely degraded solder alloys with >40% tin by weight, causing cracking and detachment of metallic chunks of lead-tin solder from copper surfaces in a matter of weeks. Pure lead and alloys with less than 30% tin corroded more uniformly in the presence of nitrate and were not subject to spallation. Nitrate corrosion also caused 1.3 times more water contamination than predicted by conventional chemical reactions that do not consider spallation, even in short-term 32-hour experiments. This severe solder spallation mechanism has never been reported previously in drinking water environments and at present seems to be unique to nitrate for solder alloys with high tin content. This discovery also raises concerns about the possibility of pipe joint failures, and associated pipe bursting and water damage, when using lead-free tin-based solders that became more commonplace after the federal ban on lead solder in 1986. Common corrosion control strategies, including the use phosphate corrosion inhibitors, failed to adequately reduce 90th percentile lead levels at the utility affected by runoff water with high nitrate after 6 months of application. Studies using new lead-tin solder and harvested pipes with aged solder demonstrated that zinc orthophosphate outperformed orthophosphate in controlling corrosion in high nitrate water, reducing lead release by 82-90% compared to phosphate alone or no inhibitor. The benefits of zinc orthophosphate improved with time and the dose of zinc delivered to the pipes. When zinc orthophosphate was applied at the water treatment plant, the 90th percentile lead levels in the affected community fell below the action level within 6 months. Analysis of the pipe scale demonstrated that zinc orthophosphate works by coating the interface usually subject to the most intense galvanic corrosion between copper and solder. Disinfectants used to kill bacteria in drinking water may also play a role in controlling lead contamination from solder. Two water utilities in the Pacific Northwest experienced lead action level exceedances for decades due to solder corrosion while using the same source water with chloramine disinfectant. After one utility switched to a similar water source using free chlorine disinfectant, lead release dropped to low levels within months. This was consistent with results from a laboratory study conducted more than three decades ago at the second utility that indicated much lower lead release using free chlorine versus chloramine using this water utility's source water. There was previously no explanation for the benefits from free chlorine, but it was recently demonstrated that chlorine can control lead pipe corrosion by reversing normal electrochemical reactions which dramatically reduced lead release to water. It was hypothesized that chlorine could have a similar effect for lead-tin solder as well. That hypothesis was confirmed when lead-tin solder and copper connections exposed to 4 mg/L free chlorine in circulating rigs experienced electrochemical reversal in a synthesized version of this water within weeks. The electrochemical reversal was accompanied by dramatic decreases in lead release, along with the formation of protective lead (IV) oxide pipe scale. These unexpected benefits of free chlorine may help explain why some water utilities with water normally considered corrosive have not been experiencing lead solder corrosion problems or lead action level exceedances. This new understanding of nitrate's ability to exacerbate lead contamination from lead-tin alloys in drinking water was then applied to concerns about lead contamination of food stored in tin-plated cans. Fruits and their juices can contain nitrate, and if lead is present in the tin plating, the resulting corrosion is predicted to cause significant contamination. Twenty-one brands of canned pears from across the U.S. were assessed for lead content, and one brand was found to contain 2-3 times higher lead in the fruit (average=14 ppb, max=38 ppb) and syrup (average=7 ppb, max=15 ppb) than other brands. The brand of cans with higher lead in the fruit also had higher levels of lead in the can materials: surface lead levels in the interior tin-plate was 0.1% by mass on average (max= 0.60%) and 7.5% by mass on average (max=29%) in the interior seam, which is up to 146 times the 0.2% value advised in FDA guidelines for lead in surfaces that contact food. Follow-up testing with three brands of canned pears confirmed lead levels in the syrup were also associated with higher levels of ammonia (a reaction product formed by nitrate corrosion of tin in the can) in the juice. To confirm that the can material and high levels of nitrate in the original food contributed to the lead contamination, the pear cans were emptied and then refilled with a variety of synthetic solutions containing up to 50 mg/L nitrate. The higher levels of nitrate always formed ammonia and were associated with higher lead release in some cases. The use of tin alloys (either lead-bearing tin-plate or solder) to package acidic food containing nitrate can create unnecessary lead exposure for consumers. This dissertation provides novel insights into lead-tin solder corrosion with profound implications for water lead contamination, the integrity of potable water infrastructure, and corrosion control strategies in potable water. Rising concerns about nitrate contamination of source waters underscore the importance of better understanding these effects on lead and public health. As illustrated by the application of these principles to lead contamination of tin-lined fruit cans, these results may also enhance understanding of corrosion of tin-based materials in electronics, museum artifacts, electrochemical water treatment, and in the automotive and aerospace industries.

No description available.

No description available.

<p> Metal contamination from anthropogenic activities is of great concern due to the associated detrimental effects on ecosystem health. An increase in metal concentrations in the dissolved phase creates greater ecosystem impacts. Thus, the relative extent of metal distribution between sediment and dissolved compartments, and an understanding of the factors that control this partitioning is key to assessing metal impacts. In this thesis, metal concentrations were determined for a suite of 12 metals (Cr, Mn, Co, Cu, Sn, Ag, As, Ni, Zn, Cd, Se and Fe) associated with three compartments, dissolved, surficial bed sediment and suspended particulate matter (SPM) in Hamilton Harbour, Ontario. Due to highly dynamic interactions of anthropogenic impacts that may work together to affect metal distributions as well as processes that occur over small or rapid scales, a high-resolution temporal and spatial scale was used to evaluate these metal distributions over a seasonal timeframe. </p> <p> Concentrations of metals amongst sediment fractions indicated that sediment metal uptake was largely controlled by the concentration of the sediment associated amorphous and crystalline oxyhydroxide fractions accounting for up to 90% of total sediment bound metal, even though the oxyhydroxides only accounted for a maximum of 23% of the total sediment mass for both surficial bed sediment and SPM compartments. The formation and dissolution of amorphous oxyhydroxides is commonly a microbially mediated process. Thus, these results underscore the important role of oxyhydroxides and the microbial processes that contribute to their formation and dissolution m controlling metal dynamics, and likely metal impacts in Hamilton Harbour. </p> <p> Metal partitioning was found to be both spatially and temporally variable for all compartments, temporally ranging 0.5 to 4 orders of magnitude for a given element; indicating highly dynamic metal exchanges between sediment and solution compartments and fluctuating distributions over the time and spatial scales examined. </p> <p> The suite of variables that are considered to control metal distribution between dissolved and sediment compartments, and thus impact metal toxicity (i.e., temperature, pH, specific conductivity, oxidation-reduction potential, dissolved organic carbon concentration, SPM concentration (for SPM associated metals only), fraction concentrations i.e. g carbonate /g solid, g amorphous oxyhydroxide I g solid, etc., and dissolved metal concentrations) did not constrain the variability in observed metal distribution behaviour, indicating that other factors in this system, such as hydrodynamic disturbances associated with shipping traffic and channelized water currents, as well as specific point source metal discharges, may play a larger role in determining metal partitioning in Hamilton Harbour, compared to less anthropogenically, impacted systems. Furthermore, no one master variable defming metal partitioning between the dissolved and sediment compartments was found, rather relationships controlling metal distribution behavior were site, compartment, sediment fraction and element specific highlighting the challenges for the development of a Harbour-wide management plan for priority metal contaminants. The results presented in this thesis, show that it is necessary to consider metal, site and compartment specific conditions as well as fully addressing temporal variability in metal behaviour. In addition, the results of this thesis point to the need to address hydrodynamic disturbance and point source influences on metal behaviour in Hamilton Harbour and likely extend to other multi-impacted metal contaminated systems. </p> / Thesis / Master of Science (MSc)