Thesis advisor: Rudolph Hon / This study characterizes the current state of water quality of surface streams and rivers in the eastern New England region. A set of water quality data for nine rivers, part of the USGS National Water-Quality Assessment (NAWQA) Program was statistically evaluated to identify natural and anthropogenic persistent influential factors on water quality in surface waters. Binary analysis and multivariate analysis, mainly Principal Component Analysis (PCA) and Factor Analysis (FA) were applied to determine the least number of independent relationships among multiple chemical components in the data set. Statistical results show that in eight of the nine rivers included in this study, four principal components can explain about 80% of the total variance of the original data. The most significant contributing factors can be identified with: (1) chemical weathering; (2) road salt applications; (3) nutrient cycling; and (4) agricultural/waste water. / Thesis (MS) — Boston College, 2009. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Geology and Geophysics.

Investigations were conducted at a salt/premix storage facility lying on top of a glacial drumlin near the coastline in eastern Massachusetts, to characterize salt contaminated groundwater. Groundwater hydrogeochemical variations at different depths were determined based on ten years of monthly or quarterly water quality data from 54 monitoring wells. Groundwater was grouped in three water categories – shallow, middle and deep. Hydrogeochemical characterization indicates that the dominant water types are Na-Cl, Na-Ca-Cl and Ca-HCO3 from the shallow to deep water group. Rock weathering is the dominant hydrogeochemical process for deep water group, whereas salt water percolation and cation exchange control chemical compositions of the shallow and middle water groups. Groundwater is classified as post-cation exchange, under-cation exchange and non-cation exchange groups. Gaseous CO2 and total dissolved inorganic carbon (TDIC) transport in unsaturated and saturated zones of the glacial drumlin was also investigated. A measurement system with non-dispersive infrared gas sensors was used to monitor the recovery of CO2 concentration in the headspace of purged monitoring wells. The transient, radial diffusion of CO2 from surrounding soil to the monitoring well is analogous to an existing slug test theory when the headspace is fully mixed. A nested Fibonacci search was performed to calibrate equilibrium soil CO2 concentration and soil gas porosity near the water table. The results demonstrate that water table wells with partially submerged screens can facilitate the equilibrium between the gaseous and dissolved phase of CO2. In the saturated zone, a new model was developed to describe the vertical transport of TDIC in the groundwater. The vertical transport was considered to be a balance of uniform vertical advection and vertical dispersion, subject to a first order source term with two boundary conditions at depth and at the water table. Fifteen years of monthly or quarterly data from 28 monitoring wells in the southern part of the site were used to calibrate a vertical dispersivity α of 5.9 cm and a first order source constant λ of 8.2 x10-9 s-1. These values suggest minimal degassing of groundwater CO2 across the water table and till deposition during Late Wisconsinan deglaciation of the region.

No description available.

In many source waters across the United States (US), chloride levels are increasing and this change could be problematic for galvanized iron pipe (GIP) installed in consumers' homes and buildings. The higher levels of chloride might increase the rate of galvanic corrosion between the sacrificial zinc coating and the underlying iron (steel) pipe. There are also concerns that the iron in GIP can accumulate lead on its surface from upstream lead service lines, occasionally causing high lead in water from GIP during scale sloughing and associated red water events. The role of high chloride and potential mitigation strategies by orthophosphate and alkalinity on galvanic iron-zinc corrosion in GIP were examined by using new iron and zinc wires, and complementary studies with 85-year-old harvested GIP coupons from the Washington Suburban Sanitary Commission (WSSC). Sequential samplings on a constructed pilot-scale test rig with copper – lead – GIP ¬– brass meter configuration were used to evaluate lead source fingerprinting methods (metal co-occurrence, correlating the plumbing configuration to sample profiling data, and evaluation of lead isotope ratios) and role of flow rate. As chloride concentration increased from 2.6 to 554 mg/L, galvanic current and weight loss of sacrificial zinc increased by about an order of magnitude. Iron leaching also increased by 4.4 times as chloride levels increased by a factor of 12 in WSSC modified water to simulate actual road salt runoff events. Increased orthophosphate or alkalinity could at least partly counter the adverse effects of chloride, as the average iron concentration decreased by 43% as orthophosphate level increased from 3.8 to 11.2 mg/L as P, and average iron concentrations decreased by 32% as alkalinity increased from 50 to 90 mg/L as CaCO3. Applying fingerprinting methods on sequential samples has the potential to determine whether premise plumbing contains GIP and/or lead pipe. Specifically, the metal co-occurrence fingerprinting technique was successful in identifying the location of GIP by the detection of low-level cadmium, and the lead isotope ratio fingerprinting technique was fairly successful in identifying lead pipe. Additionally, our study found that GIP was not contaminated by an upstream lead pipe after five months of conditioning; hence, water discoloration (iron level > 400 ppb) does not always indicate lead problems from GIP. However, with longer exposure of GIP to lead pipe, the magnitude of the problem might increase. As flow rate increased from 0.9 to 2.4 GPM, the median particulate iron release increased by 3.3 times, and the median particulate lead release (>83% particulate lead) increased by 4.9 times. / Master of Science / In many source waters across the United States (US), chloride levels are increasing and this change could be problematic for galvanized iron pipe (GIP) installed in consumers' homes and buildings. The higher levels of chloride might increase the rate of galvanic corrosion in GIP. There are also concerns that the iron in GIP can accumulate lead on its surface from upstream lead service lines, occasionally causing high lead in water from GIP during scale sloughing and associated red water events. The role of high chloride and potential mitigation strategies for GIP by adjusting orthophosphate and alkalinity were examined by conducting bench scale testing. Sequential samplings on a constructed pilot-scale test rig with different lead source pipe sections were used to evaluate lead source fingerprinting methods and role of flow rate. Higher chloride in water increased galvanic current and weight loss of zinc coating as chloride concentration increased from 2.6 to 554 mg/L in the fundamental experiments. Iron leaching also increased as chloride levels increased in the GIP coupon testing. Increasing orthophosphate or alkalinity proved to counter the adverse effects of chloride as the average iron concentration decreased. Sampling profiles can be useful in determining whether premise plumbing contains GIP or lead pipe by using fingerprinting methods. Iron and lead leaching from GIP increased as the water flow rate increased.

För att motverka halka på vägar och skapa bättre framkomlighet och trafiksäkerhet för trafikanter under vintersäsonger, används halkskyddsmedel på vägarna. I dagsläget och sannolikt under en överskådlig framtid innebär det att man använder natriumkloridbaserade medel NaCl i form av vägsalt då NaCl är det mest effektiva samt kostnadseffektiva medlet för halkskydd. Trots att NaCl är det mest effektiva medlet mot halka kan vägsalt samtidigt orsaka vissa negativa effekter på miljön. Studier visar på att vägsaltet sprider sig i miljön genom flera olika transportmekanismer vilket gör vägsaltet till ett komplext problem. Vägsalt påverkar bland annat träden negativt, långvarig exponering för salt kan försvaga träden och leda till att träden dör. Klimatförändringar har potentialen att även i framtiden öka, om än kontraintuitivt, efterfrågan på vägsalt i städer med kallt vinterklimat. Därav behövs ett proaktivt tillvägagångssätt för att minska de negativa effekterna vägsaltet har på miljön och träden. Forskning visar på att det finns behov av mer kunskap samt kvalitativa studier gällande vägsalt och dess miljöeffekter. Hittills har det inte funnits någon probabilistisk metod för att bedöma miljörisken vägsalt utgör för gatuträden för att ge nödvändigt stöd till beslutsfattare. Riskbedömningar och riskhantering är viktiga medel i beslutstödjande arbeten. Syftet med denna studie har därav varit att utveckla, tillämpa och utvärdera modeller för övergripande miljöriskbedömningar av vägsalt som ett miljöförorenande ämne. För studien valdes två gator i Stockholms stad, Vasagatan samt Sockenvägen. Studien inleds med litteraturstudier som behandlar trädens roll i urbana miljöer, vägsaltets spridningsvägar, vägsaltets påverkan på träden och miljön samt olika saltmanagementmetoder. Baserade på data från litteraturstudien utfördes miljöriskbedömningar för träd-och vegetation, grundvatten samt jord i studieområdena. En riskbedömning utfördes för ett scenario där vägsalt inte används på vägarna och risken detta kan utgöra för människor. Vidare utvecklades och arbetades det fram olika åtgärdsförslag för studieområdena. Åtgärdsförslagen bedömdes och graderades i en bedömningsmatris. Sammantaget belyser studien vikten av att kontinuerligt samla in saltdata, skapa förståelse för vägsaltets spridningsvägar, utföra miljöriskanalyser på flera miljöområden gällande vägsalt, arbeta fram olika saltmanagementmetoder samt upprätta policyn för vägsalt i syfte att minimera vägsaltets skadliga effekter på träden och ekosystemen i Stockholms stad. / To prevent slippery roads and ensure better traffic safety for road-users during winter seasons, de-icing agents are used on the roads. Currently and probably for the foreseeable future this means using the sodium chloride-based agent NaCl in the form of road salt, which currently is the most effective and cost-effective de-icer. Despite benefits for road safety road salt can at the same time pose negative effects on the environment. Several studies describe how road salt spreads in the environment through several different transport mechanisms, which deems road salt a complex problem. Road salt affects, among other things trees negatively, prolonged exposure to salt weakens the trees and can lead to the death of the damaged trees. Climate change has the potential to even in the future, albeit counterintuitively, increase the demand for NaCl based road salt, during winter seasons in cities with continental climate, as road salt is a cost-effective agent. Hence, a proactive approach is needed to be able to reduce the negative effects road salt has on the environment and trees. Research shows there is a need for more knowledge and qualitative studies regarding road salt and its environmental effects and the effects on street trees. Until now there has been no probabilistic method to assess the environmental risks posed by road salt on street trees to provide the necessary support to decision makers. Environmental risk assessments and risk management are important tools in decision support. The aim of this study has therefore been to develop, apply and evaluate a model for an overall environmental risk assessment of road salt as a pollutant. For the study two streets were chosen in the city of Stockholm, Vasagatan and Sockenvägen. The study is introduced with literature studies on the roles of trees in urban environments, the dispersal paths of road salt, the impact of road salt on trees and the environment and road salt management methods. Based on data from the literature study an environmental risk assessment was carried out for trees and vegetation, ground water and soil in the study areas. A risk assessment was carried out for a scenario where road salt is not applied on the roads and the risk this may pose to human health. Furthermore, various suggestions for mitigation methods for the study areas were developed. The proposed mitigation measures were assessed and graded in an assessment matrix. The study highlights the importance of collecting road salt data continuously over several seasons, creating an understanding of road salt's dispersal paths, performing environmental risk assessments and analysis on several environmental areas regarding road salt. The study also highlights the need for developing different salt management methods and establishing policies aimed to reduce harmful effects of road salt on the trees and ecosystems in the city of Stockholm.

Vid utformning av väginfrastruktur borde trafikrelaterade utsläpp med ursprung från väg- och däckslitage samt halkbekämpning tas hänsyn till för att nå en verklig hållbar utveckling. Exempel på vägrelaterade utsläpp är aluminium, bly, koppar, kadmium, krom och zink. I Sverige sprids det omkring 200 000 - 230 000 ton salt per år på vägarna för att bekämpa halka under vinterhalvåret. Vattenlösliga föroreningar antas spridas till omkringliggande miljöer på samma sätt som vägsalt gör. Därmed syftar projektet till att observera den elektriska resistiviteten och konduktiviteten som vägsalt ger upphov till, för att spåra utbredningen av vägsaltet och andra vattenlösliga trafikrelaterade föroreningar, samt dess påverkan på närliggande miljöer. Mätmetoderna som användes var CVES som bidrog med resistivitetsvärden samt EM som bidrog med konduktivitetsvärden. Mätningarna utfördes vid tre tillfällen; kring Arningevägen, E18 samt Skålhamravägen. På grund av tekniska fel har dock färre resistivitetsmätningar gjorts vid E18 i jämförelse med de andra vägarna som undersöktes. Resultatet från och analys av mätningar från respektive mätmetod presenteras visuellt i figurer med hjälp av programmen Res2DInv, Voxler och Surfer. Från dessa figurer kan slutsatser kring föroreningars potentiella spridning dras. Samtliga mättillfällen visade att utbredningen av vägsalt, och därmed föroreningar, spårades till områden närmast vägkanten men även ner till grundvattnet. Ett antal felkällor och begränsningar har påverkat resultatet, exempelvis att metoderna som användes i detta arbete inte undersöker exakta mängder av föroreningar. Detta eftersom mätmetoderna som har används är indirekta metoder som syftar till att spåra vägsalt. Vägarnas storlek och trafikmängd har även vägts in och överläggs kring hur dessa påverkat resultaten. Det framkommer att ju mer trafikerad en väg är desto mer sprids vattenlösliga vägrelaterade föroreningar. Det diskuteras även om hur omkringliggande miljö kan påverkas samt vilka av Sveriges miljömål och de globala målen är av relevans och motverkas. / When planning road infrastructure, traffic-related emissions originating from road and tire wear, as well as anti-skid mitigations, should be taken into account in order to achieve real sustainable development. Examples of road-related emissions are aluminum, lead, copper, cadmium, chromium and zinc. In Sweden, around 200,000 - 230,000 tonnes of salt per year are spread on roads to prevent slippage during the winter. Water-soluble pollutants are assumed to spread to surrounding environments the same way as road salt does. Thus, the project aims to observe the electrical resistivity and conductivity that road salt gives rise to, in order to trace  the distribution of road salt and other water-soluble traffic-related pollutants, as well as its impact on nearby environments. The measurement methods used were CVES which provided resistivity values  and EM which provided conductivity values. The measurements were performed on three occasions; around Arningevägen, E18 and Skålhamravägen. Due to technical errors however, fewer resistivity measurements have been made at E18 in comparison with the other roads that were investigated. The results and analysis from each measurement method are presented visually in figures using the programs Res2DInv, Voxler and Surfer. From these figures, conclusions can be drawn about the potential spread of pollutants. All measurement occasions showed that the distribution of road salt, and thus pollution, was traced to areas closest to the roadside but also down to the groundwater. A number of sources of errors and limitations have affected the result, for example that the methods used do not examine exact amounts of pollutants. This is because the measurement methods that have been used are indirect methods that aim to detect road salt. The size and amount of traffic on the roads have also been weighed in and discussed as to how these have affected the results. It appears that the busier a road is, the more water-soluble road-related pollutants are spread. It is also discussed how the surrounding environment can be affected and which of Sweden's environmental goals and Sustainable Development Goals are relevant and counteracted.

No description available.

Groundwater chemistry on the Niagara Peninsula has been identified as highly mineralized in comparison to groundwaters collected from the same bedrock formations elsewhere in southern Ontario. Three geochemical zones were discerned using hierarchical cluster analysis and other geochemical and isotopic methods. The Escarpment Zone, located along the Niagara and Onondaga Escarpments, is characterized by unconfined aquifer conditions, parameters reflective of surficial contaminants, including road salt, and elevated HCO3, DOC, NO3-, coliform bacteria and tritium. In contrast, in the Salina Zone thick, low-permeability sediments and gypsiferous bedrock results in highly mineralized groundwaters with Ca-SO4 geochemical facies and elevated S2-, Ca2+, Mg2+, K+, Na+, SO42-, Cl-, Br-, Sr2+, NH4+ and CH4. The Guelph Zone contains the lowest electrical conductivity of the three zones and elevated F-. Outliers exist with groundwater geochemistry that differs from the local geochemical zone and the host aquifer. These sites have elevated SO42- (>1000 to 5200 mg/L) with depleted δ34SSO4 (-2.2 to 14.3‰ VCDT) signatures that differs starkly from Devonian and Silurian evaporites (~20 to 32 ‰) in the host formations. This exogenic SO4 was identified in a cross-formational northeast – southwest linear trend crossing three major groundwater flow systems. The lack of down-stream impact in these systems and tritium groundwater ages that are typically only decades old indicate a young, non-geological origin and implicate anthropogenic activities. Additionally, nine samples were identified with elevated methane concentrations and δ13CCH4 signatures within the thermogenic range. As thermogenic methane is not produced within shallow aquifers and would be short-lived in the presence of the ubiquitous sulfate, these samples imply recent upward migration of methane from depth through vertical conduits. Taken together, the evidence supports large-scale upward movement of fluids in the centre of the Niagara geochemical anomaly and more sporadic upward transport of gases over a wider area of the peninsula. The most likely vector is through corroded and leaking casings or boreholes of abandoned (century) gas wells that are common across the peninsula. / Thesis / Master of Science (MSc)