An Application of a Modified Health Belief Model: Assessing Health Beliefs and Health Protective Behaviors in Mining- Impacted Communities

Purpose/Background: Toxic metal contamination poses public health risks in many mining-impacted communities. Improved understanding of risk perception and health protective behaviors is important to sustaining public health awareness. We co-developed a research study based on the Health Belief Model (HBM; Figure 1) and facilitated through a partnership with the health district in our study area, the Silver Valley of northern Idaho. Lead contamination caused by historical mining practices continues to impact both ecological and human health and contributes to health disparities. For this study, we assess how health belief constructs (i.e., perceived threats, expectations of behavioral outcomes, and confidence in personal knowledge) influence self-reported health protective behaviors and behavioral intentions. Materials & Methods: We conducted a drop-off pick-up (DOPU) household survey (n~300; estimated response rate~60%) to assess risk perception and self-reported health behaviors among residents in three mining-impacted communities of the Silver Valley. Informational interviews and a pilot survey informed survey instrument development. Health protective behavior variables were modified from the health district’s existing public recommendations. We assessed the frequency of past health protective behaviors and likelihood of future behaviors (e.g., handwashing following contact with lead contamination). Health belief constructs were modified from other HBM studies. We performed validity and reliability tests on the survey instrument. Results: We will measure the impact of threats, expectations and confidence on health protective behaviors. We hypothesize that, overall, higher confidence in personal knowledge of lead contamination will be associated with higher likelihood of taking health protective behavior. Furthermore, confidence is mediated by perceived threat and expectations of behavioral outcomes. To test our hypothesis, we will use a structural equation model to test the relationships between constructs (Figure 1). Discussion/Conclusion: By conducting a DOPU survey, we captured a range of health beliefs and health protective behaviors that are present across the study area. The challenge in educating and protecting the health of communities impacted by a persistent but low visibility contaminant such as lead is understanding the relationship between health beliefs and health protective behaviors. Our study is an initial step in this region to identify the constructs that influence decisions and actions for health protection. We will apply these findings to continue developing tailored resources for community health interventions and communication, including a youth-oriented computer game and targeted signage

A multi-tracer study of saltwater origin, cross -formational flow, and the geochemical evolution of groundwater in the Southern High Plains aquifer along the Western Caprock Escarpment, east-central New Mexico

Sustainable management of groundwater resources requires sufficient knowledge of the distribution of fresh and saline groundwater and the processes affecting saltwater intrusion that may influence the beneficial use of groundwater. A hydrogeologic investigation that coupled various chemical and isotopic tracers, including 3H/3He, 14C, δD, δ18O, 87Sr/ 86Sr, and δ11B, with the physical characteristics of the aquifer was conducted to determine source waters, the origin of saltwater and its influence through cross-formational flow, and water-rock interactions in the Southern High Plains aquifer along the Western Caprock Escarpment. Sub-aquifers or local flow systems are present along the Western Caprock Escarpment, and the study site\u27s local flow system drains a Na-Cl, high dissolved solids (2,000 to 9,500 mg/L) groundwater from the escarpment until it mixes with a regional aquifer or regional flow system that is more oxygenated and a mixed cation-HCO3- water type with low dissolved solids (390 to 520 mg/L). The local flow system contains old water (5,500 to 21,000 years) that is similar in age and composition to the underlying, upper Dockum aquifer (Na-Cl water type, 970 to 13,000 mg/L dissolved solids, 12,000 to 27,000 years). The δD and δ18O values for the local flow system (-71.74 to -47.96‰ and -9.95 to -6.52‰, respectively) and upper Dockum aquifer (-67.20 to -51.70‰ and -9.11 to -6.93‰) were lower and more variable compared to the regional flow system (-45.97 to -43.29‰ and -6.30 to -6.09‰). Groundwater δD and δ 18O values in the mixing zone (-45.19 to -43.90‰ and -6.14 to -5.85‰) indicated an additional water source or further evaporation. To resolve the groundwater evolution along the Western Caprock Escarpment, 87Sr/86Sr and δ11B values were coupled with major ion, trace element, age, and δD and δ 18O values. The 87Sr/86Sr range of 0.70845 to 0.70906 and Sr concentrations of 0.90 to 31 mg/L were sufficient to estimate source-water fractions and contributions from chemical weathering through inverse calculations. Boron concentrations (59 to 1,740 mg/L) and δ 11B values (+6.0 to +46.0‰) were used to resolve the influence of agricultural recharge in the mixing zone that was ambiguously identified with other tracers. Alteration of B and δ11B values in the mixing zone indicated the loss of B and decrease in δ11B values likely from plant uptake, adsorption, and weathering contributions in the soil/vadose zone prior to recharge beneath or near agricultural fields. With confirmation of this additional influence in the mixing zone, results from the Sr inverse calculations were used to reinterpret δD and δ 18O values to account for agricultural recharge. Geochemical tracer analysis allowed the formation of a conceptual flow model. Groundwater interaction with Permian bedded salts and Dockum Group shales produces a high dissolved-solids groundwater with a strong halite signal that can strongly influence groundwater composition in the Southern High Plains aquifer through cross-formational flow. Cross-formational flow from the Permian bedded salts into the Dockum Group provides a water source where none was expected because of the hydrologic divide of the escarpment, and this water likely originates in the Pecos River Basin and crosses beneath the hydrologic divide through the Permian bedded salts. The mixing of young (less than 100 years), local recharge from surface pathways at the Western Caprock Escarpment and much older (greater than 20,000 years) saltwater from the Permian bedded salts and Dockum Group is spatially variable and dependent on available flowpaths created by fracturing of the Dockum Group shales from Permian bedded-salt subsidence. Groundwater flow in local systems of the Southern High Plains aquifer along the Western Caprock Escarpment mixes with regional flow systems of larger saturated thickness where the geochemical signal of the halite-influenced saltwater is substantially reduced but visible in a thin mixing zone. Alteration of geochemical signals from groundwater flow through Dockum Group shales and the effect of agricultural recharge limited the effectiveness of certain tracers for identifying source waters, mixing patterns, and water-rock interactions

Effects of reservoir installation, San Juan-Chama Project water, and reservoir operations on streamflow and water quality in the Rio Chama and Rio Grande, northern and central New Mexico, 1938-2000

The coordinated operation of Heron, El Vado, and Abiquiu Dams on the Rio Chama and Cochiti Dam on the Rio Grande and the importation of Colorado River Basin water by the San Juan-Chama Project have altered streamflow and water quality of the Rio Chama and Rio Grande in northern and central New Mexico. The coordinated retention of streamflow in the four reservoirs increased median streamflows, decreased extreme flows, and decreased periods of small streamflow; inflow of San Juan-Chama Project water increased overall streamflow in the Rio Chama and Rio Grande. These changes to streamflow decreased specific conductance and suspended-sediment concentration and increased pH in the Rio Chama and the Rio Grande. Following construction of Heron and Cochiti Dams and integration of reservoir operations on the Rio Chama and the Rio Grande, the inflow of San Juan-Chama Project water and retention of snowmelt runoff influenced water quality. These influences varied by season because reservoir rele

Evolution of Carbonate Weathering and Nanoparticle Release

Carbonate weathering and release of the associated metals lacks resolution because of a wide variability in the decomposition rate of carbonate minerals. With limited atmospheric carbon dioxide, carbonate minerals will tend to weather and dissolve, releasing metal and carbonate ions into solution. This accepted dissolution process has been used to evaluate carbonate weathering and the release and transport of metals in hydrologic systems. Historically, carbonate mineral decomposition has been viewed solely as a dissolution process, but recent studies have challenged this accepted notion. Evidence of repulsive forces that eject micro- to nano-scale metal-carbonate particles from the weathering surface may be the reason we have struggled to establish consistent weathering rates. This study aims to test this new weathering mechanism by determining the variation in the size and stability of ejected particle during the weathering of calcite [CaCO3] under different aqueous and temperature conditions. Results of the study will assist in refining carbonate weathering rates and the prediction of release and transport of the associated nanoparticles

Evaluation of a pressure pulse in a fractured-rock aquifer to reduce uncertainty of hydraulic conductivity measurements, Rio Grande Rift, New Mexico, United States

Fractured-rock aquifers are inherently difficult for determining flow dynamics because of variability in fracture orientation and extension. A confined, fractured-rock aquifer in a semi-arid mountainous area of the Rio Grande Rift Zone was analysed for its response to recharge events that produced a pressure pulse within its potentiometric surface. The pulse was evaluated at the well scale and subaquifer level to evaluate flowpaths, travel times and dispersion and compare the bulk-scale aquifer response to possible velocities from slug test hydraulic conductivity measurements. Travel time and dispersion from the pulse proved comparable to probable travel times based on hydraulic conductivity measurements. Evaluation of the pressure pulse and the hydraulic conductivity measurements allowed for a holistic interpretation of the fractured-rock aquifer through analysis of two distinct data sets that provided corroborative evidence of flow dynamics and fracture connectivity. This holistic approach reduced uncertainty regarding the individual hydraulic conductivity values. © 2013 CIWEM

Seasonal and Basinal Influences on the Formation and Transport of Dissolved Trace Metal Forms in a Mining-Impacted Riverine Environment

The release of nanophase metal particles from sulfide mineral decomposition in mining-impacted environments is a growing concern because of the potential for the transport of nanoscale particles that could increase the distribution of the metals and their environmental impact. An analysis of total (unfiltered) and dissolved (450-nm filtered) metal concentrations in the mining-impacted Coeur d’Alene River indicates the leaching of dissolved metal forms from sediments and transport to and within the river. The distribution of metals between total and dissolved forms is driven by seasonal temperatures, hydraulic gradients, and ligand availability. Cd and Zn were the least influenced by changes in gradient and biological productivity between the upper and lower basins. Cd and Zn primarily travel as dissolved forms, with the lowest ratio of dissolved-to-total concentrations in spring and the highest in summer. Fe and Pb primarily travel as suspended particles, but their dissolved forms were greater during all seasons in the lower basin. A principal components analysis of upper basin data indicates that temperature and conductivity were correlated with dissolved Cd and Zn, and total Fe and Pb were correlated with streamflow. In the lower basin, dissolved Cd and Zn, conductivity, and temperature were correlated, and suspended sediment, total metals, and dissolved Pb, but not streamflow, were correlated. The correlation of metals and sediment in the lower basin is not from erosion but the availability of organic matter and Fe that form a range of dissolved to suspended metal particles. The summer decrease in surface water levels releases sediment porewater containing nanoscale-to-microscale metal particles that are transported to open water, where they may impact human and wildlife health. Such releases are unmitigated with current remediation strategies of sediment stabilization

Examination of the Desorption of Iron From Zeolites Used to Treat Acid Rock Drainage

Passive treatment of acid rock drainage relies on chemical interactions to reduce solubility of metals such as iron. Sorption has been a primary process for treatment of mine drainage and currently is being tested for use with acid rock drainage. Substrates considered for sorption of metals from acidic drainage include natural silicates, such as zeolite minerals. The weak bonding of sorption raises questions about retention of metals in a zeolite passive treatment system because of the flux of environmental conditions, such as changes in pH and temperature. Static batch sorption experiments were designed to assess the ability of zeolite to retain iron sorbed from an acidic, iron- and sulfate-rich solution. Zeolite saturated with sorbed iron was exposed to various water types—including ultrapure water, nickel-rich water, and natural creek water—under different pH and temperature conditions. Results indicate that low pH solutions 2.0 +/-0.1 for all water types greatly decreased the ability of zeolite to retain sorbed iron, with a maximum of 6.88 milligrams desorbing per liter, while pH above 4.0 +/- 0.1 and temperature variance between 5° and 20° only induced desorption of iron at a maximum of 1.02 milligrams per liter for all water types. With the knowledge gained from these experiments, protocols can be developed that maximize the effectiveness of future passive treatment systems for acid rock drainage that utilize zeolite as a substrate

Sulfur Species, Bonding Environment, and Metal Mobilization in Mining-Impacted Lake Sediments: Column Experiments Replicating Seasonal Anoxia and Deposition of Algal Detritus

The oxidation state of sulfur [S] is a primary control on mobility of metals in sediments impacted by legacy mining practices. Coeur d’Alene Lake of northern Idaho, USA, has been impacted by upstream legacy mining practices that deposited an estimated 75 Mt of metal(loid)- and S-rich sediments into the lake. Future lake conditions are expected to include algal blooms, which may alter S and metal remobilization during the seasonal euxinic environment. Cores of the lake sediments were exposed to anoxic and anoxic + algal detritus conditions for eight weeks at 4.5 °C through introduction of a N2 atmosphere and addition of algal detritus. At a location 2.5 cm below the sediment-water interface, anoxic conditions promoted a shift in S species to continually larger concentrations of reduced species and an associated shift in the bonding environment reflective of increased S–metal bonds. Anoxic + algal detritus conditions suppressed the increasing trend of reduced S species and induced greater release of Mn compared to the anoxic-only conditions but did not appear to enhance the release of As, Cd, or Fe. The addition of algal detritus to the sediment-water interface of these Fe- and S-rich sediments enhanced mobilization of Mn likely because of dissimilatory metal reduction where the anaerobic oxidation of the algal detritus stimulated Mn reduction. Results of the study indicate that future metal release from the lake sediments will be altered with the likely deposition of algal detritus, but the effect may not enhance the release of acutely toxic metals, such as As or Cd, or substantially impact Fe cycling in the sediments

Monitoring the Ambient Seismic Field to Track Groundwater at a Mountain–Front Recharge Zone

The heterogeneity of the fractured-basalt and interbedded-sediment aquifer along the eastern margin of the Columbia Plateau Regional Aquifer System has presented challenges to resource managers in quantifying recharge and estimating sustainable withdrawals. Previous studies indicated recharge pathways in alluvial sediments atop a mountain–front interface upgradient of the basalt flows. In this sedimentary zone, six seismic stations were deployed for one year to detect velocity changes in low-frequency seismic waves that could be correlated to changes in groundwater recorded by a well transducer near the center of the seismic station network. Waveforms in the 1−5 Hz range were recorded at each station to determine changes in wave velocities between station pairs and correlate these velocity changes to changes in groundwater levels. The velocity–groundwater relation allowed for estimation of daily groundwater levels beneath the seismic station network. Existing hydrogeologic information was used to estimate hydraulic gradients and hydraulic conductivities, which allowed for the calculation of the daily volume of recharge passing beneath the seismic stations and into the confined aquifer system. The daily recharge volumes across the seismic station network were summed for comparison of the total annual recharge calculated from the change in seismic wave velocities (154,660 m3) to a flow model calculation of recharge based on areal precipitation and infiltration (26,250 m3). The 6× greater recharge estimated from the seismic wave velocity changes for this portion of the recharge zone is attributed to preferential pathways of high hydraulic conductivity and greater depth associated with paleochannels beneath the seismic station network