Legacy Sources Research Articles

The Truth Fairy Project

TPS 621: Exposure to metals, Johan Friso Foyer, Floor 1, August 26, 2019, 3:00 PM - 4:30 PM Background/ Aim: Lead (Pb) is a potent neurotoxicant with no safe level of exposure. Elevated levels of Pb and arsenic (As) are found near facilities that recycle lead-acid batteries in the United States. Assessing historical exposure to toxic chemicals, especially in situations of a specific industrial source of pollution affecting a community, is critical for informing appropriate public health and policy responses. We describe a community-driven approach to integrate retrospective environmental hazard exposure assessment with community organizing to address concerns about the extent of exposure to toxic metals in a predominantly working-class, Latinx community living near a now-closed lead-acid battery smelter facility. Methods: In this pilot study coined the “Truth Fairy” Project, 50 shed deciduous teeth from 43 children living their entire lives within 2 miles of the smelter to understand in retrospective exposure to toxic metals using community-driven research approach. Concentrations of Pb and As in teeth were assessed using laser-ablation-inductively coupled plasma-mass spectrometry. Soil Pb concentrations were determined using spatial kriging of surface soil measurements. Results: The mean prenatal calcium normalized Pb concentration in teeth samples (reported as a ratio 208Pb:43Ca), was 4.104 x 10-4 (SD 4.123 x 10-4), and the mean postnatal 208Pb:43Ca level was 4.109 x 10-4 (SD 3.369 x 10-4). Adjusted for maternal education and analytical batch, we observe positive significant relationship between prenatal teeth Pb per 100 ppm increase in soil Pb (β=3.48, 95% CI 1.11, 5.86), indicating higher Pb exposures near the site of industrial exposure. Study results were disseminated to the community using infographics. Conclusions: The Truth Fairy study provides insights into assessing retrospective exposure to toxic metals among children living near legacy sources. This project integrated community mobilization with empirical research, informing residents about toxic metal exposures and improving the community’s capacity to respond to a public health crisis.

Variable impacts of contemporary versus legacy agricultural phosphorus on US river water quality

Phosphorus (P) fertilizer has contributed to the eutrophication of freshwater ecosystems. Watershed-based conservation programs aiming to reduce external P loading to surface waters have not resulted in significant water-quality improvements. One factor that can help explain the lack of water-quality response is remobilization of accumulated legacy (historical) P within the terrestrial-aquatic continuum, which can obscure the beneficial impacts of current conservation efforts. We examined how contemporary river P trends (between 1992 and 2012) responded to estimated changes in contemporary agricultural P balances [(fertilizer + manure inputs)-crop uptake and harvest removal] for 143 watersheds in the conterminous United States, while also developing a proxy estimate of legacy P contribution, which refers to anthropogenic P inputs before 1992. We concluded that legacy sources contributed to river export in 49 watersheds because mean contemporary river P export exceeded mean contemporary agricultural P balances. For the other 94 watersheds, agricultural P balances exceeded river P export, and our proxy estimate of legacy P was inconclusive. If legacy contributions occurred in these locations, they were likely small and dwarfed by contemporary P sources. Our continental-scale P mass balance results indicated that improved incentives and strategies are needed to promote the adoption of nutrient-conserving practices and reduce widespread contemporary P surpluses. However, a P surplus reduction is only 1 component of an effective nutrient plan as we found agricultural balances decreased in 91 watersheds with no consistent water-quality improvements, and balances increased in 52 watersheds with no consistent water-quality degradation.

Hydrologic Extremes and Legacy Sources Can Override Efforts to Mitigate Nutrient and Sediment Losses at the Catchment Scale.

Combating eutrophication requires changes in land and water management in agricultural catchments and implementation of mitigation measures to reduce phosphorus (P), nitrogen (N) and suspended sediment (SS) losses. To date, such mitigation measures have been built in many agricultural catchments, but there is a lack of studies evaluating their effectiveness. Here we evaluated the effectiveness of mitigation measures in a clay soil-dominated headwater catchment by combining the evaluation of long-term and high-frequency data with punctual measurements upstream and downstream of three mitigation measures: lime-filter drains, a two-stage ditch, and a sedimentation pond. Long-term hydrochemical data at the catchment outlet showed a significant decrease in P (-15%) and SS (-28%) and an increase in nitrate nitrogen (NO-N, +13%) concentrations. High-frequency (hourly) measurements with a wet-chemistry analyzer (total and reactive P) and optical sensor (NO-N and SS) showed that the catchment is an abundant source of nutrients and sediments and that their transport is exacerbated by prolonged drought and resuspension of stream sediments during storm events. Lime-filter drains showed a decrease in SS by 76% and total P by 80% and an increase in NO-N by 45% compared with traditional drains, potentially indicating pollution swapping. The effectiveness of two-stage ditch and sedimentation pond was less evident and depended on the prevalent hydrometeorological conditions that drove the resuspension of bed sediments and associated sediment-bound P transport. These results suggest that increased frequency of prolonged drought due to changing weather patterns and resuspension of SS and sediment-bound P during storm events can override the generally positive effect of mitigation measures.

Isotopic evidence for mercury photoreduction and retention on particles in surface waters of Central California, USA

Cache Creek (Coast Range, California) and the Yuba River (Sierra Nevada Foothills, California) are two river systems affected by extensive mercury (Hg) contamination due to legacy sources of Hg related to mining. Stable Hg isotope techniques have proven useful for elucidating the complex cycling of Hg within aquatic ecosystems, and we applied these techniques to improve understanding of Hg and methylmercury (MeHg) transformations in these watersheds. Total mercury (THg) concentrations and Hg stable isotope ratios were measured in filtered surface waters and suspended particulate matter collected from 14 sites within the Cache Cr. and Yuba R. watersheds. Filtered surface waters from both watersheds exhibited values of ∆199Hg (0.37‰ to 0.71‰), consistently elevated above those observed in sediments (∆199Hg average = 0.07‰). Associated suspended particulates from these surface water samples displayed a much greater range of values for ∆199Hg (−0.61‰ to 0.70‰), although suspended particulates from the Yuba R. exhibited mostly negative ∆199Hg values (−0.61‰ to 0.10‰). The relationship between ∆199Hg and ∆201Hg in the filtered surface waters and associated suspended particulates was calculated using a bivariate York regression, yielding a slope of 1.57 ± 0.49 (±2SE) for the Yuba R. and 1.40 ± 0.27 (±2SE) for Cache Cr., both within error of the previously reported experimentally-derived slopes for MeHg- and inorganic Hg(II)-photoreduction. This provides isotopic evidence that Hg photoreduction is occurring within these surface waters to a significant degree, and suspended particulate phases are retaining the reduced product of Hg photoreduction, particularly within the Yuba R. The isotopic compositions of filtered surface waters are consistent with the isotopic signatures recorded in biota at low trophic positions within these watersheds, suggesting that the reservoir of Hg incorporated within the biota of these systems is similar to the filter-passing Hg fraction in surface waters.

Differential influence of landscape features and climate on nitrogen and phosphorus transport throughout the watershed

Anthropogenic activities have led to increased transfers of nitrogen (N) and phosphorus (P) to surface waters where changes in the absolute amounts of N and P delivery, and in N:P ratios, threaten water quality. While models of riverine fluxes are increasingly good at predicting total annual nutrient loads, our understanding of which features of a watershed differentially affect N and P transport downstream is still limited. In this study, we used linear mixed models to quantify the relative transport of N and P through different landscape and limnoscape compartments (e.g. hill slopes, lakes, reservoirs,) under a variety of climate regimes over 26 years in 18 watersheds of the St. Lawrence Basin. Water retention capacity and precipitation patterns were the features that most strongly influenced nutrient export from land to water, where P was preferentially retained in the landscape over N when water retention capacity was highest. Lakes and reservoirs also emerged as features that influenced nutrient fluxes, where lakes preferentially retain more P over N and reservoirs tended to export N. Factors that favor erosion, such as flashiness of precipitation and land-use change also alter N:P ratios in receiving waters, largely by mobilizing legacy sources of P.

Zones of untreatable water pollution call for better appreciation of mitigation limits and opportunities

This opinion piece addresses subsurface legacy sources and their role in mitigation of large‐scale water pollution and eutrophication. We provide a mechanistic theoretical basis and concrete data‐based exemplification of dominant contributions from such sources to total recipient loads. We specifically develop a diagnostic test to detect such contributions, recognizing that they are inaccessible and associated with long transport times that tend to evade detection when homogeneous catchment models are calibrated to typically heterogeneous catchments. Dominant legacy‐source contributions are also in practice untreatable within the commonly short time frames given for compliance with environmental regulation. We therefore argue that, for considerable water quality improvements to be achieved within such short time frames, mitigation measures need to be spatially differentiated and directed to (sub)catchments without major legacy sources. The presented diagnostic test identifies dominant prevalence of such sources where there is linear temporal correlation between the nutrient/pollutant loads and the water discharges from a (sub)catchment. Confidence in this identification may be strengthened by independent quantification of long transport times and records of temporally extended presence of nutrient/pollutant sources in the same (sub)catchment.This article is categorized under: Science of Water > Water Quality Engineering Water > Planning Water

Tracing natural and industrial contamination and lead isotopic compositions in an Australian native bee species

This study investigates trace element concentrations (arsenic (As), manganese (Mn), lead (Pb) and zinc (Zn)) and Pb isotopic compositions in an Australian native bee species, Tetragonula carbonaria, and its products of honey and wax. Co-located soil and dust samples were simultaneously analysed with the objective of determining if the bees or their products had potential application as a proxy for monitoring environmental contamination. The most significant relationships were found between Pb concentrations in honey (r = 0.814, p = 0.014) and wax (r = 0.883, p = 0.004) and those in co-located dust samples. In addition, Zn concentrations in honey and soil were significantly associated (r = 0.709, p = 0.049). Lead isotopic compositions of native bee products collected from background sites adjacent to Sydney national parks (206Pb/207Pb = 1.144, 208Pb/207Pb = 2.437) corresponded to local geogenic rock and soil values (206Pb/207Pb = 1.123–1.176, 208Pb/207Pb = 2.413–2.500). By contrast, inner Sydney metropolitan samples, including native bees and wax (206Pb/207Pb = 1.072–1.121, 208Pb/207Pb = 2.348–2.409), co-located soil and dust (206Pb/207Pb = 1.090–1.122, 208Pb/207Pb = 2.368–2.403), corresponded most closely to aerosols collected during the period of leaded petrol use (206Pb/207Pb = 1.067–1.148, 208Pb/207Pb = 2.341–2.410). A large range of Pb isotopic compositions in beehive samples suggests that other legacy sources, such as Pb-based paints and industrials, may have also contributed to Pb contamination in beehive samples. Native bee data were compared to corresponding samples from the more common European honey bee (Apis mellifera). Although Pb isotopic compositions were similar in both species, significant differences in trace element concentrations were evident across the trace element suite, the bees and their products. The statistical association between T. carbonaria and co-located environmental contaminant concentrations were stronger than those in European honey bees, which may be attributable to its smaller foraging distance (0.3–0.7 km versus 5–9 km, respectively). This implies that T. carbonaria may be more suitable for assessing small spatial scale variations of trace element concentrations than European honey bees.

Spatial distribution, risk and potential sources of lead in soils in the vicinity of a historic industrial site

Because of measures taken by local and national government agencies to control releases of metals, former industrial sites in China that are contaminated with lead (Pb) in soils have been abandoned. Compared with historic sites themselves, little attention has been paid to contamination with Pb in areas surrounding these sites. In this study, a method by integrating sequential extraction and isotopic fingerprinting was proposed to reveal the key fractions of Pb contaminants in soils, trace their sources and determine the subject of liability for remediation. Topsoils from near a historic site, where lead oxide was produced, were found to be contaminated. Concentrations of Pb in soils were inversely proportional to distances from the industrial site and depth in soils. The predominant form of Pb was the Fe/Mn-oxide-bound fraction (FM3), which accounted for from 53.39% to 82.07% of total concentrations of Pb. Concentrations of Pb in vegetables produced on contaminated soils exceeded those allowed in food for consumption by humans. An assessment of hazards and risks posed by consumption of vegetables grown on these soils indicated relatively high potential for adverse effects on local residents around the closed plant. By use of isotopic finger printing for Pb, the abandoned factory was determined to be the most likely source of Pb in topsoils, especially fraction FM3. To mitigate exposures of people to Pb via consumption of locally produced food, recommended strategies should target legacy sources of Pb to soils in the vicinity of this historic industrial site.

Simulating and quantifying legacy topographic data uncertainty: an initial step to advancing topographic change analyses

Rapid technological advances, sustained funding, and a greater recognition of the value of topographic data have helped develop an increasing archive of topographic data sources. Advances in basic and applied research related to Earth surface changes require researchers to integrate recent high-resolution topography (HRT) data with the legacy datasets. Several technical challenges and data uncertainty issues persist to date when integrating legacy datasets with more recent HRT data. The disparate data sources required to extend the topographic record back in time are often stored in formats that are not readily compatible with more recent HRT data. Legacy data may also contain unknown error or unreported error that make accounting for data uncertainty difficult. There are also cases of known deficiencies in legacy datasets, which can significantly bias results. Finally, scientists are faced with the daunting challenge of definitively deriving the extent to which a landform or landscape has or will continue to change in response natural and/or anthropogenic processes. Here, we examine the question: how do we evaluate and portray data uncertainty from the varied topographic legacy sources and combine this uncertainty with current spatial data collection techniques to detect meaningful topographic changes? We view topographic uncertainty as a stochastic process that takes into consideration spatial and temporal variations from a numerical simulation and physical modeling experiment. The numerical simulation incorporates numerous topographic data sources typically found across a range of legacy data to present high-resolution data, while the physical model focuses on more recent HRT data acquisition techniques. Elevation uncertainties observed from anchor points in the digital terrain models are modeled using “states” in a stochastic estimator. Stochastic estimators trace the temporal evolution of the uncertainties and are natively capable of incorporating sensor measurements observed at various times in history. The geometric relationship between the anchor point and the sensor measurement can be approximated via spatial correlation even when a sensor does not directly observe an anchor point. Findings from a numerical simulation indicate the estimated error coincides with the actual error using certain sensors (Kinematic GNSS, ALS, TLS, and SfM-MVS). Data from 2D imagery and static GNSS did not perform as well at the time the sensor is integrated into estimator largely as a result of the low density of data added from these sources. The estimator provides a history of DEM estimation as well as the uncertainties and cross correlations observed on anchor points. Our work provides preliminary evidence that our approach is valid for integrating legacy data with HRT and warrants further exploration and field validation.

Relative role of transport and source-limited controls for estrogen, TDP, and DOC export for two manure application methods

Abstract Developing successful mitigation strategies for emerging contaminants can be difficult due to incomplete understanding of factors controlling their fate and transport. A variety of data analysis techniques can be used to assess the fate and transport behavior of pollutants in runoff water. Here, we use concentration-discharge, load-discharge, and coefficient of variation relationships to examine how two methods of dairy manure application (surface broadcast and shallow disk injection) affect the transport dynamics of estrogens, total dissolved phosphorus (TDP), and dissolved organic carbon (DOC). Nine surface runoff events were sampled from Oct 2014–June 2015 from 12 research plots (six with each application method) in Central Pennsylvania after fall application. The plots received inorganic fertilizer for 15 years, but only four manure applications since 2012. Both TDP and DOC exhibited similar transport behavior under both manure application methods that indicate transport-limited control of export, potentially due to legacy sources in soils. However, estrogen loads exhibited dilution responses, a sign of source-limited controls. The strength of the dilution response for estrogens was greater for surface applied manure relative to the injected manure, suggesting that manure application methods can be used to control the mobilization potential of estrogens. Additionally, results suggest the longer-term application history of inorganic fertilizer led to the transport-limited dynamics exhibited by TDP, while the short-term application history of manure caused estrogen transport to be source-limited. Our findings provide insight into how anthropogenic drivers (application type, method, and history) and natural drivers (hydrology, biogeochemistry) are interconnected in agricultural fields, and point to opportunities for protecting downstream water quality.

Applying geochemical signatures of atmospheric dust to distinguish current mine emissions from legacy sources

Resolving the source of environmental contamination is the critical first step in remediation and exposure prevention. Australia's oldest silver-zinc-lead mine at Broken Hill (>130 years old) has generated a legacy of contamination and is associated with persistent elevated childhood blood lead (Pb) levels. However, the source of environmental Pb remains in dispute: current mine emissions; remobilized mine-legacy lead in soils and dusts; and natural lead from geological weathering of the gossan ore body. Multiple lines of evidence used to resolve this conundrum at Broken Hill include spatial and temporal variations in dust Pb concentrations and bioaccessibility, Pb isotopic compositions, particle morphology and mineralogy. Total dust Pb loading (mean 255 μg/m2/day) and its bioaccessibility (mean 75% of total Pb) is greatest adjacent to the active mining operations. Unweathered galena (PbS) found in contemporary dust deposits contrast markedly to Pb-bearing particles from mine-tailings and weathered gossan samples. Contemporary dust particles were more angular, had higher sulfur content and had little or no iron and manganese. Dust adjacent to the mine has Pb isotopic compositions (208Pb/207Pb: 2.3197; 206Pb/207Pb: 1.0406) that are a close match (99%) to the ore body with values slightly lower (94%) at the edge of the city. The weight of evidence supports the conclusion that contemporary dust Pb contamination in Broken Hill is sourced primarily from current mining activities and not from weathering or legacy sources.

Two centuries of nitrogen dynamics: Legacy sources and sinks in the Mississippi and Susquehanna River Basins

AbstractGlobal flows of reactive nitrogen (N) have increased significantly over the last century in response to agricultural intensification and elevated levels of atmospheric deposition. Despite widespread implementation conservation measures, N concentrations in surface waters are often remaining steady or continuing to increase. Although such lack of response has been attributed to time lags associated with legacy N stores in subsurface reservoirs, it is unclear what the magnitudes of such stores are and how they are partitioned between shallow soil and deeper groundwater reservoirs. Here we have synthesized data to develop a 214 year (1800–2014) trajectory of N inputs to the land surface of the continental U.S. We have concurrently developed a parsimonious, process‐based model, Exploration of Long‐tErM Nutrient Trajectories (ELEMeNT) that pairs this input trajectory with a travel time‐based approach to simulate transport and retention along subsurface pathways. Using the model, we have reconstructed historic nitrate yields at the outlets of two major U.S. watersheds, the Mississippi River Basin (MRB) and Susquehanna River Basin (SRB). Our results show significant N loading above baseline levels in both watersheds before the widespread use of commercial N fertilizers, largely due to the conversion of forest and grassland to row crop agriculture. Model results also allow us to quantify the magnitudes of legacy N in soil and groundwater pools and to highlight the dominance of soil legacies in MRB and groundwater legacies in SRB. Approximately 55% and 18% of the current annual N loads in the MRB and SRB were found to be older than 10 years of age.

Managing legacy and new sources of phosphorus to reduce leaching in Mid‐Atlantic soils

Application of phosphorus (P) fertilizers and animal manures to P‐rich soils due to the historic use of P inputs can lead to greater P losses. In these soils, we need to manage legacy and new inputs of P in a way that they do not lead to P loss. Studies were conducted to (i) determine the effect of soil type on P leaching and (ii) investigate if changes in dairy and poultry diets can lead to lower P in manures and loss when manures are land applied. Earn 2 CEUs in Soil & Water Management by reading this article and taking the quiz at www.certifiedcropadviser.org/certifications/self‐study/799.

Inequitable Chronic Lead Exposure: A Dual Legacy of Social and Environmental Injustice.

Both historic and contemporary factors contribute to the current unequal distribution of lead in urban environments and the disproportionate impact lead exposure has on the health and well-being of low-income minority communities. We consider the enduring impact of lead through the lens of environmental justice, taking into account well-documented geographic concentrations of lead, legacy sources that produce chronic exposures, and intergenerational transfers of risk. We discuss the most promising type of public health action to address inequitable lead exposure and uptake: primordial prevention efforts that address the most fundamental causes of diseases by intervening in structural and systemic inequalities.

“A Mother for All the People”: Feminist Science and Chacoan Archaeology

In 1997, Alison Wylie outlined an epistemic and ontological critique of archaeological inquiry to advance feminist science studies. Wylie’s work, I argue, remains relevant and potentially transformative for analysis of the cultural florescence that took place in Chaco Canyon, New Mexico, during the ninth through twelfth centuries A.D. Archival, archaeological, and ethnographic data presented here suggest that women had important and undertheorized roles to play in the social transformations that defined emergent Chacoan society. Legacy data made available through the Chaco Research Archive provide evidence in support of Lamphere’s (2000) ritual power model interpretation of the Chacoan florescence. The advent of such open-access resources allows for a critical analysis of gender ideologies and praxis through aggregated legacy sources that augment analyses based on surviving, institutionally curated artifact collections and published sources.

Managing agricultural phosphorus to minimize water quality impacts

Eutrophication of surface waters remains a major use-impairment in many countries, which, in fresh waters, is accelerated by phosphorus (P) inputs from both point (e.g., municipal waste water treatment plants) and nonpoint sources (e.g., urban and agricultural runoff). As point sources tend to be easier to identify and control, greater attention has recently focused on reducing nonpoint sources of P. In Brazil, agricultural productivity has increased tremendously over the last decade as a consequence, to a large extent, of increases in the use of fertilizer and improved land management. For instance, adoption of the “4R” approach (i.e., right rate, right time, right source, and right placement of P) to fertilizer management can decrease P runoff. Additionally, practices that lessen the risk of runoff and erosion, such as reduced tillage and cover crops will also lessen P runoff. Despite these measures P can still be released from soil and fluvial sediment stores as a result of the prior 10 to 20 years’ management. These legacy sources can mask the water quality benefits of present-day conservation efforts. Future remedial efforts should focus on developing risk assessment indices and nonpoint source models to identify and target conservation measures and to estimate their relative effectiveness. New fertilizer formulations may more closely tailor the timing of nutrient release to plant needs and potentially decrease P runoff. Even so, it must be remembered that appropriate and timely inputs of fertilizers are needed to maintain agricultural productivity and in some cases, financial support might also be required to help offset the costs of expensive conservation measures.

Managing Phosphorus Leaching in Mid‐Atlantic Soils: Importance of Legacy Sources

Core Ideas Higher P leaching from P‐saturated mid‐Atlantic soils. Preferential flow caused more P leaching in fine‐textured soils. Matrix flow reduced P leaching from coarse‐textured soils. Use both P saturation ratio and flow pathways to predict the risk of P leaching. Application of phosphorus (P) inputs to soils saturated with legacy P can significantly increase the risk of P leaching and deteriorate water quality. Our objectives were to quantify the effect of soil type and extent of P saturation on P leaching and determine the suitability of a rapid, inexpensive soil P saturation test for use in P leaching risk assessment protocols. We collected 18 undisturbed lysimeters (30‐cm diameter, 50 cm deep), using a tractor‐mounted corer, from three typical mid‐Atlantic soils in Delaware, where P leaching is a concern. The soils were selected on the basis of Mehlich‐3 P saturation ratio (M3‐PSR) of optimum (<0.10) to environmental (>0.15) thresholds. Lysimeters were irrigated with the equivalent of 50 mm of water each week for a total of 16 wk. Concentrations of dissolved reactive P (DRP) and total P in leachate were not significantly different between optimum and environmental M3‐PSR lysimeters before fertilizer application (Weeks 1–8). However, concentrations of DRP and total P significantly increased after fertilizer application at 85 kg P ha−1 (Weeks 9–16) in the environmental M3‐PSR lysimeters. Among three soils in both M3‐PSR categories, concentrations and loads of P leached were higher from the Matapeake silt loam and Pocomoke sandy loam due to preferential leaching that limited contact of flowing water and P with the soil P‐fixing constituents (Fe, Al, and Ca), while P leaching was lower from Woodstown sandy loam due to matrix flow that resulted in greater interaction of water and P with the soil constituents. These results provide clear evidence of a greater risk of P leaching from P‐saturated soils with preferential flow pathways and show that the M3‐PSR along with information about preferential flow pathways should be used to predict the risk of P leaching.

Phosphorus fate, management, and modeling in artificially drained systems.

Phosphorus (P) losses in agricultural drainage waters, both surface and subsurface, are among the most difficult form of nonpoint source pollution to mitigate. This special collection of papers on P in drainage waters documents the range of field conditions leading to P loss in drainage water, the potential for drainage and nutrient management practices to control drainage losses of P, and the ability of models to represent P loss to drainage systems. A review of P in tile drainage and case studies from North America, Europe, and New Zealand highlight the potential for artificial drainage to exacerbate watershed loads of dissolved and particulate P via rapid, bypass flow and shorter flow path distances. Trade-offs are identified in association with drainage intensification, tillage, cover crops, and manure management. While P in drainage waters tends to be tied to surface sources of P (soil, amendments or vegetation) that are in highest concentration, legacy sources of P may occur at deeper depths or other points along drainage flow paths. Most startling, none of the major fate-and-transport models used to predict management impacts on watershed P losses simulate the dominant processes of P loss to drainage waters. Because P losses to drainage waters can be so difficult to manage and to model, major investment are needed (i) in systems that can provide necessary drainage for agronomic production while detaining peak flows and promoting P retention and (ii) in models that can adequately describe P loss to drainage waters.

Sustainable long term scientific data publication: Lessons learned from a prototype Observatory Information System for the Illinois River Basin

In 2005 a prototype Observatory Information System (OIS) was developed for the Illinois River Basin Observatory (IRBO), connected to a federated scientific data network, populated with a representative collection of legacy datasets, and linked to external data streams. The perspective of seven years' time and the disestablishment of the system provide an opportunity to study the system life cycle. We detail best practices for multi-level OIS design for long-term performance, based on a publication-mandatory metadata implementation standard using ISO-19115. These principles balance general users' requirements against the requirements of specific scientific applications, and maximize the system's capacity to deal with legacy and heterogeneous data sources, enhancing long-term sustainability and flexibility for diverse multi-level user groups. These findings are relevant to ongoing developments of networked Scientific Information Systems that are increasingly critical to support and sustain the long-term benefits of modeling and observatory science.

Soil Phosphorus Storage Capacity for Environmental Risk Assessment

Reliable techniques must be developed to predict phosphorus (P) storage and release from soils of uplands, ditches, streams, and wetlands in order to better understand the natural, anthropogenic, and legacy sources of P and their impact on water quality at a field/plot as well as larger scales. A concept called the “safe” soil phosphorus storage capacity (SPSC) that is based on a threshold phosphorus saturation ratio (PSR) has been developed; the PSR is the molar ratio of P to Fe and Al, and SPSC is a PSR-based calculation of the remaining soil P storage capacity that captures risks arising from previous loading as well as inherently low P sorption capacity of a soil. Zero SPSC amounts to a threshold value below which P runoff or leaching risk increases precipitously. In addition to the use of the PSR/SPSC concept for P risk assessment and management, and its ability to predict isotherm parameters such as the Langmuir strength of bonding,KL, and the equilibrium P concentration, EPC0, this simple, cost-effective, and quantitative approach has the potential to be used as an agronomic tool for more precise application of P for plant uptake.