Evaluating the Ecological Footprint of Landfills: A Framework and Case Study of Fargo, North Dakota.

There is growing interest in better understanding the environmental impacts of landfills and optimizing their operation. Accordingly, we developed a holistic framework to calculate a landfill's Ecological Footprint (EF) and applied that to the Fargo, North Dakota, landfill. Parallelly, the carbon footprint and biocapacity of the landfill were calculated. We calculated the EF for six scenarios (i.e., cropland, grazing land, marine land, inland fishing ground, forest land, and built land as land types) and six operational strategies typical for landfills. Operational strategies were selected based on the variations of landfill equipment, the gas collection system, efficiency, the occurrence of fugitive emissions, and flaring. The annual EF values range from 124 to 213,717 global hectares depending on land type and operational strategy. Carbon footprints constituted 28.01-99.98% of total EF, mainly driven by fugitive emissions and landfill equipment. For example, each percent increase in Fargo landfill's fugitive emissions caused the carbon footprint to rise by 2130 global hectares (4460 tons CO2e). While the landfill has biocapacity as grazing grass in open spaces, it remains unused/inaccessible. By leveraging the EF framework for landfills, operators can identify the primary elements contributing to a landfill's environmental impact, thereby minimizing it.

Land conversion and pesticide use degrade forage areas for honey bees in America's beekeeping epicenter.

A diverse range of threats have been associated with managed-bee declines globally. Recent increases of two known threats, land-use change and pesticide use, have resulted from agricultural expansion and intensification notably in the top honey-producing state in the United States: North Dakota. This study investigated the dual threat from land conversion and pesticide use surrounding ~14,000 registered apiaries in North Dakota from 2001 to 2014. We estimated the annual total insecticide use (kg) on major crops within 1.6 km of apiary sites. Of the eight insecticides quantified, six showed significant increasing trends over the time period. Specifically, applications of the newly established neonicotinoids Chlothianidin, Imidacloprid and Thiamethoxam, increased annually by 1329 kg, 686 kg, 795 kg, respectively. Also, the use of Chlorpyrifos, which was well-established in the state by 2001 and is highly toxic to honey bees, increased by ~8,800 kg annually from 6,500 kg in 2001 to 115,000 kg in 2014 on corn, soybeans and wheat. We further evaluated the relative quality changes of natural/semi-natural land covers surrounding apiaries in 2006, 2010 and 2014, a period of significant increases in cropland area. In areas surrounding apiaries, we observed changes in multiple indices of forage quality that reflect the deteriorating landscape surrounding registered apiary sites due to land-use change and pesticide-use increases. Overall, our results suggest that the application of foliar-applied insecticides, including pyrethroids and one organophosphate, increased surrounding apiaries when the use of neonicotinoid seed treatments surged and the area for producing corn and soybeans expanded. Spatially, these threats were most pronounced in southeastern North Dakota, a region hosting a high density of apiary sites that has recently experienced corn and soybean expansion. Our results highlight the value of natural and semi-natural land covers as sources of pollinator forage and refugia for bees against pesticide exposure. Our study provides insights for targeting conservation efforts to improve forage quality benefiting managed pollinators.

Effects of Inoculum Density and Cultivar Susceptibility on Rhizoctonia Damping-Off and Crown and Root Rot in Sugar Beet.

Damping-off and crown and root rot of sugar beet caused by Rhizoctonia solani anastomosis group 2-2 (AG 2-2) are important soilborne diseases in Minnesota and North Dakota. Management involves an integrated approach, including crop rotation, use of resistant cultivars, and timely fungicide application. Our objectives were to evaluate the role of inoculum density and cultivar susceptibility on the onset and development of Rhizoctonia diseases and on yield and quality in sugar beet. Three cultivars varying in susceptibility were sown in field plots inoculated with 0, 20, 40, or 60 kg/ha of R. solani AG 2-2 IIIB infested barley during 2013 and 2015. In both years, there was a significant linear effect of inoculum density with decreasing area under the stand establishment curve (AUSEC), root yield, and sucrose quality as inoculum density increased. Cultivar susceptibility significantly affected AUSEC as well as sucrose quality in both years and root yield in 2013. In both years, there was an inoculum density by cultivar interaction on disease ratings, with the partially resistant cultivar resulting in lower ratings than the moderate and susceptible cultivars, especially as inoculum density increased. These results have implications for cultivar selection and for use and timing of postemergence fungicide application based on field history of inoculum pressure.

Evaluating Inoculation Methods to Infect Sugar Beet with Fusarium oxysporum f. betae and F. secorum.

Minnesota and North Dakota combined contain 55% of the sugar beet production area in the United States, contributing to 49% of the nation's sugar beet production in 2018. Fusarium diseases caused by Fusarium oxysporum f. betae and F. secorum on sugar beet can cause significant reduction in both root yield and sucrose concentration and purity. The objective of this research was to identify an alternative artificial inoculation method to induce Fusarium diseases on sugar beet leaves and roots caused by both Fusarium spp. in greenhouse conditions to better aid in research efforts. We tested four inoculation methods, including barley to seed, barley to root, drenching, and cutting. and compared them with the conventional root-dipping inoculation method. The inoculation method of placing Fusarium-colonized barley seed close to sugar beet seed (barley to seed) caused levels of symptom severities on both leaves and roots similar to the root-dipping method. Because the traditional root-dipping method involves a laborious transplant process, use of infected barley seed as inoculum may serve as an alternative method in the evaluation of host resistance and pathogen virulence among Fusarium diseases by Fusarium spp. on sugar beet at the seed or seedling stage.

Evaluation of soil treatment techniques on remediated brine spill sites in semi-arid rangelands.

Unconventional oil and gas development (UOG) generates high volumes of flowback and produced water, byproducts of hydraulic fracturing operations, that are often released or spilled on the soil surface. Soil contamination with these wastewaters, commonly referred to as brine, has the potential to inhibit vegetation growth indefinitely. Natural attenuation of brine is not expedient in arid and semi-arid regions where most United States UOG developments are located, including the Bakken region of North Dakota. In situ (at-site) and ex situ (off-site) soil treatment techniques are commonly employed to remediate brine-contaminated soils in the Bakken. However, little is known regarding each technique's efficacy despite differences in application, cost, and efficiency. We selected 10 sites previously remediated with chemical amendments (in situ) and 11 sites with topsoil excavation (ex situ) in the United States Forest Service Little Missouri National Grasslands. We paired each remediated site with a reference to examine the ability of each strategy to return brine-contaminated sites to conditions reflective of the current state of the surrounding semi-arid rangeland ecosystem. At each site, we quantified soil electrical conductivity (ECe) as an indicator of soil salinity and measured vegetation cover, biomass production, bare ground, and litter. The difference between paired reference and remediated sites was used for analysis. Brine contamination was still evident as soil ECe was similarly increased on chemical amendment and topsoil excavation remediated sites over paired references at all soil depths tested. Due to the nature of the topsoil excavation treatment, elevated ECe in the 0-15 cm depth suggested resalinization of the new topsoil. Remediation techniques also resulted in similar plant community composition marked by an increase in exotic forb biomass, largely due to the invasion of kochia (Bassia scoparia) which was absent from reference sites. However, remediation techniques differed substantially in vegetation establishment. We found 15% more bare ground on sites remediated with chemical amendment treatment than paired references and 55% more with topsoil excavation. Our results indicate that in situ strategies may be more suitable than ex situ strategies for brine-spill remediation in semi-arid rangelands like the Bakken in North Dakota as they cause less disturbance and likely require less post-remediation management to establish adequate vegetation cover to protect the soil from further erosion.

Do the Quality and Quantity of Honey Bee-Collected Pollen Vary Across an Agricultural Land-Use Gradient?

Pollen is the source of protein for most bee species, yet the quality and quantity of pollen is variable across landscapes and growing seasons. Understanding the role of landscapes in providing nutritious forage to bees is important for pollinator health, particularly in areas undergoing significant land-use change such as in the Northern Great Plains (NGP) region of the United States where grasslands are being converted to row crops. We investigated how the quality and quantity of pollen collected by honey bees (Apis mellifera L. [Hymenoptera: Apidae]) changed with land use and across the growing season by sampling bee-collected pollen from apiaries in North Dakota, South Dakota, and Minnesota, USA, throughout the flowering season in 2015-2016. We quantified protein content and quantity of pollen to investigate how they varied temporally and across a land-use gradient of grasslands to row crops. Neither pollen weight nor crude protein content varied linearly across the land-use gradient; however, there were significant interactions between land use and sampling date across the season, particularly in grasslands. Generally, pollen protein peaked mid-July while pollen weight had two maxima in late-June and late-August. Results suggest that while land use itself may not correlate with the quality or quantity of pollen resources collected by honey bees among our study apiaries, the nutritional landscape of the NGP is seasonally dynamic, especially in certain land covers, and may impose seasonal resource limitations for both managed and native bee species. Furthermore, results indicate periods of qualitative and quantitative pollen dearth may not coincide.

Age-Dependent Resistance to Rhizoctonia solani in Sugar Beet.

Rhizoctonia crown and root rot of sugar beet (Beta vulgaris L.), caused by Rhizoctonia solani, continues to be one of the important concerns for the beet industry in Minnesota and North Dakota. Use of resistant cultivars is an important strategy in the management of R. solani in combination with seed treatment and timely fungicide application during the growing season. The objective of this greenhouse study was to determine how sugar beet plants responded to increasing age in resistance to R. solani. Each of three seed companies provided three commercial cultivars with varying R. solani resistance levels: susceptible, moderately resistant, and resistant. Seed were planted at a weekly interval to create different plant age groups from seed to 10-week-old plants, with growing degree days (GDD) ranging from 0 to 1,519 thermal time (°Cd). Seed and plants were all simultaneously inoculated with R. solani AG2-2-infested barley grains. Twenty-eight days after inoculation, plants were pulled and washed, and roots were evaluated for disease severity. All cultivars were highly susceptible to R. solani when inoculated at seed to 3 weeks old (0 to 464°Cd). At 4 and 5 weeks of plant age (617 to 766°Cd), resistant cultivars started to show significant resistance to R. solani. Proportion of the affected roots with disease score ≥ 5 followed a sigmoid response, declining with increased GDD in moderately resistant and resistant cultivars, whereas it continued to decline linearly with increased GDD in susceptible cultivars. This study demonstrated that sugar beet cultivars, regardless of their assigned level of R. solani resistance, were highly susceptible to the pathogen before they reached the six- to eight-leaf stage at 4 to 5 weeks (617 to 766°Cd) after planting. Therefore, additional protection in the form of seed treatment or fungicide application may be required to protect sensitive sugar beet seed and seedlings in fields with a history of R. solani under favorable environmental conditions.

Prevalence and Distribution of Beet Necrotic Yellow Vein Virus Strains in North Dakota and Minnesota.

Beet necrotic yellow vein virus (BNYVV) is the causal agent of rhizomania, a disease of global importance to the sugar beet industry. The most widely implemented resistance gene to rhizomania to date is Rz1, but resistance has been circumvented by resistance-breaking (RB) isolates worldwide. In an effort to gain greater understanding of the distribution of BNYVV and the nature of RB isolates in Minnesota and eastern North Dakota, sugar beet plants were grown in 594 soil samples obtained from production fields and subsequently were analyzed for the presence of BNYVV as well as coding variability in the viral P25 gene, the gene previously implicated in the RB pathotype. Baiting of virus from the soil with sugar beet varieties possessing no known resistance to rhizomania resulted in a disease incidence level of 10.6% in the region examined. Parallel baiting analysis of sugar beet genotypes possessing Rz1, the more recently introgressed Rz2, and with the combination of Rz1 + Rz2 resulted in a disease incidence level of 4.2, 1.0, and 0.8%, respectively. Virus sequences recovered from sugar beet bait plants possessing resistance genes Rz1 and/or Rz2 exhibited reduced genetic diversity in the P25 gene relative to those recovered from the susceptible genotype while confirming the hypervariable nature of the coding for amino acids (AAs) at position 67 and 68 in the P25 protein. In contrast to previous reports, we did not find an association between any one specific AA signature at these positions and the ability to circumvent Rz1-mediated resistance. The data document ongoing virulence development in BNYVV populations to previously resistant varieties and provide a baseline for the analysis of genetic change in the virus population that may accompany the implementation of new resistance genes to manage rhizomania.

Effects of a Behavioral Health and Chronic Illness Care Intervention on Patient Outcomes in Primary Care Practices in the Dakotas.

From 2012 to 2015, Sanford Health, a large health care system, integrated behavioral health services and chronic condition care management in some of its primary care practices in the Dakotas and rural Minnesota. Using difference-in-differences analyses for fee-for-service Medicare beneficiaries attributed to 22 participating practices and 91 matched comparison practices, we found that the program increased the receipt of four recommended diabetes care processes by 8.6% (p=.048) and, by slowing the increase in emergency department (ED) visits, reduced them by 4.9% (p=.07) relative to the comparison group. However, the findings are mixed: the program did not affect hospital admissions, readmissions, or Medicare spending. In addition, the program increased admissions for ambulatory care-sensitive conditions by 13.6% (p=.07) relative to the comparison group. Sanford's program provides a concrete example of how to incorporate behavioral health services in primary care in underserved areas with some positive results on quality-of-care processes and ED utilization.

Genetic Diversity and Structure in Regional Cercospora beticola Populations from Beta vulgaris subsp. vulgaris Suggest Two Clusters of Separate Origin.

Cercospora leaf spot, caused by Cercospora beticola, is a highly destructive disease of Beta vulgaris subsp. vulgaris worldwide. C. beticola populations are usually characterized by high genetic diversity, but little is known of the relationships among populations from different production regions around the world. This information would be informative of population origin and potential pathways for pathogen movement. For the current study, the genetic diversity, differentiation, and relationships among 948 C. beticola isolates in 28 populations across eight geographic regions were investigated using 12 microsatellite markers. Genotypic diversity, as measured by Simpson's complement index, ranged from 0.18 to 1.00, while pairwise index of differentiation values ranged from 0.02 to 0.42, with the greatest differentiation detected between two New York populations. In these populations, evidence for recent expansion was detected. Assessment of population structure identified two major clusters: the first associated with New York, and the second with Canada, Chile, Eurasia, Hawaii, Michigan, North Dakota, and one population from New York. Inferences of gene flow among these regions suggested that the source for one cluster likely is Eurasia, whereas the source for the other cluster is not known. These results suggest a shared origin of C. beticola populations across regions, except for part of New York, where population divergence has occurred. These findings support the hypothesis that dispersal of C. beticola occurs over long distances.

Oviposition Preference and Larval Host Range of the Sugarbeet Root Maggot (Diptera: Ulidiidae).

The sugarbeet root maggot, Tetanops myopaeformis Röder (Diptera: Ulidiidae), is native to North America. However, its primary crop host, sugarbeet, Beta vulgaris L., was introduced to the continent from Europe in the late 19th century. This field and greenhouse research was conducted to compare the relative attractiveness of eight cultivated and wild plant species for oviposition by T. myopaeformis, and the suitability of these potential host plants for larval development to elucidate the potential native and current host range of this pest. Results indicated that females preferred ovipositing in soil immediately adjacent to or on the following plant species: sugarbeet; spinach, Spinacia olerocea L.; common lambsquarters, Chenopodium album L.; redroot pigweed, Amaranthus retroflexus L.; Palmer amaranth, Amaranthus palmeri S. Wats.; and to a lesser extent, spear saltbush, Atriplex patula L. Larval survival was greatest on spinach, sugarbeet, and spear saltbush, which all belong to the family Chenopodiaceae. Larval survival on these plants suggests that T. myopaeformis could have exploited wild chenopodiaceous plants or others within the order Caryophyllales before sugarbeet was introduced to North America. Low larval survival on common lambsquarters, redroot pigweed, and Palmer amaranth suggests that these species are suboptimal hosts, despite demonstrated attractiveness for oviposition. A general lack of oviposition preference by T. myopaeformis females was observed for sunflower, Helianthus annuus L., and common ragweed, Ambrosia artemisiifolia L. These results provide insights regarding the successful and somewhat rapid host preference shift by this insect to sugarbeet after cultivation of the crop began in the continent.

Risk assessment of human exposure to Ra-226 in oil produced water from the Bakken Shale.

Unconventional oil production in North Dakota (ND) and other states in the United States uses large amounts of water for hydraulic fracturing to stimulate oil flow. Most of the water used returns to the surface as produced water (PW) containing different constituents. Some of these contents are total dissolved solids and radionuclides. The most predominant radionuclide in PW is radium-226 (Ra-226) of which level depends on several factors including the content of certain cations. A multivariate regression model was developed to predict Ra-226 in PW from the Bakken Shale based on the levels of barium, strontium, and calcium. The simulated Ra-226 activity concentration in PW was 535 pCi/L supporting extremely limited actual data based on three PW samples from the Bakken (527, 816, and 1210 pCi/L). The simulated activity concentration was further analyzed by studying its impact in the event of a PW spill reaching a surface water body that provides drinking water, irrigation water for crops, and recreational fishing. Using food transfer factors found in the literature, the final annual effective dose rate for an adult in ND was estimated. The global average annual effective dose rate via food and drinking water is 0.30 mSv, while the predicted dose rate in this study was 0.49 mSv indicating that there is potential risk to human health in ND due to Ra-226 in PW spills. This predicted dose rate is considered the best case scenario as it is based on the simulated Ra-226 activity concentration in PW of 535 pCi/L which is close to the low end actual activity concentration of 527 pCi/L.

Transgenic Bt Corn, Soil Insecticide, and Insecticidal Seed Treatment Effects on Corn Rootworm (Coleoptera: Chrysomelidae) Beetle Emergence, Larval Feeding Injury, and Corn Yield in North Dakota.

Northern, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae), and western, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), corn rootworms are economic pests of corn, Zea mays L. in North America. We measured the impacts of corn hybrids incorporated with Cry3Bb1, Cry34/35Ab1, and pyramided (Cry3Bb1 + Cry34/35Ab1) Bacillus thuringiensis Berliner (Bt) proteins, tefluthrin soil insecticide, and clothianidin insecticidal seed treatment on beetle emergence, larval feeding injury, and corn yield at five locations from 2013 to 2015 in eastern North Dakota. In most cases, emergence was significantly lower in Bt-protected corn than in non-Bt corn hybrids. Exceptions included Wyndmere, ND (2013), where D. barberi emergence from Cry34/35Ab1 plots was not different from that in the non-Bt hybrid, and Arthur, ND (2013), where D. v. virgifera emergence from Cry3Bb1 plots did not differ from that in the non-Bt hybrid. Bt hybrids generally produced increased grain yield compared with non-Bt corn where rootworm densities were high, and larval root-feeding injury was consistently lower in Bt-protected plots than in non-Bt corn. The lowest overall feeding injury and emergence levels occurred in plots planted with the Cry3Bb1 + Cry34/35Ab1 hybrid. Time to 50% cumulative emergence of both species was 5-7 d later in Bt-protected than in non-Bt hybrids. Tefluthrin and clothianidin were mostly inconsequential in relation to beetle emergence and larval root injury. Our findings could suggest that some North Dakota populations could be in early stages of increased tolerance to some Bt toxins; however, Bt corn hybrids currently provide effective protection against rootworm injury in eastern North Dakota.

Assessing Potato Cultivar Sensitivity to Tuber Necrosis Caused by Tobacco rattle virus.

Tobacco rattle virus (TRV) causes the economically important corky ring spot disease in potato. Chemical control is difficult due to the soilborne nature of the TRV-transmitting nematode vector, and identifying natural host resistance against TRV is considered to be the optimal control measure. The present study investigated the sensitivity of 63 cultivars representing all market types (evaluated at North Dakota and Washington over 2 years) for the incidence of TRV-induced tuber necrosis and severity. This article also investigates the cultivar-location interaction (using a mixed-effects model) for TRV-induced necrosis. TRV-induced tuber necrosis (P < 0.0001) and severity (P < 0.0001) were significantly different among cultivars evaluated separately in North Dakota and Washington trials. Mixed-effects model results of pooled data (North Dakota and Washington) demonstrated that the interaction of cultivar and location had a significant effect (P = 0.03) on TRV-induced necrosis. Based on the virus-induced tuber necrosis data from both years and locations, cultivars were categorized into sensitive, moderately sensitive, insensitive, and moderately insensitive groups. Based on data from North Dakota, 10 cultivars, including Bintje, Centennial Russet, Ciklamen, Gala, Lelah, Oneida Gold, POR06V12-3, Rio Colorado, Russian Banana, and Superior, were rated as insensitive to TRV-induced tuber necrosis. Similar trials assessing TRV sensitivity among cultivars conducted in Washington resulted in a number of differences in sensitivity rankings compared with North Dakota trials. A substantial shift in sensitivity of some potato cultivars to TRV-induced tuber necrosis was observed between the two locations. Four cultivars (Centennial Russet, Oneida Gold, Russian Banana, and Superior) ranked as insensitive for North Dakota trials were ranked as sensitive for Washington trials. These results can assist the potato industry in making cultivar choices to reduce the economic impact of TRV-induced tuber necrosis.

Aggregation Behavior and a Putative Aggregation Pheromone in Sugar Beet Root Maggot Flies (Diptera: Ulidiidae).

Male-biased aggregations of sugar beet root maggot, Tetanops myopaeformis (Röder) (Diptera: Ulidiidae), flies were observed on utility poles near sugar beet (Beta vulgaris L. [Chenopodiaceae]) fields in southern Idaho; this contrasts with the approximately equal sex ratio typically observed within fields. Peak observation of mating pairs coincided with peak diurnal abundance of flies. Volatiles released by individual male and female flies were sampled from 08:00 to 24:00 hours in the laboratory using solid-phase microextraction and analyzed using gas chromatography/mass spectrometry (GC/MS). Eleven compounds were uniquely detected from males. Three of these compounds (2-undecanol, 2-decanol, and sec-nonyl acetate) were detected in greater quantities during 12:00-24:00 hours than during 08:00-12:00 hours. The remaining eight compounds uniquely detected from males did not exhibit temporal trends in release. Both sexes produced 2-nonanol, but males produced substantially higher (ca. 80-fold) concentrations of this compound than females, again peaking after 12:00 hours. The temporal synchrony among male aggregation behavior, peak mating rates, and release of certain volatile compounds by males suggest that T. myopaeformis flies exhibit lekking behavior and produce an associated pheromone. Field assays using synthetic blends of the putative aggregation pheromone showed evidence of attraction in both females and males.

A Comparison of Honey Bee-Collected Pollen From Working Agricultural Lands Using Light Microscopy and ITS Metabarcoding.

Taxonomic identification of pollen has historically been accomplished via light microscopy but requires specialized knowledge and reference collections, particularly when identification to lower taxonomic levels is necessary. Recently, next-generation sequencing technology has been used as a cost-effective alternative for identifying bee-collected pollen; however, this novel approach has not been tested on a spatially or temporally robust number of pollen samples. Here, we compare pollen identification results derived from light microscopy and DNA sequencing techniques with samples collected from honey bee colonies embedded within a gradient of intensive agricultural landscapes in the Northern Great Plains throughout the 2010-2011 growing seasons. We demonstrate that at all taxonomic levels, DNA sequencing was able to discern a greater number of taxa, and was particularly useful for the identification of infrequently detected species. Importantly, substantial phenological overlap did occur for commonly detected taxa using either technique, suggesting that DNA sequencing is an appropriate, and enhancing, substitutive technique for accurately capturing the breadth of bee-collected species of pollen present across agricultural landscapes. We also show that honey bees located in high and low intensity agricultural settings forage on dissimilar plants, though with overlap of the most abundantly collected pollen taxa. We highlight practical applications of utilizing sequencing technology, including addressing ecological issues surrounding land use, climate change, importance of taxa relative to abundance, and evaluating the impact of conservation program habitat enhancement efforts.

Environmental signatures and effects of an oil and gas wastewater spill in the Williston Basin, North Dakota.

Wastewaters from oil and gas development pose largely unknown risks to environmental resources. In January 2015, 11.4ML (million liters) of wastewater (300g/L TDS) from oil production in the Williston Basin was reported to have leaked from a pipeline, spilling into Blacktail Creek, North Dakota. Geochemical and biological samples were collected in February and June 2015 to identify geochemical signatures of spilled wastewaters as well as biological responses along a 44-km river reach. February water samples had elevated chloride (1030mg/L) and bromide (7.8mg/L) downstream from the spill, compared to upstream levels (11mg/L and <0.4mg/L, respectively). Lithium (0.25mg/L), boron (1.75mg/L) and strontium (7.1mg/L) were present downstream at 5-10 times upstream concentrations. Light hydrocarbon measurements indicated a persistent thermogenic source of methane in the stream. Semi-volatile hydrocarbons indicative of oil were not detected in filtered samples but low levels, including tetramethylbenzenes and di-methylnaphthalenes, were detected in unfiltered water samples downstream from the spill. Labile sediment-bound barium and strontium concentrations (June 2015) were higher downstream from the Spill Site. Radium activities in sediment downstream from the Spill Site were up to 15 times the upstream activities and, combined with Sr isotope ratios, suggest contributions from the pipeline fluid and support the conclusion that elevated concentrations in Blacktail Creek water are from the leaking pipeline. Results from June 2015 demonstrate the persistence of wastewater effects in Blacktail Creek several months after remediation efforts started. Aquatic health effects were observed in June 2015; fish bioassays showed only 2.5% survival at 7.1km downstream from the spill compared to 89% at the upstream reference site. Additional potential biological impacts were indicated by estrogenic inhibition in downstream waters. Our findings demonstrate that environmental signatures from wastewater spills are persistent and create the potential for long-term environmental health effects.

Holistic risk assessment of surface water contamination due to Pb-210 in oil produced water from the Bakken Shale.

A holistic risk assessment of surface water (SW) contamination due to lead-210 (Pb-210) in oil produced water (PW) from the Bakken Shale in North Dakota (ND) was conducted. Pb-210 is a relatively long-lived radionuclide and very mobile in water. Because of limited data on Pb-210, a simulation model was developed to determine its concentration based on its parent radium-226 and historical total dissolved solids levels in PW. Scenarios where PW spills could reach SW were analyzed by applying the four steps of the risk assessment process. These scenarios are: (1) storage tank overflow, (2) leakage in equipment, and (3) spills related to trucks used to transport PW. Furthermore, a survey was conducted in ND to quantify the risk perception of PW from different stakeholders. Findings from the study include a low probability of a PW spill reaching SW and simulated concentration of Pb-210 in drinking water higher than the recommended value established by the World Health Organization. Also, after including the results from the risk perception survey, the assessment indicates that the risk of contamination of the three scenarios evaluated is between medium-high to high.

Artificial destratification effects on nitrogen and phosphorus dynamics in a eutrophic impoundment in the northern Great Plains.

To determine the influence of artificial destratification on nutrient variations in a small eutrophic impoundment, field monitoring and laboratory analyses were conducted in three consecutive summers (2010, 2011, and 2012). The impact of aeration among sampling locations and across the water column of nutrient concentrations, including total and dissolved inorganic nitrogen (N) and phosphorus (P) and water temperature and dissolved oxygen (DO) was evaluated under aerated and non-aerated conditions. Aeration eliminated thermal stratification and DO concentrations of bottom waters increased. Nutrients including soluble reactive phosphorus (SRP), total phosphorus (TP), and total nitrogen (TN) concentrations across the water column did not change significantly during aeration. Nevertheless, under aerated conditions, dissolved inorganic nutrients, TN, TP, and temperature were homogenously distributed throughout the water column as an effect of aeration. Results indicated that artificial destratification resuspended nutrients throughout the water column; however, it did not have a significant effect on nutrient concentrations in the water column, but SRP, TN, and TP concentrations did not reach to the recommended limit as needed by the North Dakota Department of Health requirements. Therefore, alternative aeration methods, for instance, hypolimnetic oxygenation or hypolimnetic aeration are recommended to control nutrient redistribution and/or further releases by existing aeration system.