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At least 37 records · Page 2Linked to original sources

Changes in concentrations of triazine and acetamide herbicides by bank filtration, ozonation, and chlorination in a public water supply

The changes in triazine and acetamide concentrations in water during natural and artificial treatment by bank filtration, ozonation, filtration, and chlorination were measured at the well field and drinking water treatment plant of Lincoln, Nebraska, USA. The city's groundwater supply is affected by induced infiltration and transport of triazines and acetamide herbicides from the Platte River in late spring and early summer. The objective of the study was to evaluate the effect of infiltration and treatment on the presence of triazines and acetamides in drinking water. Samples of river water, well water, and public supply water at various stages of water treatment were collected from 1997-1999 during spring-runoff when the presence of herbicides in the Platte River is largest. In 1999, parent compounds were reduced by 76% of the concentration present in river water (33% by bank filtration, 41% by ozonation, and 1.5% by chlorination). Metabolites of herbicides for which analytical techniques existed were reduced by 21% (plus 26% by bank filtration, minus 23% by ozonation, and minus 24% by chlorination). However, increases in concentrations of specific metabolite compounds were identified after bank filtration and ozonation. After bank filtration, increases in cyanazine amide, cyanazine acid, and deethylcyanazine acid were identified. After ozonation, concentrations of deisopropylatrazine, deethylatrazine, didealkylatrazine, atrazine amide-I, hydroxydeethylatrazine, hydroxydeisopopylatrazine, deethylcyanazine acid, and deethylcyanazine increased. Concentrations of cyanazine acid and ethanesulfonic and oxanilic acids of acetamides decreased during ozonation. Our findings suggest that bank filtration and ozonation of water in part can shift the assessment of risk to human health associated with the consumption of the water from the parent compounds to their degradation products.

Journal of Hydrology

Toxicity of waters from the St. Lawrence River at Massena Area-of-Concern to the plankton species Selenastrum capricornutum and Ceriodaphnia dubia

In 1972, the US and Canada committed to restore the chemical, physical, and biological integrity of the Great Lakes Ecosystem under the first Great Lakes Water Quality Agreement. During subsequent amendments, part of the St. Lawrence River at Massena NY, and segments of three tributaries, were designated as one Area of Concern (AOC) due to various beneficial use impairments (BUIs). Plankton beneficial use was designated impaired within this AOC because phytoplankton and zooplankton population data were unavailable or needed “further assessment”. Contaminated sediments from industrial waste disposal have been largely remediated, thus, the plankton BUI may currently be obsolete. The St. Lawrence River at Massena AOC remedial action plan established two criteria which may be used to assess the plankton BUI; the second states that, “in the absence of community structure data, plankton bioassays confirm no toxicity impact in ambient waters”. This study was implemented during 2011 to determine whether this criterion was achieved. Acute toxicity and chronic toxicity of local waters were quantified seasonally using standardized bioassays with green alga Selenastrum capricornutum and water flea Ceriodaphnia dubia to test the hypothesis that waters from sites within the AOC were no more toxic than were waters from adjacent reference sites. The results of univariate and multivariate analyses confirm that ambient waters from most AOC sites (and seasons) were not toxic to both species. Assuming both test species represent natural plankton assemblages, the quality of surface waters throughout most of this AOC should not seriously impair the health of resident plankton communities.

New York

U.S. recreational water quality criteria: a vision for the future

This manuscript evaluates the U.S. Recreational Water Quality Criteria (RWQC) of 2012, based upon discussions during a conference held 11–13 March 2013, in Honolulu, Hawaii. The RWQC of 2012 did not meet expectations among the research community because key recommended studies were not completed, new data to assess risks to bathers exposed to non-point sources of fecal indicator bacteria (FIB) were not developed, and the 2012 RWQC did not show marked improvements in strategies for assessing health risks for bathers using all types of recreational waters. The development of the 2012 RWQC was limited in scope because the epidemiologic studies at beach sites were restricted to beaches with point sources of pollution and water samples were monitored for only enterococci. The vision for the future is development of effective RWQC guidelines based on epidemiologic and quantitative microbial risk assessment (QMRA) studies for sewage specific markers, as well as human enteric pathogens so that health risks for bathers at all recreational waters can be determined. The 2012 RWQC introduced a program for states and tribes to develop site-specific water quality criteria, and in theory this approach can be used to address the limitations associated with the measurements of the traditional FIB.

International Journal of Environmental Research an

Challenges in linking soil health to edge-of-field water quality across the Great Lakes basin

To better understand agricultural nutrient losses, we evaluated relationships between management (e.g., manure and tillage), soil health measurements, and resulting edge-of-field (EOF) surface water quality. This work was conducted before or early into conservation implementation at 14 Great Lakes Restoration Initiative EOF sites spanning Wisconsin, Michigan, Indiana, Ohio, and New York. Analyses of site characteristics (hydroclimate, management, catchment properties) along with 3 yr of soil health measurements (chemical, biological, and physical properties) showed EOF-nutrient export depended on both site and soil properties. A pattern emerged whereby sites not receiving manure and sites with manure defined opposite ends of several gradients for soil and water data. Sites receiving manure had increased microbial activity, organic matter (3.2 vs. 2.7%), and soil test phosphorus (P) (2.8 times more) relative to sites without manure. Suspended sediments (SS), total P (TP), and total nitrogen (TN) in EOF surface runoff varied over three to five orders. Multivariate analysis among sites showed covariant linkages between soil nutrients, soil C, microbial properties, and nutrients in EOF water. There were positive univariate relationships between water-extractable soil P and annual EOF-water concentrations and yields of orthophosphate, TP, TN, and SS ( p < .01). Some soil physical properties (e.g., bulk density and infiltration) also covaried among sites but were not consistently related to runoff index or water yield variables. Given the observed among-site variability, we were not able to isolate desirable soil health signals on EOF surface water quality.

Journal of Environmental Quality

Environmental presence and persistence of pharmaceuticals: An overview

Emerging contaminants (ECs) in the environment &ndash; that is, chemicals with domestic, municipal, industrial, or agricultural sources that are not commonly monitored but may have the potential for adverse environmental effects &ndash; is a rapidly growing field of research. The use of &ldquo;emerging&rdquo; is not intended to infer that the presence of these compounds in the environment is new. These chemicals have been released into the environment as long as they have been in production or, in the case of hormones and other endogenous compounds, since the rise of animal life. What is emerging is the interest by the scientific and lay communities in the presence of these chemicals in the environment, the analytical capabilities required for detection, and the subtle effects that very small concentrations of these chemicals appear to have on aquatic biota. In December 2006, Environmental Science & Technology devoted an entire special issue (volume 40, number 23) to the topic of ECs, illustrating the increased interest in the subject. Within the EGs, one particular class that has seen a substantial increase in research over the past 10 years is pharmaceuticals and personal-care products (PPCPs). This increased research interest can be demonstrated by several means, including requests for proposals from funding agencies, but the clearest indication of a focused effort to understand the introduction, transformation, and potential health and environmental effects of PPCPs and ECs, in general, is the number of published reports. This increase can be shown by examining six environmental journals that regularly publish PPCP-related papers &ndash; Chemosphere , Environmental Science & Technology , Environmental Toxicology and Chemistry , Science of the Total Environment , Water Research , and Water Science and Technology . In 1998 there were 22 papers published on pharmaceuticals, antibiotics, or drugs in these 6 journals; by 2006, this number increased sixfold to 132 papers (Figure 1.1). This growth can be attributed to a number of factors. The presence of pharmaceuticals in surface-water samples from Europe and the United States was documented in several sentinel papers. These ground-breaking works encouraged other scientists to examine the rivers, streams, lakes, and reservoirs in their regions for such chemicals. In addition, the intense public attention paid to news reports on the environmental detections of these chemicals and possible effects of aquatic life has made this issue visible to the wastewater-treatment, drinking-water treatment, and regulatory communities. This has driven the funding bodies associated with these communities to fund studies or request proposals that address the presence, fate, and effects of PPCPs in aquatic systems. The release of the first comprehensive reconnaissance of pharmaceuticals and other wastewater contaminants in the United States provides an example of the intense media interest in this topic. Within 6 days on online publication of this study, 72 newspapers across the United States had published articles describing the results, either locally written or based on international media syndicate reports. There also was substantial concurrent coverage by local and national radio and television outlets, including the Cable News Network, ABC World News Tonight , and National Public Radio. A substantial fraction of these news stories may be attributable to press releases and media briefings prior to publication. However, the interest by television and print journalists in reporting the results of a peer-reviewed journal article to the general public was motivated by the recognition that describing the presence of PPCPs in water supplies would be of interest to the public. To better convey the results of the study published by Koplin et al. to the public, a separate general-interest fact sheet was published to summarize the important points of the study. Because PPCPs are commonly and widely used by individuals, there is likely a preexisting, personal identification with these compounds that does not occur for the wide range of other organic and inorganic contaminants whose presence in the environment has previously been described. This greater public &ldquo;name recognition&rdquo; makes itself known through the media to the regulatory and technical community and has prompted interest in sponsoring research that defines the composition and concentrations of PPCPs in potential sources and their fate and effects following relase into the environment. Independent of the drivers that potentially fuel the interest in studies of PPCPs, it is clear that PPCP research has grown beyond surface-water studies to examine issues such as: &bull; Presence in other matrices, such as groundwater, landfill leachates, sediments, and biosolids. &bull; Environmental transport and fate in surface water, groundwater, and soils amended with reclaimed water or biosolids. &bull; PPCP source elucidation, such as wastewater treatment plant (WWTP) effluents, confined animal feeding operations (CAFOs), and aquaculture. &bull; Removal during wastewater and drinking-water treatment. &bull; Effects on aquatic ecosystems, terrestrial ecosystems, and human health. The chapters in this book provide an extensive examination of current environmental pharmaceutical research and are divided into three sections: &ldquo;Occurrence and Analysis of Pharmaceuticals in the Environment,&rdquo; &ldquo;Environment Fate and Transformations of Veterinary Pharmaceuticals,&rdquo; and &ldquo;treatment of Pharmaceuticals in Drinking Water and Wastewater.&rdquo; The purpose of this introductory overview chapter is to outline current (2004-2006) knowledge about the presence and concentration of PPCPs as described in the published literature. Previous reviews should be consulted for discussions on pre-2004 publications. Those reviews will provide the reader with a comprehensive introduction to the topic of PPCPs in the environment. This chapter describes the sources of PPCPs and other organic contaminants often associated with human wastewater into the environment, the range of concentrations present in various environmental compartments, and the potential routes of removal/sequestration. An overview of the sources and fate of veterinary pharmaceuticals will be discussed in Chapter 5, &ldquo;Fate and Transport of Veterinary Medicines in the Soil Environment.&rdquo;

Book chapter

Residues in fish, wildlife, and estuaries. Indicator species near top of food chain chosen for assessment of pesticide base levels in fish and wildlife--clams, oysters, and sediment in estuarine environment

Federal efforts to determine pesticide levels in fish and wildlife are being carried out by the Bureau of Sport Fisheries and Wildlife, U. S. Department of the Interior. Monitoring estuarine pesticide levels in clams, oysters, and sediments is a joint endeavor of the Bureau of Commercial Fisheries, U. S. Department of the Interior, and the Water Supply and Sea Resources Program of the National Center for Urban and Industrial Health, Public Health Service, U. S. Department of Health, Education, and Welfare.

Pesticides Monitoring Journal

Transcriptional changes in wild Yukon River Chinook Salmon associated with Ichthyophonus infections

Objective We compared differentially expressed genes in Chinook Salmon Oncorhynchus tshawytscha with three divergent Ichthyophonus statuses (undetected, subclinical infections, or clinical disease; n = 100) to investigate associated transcriptomic responses. Disease associated with the fish parasite Ichthyophonus sp. was first diagnosed in adult Chinook Salmon from the Yukon River in the late 1980s and has subsequently been implicated in premature host mortality. Methods Chinook Salmon tissue sample collections and Ichthyophonus infection data were leveraged from a multi-agency collaboration during summer 2022 at three locations along the main-stem Yukon River that spanned nearly 2,000 km of freshwater migration (lower, middle, and upper river). We sequenced the transcriptome and compared this to infection status based on routine diagnostic procedures. Results Among the 17,569 genes for which messenger RNA was detected, we identified a transcription signature in the skeletal muscle that was associated with Ichthyophonus infections and included 53 differentially expressed genes. The differentially expressed genes and their pathways included those known for involvement in immune functions, energy synthesis, cellular breakdown, and reproduction—all processes that are known to be influenced by senescence during spawning migrations. Conclusions Results demonstrate a clear transcriptional difference between diseased fish (clinical disease group) and those in which Ichthyophonus was undetected, including identifying candidate markers for infection in this population. These results provide a foundation for development of nonlethal biomarkers to evaluate potential Ichthyophonus infections in Chinook Salmon based on gene transcription, protein products, or gene variants (e.g., polymorphisms).

Journal of Aquatic Animal Health

Assessing models of arsenic occurrence in drinking water from bedrock aquifers in New Hampshire

Three existing multivariate logistic regression models were assessed using new data to evaluate the capacity of the models to correctly predict the probability of groundwater arsenic concentrations exceeding the threshold values of 1, 5, and 10 micrograms per liter (µg/L) in New Hampshire, USA. A recently released testing dataset includes arsenic concentrations from groundwater samples collected in 2004–2005 from a mix of 367 public-supply and private domestic wells. The use of this dataset to test three existing logistic regression models demonstrated enhanced overall predictive accuracy for the 5 and 10 μg/L models. Overall accuracies of 54.8, 76.3, and 86.4 percent were reported for the 1, 5, and 10 μg/L models, respectively. The state was divided by counties into northwest and southeast regions. Regional differences in accuracy were identified; models had an average accuracy of 83.1 percent for the counties in the northwest and 63.7 percent in the southeast. This is most likely due to high model specificity in the northwest and regional differences in arsenic occurrence. Though these models have limitations, they allow for arsenic hazard assessment across the region. The introduction of well-type (public or private), well depth, and casing length as explanatory variables may be appropriate measures to improve model performance. Our findings indicate that the original models generalize to the testing dataset, and should continue to serve as an important vehicle of preventative public health that may be applied to other groundwater contaminants in New Hampshire.

New Hampshire

Intra‐Annual Changes in Waterborne Nanophyetus salmincola

An analysis of daily water samples collected from an index site on Big Soos Creek, Washington indicated intra‐annual differences in the concentrations of waterborne Nanophyetus salmincola. Waterborne concentrations, quantified as gene copies/L, peaked during the fall (October–November 2016), decreased to very low concentrations over the winter (January–March 2017), and then increased in the spring and throughout the summer. High waterborne concentrations of N. salmincola DNA (2 × 106 gene copies/L) corresponded with live N. salmincola cercariae (mean = 3 cercariae/L) that were detected in companion water samples. Spikes in waterborne N. salmincola concentrations in October and November typically coincided with increases in streamflow; this combination resulted in elevated infection pressures during high water events in the fall. The peak in waterborne N. salmincola concentrations corresponded with an accompanying peak in tissue parasite density (metacercariae/posterior kidney) in Coho Salmon Oncorhynchus kisutch that were reared in the untreated water.

Journal of Aquatic Animal Health

Mitigating the effects of landscape development on streams in urbanizing watersheds

This collaborative study examined urbanization and impacts on area streams while using the best available sediment and erosion control (S&EC) practices in developing watersheds in Maryland, United States. During conversion of the agricultural and forested watersheds to urban land use, land surface topography was graded and vegetation was removed creating a high potential for sediment generation and release during storm events. The currently best available S&EC facilities were used during the development process to mitigate storm runoff water quality, quantity, and timing before entering area streams. Detailed Geographic Information System (GIS) maps were created to visualize changing land use and S&EC practices, five temporal collections of LiDAR (light detection and ranging) imagery were used to map the changing landscape topography, and streamflow, physical geomorphology, and habitat data were used to assess the ability of the S&EC facilities to protect receiving streams during development. Despite the use of the best available S&EC facilities, receiving streams experienced altered flow, geomorphology, and decreased biotic community health. These impacts on small streams during watershed development affect sediment and nutrient loads to larger downstream aquatic ecosystems such as the Chesapeake Bay.

Maryl

Toxicity and hazard of vanadium to mallard ducks (Anas platyrhynchos) and Canada geese (Branta canadensis)

A recent Canada goose ( Branta canadensis ) die-off at a petroleum refinery fly ash pond in Delaware was attributed to vanadium (V) toxicity. Because of the paucity of V toxicity data for wild birds, a series of studies was undertaken using the forms of V believed to have resulted in this incident. In 7-d single oral dose trials with mallard drakes ( Anas platyrhynchos ), the estimated median lethal dose (LD50) for vanadium pentoxide was 113 mg/kg body weight, while the LD50 for sodium metavanadate was 75.5 mg/kg. Sodium metavanadate was found to be even more potent (LD50 = 37.2 mg/kg) in male Canada geese. The most distinctive histopathological lesion of both forms of V was lympho-granulocytic enteritis with hemorrhage into the intestinal lumen. Vanadium accumulation in liver and kidney was proportional to the administered dose, and predictive analyses based on these data suggest that V concentrations of 10 μg/g dry weight (dw) in liver and 25 μg/g dw in kidney are associated with mortality (>90% confidence that exposure is >LD50) in mallards acutely exposed to sodium metavanadate. Chronic exposure to increasing dietary concentrations of sodium metavanadate (38.5 to 2651 ppm) over 67 d resulted in V accumulation in liver and kidney (25.2 and 13.6 μg/g dw, respectively), mild intestinal hemorrhage, blood chemistry changes, and evidence of hepatic oxidative stress in mallards, although some of these responses may have been confounded by food avoidance and weight loss. Dietary exposure of mallards to 250 ppm sodium metavanadate for 4 wk resulted in modest accumulation of V in liver and kidney (<5 μg/g dw) and mild intestinal hemorrhage. Based on these data and other observations, it is unlikely that chronic low-level dietary exposure to V poses a direct lethal hazard to wildlife. However, point sources, such as the V-laden fly ash pond encountered by geese at the petroleum refinery in Delaware, may pose a significant hazard to water birds.

Journal of Toxicology and Environmental Health, Pa

Nontuberculous mycobacterial disease and molybdenum in Colorado watersheds

Nontuberculous mycobacteria (NTM) are environmental bacteria that may cause chronic lung disease. Environmental factors that favor NTM growth likely increase the risk of NTM exposure within specific environments. We aimed to identify water-quality constituents (Al, As, Cd, Ca, Cu, Fe, Pb, Mg, Mn, Mo, Ni, K, Se, Na, Zn, and pH) associated with NTM disease across Colorado watersheds. We conducted a geospatial, ecological study, associating data from patients with NTM disease treated at National Jewish Health and water-quality data from the Water Quality Portal. Water-quality constituents associated with disease risk were identified using generalized linear models with Poisson-distributed discrete responses. We observed a highly robust association between molybdenum (Mo) in the source water and disease risk. For every 1- unit increase in the log concentration of molybdenum in the source water, disease risk increased by 17.0%. We also observed a statistically significant association between calcium (Ca) in the source water and disease risk. The risk of NTM varied by watershed and was associated with watershed-specific water-quality constituents. These findings may inform mitigation strategies to decrease the overall risk of exposure.

Colorado

Assessing contributions of cold-water refuges to reproductive migration corridor conditions for adult salmon and steelhead trout in the Columbia River, USA

Diadromous fish populations face multiple challenges along their migratory routes. These challenges include suboptimal water quality, harvest, and barriers to longitudinal and lateral connectivity. Interactions among factors influencing migration success make it challenging to assess management options for improving migratory fish conditions along riverine migration corridors. We describe a spatially explicit simulation model that integrates complex individual behaviors of fall-run Chinook Salmon ( Oncorhynchus tshawytscha ) and summer-run steelhead trout ( O. mykiss ) during migration, responds to variable habitat conditions over a large extent of the Columbia River, and links migration corridor conditions to fish condition outcomes. The model is built around a mechanistic behavioral decision tree that drives individual interactions of fish within their simulated environments. By simulating several thermalscapes with alternative scenarios of thermal refuge availability, we examined how behavioral thermoregulation in cold-water refuges influenced migrating fish conditions. Outcomes of the migration corridor simulation model show that cold-water refuges can provide relief from exposure to high water temperatures, but do not substantially contribute to energy conservation by migrating adults. Simulated cooling of the Columbia River decreased reliance on cold-water refuges and there were slight reductions in migratory energy expenditure. This modeling of simulated thermalscapes provides a framework for assessing the contribution of cold-water refuges to the success of migrating fishes, but any final determination will depend on analyzing fish survival and health for their entire migration, water temperature management goals and species recovery targets.

Washington, Oregon, Idaho

Effects of dietary selenium on tissue concentrations,pathology, oxidative stress, and immune function in common eiders (Somateria mollissima)

Common eiders ( Somateria mollissima ) were fed added Se (as L-selenomethionine) in concentrations increasing from 10 to 80 ppm in a pilot study (Study 1) or 20 (low exposure) and up to 60 (high exposure) ppm Se in Study 2. Body weights of Study 1 ducks and high-exposure ducks in Study 2 declined rapidly. Mean concentrations of Se in blood reached 32.4 ppm wet weight in Study 1 and 17.5 ppm wet weight in high-exposure birds in Study 2. Mean Se concentrations in liver ranged from 351 (low exposure, Study 2) to 1252 ppm dry weight (Study 1). Oxidative stress was evidenced by Se-associated effects on glutathione metabolism. As Se concentrations in liver increased, Se-dependent glutathione peroxidase activity, glutathione reductase activity, oxidized glutathione levels, and the ratio of hepatic oxidized to reduced glutathione increased. In Study 2, the T-cell-mediated immune response was adversely affected in high-exposure eiders, but ducks in the low-exposure group exhibited evidence of an enhanced antibody-mediated immune response. Gross lesions in high-exposure ducks included emaciation, absence of thymus, and loss of nails from digits. Histologic lesions included severe depletion of lymphoid organs, hepatopathy, and necrosis of feather pulp and feather epithelium. Field studies showed that apparently healthy sea ducks generally have higher levels of Se in liver than healthy fresh-water birds, but lower than concentrations found in our study. Data indicate that common eiders and probably other sea ducks possess a higher threshold, or adverse effect level, for Se in tissues than fresh-water species. However, common eiders developed signs of Se toxicity similar to those seen in fresh-water birds.

Journal of Toxicology and Environmental Health, Pa

Detection, emission estimation and risk prediction of forest fires in China using satellite sensors and simulation models in the past three decades-An overview

Forest fires have major impact on ecosystems and greatly impact the amount of greenhouse gases and aerosols in the atmosphere. This paper presents an overview in the forest fire detection, emission estimation, and fire risk prediction in China using satellite imagery, climate data, and various simulation models over the past three decades. Since the 1980s, remotely-sensed data acquired by many satellites, such as NOAA/AVHRR, FY-series, MODIS, CBERS, and ENVISAT, have been widely utilized for detecting forest fire hot spots and burned areas in China. Some developed algorithms have been utilized for detecting the forest fire hot spots at a sub-pixel level. With respect to modeling the forest burning emission, a remote sensing data-driven Net Primary productivity (NPP) estimation model was developed for estimating forest biomass and fuel. In order to improve the forest fire risk modeling in China, real-time meteorological data, such as surface temperature, relative humidity, wind speed and direction,have been used as the model input for improving prediction of forest fire occurrence and its behavior. Shortwave infrared (SWIR) and near infrared (NIR) channels of satellite sensors have been employed for detecting live fuel moisture content (FMC), and the Normalized Difference Water Index (NDWI) was used for evaluating the forest vegetation condition and its moisture status.

International Journal of Environmental Research an

The effect of residential development on ground-water quality near Detroit, Michigan

Two water-quality studies were done on the outskirts of the Detroit metropolitan area to determine how recent residential development has affected ground-water quality. Pairs of monitor and domestic wells were sampled in areas where residential land use overlies glacial outwash deposits. Young, shallow waters had significantly higher median concentrations of nitrate, chloride, and dissolved solids than older, deeper waters. Analysis of chloride/bromide ratios indicates that elevated salinities are due to human activities rather than natural factors, such as upward migration of brine. Trace concentrations of volatile organic compounds were detected in samples from 97 percent of the monitor wells. Pesticides were detected infrequently even though they are routinely applied to lawns and roadways in the study area. The greatest influence on ground-water quality appears to be from septic-system effluent (domestic sewage, household solvents, water-softener backwash) and infiltration of stormwater runoff from paved surfaces (road salt, fuel residue). No health-related drinking-water standards were exceeded in samples from domestic wells. However, the effects of human activities are apparent in 76 percent of young waters, and at depths far below 25 feet, which is the current minimum well-depth requirement.Two water-quality studies were done on the outskirts of the Detroit metropolitan area to determine how recent residential development has affected ground-water quality. Pairs of monitor and domestic wells were sampled in areas where residential land use overlies glacial outwash deposits. Young, shallow waters had significantly higher median concentrations of nitrate, chloride, and dissolved solids than older, deeper waters. Analysis of chloride/bromide ratios indicates that elevated salinities are due to human activities rather than natural factors, such as upward migration of brine. Trace concentrations of volatile organic compounds were detected in samples from 97 percent of the monitor wells. Pesticides were detected infrequently even though they are routinely applied to lawns and roadways in the study area. The greatest influence on ground-water quality appears to be from septic-system effluent (domestic sewage, household solvents, water-softener backwash) and infiltration of stormwater runoff from paved surfaces (road salt, fuel residue). No health-related drinking-water standards were exceeded in samples from domestic wells. However, the effects of human activities are apparent in 76 percent of young waters, and at depths far below 25 feet, which is the current minimum well-depth requirement.

Michigan

Natural inactivation of MS2, poliovirus type 1 and Cryptosporidium parvum in an anaerobic and reduced aquifer

Aims The study of microbial inactivation rates in aquifer systems has most often been determined in aerobic and oxidized systems. This study examined the inactivation (i.e. loss of infectivity) of MS2, poliovirus type 1 (PV1) and Cryptosporidium parvum in an anaerobic and reduced groundwater system that has been identified as storage zones for aquifer storage and recovery (ASR) facilities. Methods and Results Anaerobic and reduced (ORP < − 250 mV) groundwater from an artesian well was diverted to an above-ground, flow-through mesocosm that contained diffusion chambers filled with MS2, PV1 or Cryptosporidium parvum . The respective infectivity assays were performed on microorganisms recovered from the diffusion chambers during 30- to 58-day experiments. The net reduction in infectivity was 5.73 log 10 over 30 days for MS2, 5.00 log 10 over 58 days for PV1 and 4.07 log 10 over 37 days for C . parvum . The best fit inactivation model for PV1 was the log-linear model and the Weibull model for MS2 and C . parvum , with respective inactivation rates (95% confidence interval) of 0.19 (0.17–0.21) log 10 day −1 , 0.31 (0.19–0.89) log 10 day −1 and 0.20 (0.14–0.37) log 10 day −1 . Conclusions The groundwater geochemical conditions in this aquifer enhanced the inactivation of MS2, PV1, and C . parvum at rates approximately 2.0–5.3-fold, 1.2–17.0-fold, and 4.5–5.6-fold greater, respectively, than those from published studies that used diffusion chambers in aerobic-to-anoxic groundwater systems, with positive redox potentials. Significance and Impact of the Study Geochemical conditions like those in the aquifer zone in this study can naturally and significantly reduce concentrations of microbial indicators and pathogens of human health concern in injected surface water. Appropriate storage times for injected surface water could complement above-ground engineered processes for microorganism removal and inactivation (e.g. filtration, disinfection) by naturally increasing overall microorganism log-inactivation rates of ASR facilities.

Journal of Applied Microbiology

Hydroecological condition and potential for aquaculture in lakes of the arid region of Khorezm, Uzbekistan

With >400 small (<1 ha) lakes, the arid Khorezm Province in Uzbekistan may be well-suited for aquaculture production. Developing water resources to provide a local food supply could increase fish consumption while improving the rural economy. Hydroecological (biological and physical) and chemical characteristics (including legacy pesticides &Sigma;DDT and &Sigma;HCH) of four representative drainage lakes in Khorezm from 2006 to 2008 were analyzed for the lakes&rsquo; capability to support healthy fish populations. Lake characteristics were categorized as &ldquo;optimal&rdquo; (having little or no effect on growth and development), &ldquo;tolerable&rdquo; (corresponding to chronic or sub-lethal toxicity) and &ldquo;lethal&rdquo; (corresponding to acute toxicity). Results indicate that three lakes are likely well-suited for raising fish species, with water quality meeting World Bank aquaculture guidelines. However, the fourth lake often had salinity concentrations > optimal levels for local fish species. Pesticide concentrations in water of all four lakes were within tolerable aquaculture ranges. Although water &Sigma;DDT concentrations were >optimal limits, results from chemical analysis of fish tissues and semi-permeable membrane devices indicated that study lake &Sigma;DDT concentrations were not accumulating in fish or posing a human health threat. Land and water management to maintain adequate lake water quality are imperative for sustaining fish populations for human consumption.

Khorezm