Lead pollution: records in Southern California coastal sediments     

T J Chow  K W Bruland  K Bertine  A Soutar  M Koide  E D Goldberg 《Science (New York, N.Y.)》1973,181(99):551-552

The present anthropogenic lead fluxes into sediments from the Santa Monica, San Pedro, and Santa Barbara basins of Southern California are, respectively, 0.9, 1.7, and 2.1 micrograms of lead per square centimeter of sea bottom per year; the natural (prepollution) rates for these three basins were, respectively, 0.24, 0.26, and 1.0 microgram of lead per square centimeter per year. Studies of isotopic composition indicate that lead pollutants in coastal sediments are derived mainly from the combustion of lead additives in gasoline.  相似文献   

Soil nitrate-nitrogen in forested versus non-forested ecosystems in a mixed-use watershed     

G.L. Bruland  C.M. Bliss  N.B. Comerford 《Geoderma》2008,148(2):220-231

In tracking nutrients that enter the Gulf of Mexico via the Suwannee Basin, a disproportionate amount of the nitrate-nitrogen (NO₃-N) has been shown to originate in the Santa Fe River Watershed (SFRW). This study investigated soil NO₃-N distributions across the range of land-use and soil order combinations that exist in the SFRW with a focus on comparing NO₃-N levels in forested versus non-forested land-uses. The SFRW consists of 52% forested land-uses (i.e. pine plantation, forest regeneration, upland forest, and forested wetland), 47% non-forested land-uses (i.e. agriculture, rangeland, and urban), and 1% water. Soil samples were collected from four depth intervals (0-30, 30-60, 60-120, 120-180 cm) at 101 to 141 sites with a stratified-random design in six sampling events (Sept. 2003, Jan. 2004, May 2004, Jan. 2005, May 2005, and Sept. 2005). No samples were collected in Sept. 2004 due to flooding associated with two hurricanes. Nitrate-nitrogen was significantly lower in forested than non-forested land-uses across all sampling events, depth intervals, and for profile average data. Within the non-forested land-use category, NO₃-N levels were highest in row crop agriculture and improved pasture sites. In terms of soil order, NO₃-N values were generally highest in Ultisols and Spodosols, but soil order explained less of the variation in the NO₃-N data than did land-use or sampling date. Nitrate-N concentrations were considerably altered by Hurricanes Frances and Jeanne which passed over the SFRW in late summer of 2004. In the post-hurricane sampling events, NO₃-N was significantly lower in both forested and non-forested sites. A year later, however, NO₃-N concentrations in forested sites remained quite low, while concentrations in non-forested sites had begun to increase.  相似文献   

Effects of Feral Pig (Sus scrofa) Exclusion on Enterococci in Runoff from the Forested Headwaters of a Hawaiian Watershed     

Dunkell  Dashiell O.  Bruland  Gregory L.  Evensen  Carl I.  Walker  Mark J. 《Water, air, and soil pollution》2011,220(1-4):313-326

Water, Air, &; Soil Pollution - The role feral pigs (Sus scrofa) as a source of fecal contamination in Pacific Island ecosystems is not well understood. This study investigated the effects of...  相似文献   

Using indicators of land-use development intensity to assess the condition of coastal wetlands in Hawai‘i     

Sandra C. Margriter  Gregory L. Bruland  Gregory M. Kudray  Christopher A. Lepczyk 《Landscape Ecology》2014,29(3):517-528

Although wetland condition assessment procedures have been developed, validated, and calibrated in the continental United States, they have not yet been fully developed or field-tested for wetlands in Hawai‘i. In order to address the need for comprehensive assessment methods for Hawaiian coastal wetlands, our research compared three indicators of landscape condition (landscape development intensity, road density, and forest cover) with wetland condition as measured by rapid assessment methods (RAM) and detailed field data collected on soil and water quality. We predicted that wetlands located in the least developed landscapes would have more nutrient rich soils, yet lower nutrient levels in the surface water, and would receive the highest rapid assessment scores. The hypotheses of our study were generally supported. However, while the correlations between landscape variables and δ¹⁵N isotopes and CRAM scores were relatively strong, the correlations between the landscape indicators and the other Level II and III field indicators were not very strong. These results suggest that further calibration and refinement of metrics is needed in order to more accurately assess the condition of Hawaiian coastal wetlands. A more detailed land use map, in addition to more comprehensive assessments of wetland water quality and biotic integrity would likely improve the relationships between indicators of landscape condition and wetland condition. Nonetheless, our research demonstrated that landscape analysis at larger scales (1,000 m buffers and watersheds) could provide managers with valuable information on how regional stressors may be affecting wetland water quality (measured as δ¹⁵N in plant tissue) as well as overall wetland condition (RAM scores).  相似文献   

Breed-specific incidence rates of canine primary bone tumors--a population based survey of dogs in Norway     

Anfinsen KP  Grotmol T  Bruland OS  Jonasdottir TJ 《Canadian journal of veterinary research》2011,75(3):209-215

This is one of few published population-based studies describing breed specific rates of canine primary bone tumors. Incidence rates related to dog breeds could help clarify the impact of etiological factors such as birth weight, growth rate, and adult body weight/height on development of these tumors. The study population consisted of dogs within 4 large/giant breeds; Irish wolfhound (IW), Leonberger (LB), Newfoundland (NF), and Labrador retriever (LR), born between January 1st 1989 and December 31st 1998. Questionnaires distributed to owners of randomly selected dogs--fulfilling the criteria of breed, year of birth, and registration in the Norwegian Kennel Club--constituted the basis for this retrospective, population-based survey. Of the 3748 questionnaires received by owners, 1915 were completed, giving a response rate of 51%. Forty-three dogs had been diagnosed with primary bone tumors, based upon clinical examination and x-rays. The breeds IW and LB, with 126 and 72 cases per 10 000 dog years at risk (DYAR), respectively, had significantly higher incidence rates of primary bone tumors than NF and LR (P < 0.0001). Incidence rates for the latter were 11 and 2 cases per 10 000 DYAR, respectively. Pursuing a search for risk factors other than body size/weight is supported by the significantly different risks of developing primary bone tumors between similarly statured dogs, like NF and LB, observed in this study. Defining these breed-specific incidence rates enables subsequent case control studies, ultimately aiming to identify specific etiological factors for developing primary bone tumors.  相似文献   

Evaluation of Liposomal Radiochemotherapy for Treatment of Cancer     

T. J.  Jonasdottir §  J. Borrebæk  ØS Bruland  G. Salberg  L. Moe  R. H. Larsen 《Veterinary and comparative oncology》2005,3(1):58-59

Introduction: Pegylated liposomes target solid tumors by exploiting the capillary leakage properties of tumor neovasculature. The goal of the study was to investigate distribution and tumor targeting properties of the alpha‐particle emitter ²²³Ra, encapsulated in doxorubicin‐containing‐liposomes (Caelyx^®/Doxil^®). Methods: Caelyx^® was given before the injection of liposomal ²²³Ra to reduce the reticulo‐endothelial‐system uptake. A pilot study was conducted to determine the optimal time interval between the pre‐treatment/treatment. Subsequently a more extensive distribution study was performed in normal BalbC mice. In addition, distribution and tumor uptake was evaluated in a human osteosarcoma xenograft mice model and in a dog with spontaneous osteosarcoma. Results: Optimal blood‐to‐liver and blood‐to‐spleen ratios of liposomal radium was achieved in animals that received pre‐treatment with Caelyx^® 4 days in advance. Blood clearance was relatively slow, in mice t_1/2 was ～28 h (BalbC mice) and in the dog t_1/2 was ～ 39 h. In mice the liver uptake appeared to be relatively low in contrast to the spleen, where there was a significant uptake. In the dog the uptake in both liver and spleen was moderate. In the xenograft model there was generally a higher retention of activity in the tumor vs. soft tissue. In the dog the 24 h uptake was considerably higher in both calcified and non‐calcified tumor metastases of different organs, than in normal tissue. Conclusions: Liposomal ²²³Ra has a relevant biodistribution and blood clearance for tumor targeting. More extensive future studies are supported by the favourable tumor/normal‐tissue ratio in a dog with spontaneous osteosarcoma.  相似文献   

Incorporation of spectral data into multivariate geostatistical models to map soil phosphorus variability in a Florida wetland     

R.G. Rivero  S. Grunwald  G.L. Bruland 《Geoderma》2007,140(4):428-443

Hybrid geostatistical prediction methods incorporate (i) spatially-explicit soil observations and exhaustive grids of ancillary environmental variables (e.g. derived from remote sensing), (ii) spatial autocorrelation, (iii) spatial covariation, and/or (iv) combinations of the above. In numerous studies of terrestrial soils it has been shown that hybrid geostatistical methods outperform univariate spatial and regression (aspatial) methods. However, hybrid methods have rarely been employed to predict soil properties in wetlands. In this study we used spectral data and derived indices from two remote sensors (Landsat ETM+ and ASTER), with different spatial resolutions, from different seasons, but with similar spectral range, ancillary environmental data, as well as floc and soil total phosphorus (TP) observations from 111 sites. The specific objective of our study was to evaluate the performance of aspatial methods (multivariate regressions — REG), univariate spatial (Ordinary Kriging — OK) and hybrid/multivariate geostatistical methods (Regression Kriging — RK and Co-kriging — CK) in predicting the spatial variability and distribution of floc and soil TP in a subtropical wetland, WCA-2A, in the Florida Everglades. Measured floc TP ranged from 194 to 1865 mg kg^− 1 with a median of 751 mg kg^− 1 and standard deviation (SD) of 381 mg kg^− 1. According to cross-validation, predictions for floc TP based on the root mean square prediction error (RMSE) were best in the following order: RK_quadratic (134.9) > RK_multivariate (201.1) > OK (206.1) > CK (212.1) > REG_multivariate (218.3) > REG_quadratic (220.3) > REG_linear (264.4); and based on the mean prediction error (ME) followed the order RK_multivariate (0.9)  RK_quadratic (1.1) > CK (− 6.7) > REG_multivariate (18.2) > REG_linear (25.1) > OK (− 27.3) > REG_quadratic (27.3). The Normalized Difference Vegetation Index (NDVI)-green derived from Landsat ETM+ showed the largest predictive power for floc TP. Measured soil TP ranged from 155 to 1702 mg kg^− 1 with a median of 433 mg kg^− 1 and standard deviation of 316 mg kg^− 1. Predictions for soil TP based on RMSE were best in the following order: RK_ASTER (200.1) > CK_ASTER (238.2)  CK_ETM (239.0) > OK (258.0) > RK_ETM (279.2) > REG_ASTER (281.8) > REG_ETM (356.1); and based on ME followed the order: CK_ASTER (0.1)  CK_ETM (0.2) > RK_ASTER (− 5.2) > RK_ETM (− 31.5) > OK (− 41.8) > REG_ASTER (94.4) > REG_ETM (133.7). The NDVI showed the largest predictive power for soil TP. This comparative study in a subtropical wetland demonstrated the benefits of incorporating remote sensing data into floc and soil TP prediction models. Overall, hybrid geostatistical methods (CK and RK) performed better than regressions and spatial univariate models (OK) in the prediction of floc and soil TP. Depending on the strength of the spatial covariance between primary and secondary variables (CK) and the ability of the regression model in RK to explain the variability of a target variable (e.g., floc or soil TP), either CK or RK performed best. Our findings in this wetland confirmed results from earlier studies on terrestrial soils indicating the superior performance of hybrid geostatistical methods in predicting soil properties.  相似文献   

An Assessment of the Phosphorus Retention Capacity of Wetlands in the Painter Creek Watershed, Minnesota, USA     

G. L. Bruland  C. J. Richardson 《Water, air, and soil pollution》2006,171(1-4):169-184

Lake Minnetonka, located in southeastern Minnesota, U.S.A., is currently experiencing increased eutrophication due to excessive phosphorus (P) loading in runoff from agriculture and urban areas. This phenomenon has been exacerbated by the isolation of wetlands in the surrounding watershed from the surface water drainage network. In order to determine if rerouting surface water through these wetlands would be a feasible method for reducing P inputs, we assessed the P retention capacity of wetlands in a subwatershed of Lake Minnetonka, the Painter Creek Watershed (PCW). The objectives of our study were to determine which of 15 different wetland sites in the PCW had the highest P sorption capacity, identify which soil properties best explained the variability in P sorption, and utilize P fractionation to determine the dominant form of soil P. Our results indicated that despite similar vegetation and hydrogeomorphic settings, wetlands in the PCW had considerably different P sorption capacities. Depth-averaged P sorption index (PSI) values showed considerable variability, ranging from 14.6 to 184. The Katrina Marsh, Painter Marsh, South Highway 26, and West Jennings Bay sites had the highest depth-averaged PSIs. The soil properties that best predicted PSI were soil organic matter, exchangeable calcium, and oxalate extractable iron. Phosphorus fractionation data revealed organic P to be the dominant form of soil P, indicating that organic matter accumulation is another P storage mechanism in these wetlands.  相似文献