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131.
Estimating Watershed Level Nonagricultural Pesticide Use From Golf Courses Using Geospatial Methods1
Garey A. Fox Gail P. Thelin George J. Sabbagh John W. Fuchs Iain D. Kelly 《Journal of the American Water Resources Association》2008,44(6):1363-1372
Abstract: Limited information exists on pesticide use for nonagricultural purposes, making it difficult to estimate pesticide loadings from nonagricultural sources to surface water and to conduct environmental risk assessments. A method was developed to estimate the amount of pesticide use on recreational turf grasses, specifically golf course turf grasses, for watersheds located throughout the conterminous United States (U.S.). The approach estimates pesticide use: (1) based on the area of recreational turf grasses (used as a surrogate for turf associated with golf courses) within the watershed, which was derived from maps of land cover, and (2) from data on the location and average treatable area of golf courses. The area of golf course turf grasses determined from these two methods was used to calculate the percentage of each watershed planted in golf course turf grass (percent crop area, or PCA). Turf‐grass PCAs derived from the two methods were used with recommended application rates provided on pesticide labels to estimate total pesticide use on recreational turf within 1,606 watersheds associated with surface‐water sources of drinking water. These pesticide use estimates made from label rates and PCAs were compared to use estimates from industry sales data on the amount of each pesticide sold for use within the watershed. The PCAs derived from the land‐cover data had an average value of 0.4% of a watershed with minimum of 0.01% and a maximum of 9.8%, whereas the PCA values that are based on the number of golf courses in a watershed had an average of 0.3% of a watershed with a minimum of <0.01% and a maximum of 14.2%. Both the land‐cover method and the number of golf courses method produced similar PCA distributions, suggesting that either technique may be used to provide a PCA estimate for recreational turf. The average and maximum PCAs generally correlated to watershed size, with the highest PCAs estimated for small watersheds. Using watershed specific PCAs, combined with label rates, resulted in greater than two orders of magnitude over‐estimation of the pesticide use compared to estimates from sales data. 相似文献
132.
Lability of drinking water treatment residuals (WTR) immobilized phosphorus: aging and pH effects 总被引:3,自引:0,他引:3
Time constraints associated with conducting long-term (>20 yr) field experiments to test the stability of drinking water treatment residuals (WTR) sorbed phosphorus (P) inhibit improved understanding of the fate of sorbed P in soils when important soil properties (e.g., pH) change. We used artificially aged samples to evaluate aging and pH effects on lability of WTR-immobilized P. Artificial aging was achieved through incubation at elevated temperatures (46 or 70 degrees C) for 4.5 yr, and through repeated wetting and drying for 2 yr. Using a modified isotopic ((32)P) dilution technique, coupled with a stepwise acidification procedure, we monitored changes in labile P concentrations over time. This technique enabled evaluation of the effect of pH on the lability of WTR-immobilized P. Within the pH range of 4 to 7, WTR amendment, coupled with artificial aging, ultimately reduced labile P concentrations by > or = 75% relative to the control (no-WTR) samples. Soil samples with different physicochemical properties from two 7.5-yr-old, one-time WTR-amended field sites were utilized to validate the trends observed with the artificially aged samples. Despite the differences in physicochemical properties among the three (two field-aged and one artificially aged) soil samples, similar trends of aging and pH effects on lability of WTR-immobilized P were observed. Labile P concentrations of the WTR-amended field-aged samples of the two sites decreased 6 mo after WTR amendment and the reduction persisted for 7.5 yr, ultimately resulting in > or = 70% reduction, compared to the control plots. We conclude that WTR application is capable of reducing labile P concentration in P-impacted soils, doing so for a long time, and that within the commonly encountered range of pH values for agricultural soils WTR-immobilized P should be stable. 相似文献
133.
Burchell MR Skaggs RW Lee CR Broome S Chescheir GM Osborne J 《Journal of environmental quality》2007,36(1):194-207
A wetland mesocosm experiment was conducted in eastern North Carolina to determine if organic matter (OM) addition to soils used for in-stream constructed wetlands would increase NO3--N treatment. Not all soils are suitable for wetland substrate, so OM addition can provide a carbon and nutrient source to the wetland early in its development to enhance denitrification and biomass growth. Four batch studies, with initial NO3--N concentrations ranging from 30 to 120 mg L-1, were conducted in 2002 in 21 surface-flow wetland mesocosms. The results indicated that increasing the OM content of a Cape Fear loam soil from 50 g kg-1 (5% dry wt.) to 110 g kg-1 (11% dry wt.) enhanced NO3--N wetland treatment efficiency in spring and summer batch studies, but increases to 160 g kg-1 (16% dry wt.) OM did not. Wetlands constructed with dredged material from the USACE Eagle Island Confined Disposal Facility in Wilmington, NC, with initial OM of 120 g kg-1 (12% dry wt.), showed no improvement in NO3--N treatment efficiency when increased to 180 g kg-1 (18% dry wt.), but did show increased NO3--N treatment efficiency in all batch studies when increased to 220 g kg-1 (22% dry wt.). Increased OM addition and biosolids to the Cape Fear loam and dredged material blends significantly increased biomass growth in the second growing season when compared to no OM addition. Results of this research indicate that increased OM in the substrate will reduce the area required for in-stream constructed wetlands to treat drainage water in humid regions. It also serves as a demonstration of how dredged material can be used successfully in constructed wetlands, as an alternative to costly storage by the USACE. 相似文献
134.
Sand-sized particles (>63 microm) in whole storm water samples collected from urban runoff have the potential to produce data with substantial bias and/or poor precision both during sample splitting and laboratory analysis. New techniques were evaluated in an effort to overcome some of the limitations associated with sample splitting and analyzing whole storm water samples containing sand-sized particles. Wet-sieving separates sand-sized particles from a whole storm water sample. Once separated, both the sieved solids and the remaining aqueous (water suspension of particles less than 63 microm) samples were analyzed for total recoverable metals using a modification of USEPA Method 200.7. The modified version digests the entire sample, rather than an aliquot, of the sample. Using a total recoverable acid digestion on the entire contents of the sieved solid and aqueous samples improved the accuracy of the derived sediment-associated constituent concentrations. Concentration values of sieved solid and aqueous samples can later be summed to determine an event mean concentration. 相似文献
135.
Cost-efficient sample designs for collection of ground data and accurate mapping of variables are required to monitor natural
resources and environmental and ecological systems. In this study, a sample design and mapping method was developed by integrating
stratification, model updating, and cokriging with Landsat Thematic Mapper (TM) imagery. This method is based on the spatial
autocorrelation of variables and the spatial cross-correlation among them. It can lead to sample designs with variable grid
spacing, where sampling distances between plots vary depending on spatial variability of the variables from location to location.
This has potential cost-efficiencies in terms of sample design and mapping. This method is also applicable for mapping in
the case in which no ground data can be collected in some parts of a study area because of the high cost. The method was validated
in a case study in which a ground and vegetation cover factor was sampled and mapped for monitoring soil erosion. The results
showed that when the sample obtained with three strata using the developed method was used for sampling and mapping the cover
factor, the sampling cost was greatly decreased, although the error of the map was slightly increased compared to that without
stratification; that is, the sample cost-efficiency quantified by the product of cost and error was greatly increased. The
increase of cost-efficiency was more obvious when the cover factor values of the plots within the no-significant-change stratum
were updated by a model developed using the previous observations instead of remeasuring them in the field. 相似文献
136.
Zoning and applying Limits of Acceptable Change (LAC) are two promising strategies for managing tourism in Marine Protected
Areas (MPAs). Typically, these management strategies require the collection and integration of ecological and socioeconomic
data. This problem is illustrated by a case study of Koh Chang National Marine Park, Thailand. Biophysical surveys assessed
coral communities in the MPA to derive indices of reef diversity and vulnerability. Social surveys assessed visitor perceptions
and satisfaction with conditions encountered on snorkelling tours. Notably, increased coral mortality caused a significant
decrease in visitor satisfaction. The two studies were integrated to prescribe zoning and “Limits of Acceptable Change” (LAC).
As a biophysical indicator, the data suggest a LAC value of 0.35 for the coral mortality index. As a social indicator, the
data suggest that a significant fraction of visitors would find a LAC value of under 30 snorkellers per site as acceptable.
The draft zoning plan prescribed four different types of zones: (I) a Conservation Zone with no access apart from monitoring
or research; (II) Tourism Zones with high tourism intensities at less vulnerable reefs; (III) Ecotourism zones with a social
LAC standard of <30 snorkellers per site, and (IV) General Use Zones to meet local artisanal fishery needs. This study illustrates
how ecological and socioeconomic field studies in MPAs can be integrated to craft zoning plans addressing multiple objectives. 相似文献
137.
George William Kajjumb Rachael E. Bokot Matias Attene-Ramos Erica J. Marti 《环境科学学报(英文版)》2022,34(7):295-304
In the race to deliver clean water to communities through potable water reuse, disinfection and water quality assessment are and will continue to be fundamental factors. There are over 700 disinfection byproducts (DBPs) in water; evaluating each compound is practically impossible and very time consuming. A bioanalytical approach could be an answer to this challenge. In this work, the response of four major classes of DBPs toward mitochondrial membrane potential (ΔΨm) and cytoplasmic adenosine triphosphate (C-ATP) was investigated with human carcinoma (HepG2) cells. Within 90 min of cell exposure, only the haloacetic acid (HAA) mixture caused a cytotoxic response as measured by C-ATP. All four groups (haloacetonitriles (HANs), trihalomethanes (THMs), nitrosamines (NOAs), and HAAs) responded well to ΔΨm, R2 > 0.70. Based on the half-maximum concentration that evoked a 50% response in ΔΨm, the response gradient was HANs >> HAAs ∼ THM > NOAs. The inhibition of the ΔΨm by HANs is driven by dibromoacetonitrile (DBAN), while dichloroacetonitrile (DCAN) did not cause a significant change in the ΔΨm at less than 2000 µM. A mixture of HANs exhibited an antagonistic behavior on the ΔΨm compared to individual compounds. If water samples are concentrated to increase HAN concentrations, especially DBAN, then ΔΨm could be used as a biomonitoring tool for DBP toxicity. 相似文献
138.
Excessive exploitation of and skewed access to dwindling water resources raise serious water justice concerns. Environmental justice movements and related literature have raised critical questions regarding the unequal distribution of the costs and benefits of a development paradigm that is founded on excessive exploitation and appropriation of natural resources. This paper explores the growing relevance of a water justice framework that addresses both the social and ecological aspects of water use and appropriation, with reference to a four-decade long water conflict over the Chaliyar River in Kerala, South India. It highlights how ecosystem degradation and denial of justice go hand in hand. The paper argues that the framing and articulation of the conflict in a partisan manner led to the glossing over of certain critical features, thus preventing a full view of water injustices. It also failed to inform subsequent policies and practices in this regard. 相似文献
139.
The South African abalone Haliotis midae is a commercially valuable species, but its numbers are seriously depleted due to illegal fishing. Overfishing not only affects the targeted species, but also potentially influences the integrity and functioning of the ecosystem through associated changes in community composition. We assessed the herbivorous effects of H. midae on the benthos through a 6-month field experiment involving exclusion/inclusion plots. This showed that benthic community composition remained largely unchanged whether H. midae was present or absent and specifically revealed no evidence that H. midae diminishes algal biomass, probably because in the region where we worked, it feeds mainly by trapping drift kelp rather than grazing on attached algae. The absence of responses to the removal of abalone was additionally evident in comparison with indices of abundance and diversity, functional groups and individual species. In the absence of abalone, there were subtle increases in the green alga Codium stephensiae and the crustose brown alga Zeacarpa leiomorpha and decreases in the four species of foliose macroalgae, but none of these effects were significant. The presence of H. midae thus had no negative grazing effects on any elements of the epilithic community composition. It does, however, have other influences, including occupation of space and provision of habitat in the form of its shell, which supports a community significantly different from the surrounding rocks. 相似文献
140.