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前不久,镉超标大米引发社会对于土壤污染的关注。应该说,清除"镉米"背后的土壤污染,最重要任务之一就是全面会诊土壤重金属污染现状,通过调查取样,全面、系统、准确掌握我国土壤污染的真实"家底"。记者近日从国土资源部、中国地质调查局获悉,我国正在绘制土壤重金属"人类污染图"。 相似文献
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论述了在Mapinfo系统辅助下的农用地分等技术方法,探讨了如何运用Mapinfo强大的数据采集存储、图形编辑、空间分析、地理分析功能进行农用地的分等参数的计算和成果图的输出等关键步骤的实现过程,并以洪湖市为例进行实证分析.结果证明,在Mapinfo辅助下进行县(市)级农用地分等过程中达到了图件和数据处理程序的一体化,具有较高的工作效率和数据精度,是十分可行的农用地分等技术方法. 相似文献
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Paul L. Mosquin Jeremy Aldworth Phillip S. Kott Wenlin Chen Shanique Grant 《Journal of the American Water Resources Association》2023,59(1):16-28
The estimation of upper percentiles of chemical concentrations in surface water systems within sites and regions may be necessary for the assessment of potential risk to ecosystems and human health. Limited sample sizes at monitoring sites often limit the use of direct methods to estimate upper percentiles. In such cases, upper percentiles within regions within a time frame may be estimated by pooling data across sites and years, and then deriving percentile estimates from the pooled dataset. The method uses the observations resulting from either a known probability-sampling design or a sampling design treated like one because its observations come close to matching that of a probability-sample. These observations are then weighted to ensure that estimates are representative of a target population across all the sites within the region and the range of years in the time frame. This method of estimating upper percentiles of annual site concentration profiles is demonstrated using atrazine and validated using the monitoring data from both sparsely sampled and high-frequency water monitoring programs, where point and interval estimates of the 90th, 95th, and 99th pooled population percentiles are provided. This method shows that the pooled data from multiple sparse datasets can be used to provide estimates of near-peak concentrations with greater certainty, which are consistent with those generated by high-frequency sampling monitoring programs. 相似文献
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The state of North Carolina's Department of Environment and Natural Resources (NCDENR) conducts routine water quality monitoring
throughout the state to assess the health of aquatic systems. The current study reports the results of a retrospective (1990–2000)
ecological risk assessment of six heavy metals (arsenic, cadmium, copper, lead, mercury, and zinc) in 17 North Carolina basins
that was conducted to estimate the risk of heavy metal toxicity to freshwater organisms and assess the sufficiency of NCDENR's
monitoring data to identify water-quality-related ecological threats. Acute and chronic ecotoxicological thresholds (ETs)
were calculated for each metal based upon the 10th percentile of species sensitivity distributions and were normalized for
water hardness. Statewide probabilities (expressed as percentages) of a random sample exceeding acute or chronic ETs among
the six metals ranged from 0.01% to 12.19% and 0.76% to 21.21%, respectively, with copper having the highest and arsenic and
mercury the lowest risk. Basin-specific probabilities varied significantly depending upon water hardness and presumably watershed
development. Although the majority of specific sites where data were collected were at low risk for metal toxicity, some specific
sites had a high probability of toxic events associated with one or more metals. Analytical detection limits for metals were
frequently higher than estimated chronic ET, limiting the ability to assess the risk of chronic toxicity in soft-water basins.
Results suggest risk-based criteria may be useful for assessing and validating the sufficiency of monitoring programs and
prioritizing management goals. 相似文献
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D. G. Guerrant W. W. Miller C. N. Mahannah R. Narayanan 《Journal of the American Water Resources Association》1990,26(1):127-134
ABSTRACT: Little quantitative site-specific infiltration, runoff and sediment transport data for Tahoe Basin soils under varying storm events or stage of development are available. Modular (Ml), F-type (M2), Impact nozzle (M3), and Impact-Fan nozzle (M4) rainfall simulators were evaluated as to their practicality and ability to characterize infiltration for the Cagwin Soil Series within the Tahoe Basin. Three slope (0–15,15–30, >30%) and four plot conditions (natural with duff [P1], natural without duff [P2], disturbed without duff [P3], and disturbed with duff [P4]) were studied. The measured data were incorporated into a modified Philip's infiltration model and multiple non-linear regression analyses were used to examine relationships between method, slope, plot condition, and infiltration characteristics.t Simulation methods Ml and M4 produced statistically similar (P=0.01) infiltration data, as did M2 and M3 which produced lower infiltration rates. All were found suitable for use in Sierra Nevada watersheds. Ml was considered most practical. Slope had negligible effect on infiltration. The plot condition was found to significantly influence infiltration, and the effect of each plot condition was significantly different. Final infiltration rates ranged from 4.7 to 6.2 cm/hr. Thus, the Cagwin soil demonstrated moderate to high infiltration rates even when exposed to extreme storm conditions (8–10 cm/hr). 相似文献
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The N simulation model, DRAINMOD-N II, was field-tested using a 6-yr data set from an artificially drained agricultural site located in eastern North Carolina. The test site is on a nearly flat sandy loam soil which is very poorly drained under natural conditions. Four experimental plots, planted to a corn (Zea mays)-wheat (Triticum aestivum L.)-soybean (Glycine max.) rotation and managed using conventional and controlled drainage, were used in model testing. Water table depth, subsurface drainage, and N concentration in drain flow were measured and meteorological data were recorded continuously. DRAINMOD-N II was calibrated using the data from one plot; data sets from the other three plots were used for model validation. Simulation results showed an excellent agreement between observed and predicted nitrate-nitrogen (NO(3)-N) losses in drainage water over the 6-yr period and a reasonable agreement on an annual basis. The agreement on a monthly basis was not as good. The Nash-Sutcliffe modeling efficiency (EF) for monthly predictions was 0.48 for the calibration plot and 0.19, 0.01, and -0.02 for the validation plots. The value of the EF for yearly predictions was 0.92 for the calibration plot and 0.73, 0.62, and -0.10 for the validation plots. Errors in predicting cumulative NO(3)-N losses over the 6-yr period were remarkably small; -1.3% for the calibration plot, -8.1%, -2.8%, and 4.0% for the validation plots. Results of this study showed the potential of DRAINMOD-N II for predicting N losses from drained agricultural lands. Further research is needed to test the model for different management practices and soil and climatological conditions. 相似文献
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The US Army Land Condition-Trend Analysis (LCTA) program is a standardized method of data collection, analysis, and reporting
designed to meet multiple goals and objectives. The method utilizes vascular plant inventories, permanent field plot data,
and wildlife inventories. Vascular plant inventories are used for environmental documentation, training of personnel, species
identification during LCTA implementation, and as a survey for state and federal endangered or threatened species. The permanent
field plot data documents the vegetational, edaphic, topographic, and disturbance characteristics of the installation. Inventory
plots are allocated in a stratified random fashion across the installation utilizing a geographic information system that
integrates satellite imagery and soil survey information. Ground cover, canopy cover, woody plant density, slope length, slope
gradient, soil information, and disturbance data are collected at each plot. Plot data are used to: (1) describe plant communities,
(2) characterize wildlife and threatened and endangered species habitat, (3) document amount and kind of military and nonmilitary
disturbance, (4) determine the impact of military training on vegetation and soil resources, (5) estimate soil erosion potential,
(6) classify land as to the kind and amount of use it can support, (7) determine allowable use estimates for tracked vehicle
training, (8) document concealment resources, (9) identify lands that require restoration and evaluate the effectiveness of
restorative techniques, and (10) evaluate potential acquisition property. Wildlife inventories survey small and midsize mammals,
birds, bats, amphibians, and reptiles. Data from these surveys can be used for environmental documentation, to identify state
and federal endangered and threatened species, and to evaluate the impact of military activities on wildlife populations.
Short- and long-term monitoring of permanent field plots is used to evaluate and adjust land management decisions. 相似文献
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Newcombe AC Gustafson DI Fuhrman JD van Wesenbeeck IJ Simmons ND Klein AJ Travis KZ Harradine KJ 《Journal of environmental quality》2005,34(3):1004-1015
The Acetochlor Registration Partnership conducted a prospective ground water (PGW) monitoring program to investigate acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-acetamide] transport to ground water at eight sites. The distribution of soil textures among these sites was weighted toward coarser soil types, while also including finer-textured soils that dominate most corn (Zea mays L.)-growing areas of the United States. Each site consisted of a 1.2-ha test plot adjacent to a 0.2-ha control plot. Suction lysimeters and monitoring wells were installed at multiple depths within each test and control plot to sample soil-pore water and near-surface ground water. Irrigation was applied to each site during the growing season to ensure water input of 110 to 200% of average historical rainfall. Acetochlor dissipated rapidly from surface soils at all sites with a DT(50) (time for 50% of the initial residues to dissipate) of only 3 to 9 d, but leaching was not an important loss mechanism, with only 0.25% of the 15,312 soil-pore water and ground water samples analyzed containing parent acetochlor at or above 0.05 microg L(-1). However, quantifiable residues of a soil degradation product, acetochlor ethanesulfonic acid, were more common, with approximately 16% of water samples containing concentrations at or above 1.0 microg L(-1). A second soil degradation product, acetochlor oxanilic acid, was present at concentrations at or above 1.0 microg L(-1) in only 0.15% of water samples analyzed. The acetochlor PGW program demonstrated that acetochlor lacks the potential to leach to ground water at detectable concentrations, and when applied in accordance with label restrictions, is unlikely to move to ground water at concentrations hazardous to human health. 相似文献
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Michael W. Suplee Arun Varghese Joshua Cleland 《Journal of the American Water Resources Association》2007,43(2):453-472
Abstract: The U.S. Environmental Protection Agency recommends two statistical methods to States and Tribes for developing nutrient criteria. One establishes a criterion as the 75th percentile of a reference‐population frequency distribution, the other uses the 25th percentile of a general‐population distribution; the U.S. Environmental Protection Agency suggests either method results in similar criteria. To evaluate each method, the Montana Department of Environmental Quality (MT DEQ) assembled data from STORET and other sources to create a nutrient general population. MT DEQ’s reference‐stream project provided reference population data. Data were partitioned by ecoregions, and by seasons (winter, runoff, and growing) defined for the project. For each ecoregion and season, nutrient concentrations at the 75th percentile of the reference population were matched to their corresponding concentrations in the general population. Additionally, nutrient concentrations from five regional scientific studies were matched to their corresponding reference population concentrations; each study linked nutrients to impacts on water uses. Reference‐to‐general population matches were highly variable between ecoregions, as nutrients at the 75th percentile of reference corresponded to percentiles ranging from the 4th to the 97th of the general population. In contrast, case studies‐to‐reference matches were more consistent, matching on average to the 86th percentile of reference, with a coefficient of variation of 13%. 相似文献
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The Olsen-P status of grazed grassland (Lolium perenne L.) swards in Northern Ireland was increased over a 5-yr period (March 2000 to February 2005) by applying different rates of P fertilizer (0, 10, 20, 40, or 80 kg P ha(-1) yr(-1)) to assess the relationship between soil P status and P losses in land drainage water and overland flow. Plots (0.2 ha) were hydrologically isolated and artificially drained to v-notch weirs, with flow proportional monitoring of drainage water and overland flow. Annually, the collectors for overland flow intercepted between 11 and 35% of the surplus rainfall. Single flow events accounted for up to 52% of the annual dissolved reactive phosphorus (DRP) load. The Olsen-P status of the soil influenced DRP and total phosphorus (TP) concentrations in land drainage water and overland flow. Annual TP loss was highly variable and ranged from 0.19 to 1.55 kg P ha(-1) yr(-1) for the plot receiving no P fertilizer and from 0.35 to 2.94 kg P ha(-1) yr(-1) for the plot receiving 80 kg P ha(-1) yr(-1). Despite the Olsen-P status in the soils ranging from 22 to 99 mg P kg(-1), after 5 yr of fertilizer P applications it was difficult to identify a clear Olsen-P concentration at which P losses increased. Any relationship was confounded by annual variability of hydrologic events and flows and by hydrologic differences between plots. Withholding P fertilizer for over 5 yr was not long enough to lower P losses or to have an adverse effect on herbage P concentrations. 相似文献
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Few urban environmental stewardship, or civic ecology, practices monitor their impacts on local communities and ecosystems. This lack of monitoring prevents lay stewards from adapting their practices based on outcomes. For those that do collect data on their practices, we see different forms of practitioner engagement in outcomes monitoring. We categorise these different forms of engagement according to five published models of public participation in scientific research, revealing different strategies for collecting and analysing data towards adaptive co-management in urban ecosystems. We propose two broad strategies for expanding outcomes monitoring in these contexts: creating openly accessible tools and protocols for do-it-yourself inquiry and supporting more resource-intensive partnerships between practitioners and scientists for more complex forms of outcomes monitoring. 相似文献