Effects of Compost on the Chemistry of an Urban Upper Piedmont South Carolina Soil

Composting is an effective method to improve the fertility of degraded soils. However, the potential beneficial effects of composting on the fertility of urban soils have not been reported. This study compared nutrients measured in compost and soil samples collected from a residential urban plot in Clemson, SC. The dominant soil type present was an eroded Cecil sandy loam (fine, kaolinitic, thermic, Typic Kanhapludults), and the collected samples represented the following treatments: compost, garden, front lawn, backyard lawn, and basement (nonvegetated control). Tissues of leaf detritus were also analyzed to establish the nutrient contribution from leaves to soil. Standard soil tests were conducted to characterize soil macronutrients, macrominerals, and micronutrients, as well as soil parameters such as pH and cation exchange capacity (CEC). Analysis of variance (ANOVA) was used to compare the treatment means for each soil parameter and nutrient measured. In all cases, the different treatments had significantly different levels of nutrients based on Fisher’s least significant difference (LSD) (P < 0.05). Our results show that composting can be a significant source for major soil nutrients and minerals in urban soils. Therefore, utilization of compost and leaf detritus should be beneficial for improving degraded soil in urban environments.     

Dry-Weather Metals and Bacteria Loading in an Arid, Urban Watershed: Ballona Creek, California

Dry-season urban runoff from watersheds in arid regions can contribute substantial concentrations and loads of bacteria and metals to downstream receiving waters. However, there are few studies that have evaluated the relative contributions of different sources of these constituents along a specific creek or channel. This study involved analysis of the relative contribution of various storm drain sources to the total dry-season loading of metals and bacteria in the Ballona Creek (California) watershed. Approximately 40 actively flowing storm drains and 12 in-river sites were sampled three times during the spring and summer of 2003 for flow, total and dissolved metals, and bacteria. These data were analyzed in terms of mean concentration and load, temporal variability, and spatial distribution of substantial inputs to the creek. In general, Ballona Creek exhibited a bimodal distribution of elevated metals and bacteria, corresponding to locations where storm drains with consistently high concentrations and loads discharge to the creek. Of the 40 drains sampled, 4 accounted for 85% of the daily storm drain volume. Between 91% and 93% of the total daily load for metals was contributed by eight drains, while nine drains consistently had the highest concentrations of metals and bacteria. Metals concentrations were observed to vary by up to five-fold and bacterial counts by up to five orders of magnitude on an intra- and inter-annual basis. However, despite this variability, a relatively small number of storm drain inputs can be expected to account for the majority of loading.     

Influence of Watershed Topography on the Chemistry of Stream Water in a Mountainous Area

Water, Air, & Soil Pollution - The relation among the mean slope angle of a watershed, the stream water quality, and the chemical composition of the plagioclase component of granite was...     

The Relationship Between Stream Chemistry and Watershed Land Cover Data in the Mid-Atlantic Region,U.S.

In order to investigate the relationship between stream chemistry and watershed land cover at the regional scale, we analyzed data from 368 wadeable streams sampled in the mid-Atlantic region of the U.S. during spring 1993-1994. Study sites were selected using a probability sample and the digitized version of the 1:100,000 scale USGS map stream network as the sample population. Both classified Thematic Mapper (TM) and USGS Land Use/Land Cover (LULC) data were used to quantify land cover in the study watersheds. On average, the most common land cover was forest (77%) followed by agriculture (20%), and urban (1%). Multiple regression analysis showed that concentrations of Cl-, nutrients, acid neutralization capacity, and base cations were the analytes most strongly related to watershed land cover. Despite large differences in resolution and age of the TM and LULC data sources, similar results were obtained with the two sources. Using a greater number of land cover subclasses did not greatly improve the land cover-chemistry relationships. Ecoregions with predominantly forested land cover had weaker relationships than ecoregions with more agricultural and/or urban land cover. In studies or databases without land cover information, Cl- concentration is a good surrogate indicator for general human disturbance in the watershed.     

Mapping the Distribution of the Bioaccessible Fraction of Trace Metals in the Sediments of an Urban Stream,Park River Watershed,Connecticut

The Park River watershed (PRW), a sub-basin of the Lower Connecticut River watershed, has experienced increased urbanization over the last century as the city of Hartford and its surrounding towns have grown and developed. We present watershed-wide and outflow scale maps of the trace metals Cd, Cu, Zn, and Pb to determine patterns of contamination in fine (<63 μm) stream sediment. Results are compared to established sediment quality guidelines (SQG) and probable effect concentrations (PEC) for each metal. Throughout the watershed, higher concentrations of trace metals are observed in the more urbanized south branch of the PRW. In this sub-basin, there are more industries that use, and waste, metals in their manufacturing processes that contribute to acutely high concentrations of metals in the fine bedload sediments. Impervious surfaces are examined as well in the context of the entire watershed. While an increase in metals can be attributed to an increase in impervious surfaces, these increases do not generally exceed SQGs and PECs. Two focused mapping studies were conducted at the storm water outflow of the West Hartford Landfill and the Trout Brook Sanitary Sewer Overflow (SSO). The purpose of these studies was to analyze the local effects of natural stream features such as channel bar deposits next to the outfalls. We determined that the sediment directly below the two outfalls often exceeded the PEC, while the accumulated sediment around the channel bar deposits was not contaminated beyond background stream levels. We believe mapping at both the small (watershed) and large (outfall) scale can be helpful in future urban studies to determine the extent of trace metal sediment contamination in both channelized and natural sections and may provide a useful method for sediment mitigation endeavors.

     

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

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.     

Geochemical Comparison of Stream Water, Rain Water, and Watershed Geology in Central Korea

A hilly to mountainous watershed in Chonju in central Korea does not receive acid rain (average pH: 6.2); however, the stream water in the granite watershed is slightly acidic (6.4–6.7) and contains a low concentration of Ca compared to the stream water in sedimentary and volcanic rock watersheds (6.8–7.6). Although the concentrations of Ca and Sr and the ⁸⁷Sr/⁸⁶Sr ratio in the stream water change in accordance with the watershed geology, the stream ⁸⁷Sr/⁸⁶Sr ratios are closer to the ⁸⁷Sr/⁸⁶Sr ratios of rain than to those of the substrate rocks, suggesting the selective but sluggish weathering of Ca-containing minerals neutralizes acid. The concentrations of trace metals (As, Cr, Cu, Mo, Ni, Pb) in the water are lower than those in rain and less dependent on the watershed geology, indicating that they originated dominantly from the atmosphere. This result is consistent with the stream water having Pb isotope ratios close to that of rain but distinct from that of the rocks. We assume that the soil pool of exchangeable ions dominantly contains atmospherically derived heavy metals, which are subsequently discharged into streams. It is likely that the poor acid-neutralizing capacity of granite makes the aquatic systems in the granite watershed in Chonju sensitive to atmospheric acidification.     

Variation in Stream Water Quality in an Urban Headwater Stream in the Southern Appalachians

We examined the influence of a forested landscape on the quality of water in a stream originating on an urban landscape and flowing through National Forest lands. Sample sites included an urban stream (URB), a site on the same stream but within a National Forest (FOR) and 2 km downstream from the URB site, and a small, undisturbed, forested reference tributary of the main stream (REF). We monitored stream water quality from March 2002 through June 2003. Average base flows for the three stream sites were URB = 184 L s^?1, FOR = 420 L s^?1, and REF = 17 L s^?1. We analyzed weekly stream water samples for NO₃ ^?, NH₄ ⁺, PO₄ ⁺, Cl^?, K, Ca, Mg, SO₄, SiO₂, pH, conductivity, total suspended solids (TSS), and bacteria on a monthly basis. Most solutes were higher in concentration at the URB site, as were conductivity, TSS, and bacteria counts. Reductions in NO₃ ^?, NH₄ ⁺, and PO₄ ⁺ concentrations between the URB and FOR sites were inferred from changes in nutrient:chloride ratios. Bacteria populations were greater and more responsive to stream temperature at the URB site. Water quality responses to changes in stream discharge varied among sites but were greater at the URB site. By all measures, water quality was consistently higher at the FOR site than at the URB site.     

Model Assessment of Cattle and Climate Impacts on Stream Fecal Coliform Pollution in the Salmon River Watershed, British Columbia, Canada

A bacterial water quality model (BWQM) was developed and used to evaluate the impacts of cattle farming and climate change on the stream fecal coliform pollution in the Salmon River watershed in south-central British Columbia, Canada. The accuracy of the model simulation was evaluated using the Nash-Sutcliffe coefficient of efficiency (COE). The BWQM simulated the observed field data well, with the values of the COE ranging from 0.76 to 0.78 for the stream flow, from 0.55 to 0.60 for the fecal coliform (FC) concentration, and from 0.85 to 0.89 for the FC loading. The BWQM captured more than 79%, 66%, and 90% variation of the daily stream flow, FC concentration, and FC loading, respectively. The BWQM predicts that between 70% and 80% of the FC were transferred from the cattle farm to the Salmon River through the snowmelt-caused surface runoff during late winter and early spring, with the balance 20% to 30% coming from the soil-lateral flow and the groundwater return flow. The model also indicates that the stream FC concentration is sensitive to the distance of the cattle farm to the Salmon River. The model scenario analysis reveals that the climate change, at an assumed 1??C increment of daily air temperature, results in an increase in the stream FC concentration in the spring, fall, and winter, but there is also a decrease in the summer. The increased air temperature also changes the seasonal pattern of the stream FC concentration. Rainfall can reduce the stream FC concentration and mitigate the impact of the increased air temperature on the stream FC concentration as long as it does not result in a surface runoff or flooding event.     

Lead in the Soils and Stream Sediments of an Urban Catchment in Tyneside,UK

This paper focuses on lead contamination in topsoils and stream sediments of public access areas in a largely urban UK catchment. It compares severity of contamination with accepted trigger thresholds, examines spatial patterns relative to urban and industrial development, and explores potential mobility of lead using ‘plant available’: total lead ratios. Total and ‘plant available’ lead concentrations, organic content and pH were determined on 298 topsoil and 54 stream sediment samples using standard laboratory procedures. At the lowest total lead trigger threshold, approximately two thirds of topsoil and one third of stream sediment samples were contaminated. For ‘plant available’ lead the proportions were somewhat lower. The spatial pattern was characterised by ‘hot spot’ contamination, with highest values occurring in central and southern parts of the catchment which have a long urban and industrial history. Potential lead mobility is greatest in rural western and northern parts of the catchment where the lead fractions are probably derived from pedological alteration and weathering of soil parent materials. Conversely, in the urban and industrial areas, much of the lead probably consists of less mobile particulate forms. The implications of these findings for assessment, monitoring and management of contaminated areas are discussed.     

浦城县南浦溪流域水土保持问题探析

通过对浦城县南浦溪流域的水土保持调查分析与评价,针对流域水土流失逐渐恶化问题作深入探讨,并提出了该流域水土保持的主要措施与对策。     

Impacts of coal pile leachate on a forested wetland in South Carolina

This study was conducted to: (1) determine the probable cause of several areas of stressed and dead vegetation adjacent to a 15-yr-old reject coal pile in western South Carolina and (2) identify the factors limiting successful revegetation of the site. Data from an earlier study suggested that solution pH, total dissolved solids (TDS) and electrical conductivity (EC), and/or elevated trace element concentrations may have contributed to the stress and dieback. Soil water in the two vegetation kill zones is saline (TDS>10 000 mg L^?1 and EC>4 dS m^?1), highly acidic (soil pH<3.5), and high in Al and Mn (Al conc.>200 mg L^?1 and Mn conc.>10 mg L^?1). Soil water in areas of sparse vegetation is brackish (TDS>1000 mg L^?1 and EC>2 dS m^?1) and acidic (soil pH<4.0), with elevated Al values (> 40.5 mg Al L^?1). Tissue samples were collected from volunteer loblolly pine (Pinns taeda L.) seedlings growing in the study area and analyzed for essential and non-essential elements. Seedling tissues did not contain abnormal concentrations of nutrients or trace elements. The strong relationship between the zones of vegetation stress and dieback and solution pH and soluble salt concentrations, and the lack of excessive metal accumulations by tree seedlings which have become established in the less toxic portions of the study area, suggest that low solution pH and high soluble salts are more important factors limiting plant establishment on this site than solution metal concentrations. The results of this study demonstrate the importance of site hydrology in determining the impacts of coal waste disposal on adjacent ecosystems.     

Hydrologic and wetland characteristics of a piedmont bottom in South Carolina

A four hectare mixed bottomland hardwood site on Ninety Six Creek in the Piedmont of South Carolina near Ninety Six, SC was studied for two years to characterize wetland traits. The soils were thermic Fluventic or Fluvaquentic Dystrochrepts predominantly Shellbluff series and well drained. Overbank flooding occurred on the average of 4 times per year and 1.5 times during the growing season for a 13 year period. High water table levels during the early growing season were related to rainfall events. A hydrologic model (WATRCOM-2D), soils, water table levels, and GIS techniques were used to estimate the portion of the bottom that met wetland criteria similar to those defined in the 1987 and 1989 federal wetland delineation manuals. Less than one hectare met these criteria. The wetland “status” of the vegetation within the bottom and adjacent slope was not correlated with water table levels, predicted wetland areas, or landforms. Wetland traits of the site were closely related to hydric soil traits within the upper 25 cm of the Chewacla and Chenneby soils and landform characteristics. Wetlands in this bottom were primarily driven by local precipitation and not by overbank flooding as originally suspected. Songbirds and small mammals were relatively abundant in the small bottom during the spring and summer of 1992. Protection of only the jurisdictional wetlands in this bottom would not be adequate to sustain riverine functions (conveyor) and to provide wildlife travel corridors between adjacent forested areas.     

The Impact of Wastewater Treatment Effluent on the Biogeochemistry of the Enoree River,South Carolina,During Drought Conditions

Drought conditions should magnify the effect of wastewater treatment plant (WWTP) effluent on river biogeochemistry. This study examined the impact of WWTP effluent on the Enoree River in the piedmont region of South Carolina during a period of significant drought. The Enoree River lacks impoundments, upstream agricultural runoff, and significant industrial point sources, so the single most important human influence on river chemistry is WWTP effluent. Water samples were collected from 28 locations on the Enoree River, 13 of its tributaries, and the effluent of four WWTPs. Effluent from the WWTP furthest upstream increased the salinity of the river and temporal variation and concentrations of most ions, especially nitrate, phosphate, sulfate, sodium, and chloride. The upstream WWTP set the downstream chemical composition of the river, with increasing proportions of chloride, sodium, and sulfate and decreasing proportions of dissolved silicon and bicarbonate. Downstream WWTPs had little or no impact on the chemical composition of the river. Mixing model results show that dilution was the dominant process of the downstream decrease in solute concentrations, but in-channel uptake mechanisms also contributed to declines in concentrations of nitrate, phosphate, and carbon dioxide. Despite dilution and uptake, the chemical signature of WWTP effluent was still evident 135 km downstream. These results lead to a better understanding of the effects of WWTP effluent on the biogeochemistry of rivers.     

Variation in Total and Extractable Elements with Distance from Roads in an Urban Watershed,Honolulu, Hawaii

Roads play a major role intransporting sediment associated nonpoint sourcepollutants to urban stream networks via storm drains. In urban areas the relationship of erodible soil toroads may be of critical importance in controllingmetal contributions to roads. Two 50-m transects(Park and School) were investigated perpendicular toroads in Manoa basin, Oahu, Hawaii. Concentrations ofnine elements were compared to background control soillocations and to five supplemental samples from nearbyrecreational parks. Sediment from curbside areas ofroads (road deposited sediment) was collected as thestarting point of each transect, and subsequently soilwas sampled from two depths (0–2.5 cm and 7.5–10.0 cm)along the transects. Total and 0.5 M HCl extractableconcentrations were determined for aluminum (Al),calcium (Ca), chromium (Cr), copper (Cu), iron (Fe),manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn)using either inductively coupled plasma-atomicemission spectroscopy (ICP-AES) or flame atomicemission spectroscopy (FAAS). Ca, Cu, Pb and Znexhibited anthropogenic enhancement, with Pb and Znhaving the greatest enrichment in road sedimentfollowed by locations nearest the road. Copperdisplayed a narrower band of contamination than eitherPb or Zn, and this may reflect larger aerosolassociations and more rapid fall velocities. Lead andZn exhibited substantial decay in concentration at 50 m compared to the road sediment, but enrichment wasstill apparent. The positioning of a band of soilbetween the road-curb area and the sidewalk for thePark transect facilitated deposition and storage oftrace metals, and with subsequent erosion by splash orconcentrated flow this area can account for continuedtransport of contaminated sediment to adjacent roadsurfaces. On the other hand the School transect hadno soil directly beside the road, and the nearestsample from the road (5 m) displayed enrichment butsubstantially lower than the Park transect. Thesepreliminary data suggest that remobilization of soilstored metals in close proximity to roads cansignificantly prolong the environmental contaminationof urban road systems and eventually stream sediments.     

Trends of bulk precipitation and Streamwater Chemistry in a Small Mountainous Watershed on the Shikoku Island of Japan

For this study, characteristics and trends of the chemical constituents in bulk precipitation and streamwater were observed in a small mountainous watershed on the Shikoku Island of Japan, which covered an area of 27.4 hectares. Bulk precipitation and streamwater chemistry data spans from May 1997 to October 2004, and January 1996 to October 2004, respectively. The data were tested for two types of trends: (1) a monotonic trend to determine if concentrations of the chemical constituents were generally decreasing, increasing, or stable during the study period, and (2) a step trend to determine if a change occurred following the December 1999-January 2000 forest thinning. Both parametric and non-parametric statistical analyses were carried out in this study. Although the study area is only 35 km away from the Pacific Ocean, bulk precipitation chemistry was also influenced by terrestrial sources to a large extent. Streamwater chemistry was influenced by bedrock weathering, which was dominated by Ca²⁺ and HCO_3?, and was not strongly related top recipitation chemistry.Non?parametric Seasonal Kendall Test(SKT)showedadeceasingtr end of Ca ₂₊ and anincreasing tr end of K ₊ in bulk precipitation.Despite the decreasing trend of Mg ₂₊, an increasing trend of pH was found in the stream water.Non?paramet ric Mann?Whit ney?Wilcoxon Rank Sum test showed statistically sign if icantin creases of NO _3? and Ca ₂₊ in stream water followed by a moderate thinning operation.     

亚热带典型农林混合流域河岸带景观格局对河流磷输出的影响

为进一步明确流域河岸带景观尺度范围差异性及对河流磷(P)输出的影响,量化解析河岸带尺度下景观与河流P之间的关系。以亚热带典型农林混合流域为研究对象,基于长期水文、水质监测数据,利用冗余分析明确不同河岸带尺度景观格局特征与不同水文季节河流P浓度的关系,并采用变点分析量化导致丰水期、平枯水期河流P浓度突变的核心景观指数的阈值范围。结果表明:(1)河岸带景观格局对河流P浓度的影响具有显著的空间尺度性特征,300,400 m分别是影响丰水期和平枯水期河流磷浓度变化的关键临界尺度。(2)河岸带居民地斑块最大斑块面积指数(LPI_居)和农田斑块分散指数(SPLIT_农)分别是影响平枯水期和丰水期河流磷浓度的核心景观格局特征指数,当SPLIT_农＞15.76~23.83,LPI_居＜28.8%~36.5%时,能够降低河流P浓度的突变概率。研究结果可为以缓解P面源污染为目标的土地利用和景观规划提供重要理论依据。     

Initial Effects of Wood Ash Application on the Stream Water Chemistry in a Boreal Catchment in Central Sweden

Due to increased whole-tree harvesting in Swedish forestry, concern has been raised that a depletion of nutrients in forest soil will arise. The Swedish Forest Agency recommends compensation fertilization with wood ash to ensure that unwanted effects are avoided in the nutrient balance of the forest soil and in the quality of surface water. In this investigation, the chemistry of two first-order streams, of which one was subjected to a catchment scale treatment with 3 tonnes of self-hardened wood ash/ha in the fall of 2004, was monitored during 2003?C2006. Large seasonal variations in stream water chemistry made changes due to ash application difficult to detect, but evaluating the ash treatment effects through comparison of the stream water of the treated catchment with the reference was possible via statistical tools such as randomized intervention analysis in combination with cumulative sum charts. The wood ash application did not yield any significant effect on the pH in the stream water and hence did not affect the bicarbonate system. However, dissolved organic carbon increased, a previously unreported effect of WAA, bringing about an increase of organic anions in the stream water. The wood ash application also induced significant increases for Ca, Mg, K, Si, Cl and malonate, of which K was most prominent. Although significant, the changes induced by the wood ash application were all small compared to the seasonal variations. As a tool to counteract acidification of surface waters, WAA seems to have limited initial effects.     

大宁河流域坡度与坡向对土地利用/覆盖变化的影响

通过解译同源不同时期卫星遥感影像数据,应用GIS对空间数据和属性数据的有效管理和分析,阐述了大宁河流域土地利用/覆盖随坡度和坡向的分布规律以及坡度和坡向的变化对土地利用/覆盖动态变化度和综合土地利用动态变化度的影响,分析了社会经济和政治因素对流域内土地利用/覆盖动态变化的正向和负向的驱动力作用。研究表明,大宁河流域内人类活动主要集中在坡度较低的区域,受社会因素的影响,人类活动正向较陡坡区域发展,陡坡耕地和极陡坡耕地在流域内分布过多,森林面积分布过少,从而对环境造成了负面影响。     

Effect of Episodic and Regular Sewage Discharges on the Water Chemistry and Macroinvertebrate Fauna of a Mediterranean Stream

Physical, chemical and biological parameters were used to investigate the effects of regular and episodic sewage inputs,either domestic or industrial, on the water quality of a smallMediterranean stream (River Magro, eastern Spain). Although results from chemical analyses were useful for monitoring waterquality in areas where sewage discharge was regular, episodic andlocalised discharges from industries or farms were not detected by chemical analyses because sampling was performed seasonally. An adequately small number of macroinvertebrate taxa were foundto indicate water quality changes within R. Magro, and the presence/absence and relative abundance of these taxa can be usedas a simple, rapid, low cost method for detecting changes in water quality. Macroinvertebrates are highly sensitive to episodic sewage discharges, which are difficult to detect by classical physical and chemical monitoring.