Stream Load Research Articles

Amiodarone and Trypanosoma cruzi parasitemia in patients with Chagas disease

Amiodarone and Trypanosoma cruzi parasitemia in patients with Chagas disease

A 2500-yr late Holocene multi-proxy record of vegetation and hydrologic changes from a cave guano-clay sequence in SW Romania

We provide sedimentological, geochemical, mineral magnetic, stable carbon isotope, charcoal, and pollen-based evidence from a guano/clay sequence in Gaura cu Muscă Cave (SW Romania), from which we deduced that from ~1230 BC to ~AD 1240 climate oscillated between wet and dry. From ~1230 BC to AD 1000 the climate was wetter than the present, prompting flooding of the cave, preventing bats from roosting, and resulting in a slow rate of clay accumulation. The second half of the Medieval Warm Period (MWP) was generally drier; the cave experienced occasional flash flooding in between which maternity bat roosts established in the cave. One extremely wet event occurred around AD 1170, when Fe/Mn and Ti/Zr ratios show the highest values coincident with a substantial increase of sediment load in the underground stream. The mineral magnetic characteristics for the second part of the MWP indicate the partial input of surface-sourced sediments reflecting agricultural development and forest clearance in the area. Pollen and microcharcoal studies confirm that the overall vegetation cover and human land use have not changed much in this region since the medieval times.

Instream wood loads in montane forest streams of the Colorado Front Range, USA

Although several studies examine instream wood loads and associated geomorphic effects in streams of subalpine forests in the U.S. Southern Rocky Mountains, little is known of instream wood loads in lower elevation, montane forests of the region. We compare instream wood loads and geomorphic effects between streams draining montane forest stands of differing age (old growth versus younger) and disturbance history (healthy versus infested by mountain pine beetles). We examined forest stand characteristics, instream wood load, channel geometry, pool volume, and sediment storage in 33 pool–riffle or plane-bed stream reaches with objectives of determining whether (i) instream wood and geomorphic effects differed significantly among old-growth, younger, healthy, and beetle-infested forest stands and (ii) wood loads correlated with valley and channel characteristics. Wood loads were standardized to drainage area, stream gradient, reach length, bankfull width, and floodplain area. Streams flowing through old-growth forests had significantly larger wood loads and logjam volumes (pairwise t-tests), as well as logjam frequencies (Kruskal–Wallis test), residual pool volume, and fine sediment storage around wood than streams flowing through younger forests. Wood loads in streams draining beetle-infested forest did not differ significantly from those in healthy forest stands, but best subset regression models indicated that elevation, stand age, and beetle infestation were the best predictors of wood loads in channels and on floodplains, suggesting that beetle infestation is affecting instream wood characteristics. Wood loads are larger than values from subalpine streams in the same region and jams are larger and more closely spaced. We interpret these differences to reflect greater wood piece mobility in subalpine zone streams. Stand age appears to exert the dominant influence on instream wood characteristics within pool–riffle streams in the study area rather than beetle infestation, although this may reflect the relatively recent nature (<10years) of the infestation.

Linking land use/land cover with climatic and geomorphologic factors in regional mean annual streamflow models with geospatial regression approach

Estimates of annual streamflow in connection with key natural and anthropogenic factors are necessary and important for different purposes, such as water resource planning and management, sediment and nutrient loading in streams and rivers, hydropower, and navigation. This study is an attempt to use the spatial statistical regression approach to develop regression models for mean annual streamflow at regional scale while adequately dealing with the common spatial dependency issue in input and output variables used in regression models. The proposed modeling approach is illustrated with a case study of the Upper Mississippi River Basin. The R-squared and the Nash–Sutcliffe model efficiency coefficient of the regional model were 0.993 and 0.985, respectively, while those of the sub-regional model were 0.995 and 0.990, respectively. Methodologically, the proposed model provided an effective way to utilize an extensive spatial dataset of various climatic, geomorphologic, and land cover variables for a large region like the Upper Mississippi River Basin to assess and compare the impact of various factors on mean annual streamflow at regional scale. Furthermore, the model was able to handle spatial dependency in data.

Eco-friendly waste management strategies for greener environment towards sustainable development in leather industry: a comprehensive review

The leather industry deals with proteinous skin material for the conversion of leather and this generates huge amount of solid and liquid wastes giving rise to pollution that needs to be overcome by introducing sustainable cleaner technologies. This review describes various eco-friendly challenges and major achievements for abatement of pollution in leather processing. Different cleaner technological methods in preservation of raw hides/skins, unhairing, tanning and dyeing operations are discussed here. Cleaner-preservation techniques by using chemicals and biological agents have been developed to reduce pollution problems of salt up to a great extent in leather processing operations. Process intensified operations have helped to achieve better uptake and to manage pollution load. Enzymatic dehairing are implemented to reduce Bio-chemical-Oxygen-Demand (BOD) at the level of 40%, Chemical-Oxygen-Demand (COD) up to 50%. Improved biological methods for bio-degradation of dyes, azo-dyes and their mixtures and to reuse the liquors in the process to reduce the dye pollution load in the effluent streams are reviewed. Nano-Particle polymers and improved retanning materials have been synthesized for high exhaustion of dyeing and retanning properties. Mathematical models predicting kinetics and growth for the above processes are also reviewed. It could be concluded by utilization of these technologies, a possible reduction in pollution loads such as BOD & COD, upto levels of 50% & 40%, could be achieved in leather processing.

A revised cache allocation algorithm for VoD multicast service

The Internet is replacing the traditional telephone network as the ubiquitous network infrastructure. Internet customers are increasing at an exponential rate and will continue to increase in the near future. Among the various Internet services, IPTV VoD (Video on Demand) service is expected to be one of the most popular services. In general, for deploying streamed video service, it is likely to use proxy by locating it nearby end-users. The use of proxy in on-demand media streaming service can help reduce the server streaming load and reduce the startup delay of media playback due to swift retrieval of beginning portion of media. We had proposed a cache allocation scheme for server-proxy media streaming environment by utilizing the advantage of threshold-based multicast mechanism. However it suffer from a little radical change of threshold value. In this paper, enhanced multicast-based server-proxy on-demand media streaming algorithm to IPTV VoD services is presented from the storage, caching size and bandwidth requirement viewpoints.

Evaluating Potential Impacts of On-Site Wastewater Treatment Systems on the Nitrogen Load and Baseflow in Streams of Watersheds in Metropolitan Atlanta, Georgia

Evaluating Potential Impacts of On-Site Wastewater Treatment Systems on the Nitrogen Load and Baseflow in Streams of Watersheds in Metropolitan Atlanta, Georgia

Measured hillslope erosion rates in the wet-dry tropics of Cape York, northern Australia: Part 2, RUSLE-based modeling significantly over-predicts hillslope sediment production

Hillslope erosion rates have been estimated from models based on the widely used Revised Universal Soil Loss Equation (RUSLE) over large areas of Australia as a basis for catchment and river management. In this paper we present data from erosion plots in the Normanby catchment, Cape York, Australia. Extremely high rates of hillslope erosion are predicted in areas of the Normanby, producing extremely high modeled suspended sediment loads in streams which drain into the Great Barrier Reef (GBR) Lagoon. Using a novel, low budget sediment trap, total sediment yield is measured across the annual wet season (November to April) in 11 plots ranging in size from 0.1 to 1.9ha. Total hillslope erosion rates (i.e., suspended and bed material load) measured within the four main geologies in the catchment, range between 0.03–256kg/ha/yr. across two distinctly different wet seasons. These data are compared with the RUSLE modeled sediment yields determined for the same sites, for the same periods of time, using five different model formulations; two existing catchment scale models along with three plot scale formulations based on measured plot scale parameters. Modeled sediment yields using the first catchment scale model ranged from 4290 to 57,040kg/ha/yr.; while the second catchment scale model predicted values of 730–9680kg/ha/yr. Modeled yields using plot scale metrics together provided values ranging from 1550 to 331,700kg/ha/yr. Depending on which modeled data are used, this represents an average ratio of over prediction by the RUSLE model (cf the measured rates for the same period) of between 12 and 13,300 times. We suggest that the over-prediction is due to four key reasons: 1) K factors have been incorrectly extrapolated from empirical data collected elsewhere on agricultural soils that vary greatly from the typical savannah rangeland soils; 2) the high stone content of the soils typically found on many of the savannah hillslopes is not adequately represented in either the C or K factor, 3) the model assumes that sediment supply is a linear function with time, when in fact the K factor (and hence supply) is likely to be non-linear though time—i.e. exhibiting supply exhaustion over an individual wet season or over the longer term (e.g. 103–104years), and 4) the vegetative cover factors applied in previous modeling have used the late dry season C values, when the average cover factor across the wet season is significantly lower (where lower C factor=higher cover). We have derived new K factor values from our data for application in a new catchment model.

Effects of urbanization on mercury deposition and accumulation in New England

We compare total mercury (HgT) loading and methylmercury (MeHg) accumulation in streams and lakes from an urbanized area (Boston, Massachusetts) to rural regions of southern New Hampshire and Maine. The maximum HgT loading, as indicated by HgT atmospheric deposition, HgT emissions, and sediment HgT concentrations, did not coincide with maximum MeHg concentrations in fish. Urbanized ecosystems were areas of high HgT loading but had low MeHg concentrations in fish. Controls on MeHg production and accumulation appeared to be related primarily to HgT loading in undeveloped areas, while ecosystem sensitivity to MeHg formation appeared to be more important in regulating accumulation of MeHg in the urban area.

Acidity Loading Behavior in Coal-Mined Watersheds

In this paper, we propose a method (the Stoertz Water Quality Evaluation Method) to estimate the reduction in acidity load at mean annual discharge (l) in acid mine drainage impaired streams. For a given stream, acidity loading (L), defined as the product of measured acidity concentration and discharge (Q) for a range of streamflow conditions, is proportional to l and the ratio (Qn) of Q and the mean daily discharge (Q), according to the following equations: L = l (Q/Q)F = l Qn F and log L = log l + F log Qn, where F is a ‘flushing factor’ characterizing the stream loading behavior, such that F = 0 in pure dilution, F > 0 for flushing behavior, and F < 0 for sparing behavior. The assumed power-law relation between acidity load and discharge is supported by test cases. Acidity load at mean annual discharge can be a useful measure of the quantity of acid removed by mine drainage treatment, particularly where data for pre- and post-treatment cases can be compared. The proposed measure allows resource managers to assess and report the effectiveness of source control, passive treatment, and active treatment in alleviating acidity loads. This method can also be used to assess inputs of contamination to streams compared to pristine or background conditions.

Load Balancing Algorithm of Stream Data Based on Correlation Analysis

With the development of stream processing technology, achieving load balance of resource accessing becomes one of key problems. However, the existing technologies are difficult to balance the system and maintain the data integrity requirements when large data stream arrive. In this paper, combined with the dynamic load balancing algorithm, we propose a load balancing algorithm of stream data based on correlation analysis (SDCA-LBA). The algorithm analyses correlation of stream data through the window feature statistics. On the basis of ensuring the load balancing of the stream data system, we consider the data correlation. The experiment results show that this method can effectively solve the problem of stream data load balancing, maintain the data integrity, and improve the system data processing capabilities.

Behavior and Loading of Suspended Sediment and Nutrients from River Basins in the Hilly Catena Under Intensive Agriculture Cropping: A Case Study in Upper Kotmale Basin in Sri Lanka

Suspended matter and nutrient are major factors for water pollution studies and this study is focused on behavior and loading of suspended sediment and nutrient in Upper Kotmale Basin (UKB). Nanu Oya, Dambagasthalawa Oya and Agra Oya are three major streams fed by Kotmale Oya proper in UKB. Eight sampling locations were selected considering all major rivers and eight months samples were collected on monthly basis. Data analysis is used cluster analysis and descriptive statistic was used for analysis of nutrient and suspended sediment loading in streams. Results reveal that, highest nutrient loads bring by Nanu Oya and calculated mean daily nutrient loads namely; ammonia-N, nitrite-N, nitrate-N, and dissolve phosphate were found to be in Agra Oya; 33.6 kg/day, 2.3 kg/day, 383.1 kg/day and 48.2 kg/day, Nanu Oya; 64.1 kg/day, 9.1 kg/day, 1459.1 kg/day & 530.4 kg/day and Dabagasthalawa Oya; 19.5 kg/day, 1.7 kg/day, 310.6 kg/day & 109.6 kg/day respectively. Also, the calculated highest suspended sediment (SS) load were found to be in Agra Oya; 4839 kg/day, Nanu Oya; 22083 kg/day and Dambagasthalawa Oya; 5843 kg/day respectively. Therefore, Nanu Oya contribute highest SS and nutrient load to Kotmale Oya proper, because of landuse change. This scenario is vulnerable to deterioration of the water quality and aquatic environment in downstream and Kotmale Oya proper. DOI: http://dx.doi.org/10.4038/jepsl.v2i2.6327 Journal of Environmental Professionals Sri Lanka, Vol. 2 No. 2 2013, 13-31

Effects of long-term land use change on dissolved carbon characteristics in the permafrost streams of northeast China

Permafrost soils act as large sinks of organic carbon but are highly sensitive to interference such as changes in land use, which can greatly influence dissolved carbon loads in streams. This study examines the effects of long-term land reclamation on seasonal concentrations of dissolved carbons in the upper reaches of the Nenjiang River, northeast China. A comparison of streams in natural and agricultural systems shows that the dissolved organic carbon (DOC) concentration is much lower in the agricultural stream (AG) than in the two natural streams (WAF, wetland dominated; FR, forest dominated), suggesting that land use change is associated with reduced DOC exporting capacity. Moreover, the fluorescence indexes and the ratio of dissolved carbon to nitrogen also differ greatly between the natural and agricultural streams, indicating that the chemical characteristics and the origin of the DOC released from the whole reaches are also altered to some extent. Importantly, the exporting concentration of dissolved inorganic carbon (DIC) and its proportion of total dissolved carbon (TDC) substantially increase following land reclamation, which would largely alter the carbon cycling processes in the downstream fluvial system. Although the strong association between the stream discharge and the DOC concentration was unchanged, the reduction in total soil organic carbon following land reclamation led to remarkable decline of the total flux and exporting coefficient of the dissolved carbons. The results suggest that dissolved carbons in permafrost streams have been greatly affected by changes in land use since the 1970s, and the changes in the concentration and chemical characteristics of dissolved carbons will last until the alteration in both the traditional agriculture pattern and the persistent reclamation activities.

English

The soil and water assessment tool (SWAT), a large-scale hydrologic model, is used to estimate phosphate (P) loading in streams and water bodies. The labile, active, and stable P pools are currently used to represent P cycling in SWAT; however, these pools are conceptual without any chemical basis. The current structure allows SWAT to reasonably represent P cycling; however, restructuring and incorporation of recent research results should produce more accurate P simulations. This paper presents a redefined SWAT structure using four inorganic soil P pools (water soluble, labile, active, and stable) combined with soil extraction methods to determine initial values for each pool. The redefined structure was selected by examining the chemical characteristics of laboratory tests relative to soil P pools and analyzing the relationships between test results. Water soluble P, labile P and active P are determined using water, H3A, Mehlich 3 extraction, respectively. Stable P is determined with an acid digestion. Redefining SWAT&rsquo;s inorganic soil P pools based on soil and extractant chemistry will improve the defensibility, credibility, and the accuracy of SWAT P routines in water resource planning, management, and decision making.&nbsp; Key words: Soil and water assessment tool (SWAT), phosphate, soil extractants, H3A, Olsen, Mehlich 3. &nbsp; &nbsp; &nbsp

Investigation of Biogeochemical Functional Proxies in Headwater Streams Across a Range of Channel and Catchment Alterations

Historically, headwater streams received limited protection and were subjected to extensive alteration from logging, farming, mining, and development activities. Despite these alterations, headwater streams provide essential ecological functions. This study examines proxy measures of biogeochemical function across a range of catchment alterations by tracking nutrient cycling (i.e., inputs, processing, and stream loading) with leaf litter fall, leaf litter decomposition, and water quality parameters. Nutrient input and processing remained highest in second growth forests (the least altered areas within the region), while recently altered locations transported higher loads of nutrients, sediments, and conductivity. Biogeochemical functional proxies of C and N input and processing significantly, positively correlated with rapid assessment results (Pearson coefficient=0.67-0.81; P=0.002-0.016). Additionally, stream loading equations demonstrate that N and P transport, sediment, and specific conductivity negatively correlated with rapid assessment scores (Pearson coefficient=0.56-0.81; P=0.002-0.048). The observed increase in stream loading with lower rapid assessment scores indicates that catchment alterations impact stream chemistry and that rapid assessments provide useful proxy measures of function in headwater ecosystems. Significant differences in nutrient processing, stream loading, water quality, and rapid assessment results were also observed between recently altered (e.g., mined) headwater streams and older forested catchments (Mann-Whitney U=24; P=0.01-0.024). Findings demonstrate that biogeochemical function is reduced in altered catchments, and rapid assessment scores respond to a combination of alteration type and recovery time. An analysis examining time and economic requirements of proxy measurements highlights the benefits of rapid assessment methods in evaluating biogeochemical functions.

Physicochemical parameters and nutrients variations of streams and rivers in Abakaliki, Ebonyi State, Nigeria

&lt;p&gt;Physicochemical parameters and nutrient loads of major rivers and streams in Abakaliki, Ebonyi State were studied for a period of seven (7) months from May to November, 2011. Regular and constant monitoring of water bodies is vital to ensure that water quality characteristics are maintained. The results obtained showed; temperature (28.60&amp;ndash;30.00 &amp;deg;C), pH (6.80&amp;ndash;7.93), DO (1.40&amp;ndash;3.53 mg l-1), turbidity (41.33&amp;ndash;97.67 NTU), conductivity (19.00&amp;ndash;613.30 &amp;micro;S cm-1), total acidity (9.17&amp;ndash;17.23 mg l-1), total alkalinity (6.43&amp;ndash;10.97 mg l-1), BOD (1.20&amp;ndash;7.03 mg l-1), COD (16.200&amp;ndash;53.533 mg l-1), Phosphate (0.11&amp;ndash;1.17 mg l-1) and Nitrate (0.12&amp;ndash;1.45 mg l-1) ranges respectively. The turbidity and BOD were well above the prescribed standards. The results suggest that refuse disposal, fertilizer use, and natural phenomena e.g. soil erosion; flooding, etc. may have contributed in various ways to the impairment of the water quality of the studied sites. Although the results do not indicate adverse pollution status of any of the sites, they provided the need for further investigations and monitoring.&lt;/p&gt;

Leaf-litter stoichiometry is affected by streamwater phosphorus concentrations and litter type

The stoichiometric ratios of organisms and their food resources can influence C and nutrient dynamics in aquatic ecosystems. Several investigators have quantified linkages between nutrient enrichment and consumer stoichiometry for stream detritivores, but very few have systematically quantified the effect of P enrichment on leaf-litter stoichiometry. Here, we examine the potential stoichiometric changes of 2 species of leaf litter subjected to varying levels of P enrichment in laboratory microcosms and mixed species across a natural P gradient of streams in the Ozark Highlands Region, Arkansas, USA. Leaf-litter %P content increased and C∶P ratios decreased with increasing levels of P enrichment and with increasing lability of the leaf species. In the laboratory study, C∶P of maple and oak leaves in the control treatment was ∼2500, whereas this ratio decreased to 500 and 1000 in the high-P treatments, respectively. Total P (TP) was inversely related to leaf-litter C∶P along the natural P gradient of streams in the Ozarks. Our results add to the growing body of information on the potential bottom-up effects of anthropogenic nutrient loading in streams and the influence of water-column nutrients and leaf quality on this response.

The role of irrigation runoff and winter rainfall on dissolved organic carbon loads in an agricultural watershed

We investigated the role of land use/land cover and agriculture practices on stream dissolved organic carbon (DOC) dynamics in the Willow Slough watershed (WSW) from 2006 to 2008. The 415km2 watershed in the northern Central Valley, California is covered by 31% of native vegetation and the remaining 69% of agricultural fields (primarily alfalfa, tomatoes, and rice). Stream discharge and weekly DOC concentrations were measured at eight nested subwatersheds to estimate the DOC loads and yields (loads/area) using the USGS developed stream load estimation model, LOADEST. Stream DOC concentrations peaked at 18.9mgL−1 during summer irrigation in the subwatershed with the highest percentage of agricultural land use, demonstrating the strong influence of agricultural activities on summer DOC dynamics. These high concentrations contributed to DOC yields increasing up to 1.29gm−2 during the 6 month period of intensive agricultural activity. The high DOC yields from the most agricultural subwatershed during the summer irrigation period was similar throughout the study, suggesting that summer DOC loads from irrigation runoff would not change significantly in the absence of major changes in crops or irrigation practices. In contrast, annual DOC yields varied from 0.89 to 1.68gm−2yr−1 for the most agricultural watershed due to differences in winter precipitation. This suggests that variability in the annual DOC yields will be largely determined by the winter precipitation, which can vary significantly from year to year. Changes in precipitation patterns and intensities as well as agricultural practices have potential to considerably alter the DOC dynamics.

Does it make economic sense to restore rivers for their ecosystem services?

Summary Temperate forests managed to maximize sustainable yield of wood products can reduce the availability of dead wood on the forest floor and in adjacent streams, which in turn can impair ecological processes such as retention and transformation of organic matter. Lack of tools to link ecological processes with their effects on human well‐being leads forest managers to ignore the cost on other services from terrestrial and aquatic ecosystems. We examine how adding dead wood to restore stream channel complexity affects the provision and value of selected ecosystem services, mainly related to the retention and transformation of matter and cycling of nutrients, as well as to the effects on aquatic biota. Specifically, we evaluated the cost‐effectiveness of stream restoration through a comparative analysis of four reach‐scale projects in streams flowing through temperate forest and into a drinking water reservoir and two scenarios of active and passive restoration at the basin scale. Results indicate that the lack of dead wood in streams has an important economic cost because of the effects on fish provisioning, opportunities for recreation and tourism, water purification and erosion control. Active reach‐scale restoration resulted in a 10‐ to 100‐fold increase in the monetary benefits provided by streams, accounting as much as 1·8 € per metre of restored river length each year. Results of the reach‐scale cost–benefit analyses estimated that the time required to recover the active restoration investment ranged from 15 to 20 years in low‐ to middle‐order streams. Synthesis and applications. Our study showed that restoration of natural wood loading in streams greatly increases the ecosystem services they provide. The benefits in terms of the analysed services surpass the costs of active restoration over realistic timeframes, whereas this was not the case for passive restoration. Inclusion of other ecosystem services such as conservation of biodiversity might make restoration more economically profitable. Overall, our study provides a decision framework for managing temperate riparian forests in the context of ecological services.

The Treatment of Actual Industrial Wastewaters Using Electrochemical Techniques

The electrochemical oxidation of an actual waste which comes from a chemical plant was studied. This effluent is generated in a polymerization unit and is mainly composed of a great variety of organics (including a complex mixture of water-soluble polymers of very different molecular weights) and solvents. The high variability of the organic load in industrial waste stream (4,000–20,000 mg dm−3 of chemical oxygen demand (COD)) makes the study of the system difficult. The results show that the key for an efficient electrolytic treatment is the selection of the anode material. The replacement of dimensional stable anodes by non-active electrodes is technically feasible as it leads to a very efficient process in terms of COD and total organic carbon removal. However, the use of PbO2 favours the release of toxic lead ions to the reaction medium. The efficiencies seem to depend on the pH and supporting electrolyte. This does not seem to be related to the electrochemical process, but to the oxidizability of the pollutant (mainly polymers) that should strongly depend on the pH. It is suspected that some functional groups of the polymer were more easily attacked by reagents electrogenerated under extreme pH values and that hypochlorite is less effective than persulphate. Regarding economic viability, electrochemical oxidation with a boron-doped diamond electrode can be used in an economically adequate way for the pretreatment of waste, but the energy cost necessary to deal with mass transfer limitations made this technique unsuitable for its use in a refining process of the quality of an effluent.