Non-intrusive characterization methods for wastewater-affected groundwater plumes discharging to an alpine lake

Streams and lakes in rocky environments are especially susceptible to nutrient loading from wastewater-affected groundwater plumes. However, the use of invasive techniques such as drilling wells, installing piezometers or seepage meters, to detect and characterize these plumes can be prohibitive. In this work, we report on the use of four non-intrusive methods for this purpose at a site in the Rocky Mountains. The methods included non-invasive geophysical surveys of subsurface electrical conductivity (EC), in-situ EC measurement of discharging groundwater at the lake-sediment interface, shoreline water sampling and nutrient analysis, and shoreline periphyton sampling and analysis of biomass and taxa relative abundance. The geophysical surveys were able to detect and delineate two high-EC plumes, with capacitively coupled ERI (OhmMapper) providing detailed two-dimensional images. In situ measurements at the suspected discharge locations confirmed the presence of high-EC water in the two plumes and corroborated their spatial extent. The nutrient and periphyton results showed that only one of the two high-EC plumes posed a current eutrophication threat, with elevated nitrogen and phosphorus levels, high localized periphyton biomass and major shifts in taxonomic composition to taxa that are commonly associated with anthropogenic nutrient loading. This study highlights the need to use non-intrusive methods in combination, with geophysical and water EC-based methods used for initial detection of wastewater-affected groundwater plumes, and nutrient or periphyton sampling used to characterize their ecological effects.     

An appraisal of changes in seasonal water quality during passage through a shallow reservoir in Western Poland

Following restoration changes in Antoninek Reservoir physico-chemical and biological processes in the water column and bottom sediments were measured to outline mechanisms of changes in nitrogen, phosphorus and organic matter concentrations during water flow through this reservoir. Intensive mineralisation of organic matter in the shallow sediments stimulated primary production and influenced increasing ammonia and nitrite nitrogen concentrations. Two main factors affected concentrations of phosphorus: (1) its presence in the external loads of river waters entering the reservoir, more important in the colder seasons as the water discharge was higher and (2) from the internal loads coming from bottom sediments. The quality of the river water during its flow through this reservoir improved for most parameters and seasons. However, concentrations of nutrients were still high in waters flowing out from the reservoir and in some months they were higher in the outflow than in waters entering the reservoir.     

Risk assessment and distribution of soil Pb in Guangdong, China

In this study, the spatial distributions of soil lead (Pb) concentration in three horizontal soils in Guangdong, China, were surveyed and analyzed using geostatistics and geography information systems (GIS). Findings indicated that the Pb geometric mean concentration of 23.3 mg/kg in surface soils was found to be higher than those in global soils, which ranged from 2.3–235 mg/kg. In addition, the Pb geometric mean concentrations from A- to C-horizon were found to be 23.3, 27.2, and 28.6 mg/kg, respectively. The classification of a soil Pb environmental risk in an area was likewise presented based on the different levels of environmental quality of Pb and was done by GIS technology. Accordingly, there is a higher local concentration of Pb in the surrounding areas of Guangzhou where there is higher population density and in the north of Guangdong, which is a historic mining area. The results obtained by the environmental risk assessment reveal that about 46% of total surveyed area was above the background value, that is, 2.7% of the total area was at risk of pollution.     

Assessing benthic community condition in Chesapeake Bay: does the use of different benthic indices matter?

Federal and state environmental agencies conduct several programs to characterize the environmental condition of Chesapeake Bay. These programs use different benthic indices and survey designs, and have produced assessments that differ in the estimate of the extent of benthic community degradation in Chesapeake Bay. Provided that the survey designs are unbiased, differences may exist in the ability of these indices to identify environmental degradation. In this study we compared the results of three indices calculated on the same data, and the assessments of two programs: the Chesapeake Bay Program and the Mid-Atlantic Integrated Assessment (MAIA). We examined the level of agreement of index results using site-based measures of agreement, evaluated sampling designs and statistical estimation methods, and tested for significant differences in assessments. Comparison of ratings of individual sites was done within separate categories of water and sediment quality to identify which indices summarize best pollution problems in Chesapeake Bay. The use of different benthic indices by these programs produced assessments that differed significantly in the estimate of degradation. A larger fraction of poor sites was classified as good by the Environmental Monitoring and Assessment Program’s Virginian Province and MAIA benthic indices compared to the Chesapeake Bay benthic index of biotic integrity, although overall classification efficiencies were similar for all indices. Differences in survey design also contributed to differences in assessments. The relative difference between the indices remained the same when they were applied to an independent dataset, suggesting that the indices can be calibrated to produce consistent results.     

IFTCIP: An Integrated Optimization Model for Environmental Management under Uncertainty

In this study, an interval-fuzzy two-stage chance-constrained integer programming (IFTCIP) method is developed for supporting environmental management under uncertainty. The IFTCIP improves upon the existing interval, fuzzy, and two-stage programming approaches by allowing uncertainties expressed as probability distributions, fuzzy sets, and discrete intervals to be directly incorporated within a general mixed integer linear programming framework. It has advantages in uncertainty reflection, policy investigation, risk assessment, and capacity-expansion analysis in comparison to the other optimization methods. Moreover, it can help examine the risk of violating system constraints and the associated consequences. The developed method is applied to the planning for facility expansion and waste-flow allocation within a municipal solid waste management system. Violations of capacity constraints are allowed under a range of significance levels, which reflects tradeoffs between the system cost and the constraint-violation risk. The results indicate that reasonable solutions for both binary and continuous variables have been generated under different risk levels. They are useful for generating desired decision alternatives with minimized system cost and constraint-violation risk under various environmental, economic, and system-reliability conditions. Generally, willingness to take a higher risk of constraint violation will guarantee a lower system cost; a strong desire to acquire a lower risk will run into a higher system cost.     

The Statistical Investigation on Posidonia Oceanica (L.) Delile Meadows in Izmir, Turkey

In this study, variance analysis technique on unbalanced data was examined, and in this sense, Type II (fitting constants) methods were studied. The aim of this study was to show that meaningful evaluations can be performed even in unbalanced conditions and to contribute to the present investigations in biological area. In the implementation part of the study, the juvenile leaf densities of Posidonia oceanica—which is a sea grass that grows in Izmir Bay, and has very important ecological effects—in various regions and in various depths were determined. The results revealed that depth affect number of juvenile leaf (d.f.?=?3, F?=?523.90, R ²?=?0.998, p?F?=?41.53, p?F?=?19.65, p?p?p?p?p?相似文献   

Using diatoms as quality indicators for a newly-formed urban lake and its catchment

Periphytic diatoms were studied to evaluate the water quality of a newly created lake, formed by the enclosure of the formerly tidal Cardiff Bay (Wales, UK), and the effects of two inflowing rivers which drain densely populated and industrialised catchments. Seven sites in Cardiff Bay and two locations on the inflowing rivers were monitored for diatoms and water chemistry over 2 years. Water quality was assessed using a revised UK trophic diatom index (TDI) and new methods to determine ecological quality ratios and ecological status classes as required by the EU Water Framework Directive. Diatom assemblages reflected spatiotemporal variations in environmental conditions between the rivers and Cardiff Bay and within the bay. In the bay, diatoms reflected differences in river quality and possibly local pollution in certain areas of the lake. High values of the TDI indicated eutrophic to hypertrophic conditions in both rivers and in the bay and diatoms indicated poor ecological status.     

Monitoring and assessing variation of sewage quality and microbial functional groups in a trunk sewer line

In this study, the variation of sewage quality was investigated and the active fraction of different microbial functional groups in biofilm was quantified in a 5.6-km trunk sewer line. The sewage quality including suspended solids, biochemical oxygen demand, total chemical oxygen demand (COD), total nitrogen, total Kjeldahl nitrogen, ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen were measured and compared with the values in literatures. The results indicated that since the wastewater treatment plant was not operated at its full capacity, the concentrations of different compounds were lower compared with the values in literatures. The values of heterotrophic growth rate constant lay between 5.6 and 8.6 day^???1. Its average value was 7.7 day^???1. The values of heterotrophic lysis rate constant lay between 0.2 and 0.4 day^???1. The active heterotrophic biomass in biofilm varied from 240 to 800 mg COD m^???2 and average value was 497 mg COD m^???2. The biofilm mass varied from 880 to 1,080 mg m^???2. The percentage of heterotroph to biofilm mass fall within the range of 24.0–90.9% and average value was 52.9%. In the oxygen uptake rate batch tests, the biomass, growth rate constant, and lysis rate constant of autotroph could not be determined because the fraction of autotroph in biofilm was relatively few. It revealed that the degradation of organic matters, nitrification, and denitrification occurred in the trunk sewer line. But the results indicate that the condition seem favorable for nitrification.     

Development of the concept of spatial–temporal mask for testing effects of discharge from well-drilling activities on biological communities

This paper describes the use of Bayesian spatial models to develop the concept of a spatial–temporal mask for the purpose of identifying regions in which before and after drilling effects are most clearly defined and from which the consequences of exposure of macrofauna and meiofauna to the release of drilling discharges can be evaluated over time. To determine the effects of drilling fluids and drill-cuttings on the marine benthic community, it is essential to know not only where discharged materials ended up within the possible impact area, but also the chemical concentrations to which biota were exposed during and after drilling. Barium and light hydrocarbons were used as chemical tracers for water-based and non-aqueous-based fluids in a shallow water site in the Campos Basin, off the coast of Brazil. Since the site showed evidence of exposure to waste material from earlier drilling, the analysis needed to take into account the background concentrations of these compounds. Using the Bayesian models, concentrations at unsampled sites were predicted and regions altered and previously contaminated were identified.     

Risk of boron and heavy metal pollution from agro-industrial wastes applied for plant nutrition

In this study, the effects of various agro-industrial wastes were investigated when applied to soil alone or in combination with chemical fertilizers, regarding the risks of boron and heavy metal pollution of soils and plants. Nine combinations of production residues from various agro-industries, urban wastes, and mineral fertilizers were applied to potatoes in a field experiment. The content of available boron in the soil differed significantly (p < 0.05) among the applications. Generally, B values were found to be slightly higher when soapstock, prina, and blood were used alone or in combination. Although total Co, Cd, and Pb contents of soils showed no significant differences between the applications, Cr content differed significantly (p < 0.05). No pollution risk was observed in soil in respect to total Co, Cd, Pb, and Cr contents. The amount of boron and heavy metals in leaves showed no significant differences among the applications. Cobalt, Cd, and Pb in leaves were at normal levels whereas Cr was slightly above normal but well under the critical level. Boron was low in tubers and varied significantly between applications such as Co and Cd. The Co content of tubers was high, Cd and Cr contents were below average, and Pb content was between the given values. Some significant correlations were found between soil characteristics and the boron and heavy metal content of soil, leaves, and tubers.