Nearby Surface Water Research Articles

Effect of Disc Filtration with and without Addition of Flocculent on Nano- and Micro-Particles and Their Associated Polycyclic Aromatic Hydrocarbons in Stormwater

Many municipalities in Denmark and around Europe currently work towards separating stormwater and sewage. In existing urban areas this may imply disconnecting stormwater from the old combined sewer systems suffering from hydraulic overloading and discharging directly to nearby surface waters. Stormwater runoff may, however, be heavily polluted and Best Available Technologies (BAT) are therefore needed to treat the stormwater before discharge. The aim here was to determine the sizes of particles found in stormwater from roads and to evaluate the use of a cationic organic flocculant to increase the size of the particles and thereby increase the removal efficiency of a 10 µm woven polyester disc filter. The samples were collected in connection with a project testing a pilot scale disc filter for treating stormwater runoff. The micro-sized particles were found to be mainly below 10 µm (6.9–19 µm) and nano-sized particles were also observed (ca. 76–228 nm). The flocculent increased the observed particle micrometer sizes by 46% and the removal of particle-associate Polycyclic Aromatic Hydrocarbons (PAHs) was confirmed. The majority of the particles were, however, still below 10 µm after addition of flocculant, which shows that application of flocculants with the woven disc filter technology for stormwater treatment needs further refinement.

At-grade stabilization structure impact on surface water quality of an agricultural watershed

Decades of farming and fertilization of farm land in the unglaciated/Driftless Area (DA) of southwestern Wisconsin have resulted in the build-up of P and to some extent, N, in soils. This build-up, combined with steep topography and upper and lower elevation farming (tiered farming), exacerbates problems associated with runoff and nutrient transport in these landscapes. Use of an at-grade stabilization structure (AGSS) as an additional conservation practice to contour strip cropping and no-tillage, proved to be successful in reducing organic and sediment bound N and P within an agricultural watershed located in the DA. The research site was designed as a paired watershed study, in which monitoring stations were installed on the perennial streams draining both control and treatment watersheds. Linear mixed effects statistics were used to determine significant changes in nutrient concentrations before and after installation of an AGSS. Results indicate a significant reduction in storm event total P (TP) concentrations (P = 0.01) within the agricultural watershed after installation of the AGSS, but not total dissolved P (P = 0.23). This indicates that the reduction in P concentration is that of the particulate form. Storm event organic N concentrations were also significantly reduced (P = 0.03) after the AGSS was installed. We conclude that AGSS was successful in reducing the organic and sediment bound N and P concentrations in runoff waters thus reducing their delivery to nearby surface waters.

Survey of two perfluorinated organic compounds (PFOA and PFHxA) in water and biota surrounding a polyfluorinated chemical plant

Perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA) concentrations were measured in water and biota samples collected within and near a polyfluorinated chemical plant in coastal Mississippi. Effluents from the site and from the local public water treatment plant were sampled along with municipal water supplies, shallow groundwater beneath the site, nearby surface waters, and local biota. Highest concentrations were from stormwater ([PFOA] = 85—530 ng/l; PFHxA = 140—590 ng/l) and shallow groundwaters ([PFOA] = 44—1000 ng/l; PFHxA = 210—3100 ng/l) collected at the site. The local public water treatment effluent also had relatively high PFHxA concentrations (310—590 ng/l). Intermediate PFOA concentrations were measured in effluent samples (21—33 ng/l) and irrigation water from a public works facility (15—48 ng/l). Drinking water and all surface waters had low PFOA and PFHxA concentrations (PFOA = 1.1—3.0 ng/l; PFHxA < 1.4 ng/l). Tissues from local fish and blue crab had undetectable PFOA and PFHxA concentrations. Results suggest that evaporation and subsequent percolation of contaminated stormwater into the shallow aquifer is the major pathway for perfluorinated contaminants to escape from this site.

Environmental Health Impact of Potentially Harmful Element Discharges from Mining Operations in Nigeria

Widespread artisanal, alongside small-scale mining operations are currently increasing in intensity in Nigeria. These activities are causing immeasurable damage to the environment and populations that live in the vicinity of these mine fields. The discharges of Potentially Harmful Elements (PHEs) from the exposed mine-out /mineral processing sites and their subsequent remobilization into the soils, and natural water bodies constitute serious human health problems. A study aiming at understanding the extent by which these elements contaminate the soils at the vicinity of the mining operations was conducted. This study also sought to identify the possible effects on human health and how it can be best mitigated. Geochemical results suggest that the discharges of PHEs from the mining/mineral ore processing operations have contributed significantly to the enrichment of these elements in the surrounding environment, thereby contaminating drinking water sources, food crops, and are disposed to subsequent entry into the human body through the food chain. Many of the mining communities make their living from subsistence farming, growing food from the surroundings, and obtaining drinking water from nearby surface and sub-surface water resources. The direct or indirect exposure of the human population to PHEs constitutes a potential risk to human health if not monitored and abated. Reports of in-vitro bio-accessibility tests show that less than 50% of bio available heavy metal contaminants in ingested soil are bio accessible during digestion process. Thus, there is need for the reduction of bio-available PHE in the soil by ensuring that mining operations generally are done in a manner that will secure a quality of environment adequate for good health and well-being of the communities around.

The Development of Rural Domestic Wastewater Treatment in China

Agriculture is one of the foundations of China’s national economy. The rural population is more than half of China’s total population. However, rural domestic wastewater treatment has not been solved, mostly household wastewater untreated directly discharged into nearby surface water bodies. With the development of rural economy, domestic wastewater treatment has become a serious problem in rural sustainable development in China. Emission characteristics and status of rural domestic wastewater treatment in China were presented in this paper. On this basis, several rural wastewater treatment technologies commonly used were reviewed in China rural area, including septic tanks, land treatment system, methane-generating pit, stabilization lagoon and constructed wetland. The current problems and future development in rural domestic wastewater treatment were discussed, and some suggestions proposed. On the one hand, new integrated technology should be actively developed in rural domestic wastewater. On the other hand, the management of rural domestic wastewater should be strengthened. Thus, effective protection will be provided for the sustainable development of rural areas in China.

Condições físico-químicas e biológicas em águas superficiais do Rio Tapajós e a conservação de Floresta Nacional na Amazônia, Brasil

A bacia amazônica detém uma grande quantidade de água que deve ser conservada para atender as necessidades desta e das futuras gerações. O objetivo deste trabalho foi avaliar condições físico-químicas e biológicas em águas superficiais do Rio Tapajós como indicadores da conservação de Floresta Nacional na Amazônia. Para a tomada de decisão quanto ao período de coleta levou-se em consideração apoio logístico e financeiro, sendo possível as coletas na época de menor oferta pluvial com base em informações climáticas na Flona e seu entorno. As coletas no rio Tapajós ocorreram em áreas de influência quanto ao uso e ocupação do solo. Foram realizadas avaliações no local, bem como análises em laboratório. Os resultados apontaram que dezembro de 2012 foi mais chuvoso em relação a climatologia. Os resultados do Índice de Qualidade de Água (IQA) indicaram o predomínio na qualidade "boa" a "ótima", nas quais as faixas variaram entre 70 < IQA < 90 e 90 < IQA <100, totalizando 70,0% das amostras coletadas. Os balneários de Alter do Chão e Pindobal foram os que apresentaram valores elevados de coliformes termotolerantes, possivelmente devido os efeitos antrópicos que poderiam ser mitigados com práticas de turismo adequadas. O maior IQA e a maior transparência da água, identificados próximo a Tauarí, evidenciaram efeitos mínimos nas águas superficiais pela ação antrópica nessa localidade. Conclui-se que os corpos hídricos são sensíveis a alterações na cobertura da terra e estas podem ameaçar à manutenção de áreas de uso conservacionista.

Biosolids and distillery effluent amendments to Irish short rotation coppiced willow plantations: Impacts on overland flow and surface water quality

It's necessary to determine risks of pollution arising from amendment of organic by-products (OBs) to energy crops. The impact of applying two OBs on the quality of overland flow (OLF) from plantations of short rotation coppiced willow was assessed. Municipal biosolids (BS) and distillery effluent (DE) were spread annually on six 0.1174ha treatment plots at rates of 100% (W-BS100, W-DE100), 50% (W-BS50, W-DE50) and 0% (W-BS0, W-DE0). The 100% rate was the maximum load of 15t Pha−1 as per the current Irish regulation based on crop uptake of P. Surface flows were sampled over 18 months and tested for pH, electrical conductivity, NO3−, PO43−, total P, K, Cu, Cd, Cr, Pb, Ni, and Zn. Results showed NO3−, Cu, Cd, Cr, Pb, Ni, and Zn concentrations in OLF were well below quality standard limits set out in European Union (EU) drinking water (DW) and surface water (SW) regulation. For P–PO43− and K, concentrations in OLF exceeded these limits. There were treatment responses for all OLF species, except P and Ni; in some cases there were large increases in OLF concentration as OB treatment rate increased. There was build-up in soil-P, -K and in heavy metals (HMs) following application of BS, but not distillery effluent (DE). Results suggest increased OB application could result in increased export from plots treated with OBs. Despite high PO43− and K OLF concentrations, the occurrence of OLF was rare and volumes lost from plots were low; actual exports of nutrient and HMs by this pathway were small. It was unlikely OLF streams transported particulate matter far from plots, and no preferential flow routes were available to the OLF streams. For these reasons, the OLF encountered during experiments did not pose any serious threat to the quality of nearby surface waters. CapsuleOrganic by-products (OBs), biosolid and distillery effluent, amended to short rotation coppice willow. Impact on quality of surface (overland) flows (OLF) assessed by analysis of nutrients and heavy metals (HMs). Evidence of export of all three major agricultural nutrients and some heavy metals. Concentrations of P and K exceeded DW regulation limits in some instances. However, small volumes and rare occurrence of OLF indicated no risk to nearby surface waters. The practice of OB amendment resulted in little risk to surface waters at these scales. If scaled up to plantation scale, in areas vulnerable to OLF, careful consideration must be made about P-loss (on a catchment scale) before amendments carried out.

Assessment of the impact of traditional septic tank soakaway systems on water quality in Ireland.

One of the key threats to groundwater and surface water quality in Ireland is the impact of poorly designed, constructed or maintained on-site wastewater treatment systems. An extensive study was carried out to quantify the impact of existing sites on water quality. Six existing sites, consisting of a traditional septic tank and soakaway system, located in various ranges of subsoil permeabilities were identified and monitored to determine how well they function under varying subsoil and weather conditions. The preliminary results of the chemical and microbiological pollutant attenuation in the subsoil of the systems have been assessed and treatment performance evaluated, as well as impact on local surface water and groundwater quality. The source of any faecal contamination detected in groundwater, nearby surface water and effluent samples was confirmed by microbial source tracking. From this, it can be seen that the transport and treatment of percolate vary greatly depending on the permeability and composition of the subsoil.

Investigation of insecticide leaching from potted nursery stock and aquatic health benefits of bioretention cells receiving nursery runoff.

Tree nurseries and greenhouses within the USDA red imported fire ant (RIFA) quarantine zone are required to incorporate insecticides into their potting media to prevent artificial spread of RIFA. Bifenthrin and fipronil are two common insecticides that are incorporated into potting media. During irrigation and stormwater events, there is potential for insecticides to leach from nursery pots, resulting in the contamination of nearby surface waters. In this study, occurrences of insecticides in simulated nursery runoff were compared with two irrigation strategies and two types of containers in single pot leaching and field runoff simulations. In addition, toxicity of pot leachate to the aquatic invertebrate, Hyallela azteca, was measured, and removal efficiencies of insecticides from bioretention cell media were evaluated. Overhead irrigation resulted in significantly higher concentrations than drip irrigation, and RootMaker pots allowed more leaching as compared to standard slick-wall pots. However, in all tests, the average concentration of bifenthrin during 15 days of leaching in both pot and field simulations was greater than 200 ng/L; more than 100-fold greater than the LC₅₀ for H. azteca. Toxicity studies confirmed this level of toxicity. Higher amounts of compost, 20 and 40%, in bioretention cell media resulted in greater percent reduction of both bifenthrin and fipronil. This study determined that management techniques may be able to limit the amount of insecticide that leaches from pots and runs off to receiving water bodies. Specifically, the selection of appropriate pot types, irrigation strategies, or filtering runoff through bioretention cells may reduce contamination loads. Thus, further best management strategies such as the use of bioretention cells are needed in nursery and greenhouse facilities to prevent surface water runoff from transporting toxic insecticides.

COUPLED NITROGEN AND OXYGEN ISOTOPE STUDY OF NITRATE AT A RURAL UNLINED LANDFILL IN WESTERN VICTORIA, AUSTRALIA

Understanding of site-scale physical and chemical heterogeneities will inform remediation strategies for unlined rural landfills worldwide. The aim of this study was to characterize potential sources of nitrogen contamination to groundwater at an unlined landfill in rural western Victoria, Australia. Results revealed simultaneously high concentrations of both nitrate and ammonia within several wells, indicative of heterogeneous redox potentials within the unconfined aquifer. Combined isotopic analyses of δ15N and δ18O in nitrate identified a leachate-derived source and active denitrification across two sites hydraulically down-gradient from the landfill cell. Groundwater at an up-gradient site, as well as nearby surface water samples from a riparian creek, reflected primarily the isotopic signature of agriculturally-derived nitrate with overprinting from atmospheric exchanges of nitrogen and oxygen. Nitrate and ammonia in the creek were interpreted to result from a mixture of leachate and agricultural sources. Results illustrate how redox gradients across a landfill leachate plume impact biogeochemical nitrogen cycling.

Quality Assessment of Soil and Groundwater near Kaduna Refinery and Petrochemical Company, Northwest Nigeria

Soil and water are precious natural resources on which rely the sustainability of agriculture, industrialization and the civilization of mankind. Unfortunately, they have been subjected to contamination due to anthropogenic activities leading to the release of heavy metals into the environment. The history of petroleum exploration, exploitation, refining and marketing in Nigeria is a long, complex and painful one in terms of soil and groundwater pollution, which has resulted to multiple environmental and health problems. The study reveals that in some locations near the refinery, the soil and the groundwater are slightly polluted with heavy metals in the order of Fe > As > Zn > Cu > Pb > Cr > Cd > Mn, which may be attributed to the natural enrichment of groundwater through weathering of bedrock in the course of groundwater migration and anthropogenic via dumping of untreated effluents from the refinery and petrochemical into the nearby soil and surface water. The use of groundwater from the shallow hand-dug wells by host communities should be discouraged and alternative source of water should be provided by the company or government. Deep sited boreholes should be sunk to replace the existing Original Research Article Amadi et al.; JSRR, Article no. JSRR.2014.010 885 shallow hand-dug wells in the area. Effluents and waste-water from the refinery and petrochemical should be treated before disposing into the nearby farmlands or surface water.

Manage Storm Water by Using Porous Pavement

As cities grow, the amount of impermeable surfaces—those that do not allow water to infiltrate into the ground—increases Examples of impervious surfaces are asphalt roads, concrete sidewalks, parking lots, building roofs, and areas of highly compacted soils such as in subdivisions. If not properly managed, the storm water runoff produced by these impermeable surfaces can have negative effects on nearby surface waters. When waters from storm events do not infiltrate the soil, the storm water management system, consisting of storm water structures and pipes, quickly directs them to streams, rivers, and lakes. Such increases in storm water runoff can have detrimental effects on nearby lands and receiving streams resulting in flooding, increased peak flows, groundwater or stream base flow reductions, increased stream velocities and stream bank erosion, increased water temperatures, and reduced water quality. Storm water must be managed in such a way as to prevent or minimize these negative impacts from urban growth. One method of storm water management is to reduce runoff by increasing infiltration through the use of permeable or pervious pavement. Permeable pavement allows storm water to percolate through the pavement and infiltrate the underlying soils thereby reducing runoff from a site, unlike standard pavement which prohibits infiltration. In previous concrete, carefully controlled amounts of water and cementations materials are used to create a paste that forms a thick coating around aggregate particles. Permeable pavement looks similar to standard asphalt or concrete except void spaces are created by omitting fine materials. Compacted gravel is not considered permeable pavement. Permeable paving surfaces keep the pollutants in place in the soil or other material underlying the roadway, and allow water seepage to groundwater recharge while preventing the stream erosion problems. However, some properties of most permeable pavements limit their applicability. Permeable pavements are not generally used in applications where high traffic loads, in terms of volume and weight, and/or high rates of speed are encountered. Their use should be limited to pedestrian and light to medium vehicle traffic. Greenways, sidewalks, driveways. Key Word: Construction, Types, Advantages, Disadvantages, Maintenances I. Introduction: Pervious pavement is made of either pervious asphalt or pervious concrete. Both materials resemble conventional asphalt and concrete, but have more air spaces that allow water to pass through the pavement into a reservoir base of crushed aggregate, then infiltrate into the ground. Pervious pavement is designed to accept precipitation only and is typically thicker than traditional concrete to support the same loads. Pervious asphalt consists of coarse stone aggregate and asphalt binder, with very little fine aggregate. Water percolates through the small voids left in the finished asphalt. A thick layer of gravel underneath allows water to drain through quickly. Pervious asphalt looks similar to conventional asphalt, although with rougher surface. Pervious concrete consists of specially formulated mixtures of Portland cement open-graded coarse aggregate, and water. It has enough void space to allow rapid percolation of water and resembles exposed aggregate concrete. Pervious concrete pavement is a unique and effective means to address important environmental issues and support green, sustainable growth. By capturing storm water and allowing it to seep into the ground, porous concrete is instrumental in recharging groundwater, reducing storm water runoff, and meeting U.S. Environmental Protection Agency (EPA) storm water regulations.

Electrocoagulation of Landfill Leachate with Monopolar Aluminum Electrodes

In this paper, the removal of COD from landfill using aluminum electrode by the electrocoagulation method was investigated. The studies were run with the parallel plate monopolar aluminum electrodes and the effect of pH and current density on removal efficiency of COD and energy consumption were determined. The initial COD concentration of 4100 mg/L was reduced to 1763 mg/L with the removal efficiency of 57% at the current density of 75 mA/cm 2 and pH 5. Index Terms—Aluminium electrode, landfill leachate, treatment. I. I NTRODUCTION The most common and desirable integral indispensable solid waste management strategy is sanitary landfilling because it is simple and has low exploitation and capital costs. Up to 95% of the total municipal solid waste collected in the world is disposed of in landfills (1). Physico-chemical and biological conversions are occurred during the landfilling process and a result of conversions degregated organic compounds that soluble in rainwater are formed. Any liquid material that drains from land material is called leachate and it is highly toxic liquid with dissolving organic compounds, heavy metals and different soluble materials derived from the material that it has passed through. The composition of from a landfill depends on the age of the landfill and the type of waste that it contains. Leachate can potentially contaminate nearby surface and ground water if left untreated. Therefore landfills require close environmental monitoring during their design, operation, and long-term post-closure period. Leachate must be treated before discharging to environment. Many different physico-chemical techniques such as adsorption (2), chemical precipitation (3), coagulation/flocculation (4), chemical oxidation (5) and biological methods (6) have been being applied for the treatment of landfill leachate. Electrocoagulation, one of the most useful electrochemical methods, is a comparatively new technique for wastewater treatment. Also, electrocoagulation has some advantages such as, short retention time, easy operation, not needed the chemical addition, simple equipment, high sedimentation velocity and possibility of complete automation (7).

An Optical High and Medium Spatial Resolution Approach for Erosion-Prone Areas Assessment in Mustang, Nepal

Every year during the rainy season, water-induced soil erosion poses serious spatial-environmental problems, causing heavy damage to agricultural lands, sedimentation in reservoirs, and water quality problems in nearby surface water bodies, from the plains to the mountain areas in Nepal. The goal of this study is to identify potential areas for soil erosion in sub and macro watershed in Mustang, Nepal using remote sensing (RS) and geographic information systems (GIS) techniques. The study examines the possibility of advanced mapping of soil erosion-prone areas using a high spatial resolution image of QuickBird satellite and medium spatial resolution of Landsat satellite. The satellite image was classified using object-based image analysis (OBIA) techniques, taking into account spectral, spatial, and context information as well as hierarchical properties. The resulting land cover classification was thereafter combined with additional data in ArcGIS, where the input layers were reclassified and all classes of the input layers were ranked according to their proneness to soil erosion. Soil erosion-prone areas were delineated in five classes ranging from “very high” to “very low”. Using high spatial resolution image the study revealed that 22% area categorized as “high erosion-prone” areas and 5% as “very high” or “extremely erosion-prone”. Using medium resolution image the study exposed that 27% area categorized as “high erosion-prone” areas and 6% as “very high” or “extremely erosion-prone”. Comparison between two analysed erosion results almost all the erosion zone area was very close excluding medium erosion-prone category. The study proved GIS modeling techniques can successfully identify soil erosion-prone areas. The soil erosion-prone map produced out of the exercise can be used in decision making, particularly in selecting conservation measures to reduce soil loss.

폐기물 매립시설의 배수층 및 보호층으로서의 Geo-Multicell-Composite(GMC)의 적합성에 관한 연구

Landfill require special care due to the dangers of nearby surface water and underground water pollution caused by leakage of leachate. The leachate does not leak due to the installation of the geomembrane but sharp wastes or landfill equipment can damage the geomembrane and therefore a means of protecting the geomembrane is required. In Korea, in accordance with the waste control act being modified in 1999, protecting the geosynthetics liner on top of the slope of landfill and installing a drainage layer to fluently drain leachate became mandatory, and technologies are being researched to both protect the geomembrane and quickly drain leachate simultaneously. Therefore, this research has its purpose in studying the drainage functions of leachate and protection functions of the geomembrane in order to examine the application possibilities of Geo-Multicell-Composite (GMC) as a Leachate Collection?Removal and Protection System (LCRPs) at the slope on top of the geomembrane of landfill by observing methods of inserting filler with high-quality water permeability at the drainage net. GMC’s horizontal permeability coefficient is 8.0 × 10-4m2/s to legal standards satisfeid. Also crash gravel used as filler respected by vertical permeability is 5.0 cm/s, embroidering puncture strength 140.2 kgf. A result of storm drain using artificial rain in GMC model facility, maximum flow rate of 1,120 L/hr even spray without surface runoff was about 92~97% penetration. Further study, instead of crash gravel used as a filler, such as using recycled aggregate utilization increases and the resulting construction cost is expected to savings.

The effect of glyphosate-based herbicide on aquatic organisms – a case study

AbstractThe non-selective, post-emergence herbicides based on glyphosate [N-(phosphonomethyl) glycine] are one of the most widely used pesticides in agriculture, urban areas and forestry. Although there has been documentation on the physical, chemical and toxicological properties of glyphosate, the aquatic toxicity of such formulations still requires assessment and evaluation. In the present study, we describe deliberate use of glyphosate-based herbicide in a bathing area of Lake Lednica (Wielkopolska, Poland) by unknown perpetrators in April, 2011. Glyphosate was detected using gas chromatography mass spectrometry (GC-MS) in the water samples collected from the bathing area at a mean concentration of 0.09 mg dm-3. Aboveground parts of emerged macrophytes (Phragmites australis and Typha latifolia) covering the investigated area were completely withered. Studies of benthic macroinvertebrates revealed no significant differences in taxa number between event (13 taxa) and control (14 taxa) sites although differences in abundance of particular taxa were observed. Significantly lower numbers of Chironomidae (by 41%), Oligochaeta (by 43%), Vivipariae (by 75%), Hirudinae (by 75%), Asellus aquaticus (by 77%), Gammarus pulex (by 38%) and Dreissena polymorpha (by 42%) were found at the glyphosate-treated site. Furthermore, compared to the control, chironomids (Chironomidae) exposed to glyphosate were represented by specimens smaller in length while A. aquaticus only showed large adults. The ranges of glyphosate concentration in the tissues of sampled macroinvertebrates and Phragmites australis organs were 7.3-10.2 μg kg-1 and 16.2-24.7 μg kg-1, respectively. Our study indicates that glyphosate-based herbicides may have adverse effects on aquatic organisms including macroinvertebrates, thus their use in (or nearby) surface waters should be subject to strict limitation.

Horticultural Use of Copper-Based Fungicides Has Not Increased Copper Concentrations in Sediments in the Mid- and Upper Yarra Valley

The use of Cu-based fungicide can pose a risk to nearby surface water bodies due to the run-off of accumulated Cu from agricultural soils. In 2008, we conducted a reconnaissance survey of the presence and concentration of copper in sediments at 18 sites within the Yarra River Catchment, an important horticultural production system in south-eastern Australia. Observed Cu concentrations in sediment samples from the study sites (mean (95 % confidence interval) 12.0 (10.6–13.6) mg/kg dry weight) were similar to the concentrations present in the samples from the reference sites (mean (95 % confidence interval) 12.0 (6.7–16.8) mg/kg dry weight). The data on Cu and other metals in the sediments suggest that that there is unlikely to have been wide spread, diffuse, off-site transport of Cu from the soils of horticultural properties to nearby surface waterways in the Yarra River Catchment and that that observed sediment metal concentrations are unlikely to pose an ecological risk to sediment-dwelling organisms at the study sites.

Distinct dissolved organic matter sources induce rapid transcriptional responses in coexisting populations of Prochlorococcus, Pelagibacter and the OM60 clade

A considerable fraction of the Earth's organic carbon exists in dissolved form in seawater. To investigate the roles of planktonic marine microbes in the biogeochemical cycling of this dissolved organic matter (DOM), we performed controlled seawater incubation experiments and followed the responses of an oligotrophic surface water microbial assemblage to perturbations with DOM derived from an axenic culture of Prochlorococcus, or high-molecular weight DOM concentrated from nearby surface waters. The rapid transcriptional responses of both Prochlorococcus and Pelagibacter populations suggested the utilization of organic nitrogen compounds common to both DOM treatments. Along with these responses, both populations demonstrated decreases in gene transcripts associated with nitrogen stress, including those involved in ammonium acquisition. In contrast, responses from low abundance organisms of the NOR5/OM60 gammaproteobacteria were observed later in the experiment, and included elevated levels of gene transcripts associated with polysaccharide uptake and oxidation. In total, these results suggest that numerically dominant oligotrophic microbes rapidly acquire nitrogen from commonly available organic sources, and also point to an important role for carbohydrates found within the DOM pool for sustaining the less abundant microorganisms in these oligotrophic systems.

Removal of malathion using ceramic nanofiltration/adsorption system

Residual pesticides in industrial effluents of pesticide industry manifests a serious threat for sustainability of the biological wastewater treatment plants and also to nearby surface and ground water. This article is concerned with the separation of malathion using nanofiltration (NF), clay adsorption, and combination of both processes. Malathion removal using NF tubular ceramic membrane is ranged from 93.5 to 99.4% with malathion concentration range from 5.7 to 17.1 mg/l. Adsorption of malathion (0.4–2.9 mg/l) using Egyptian clays (kaolin and bentonites) reached about 0.65 mg/g. Sodium bentonite (Na–B) exhibited maximum adsorption capacity and removal as compared to kaolin (K) and calcium bentonite (Ca–B). The natural pH values of the different investigated clays in malathion solutions were 6.7, 7.3, and 9.5 for K, Ca–B, and Na–B, respectively. An integrated system of NF and clay adsorption permits effective control on the quality of NF permeates. Endeavors are currently underway to explore cost-effective treatment of NF concentrate.

Reusing by‐products in agricultural fields

Reusing by‐products in agricultural fields