Comparison of constructed reed beds with different filter media and macrophytes treating urban stream water contaminated with lead and copper

The aim of this study was to investigate the treatment efficiency of passive vertical-flow constructed wetland filters containing different macrophytes (Phragmites and/or Typha) and granular media with different adsorption capacities. Different concentrations of lead and copper sulphate were added to the polluted urban stream inflow water to simulate pre-treated mine wastewater. A fertilizer was added to one filter only. The relationships between growth media and plant communities as well as the reduction of predominantly lead and copper were investigated. Lead, copper and 5-day biochemical oxygen demand (BOD) concentrations were reduced similarly for all the wetlands. An analysis of variance showed that the concentration reductions (mg/l) of lead, copper and BOD were significantly similar for the six experimental wetlands. There appears to be no additional benefit in using expensive adsorption media like granular activated carbon to enhance biomass performance during the first 10 months of operation.     

Performance comparison of experimental constructed wetlands with different filter media and macrophytes treating industrial wastewater contaminated with lead and copper

The aim of this study was to investigate the treatment efficiency of passive vertical-flow wetland filters containing different macrophytes (Phragmites and/or Typha) and granular media with different adsorption capacities. Gravel, sand, granular activated carbon, charcoal and Filtralite (light expanded clay) were used as filter media. Different concentrations of lead and copper sulfate were added to polluted urban stream inflow water to simulate pretreated mine wastewater. The relationships between growth media, microbial and plant communities as well as the reduction of predominantly lead, copper and five-day biochemical oxygen demand (BOD5) were investigated. An analysis of variance showed that concentration reductions (mg l(-1)) of lead, copper and BOD5 were significantly similar for the six experimental wetlands. Microbial diversity was low due to metal pollution and similar for all filters. There appears to be no additional benefit in using adsorption media and macrophytes to enhance biomass performance during the first 10 months of operation.     

Roles of oyster shells in an integrated constructed wetland system designed for P removal

This research aimed to investigate the applicability of an integrated constructed wetland system for P removal from low-strength wastewaters. The integrated system consisted of a constructed wetland and a post-filter unit, in series; both units were packed with oyster shells (OS) as adsorption and filtration media. Based on 1 year of operation under the overall hydraulic retention time of 3.5 days, the integrated system was found to be highly effective in removing BOD₅ (92.3%), N (85.7%), P (98.3%) and total suspended solids (TSS) (94.4%) compounds, in which the constructed wetland unit was responsible for most of the treatment performance, while the post-filter unit served as a polishing unit, especially in the removal of the remaining N, P and TSS. To simulate heavy rainfall conditions, the integrated system was tested under hydraulic shock loading at the overall hydraulic retention time of 0.7 day for 14 days that represented the extreme period of high drainage flows. There were some increases of P concentrations in the post-filter effluent during the 14 days of operation up to about 5 mg/l, but these P concentrations were later decreased to about 1 mg/L after the shock loading period. These experimental results suggested the applicability of the integrated constructed wetland system which used oyster shells as adsorption and filtration media for P removal which should help to minimize eutrophication problems in receiving waters.     

Biosorption of copper(II) ions onto powdered waste sludge in a completely mixed fed-batch reactor: estimation of design parameters

Biosorption of Cu(II) ions onto pre-treated powdered waste sludge (PWS) was investigated using a fed-batch operated completely mixed reactor. Fed-batch adsorption experiments were performed by varying the feed flow rate ( 0.075-0.325 l h(-1)), feed copper (II) ion concentrations (50-300 mg l(-1)) and the amount of adsorbent (1-6 g PWS) using fed-batch operation. Breakthrough curves describing the variations of effluent copper ion concentrations with time were determined for different operating conditions. Percent copper ion removals from the aqueous phase decreased, but the biosorbed (solid phase) copper ion concentrations increased with increasing the feed flow rate and Cu(II) concentration. A modified Bohart-Adams equation was used to determine the biosorption capacity of PWS and the rate constant for Cu(II) ion biosorption. Adsorption rate constant in fed-batch operation was an order of magnitude larger than those obtained in adsorption columns because of elimination of mass transfer limitations encountered in the column operations while the biosorption capacity of PWS was comparable with powdered activated (PAC) in column operations. Therefore, a completely mixed reactor operated in fed-batch mode was proven to be more advantageous as compared to adsorption columns due to better contact between the phases yielding faster adsorption rates.     

CADMIUM, COPPER AND LEAD IN GASTROPODS OF THE LOWER NELSON RIVER SYSTEM, MANITOBA, CANADA

Cadmium, copper and lead were examined in whole snails fromthe Lower Nelson River system. Concentrations of the three metalswere significantly correlated with each other. Lead was accumulatedleast, while copper was present in the greatest concentrations.Significant interspecific differences were found for copper.Total body burdens increased with snail size and weight, butconcentrations per unit dry weight decreased with size and weightin some species. Metal concentrations in snails were not significantlycorrelated with metal content of the sediments. In Gyraulus,copper and lead concentrations were correlated with levels ofthese metals in the host macrophytes. Seasonal differences inmetal concentration appeared to be related to differences inage structure of the populations. (Received 5 September 1991; accepted 30 October 1991)     

Cadmium,copper and lead in aquatic macrophytes in Shoal Lake (Manitoba-Ontario)

Cadmium, copper and lead concentrations were surveyed in several species of submerged aquatic macrophytes in a Precambrian Shield Lake. Values were variable within each species and interspecific differences in metal concentration were not significant over the season as a whole. Cadmium concentration increased during the season in Potamogeton foliosus and Myriophyllum exalbescens, while copper and lead declined in P. foliosus. No identifiable seasonal trends were seen in P. zosteriformis and P. robbinsii. In P. foliosus, copper and lead concentrations increased with water depth. Few significant correlations were found between metal concentrations in the shoots and each of several water chemistry parameters, temperature, and shoot chlorophyll, soluble sugar and starch content. Roots yielded greater metal concentrations than shoots.     

The susceptibility of the giant freshwater prawn Macrobrachium rosenbergii to Lactococcus garvieae and its resistance under copper sulfate stress.

Addition of copper sulfate (0.1 to 0.4 mg l(-1)) to tryptic soy broth (TSB) had no effect on growth rate of the bacterial pathogen Lactococcus garvieae. Giant freshwater prawns Macrobrachium rosenbergii were injected with L. garvieae (4 x 10(6) colony-forming units [cfu] prawn(-1)) grown in TSB or TSB containing copper sulfate at 0.1, 0.2, 0.3 or 0.4 mg l(-1). After 48 h, the cumulative mortality was significantly (p < 0.05) higher for prawns exposed to L. garvieae grown in 0.4 mg l(-1) copper sulfate than at the lower concentrations examined. In other experiments, prawns were injected with TSB-grown L. garvieae (4 x 10(6) and 2 x 10(5) cfu prawn(-1)), then held in water containing copper sulfate. After 8 h the mortality of L. garvieae-exposed prawns held in water containing 0.4 mg l(-1) copper sulfate was significantly higher than prawns held in water containing 0.2 and 0.3 mg l(-1) copper sulfate. At the lower L. garvieae density, cumulative mortality of prawns increased directly with ambient copper sulfate concentrations in the range of 0.2 to 0.4 mg l(-1). All prawns survived a 168 h exposure to 0.1 mg l(-1) copper sulfate. Prawns exposed to different concentrations of copper sulfate were examined for hemocyte density, phenoloxidase activity and respiratory burst. No significant differences in hemocyte density were observed among treatments. In prawns following a 48 h exposure to 0.1 mg l(-1) copper sulfate, phenoloxidase activity was decreased, but respiratory burst was increased. In conclusion, copper sulfate increased the virulence of L. garvieae to M. rosenbergii and modulated its immune system. Copper sulfate at 0.1 mg l(-1) decreased susceptibility of M. rosenbergii to L garvieae infection, whereas at 0.2 mg l(-1) the susceptibility was increased. The generation of superoxide anion by M. rosenbergii exposed to copper sulfate at a concentration higher than 0.2 mg l(-1) was considered to be cytoxic.     

Trophic interactions in a shallow lake following a reduction in nutrient loading: a long-term study

After the diversion of a nutrient-rich inflow, the eutrophic lake, Alderfen Broad, initially showed reduced total phosphorus concentrations and phytoplankton populations, clear water and the establishment of submerged macrophytes. Internal P loading then increased, perhaps stimulated by the senescence of submerged macrophytes and exacerbated by the lack of flushing. Cyanophytes appeared in the summer of two years. As a consequence of poor recruitment of roach (Rutilus rutilus (L.)), the chief zooplanktivore, and a summerkill of the fish population, populations of large-bodied Cladocera (Daphnia hyalina/ longispina and ultimately D. magna) developed. In the long-term, these may have limited the further development of phytoplankton populations and clear water and submerged macrophytes returned. During this latter period, internal P release has remained high (> 380 µg l^-1), thereby indicating the scope for biomanipulation even in eutrophic conditions. However, isolation of the lake has led to a decrease in water level (which through increased temperatures and lowered dissolved oxygen levels was probably responsible for the fish deaths) and further concentration of internal P load. Sediment is now being removed to reestablish greater water depth.     

Biosorption of copper,lead and nickel on immobilized Bacillus coagulans using experimental design methodologies

Biosorption of copper, lead and nickel onto immobilized Bacillus coagulans (IBC) from aqueous solution in single- and multi-metal systems was investigated. The results of scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDXA) and Fourier transform infrared (FTIR) spectrometry demonstrated the importance of surface morphology and identified the active groups involved in adsorption. In batch studies, the most significant factors were screened by Minimum Run Res V Design. The Simplex Lattice Mixture Design was then successfully applied to explore the maximum adsorption capacity of the three metals (75.3 mg/g for copper, 118.3 mg/g for lead and 68.4 mg/g for nickel) and the preferential adsorption of IBC followed the order: Pb (II)?>?Cu (II)?>?Ni (II). Furthermore, adsorption kinetics and adsorption isotherms of single-, binary-, and ternary-metal systems were studied and the experimental data was found to fit well to the Freundlich isotherm and pseudo-second-order kinetics.     

Responses of primary producers to mouth closure in the temporarily open/closed Great Brak Estuary in the warm-temperate region of South Africa

Low river inflow conditions during 2009/2010 resulted in the mouth of the Great Brak Estuary remaining closed for almost two years. The low water level in Wolwedans Dam resulted in no annual environmental flow releases being made, causing mouth closure. The response of primary producers to this prolonged period of mouth closure was investigated in 2010/2011. Urban and agricultural development in the river catchment and along the estuary banks had increased the nutrient inputs into the estuary. Mouth closure, combined with elevated nutrient concentrations, increased the growth of both macroalgae and microalgae, but little change was observed in the submerged macrophytes. Macroalgal mats covered large areas of open-water surface, smothering the salt marsh and causing a decrease in its cover. These results have important implications for the management of temporarily open/closed estuaries, as increased development, freshwater abstraction and reduced river flow will result in prolonged periods of closure and reduced tidal exchange, which is likely to lead to eutrophication.     

Long-term performance of constructed wetlands with horizontal sub-surface flow: Ten case studies from the Czech Republic

Constructed wetlands with horizontal sub-surface flow (HF CWs) have been in use in the Czech Republic since 1989. Evaluation of the long-term performance of horizontal sub-surface flow constructed wetlands in the Czech Republic indicates that removal of organics and suspended solids is very effective; efficiencies are steady throughout the year and are not affected by season and also by the length of operation. The results from systems treating wastewaters from combined sewer systems clearly indicate that HF CWs can very effectively cope with low inflow concentrations of organics and can provide effluent BOD₅ concentrations less than 5 mg l⁻¹. Phosphorus removal is seasonally steady but low as Czech constructed wetlands do not use special filtration media with high sorption capacity. This is not a problem, because in the Czech Republic, there is currently no discharge limit for phosphorus for wastewater treatment plants up to 2000 person equivalents (PE). Removal of ammonia-N is limited by lack of dissolved oxygen in filtration beds caused by permanent saturation. The removal of ammonia-N is steady over the life of operation but is affected by season but the decrease in ammonia removal efficiency during winter is not large.     

黏土矿物中重金属离子的吸附规律及竞争吸附

采用等温吸附法,研究了重金属铜、铅、镉、镍在膨润土中的吸附特征,发现膨润土对铜、铅的吸附明显强于镉、镍,吸附强度大小顺序为Pb2 >Cu2 >Ni2 >Cd2 。Langmuir和Freundlich方程对这4种金属离子等温吸附的拟合均呈极显著关系。Pb2 、Cd2 、Ni2 分别与Cu2 的双组分竞争吸附表明,黏土矿物对4种离子具有"选择性吸附"。在Pb2 、Ni2 、Cd2 的存在条件下,黏土矿物对Cu2 的吸附产生不同程度的下降;100mg/LCu2 对Pb2 的影响不大,但可完全抑制Ni2 、Cd2 的吸附。建立了IAS和LCA模型来预测Pb2 与Cu2 的双组分竞争吸附,并对LCA模型进行修正,提出了更符合实际情况的竞争吸附模型。文章最后用LCA修正模型对Pb2 与Cu2 的双组分竞争吸附进行了模拟。     

Modeled impacts of farming practices and structural agricultural changes on nitrogen fluxes in the Netherlands

In the Netherlands, nutrient emissions from intensive animal husbandry have contributed to decreased species diversity in (semi) natural terrestrial and aquatic ecosystems, pollution of groundwater, and possibly global warming due to N2O emissions. This paper presents the results of a modelling study presenting the impacts of both structural measures and improved farming practices on major nitrogen (N) fluxes, including NH3 and N2O emission, uptake, leaching, and runoff, in the Netherlands, using input data for the year 2000. Average annual fluxes (Gg N year(-1)) for the year 2000 were estimated at 132 for NH3 emission (160 Gg NH 3 year(-1)), 28 for N2O emission, 50 for N inflow to groundwater, and 15 for N inflow to surface water at a total N input of 1046. At this input, nitrate (NO3) concentrations in groundwater often exceeded the target of 50 mg NO3 l(-1), specifically in well-drained sandy soils. The ammonia (NH3) emissions exceeded emission targets that were set to protect the biodiversity of nonagricultural land. Improved farming practices were calculated to lead to a significant reduction in NH3 emissions to the atmosphere and N leaching and runoff to groundwater and surface water, but these improvements were not enough to reach all the targets set for those fluxes. Only strong structural measures clearly improved the situation. The NH3 emission target of 30 Gg NH3 year(-1), suggested for the year 2030, could not be attained, however, unless pig and poultry farming is completely banned in the Netherlands and all cattle stay almost permanently in low emission stables.     

Responses to food web manipulation in a shallow waterfowl lake

The effects of fish stock reduction have been studies in 3 Dutch lakes (Lake Zwemlust, Lake Bleiswijkse Zoom and Lake Noorddiep) and 1 Danish lake (Lake Væng) during 4–5 years. A general response id described. The fish stock reduction led in general to a low fish stock, low chlorophyii-a, high transparency and high abunuance of macrophytes. Large Daphnia became abundant, but their density decreased, due to food limitation and predation by fish. The total nitrogen concentration became low due to N-uptake by macrophytes and enhanced denitrification. In Lake Bleiswijkse Zoom the water transparency deteriorated and the clear water state was not stable. The fish stock increased and the production of young fish in summer was high. lear water occurred only in spring. Large daphnids were absent in summer and the macrophytes decreased.In Lake Zwemlust, Lake Væng and Lake Noorddiep the water remained clear during the first five years. In summer of the sixth year (1992) transparency decreased in Lake Zwemlust (with high P-concentration of 1.0 mg P l^-1). Also in Lake Væng (with a low nutrient concentration of 0.15 mg P.^-1) a short term turbid stage (1.5 month) occurred in summer 1992 after a sudden collapse of the macrophytes. Deterioration of the water quality seems to start in summer and seems related to a collapse in macrophytes. At a low planktivorous fishstock (e.g. Lake Væng)thhe duration of the turbid state is shorter. than in presence of a high planktivorous fish biomass (e.g. Lake Zwemlust, and later years of Lake Bleiswijkse Zoom).     

用镶嵌组合植物群落控制湖泊饮用水源区藻类及氮污染

依据湖泊中不同生态类型水生高等植物的微生境特点,设计建造了由漂浮、浮叶、沉水植物为优势种的斑块小群丛构成的镶嵌组合水生植物群落（ＭｏｓａｉｃＣｏｍｍｕｎｉｔｙｏｆＭａｃｒｏｐｈｙｔｅｓ：ＭＣＭ）,并在太湖五里湖一湖湾内以动态模拟试验,从群落水平研究了水生高等植物群落对富营养化湖泊饮用水源区湖水的净化能力。结果表明,富营养化湖水经ＭＣＭ净化后,藻类生物量（以Ｃｈｌａ计）下降５７７％,藻类数量下降２～３个数量级,氨氮下降６６７％,总氮下降６００％,水质得到明显改善。与以该湖湾湖水为水源的水厂出水相比,经ＭＣＭ净化的湖水其氨氮比水厂出水的氨氮平均低４５１％,总氮低３７３％,可见经ＭＣＭ净化的湖水部分指标优于同源的自来水。综合群落的微生境特征及水生高等植物群落内硝化反硝化细菌分布特点,探讨了ＭＣＭ的除氮机理。     

Acclimatable cardiac and ventilatory responses to copper in the freshwater crayfish Procambarus clarkii

Mortality and physiological tests following exposure to waterborne copper were performed in the red swamp crayfish Procambarus clarkii from a central Italian population. Mortality tests gave an estimated 96 h LC50 value (with 95% confidence limits) of 162 (132-211) mg L(-1) waterborne copper II. Variations in cardiac and ventilatory rates were simultaneously monitored using a non-invasive plethysmographic technique. In experiments with different sub-lethal copper concentrations (control, 0.5, 1 and 10 mg L(-1)) performed at different times (3, 6, 96 h), copper exposure elicited a reduction in both heart and scaphognatite rates. Following exposure to 10 mg L(-1) copper for 96 h, the heart and scaphognatite rates decreased to about 35% of the initial values. The reduction was fully reversible, since crayfish exposed to 0.5, 1 and 10 mg Cu L(-1) for 96 h resumed control rates after a 3-h residence in clean water. In crayfish pre-exposed (96 h) to sub-lethal copper concentrations (0.1 and 1 mg L(-1)) and then held in control water (3 h), the reduction of heart and scaphognatite rates after exposure to 10 mg Cu L(-1) were significantly lower than in specimens pre-exposed to control water. Therefore, copper induces a concentration and time dependent reduction of both cardiac and ventilatory activity in P. clarkii; these responses can be reduced or fully abolished by pre-exposure to sub-lethal levels of the metal.     

Heavy metals (Cd, Pb, Zn, Ni, Cu and Cr(III)) removal from water in Malaysia: post treatment by high quality limestone

This paper presents the results of research on heavy metals removal from water by filtration using low cost coarse media which could be used as an alternative approach to remove heavy metals from water or selected wastewater. A series of batch studies were conducted using different particle media (particle size 2.36-4.75 mm) shaken with different heavy metal solutions at various pH values to see the removal behaviour for each metal. Each solution of cadmium (Cd), lead (Pb), zinc (Zn), nickel (Ni), copper (Cu) and chromium (Cr(III)) with a concentration of 2 mg/L was shaken with the media. At a final pH of 8.5, limestone has significantly removed more than 90% of most metals followed by 80% and 65% removals using crushed bricks and gravel, respectively. The removal by aeration and settlement methods without solid media was less than 30%. Results indicated that the removal of heavy metals was influenced by the media and not directly by the pH. Investigations on the removal behaviour of these metals indicated that rough solid media with the presence of carbonate were beneficial for the removal process. Adsorption and precipitation as metals oxide and probably as metals carbonate were among the two mechanisms that contributed to the removal of metals from solution.     

Adsorption, absorption, and biological degradation of ammonia in different biofilter organic media

A tailor-made apparatus called ammoniometer, which is a batch mode respirometer applied to the study of ammonia biodegradation in biofilter media, has been used to evaluate adsorption, absorption, and biodegradation in five different organic materials (compost, coconut fibre, bark, pruning wastes, and peat) obtained from full-scale biofilters in operation in several waste treatment plants. The results showed that absorption could be represented by a Henry's law linear equation, with values of the Henry coefficient significantly higher (from 1,866 to 15,320) than that of pure water (1,498). Adsorption data were successfully fitted to Langmuir and Freundlich isotherms and maximum adsorption capacity varies from 1.06 to 1.81 mg NH(3)/g dry media. Ammonia biodegradation rates for each organic material were also calculated. Biodegradation rates varied from 0.67 to 7.82 mg NH(3)/kg media/d depending on the material tested. The data obtained showed important differences in the behaviour of the biofilter organic media, which has important implications in the design and modelling of these systems.     

Effect of copper deficiency and Sodium intake upon liver lipid and mineral composition in the rat

The effect of copper and sodium intake upon liver cholesterol concentrations, fatty acid profile, and mineral concentrations were studied in the Long-Evans rat. Forty-eight male weaning rats were divided into three groups of 16 each and fed a semipurified diet containing either 0, 3, or 8 mg of added copper/kg of diet. At 100 d of age, half of the animals in each group were given 1% NaCl as drinking water and the other half was given deionized-distilled water for 12 wk. Copper deficiency in rats produced elevations in liver palmitate and oleate concentrations, but decreases in linoleate concentrations. The ratio of oleate:stearate was higher in copper deficient rats. Liver copper levels were decreased, but liver iron concentrations were elevated in copper deficient rats. Sodium intake did not have an effect on any of the parameters studied. These results suggested that dietary copper deficiency alters both liver mineral and fatty acid composition.     

洱海三种生活型水生植物叶片中碳、氮与总酚含量的比较研究

植物体内的C、N和总酚是影响其被牧食和凋落物降解的重要因素,从而影响C和N在食物链的传递和生物地化循环。本研究测定了云南洱海3种生活型（挺水、沉水和浮叶）26种水生植物叶片中C、N和总酚含量以及C/N比率,并分析了它们与总酚的关系。结果表明:挺水植物叶片的C、N和总酚平均含量为448.08、39.30和24.70 mg/g,浮叶植物叶片的C、N和总酚平均含量为433.32、35.16和28.05 mg/g,沉水植物叶片的C、N和总酚平均含量为378.36、27.31和10.28 mg/g;总体上看,植物叶片C和N含量:挺水植物 浮叶植物 沉水植物;挺水和浮叶植物叶片的总酚含量差异不显著,且均远高于沉水植物叶片的总酚含量;26种植物叶片中C和N与总酚含量均呈显著正相关。在富营养化条件下,3种生活型植物所处生境的光照和CO2供给均差异显著,会对这些植物叶片的C、N和总酚含量有一定影响,此外由于应对生境中的胁迫（草食性昆虫、病原体及紫外线辐射等）压力以及自身的生长策略的不同也可能导致C、N和酚在三者中形成差异;通过对13种沉水植物叶片总酚含量比较,推测光叶眼子菜和微齿眼子菜较为适合作为洱海耐牧食恢复先锋物种;N与总酚正相关的关系可能在富营养化进程中加速湖泊沼泽化。