scholarly journals Heavy metals in a constructed wetland treating industrial wastewater: distribution in the sediment and rhizome tissue

2009 ◽  
Vol 60 (6) ◽  
pp. 1425-1432 ◽  
Author(s):  
Sergio Domingos ◽  
Stewart Dallas ◽  
Mark Germain ◽  
Goen Ho
Keyword(s):  
Constructed Wetland ◽  
Water Samples ◽  
Profile Analysis ◽  
Sediment Quality ◽  
Sediment Layer ◽  
Inlet Pipe ◽  
Quality Guidelines ◽  
Copper And Zinc ◽  
Bioavailable Fraction ◽  
Cu And Zn

This study assessed copper and zinc distribution in the surface layer of sediment and rhizome tissue within the saturated surface vertical flow constructed wetland of CSBP Ltd, a fertiliser and chemical manufacturer located in Western Australia. Sediment and Schoenoplectus validus rhizome samples were collected at various distances from the inlet pipe while water samples are routinely collected. Water samples were analysed for nutrients and metals, sediments were analysed for total and bioavailable metals and rhizomes were analysed for total metals only. Mean influent copper and zinc concentrations were 0.19 mg/L and 0.24 mg/L respectively. The distribution of bioavailable Cu and Zn in the top sediment layer follows a horizontal profile. Analysis of variance (ANOVA) showed that the bioavailable fraction of these metals in sediments near the inlet pipe (30.2 mg/kg Cu and 60.4 mg/kg Zn) is significantly higher than in sediments at the farthest location (10.3 mg/kg Cu and 26.1 mg/kg Zn). The average total Cu concentration in the sediment at the 2 m location has reached the 65 mg/kg trigger value suggested by the Interim Sediment Quality Guidelines (ANZEEC 2000). Cu and Zn concentrations in the rhizome of S. validus do not vary significantly among different locations. Whether Cu and Zn concentrations at the CSBP wetland may reach toxic levels to plants and bacteria is still unknown and further research is required to address this issue. The surface component of the wetland favours sedimentation and binding of metals to the organic matter on the top of the sediment, furthermore, the sediment which tends to be anoxic with reducing conditions acts as a sink for metals.

scholarly journals Mine Drainage Residual Additions to Lake Sediments Alter Phosphorus and Trace Metal Distributions

2021 ◽  
Vol 232 (2) ◽  
Author(s):  
Zepei Tang ◽  
Robert W. Nairn
Keyword(s):  
Trace Metal ◽  
Agricultural Land ◽  
Mine Drainage ◽  
Sediment Quality ◽  
Mining District ◽  
Sediment Layer ◽  
Mine Waters ◽  
Large Reservoir ◽  
Chl A ◽  
Quality Guidelines

AbstractA greenhouse microcosm study investigated the impacts of recovered iron oxyhydroxide mine drainage residuals (MDRs) on phosphorus (P) and trace metal distributions at the sediment layer/water column interface in Grand Lake o’ the Cherokees, a large reservoir receiving waters impacted by both historic mining and current agricultural land uses. Each mesocosm included 5 kg of lake sediment and 20 L of on-site groundwater. Three treatments were examined in triplicate: control (C) with no additions, low MDR (LM) with 0.3 kg added MDR, and high MDR (HM) with 0.9 kg added MDR. In the first 10 days, aqueous soluble reactive phosphorous (SRP) concentrations decreased likely due to colonizing biomass uptake with no significant differences among the three treatments. LM and HM treatments showed delayed peaks in dissolved oxygen (DO) and lesser peaks in chlorophyll-a (Chl-a) concentrations compared to the C treatment, indicating MDR addition may suppress biomass growth. During days 11 to 138, the C treatment demonstrated increasing pH, decreasing ORP, and biomass decay resulting in significantly increased SRP concentrations. In LM and HM treatments, sufficient P sorption by the MDR maintained low SRP concentrations. Although the MDRs are derived from metal-rich mine waters, all aqueous concentrations were below both hardness-adjusted acute and chronic criteria, except for Pb with regard to the chronic criterion. Metal concentrations in sediments were below the Tri-State Mining District (TSMD)–specific Sediment Quality Guidelines (SQGs). MDR additions may serve as stable long-term P sinks to prevent P release from dead biomass, decrease internal P cycling rates, and mitigate eutrophication, with limited concern for trace metal release.

Technology of the Contact Wire Manufacture for High-Speed Railways

2021 ◽  
Vol 410 ◽  
pp. 173-178
Author(s):  
Andrey V. Sulitsin ◽  
Raisa K. Mysik ◽  
Vadim V. Morgunov
Keyword(s):  
High Speed ◽  
Profile Analysis ◽  
Cold Drawing ◽  
Casting Process ◽  
Sediment Layer ◽  
Contact Wire ◽  
X Ray ◽  
Inner Surface ◽  
Full Profile ◽  
Continuously Cast

The article presents an overview of possible technological schemes to produce an overhead contact wire for railways. Pilot experiments were carried out on the manufacture of a contact wire made of CuMg0.3, CuMg0.4 and CuMg0.5 alloys and having a nominal cross section of 100 mm2. The contact wire was obtained from a continuously cast rod with small section, which was subjected to plastic deformation using the Conform technology and cold drawing of the extruded rod. In the casting process, we encountered the formation of cracks on the cast rod surface and the rods breakage. The inner surface of the graphite bushings of the mold after casting the rod was studied and a thin gray layer was found on the inner surface of the graphite bushings. Areas of the graphite bushing with gray layer were studied by scanning electron microscopy and element-by-element mapping was performed with the selection of a spectrum in the sediment layer area. In order to determine the phase composition of the sediment layer it was analyzed by the method of full-profile analysis of the X-ray diffraction pattern according to Rietveld. X-ray phase analysis showed the CuMg2 and Cu2Mg phases presence. This allowed us to assume a possible mechanism for the formation of the sediment layer. Ultimate tensile strength, elongation and electrical resistivity was determined. Analysis showed that the overhead wires made of CuMg0.3, CuMg0.4, CuMg0.5 alloys meets the requirements of GOST R 55647-2018 for wires made of the second conditional group bronze.

Using sediment cores to establish targets for the remediation of aquatic environments

2015 ◽  
Vol 73 (3) ◽  
pp. 628-635 ◽  
Author(s):  
Anna Lintern ◽  
Marion Anderson ◽  
Paul Leahy ◽  
Ana Deletic ◽  
David McCarthy
Keyword(s):  
Sediment Cores ◽  
Sediment Quality ◽  
Aquatic Systems ◽  
Quality Data ◽  
Aquatic Environments ◽  
Site Specific ◽  
European Settlement ◽  
Quality Guidelines ◽  
Water And Sediment ◽  
Water And Sediment Quality

When assigning site-specific restoration targets for deteriorating aquatic systems, it is necessary to have an understanding of the undisturbed or background state of the system. However, the site-specific characteristics of aquatic systems prior to disturbance are mostly unknown, due to the lack of historical water and sediment quality data. This study aims to introduce a method for filling this gap in our understanding, using dated sediment cores from the beds of aquatic environments. We used Bolin Billabong, a floodplain lake of the Yarra River (South-East Australia), as a case study to demonstrate the application of this method. We identified the concentrations of aluminium, cadmium, chromium, copper, iron, lead, manganese, nickel, tin and zinc at 8 cm intervals through the sediment core. This showed that aluminium, chromium, copper, iron, lead, nickel, tin and zinc concentrations in Bolin Billabong sediments significantly increased after European settlement in the river catchment in the mid-19th century. The differences between current Australian sediment quality guidelines trigger values and the background metal concentrations in Bolin Billabong sediments underscore the value of using locally relevant background toxicant concentrations when setting water and sediment quality targets.

scholarly journals Contamination and ecological risk assessment of trace elements in sediments of the Anzali Wetland, Northern Iran

2021 ◽  
Author(s):  
Marjan Esmaeilzadeh ◽  
Elham Mahmoudpuor ◽  
Somayeh Haghighat Ziabari ◽  
Sara Esmaeilzadeh ◽  
Hamideh Aliani ◽  
...  
Keyword(s):  
Ecological Risk ◽  
Risk Index ◽  
Sediment Quality ◽  
Aquatic Organisms ◽  
Pollution Load Index ◽  
Pollution Indices ◽  
Anzali Wetland ◽  
Northern Iran ◽  
Pollution Levels ◽  
Quality Guidelines

Abstract In this paper, concentrations of some heavy metals in surficial sediments of the International Anzali Wetland were measured, this wetland is located in northern part of Iran. Sediment pollution levels were examined and analyzed using reliable pollution indices including Pollution Load Index (PLI), Geoaccumulation Index (Igeo) and Enrichment Factor (CF), and finally it was revealed that heavy metal pollution ranged from low to moderated loads in the wetland. According to Sediment Quality Guidelines (SQGs) and Ecological Risk Index (ERI), it was concluded that As and Ni may have significant toxic impacts on aquatic organisms and also according to Effect Range Median (ERM), the toxicity probability of sediments in the Anzali wetland was estimated at 21%.

scholarly journals An Assessment of Metal Contamination Risk in Sediments of the Mohammad Abad River, Northern Iran

2021 ◽  
Vol 2 (8) ◽  
pp. 696-704
Author(s):  
Hassan Malvandi
Keyword(s):  
Heavy Metals ◽  
Biological Effects ◽  
Sediment Quality ◽  
Contamination Factor ◽  
Anthropogenic Source ◽  
Degree Of Contamination ◽  
Northern Iran ◽  
Pollution Levels ◽  
Quality Guidelines ◽  
Very High

Background: Sediments in the aquatic ecosystems can be used as suitable indicators for monitoring contaminants. Then, objectives of this study were to evaluate the concentration of heavy metals in the surface sediments of the Mohammad Abad River, to determine the degree of pollution of heavy metals in sediments using some major contamination indices; to identify the major sources (anthropogenic or natural sources) of the studied metals; and to evaluate the “reference river” of the river under study for ecotoxicology studies. Methods: Samples of sediment were taken from six sites of the river. The present study, eleven heavy metals (chromium, manganese, iron, cobalt, nickel, zinc, selenium, magnesium, silver, aluminum and arsenic) were studied. Results: Comparison of metal concentrations with those of Sediment Quality Guidelines (SQGs) showed no association with harmful biological effects for the heavy metals studied except for Se and As. The results of the contamination factor index showed low pollution levels for most metals (Cr, Mn, Fe, Co, Ni, Zn and Al), moderate pollution levels for As, and very high pollution levels for Se. The degree of contamination (Cd) and modified degree of contamination (mCd), showing the total contamination of elements, demonstrated very high degree contamination status in the study area. According to the index of quantification of contamination, the values of Cr, Mn, Fe, Ni, Zn and Al were derived mainly from geogenic sources of enrichment, while the values for Se and As were enriched by anthropogenic source of enrichment. Conclusion: These findings suggest that continuous monitoring of Se and As in sediment and organisms of the Mohammad Abad River should be directed to evaluate the threat of these elements to the public health and to the ecology of the river under study.

scholarly journals Ecological risk by potentially toxic elements in surface sediments of the Lake Maracaibo (Venezuela)

2021 ◽  
Vol 27 (4) ◽  
pp. 210232-0
Author(s):  
Julio Marín ◽  
Marinela Colina ◽  
Hilda Ledo ◽  
P.H.E. Gardiner
Keyword(s):  
Ecological Risk ◽  
Toxic Elements ◽  
Sediment Quality ◽  
Potential Ecological Risk ◽  
Potentially Toxic Elements ◽  
Lake Area ◽  
Risk Assessment Code ◽  
Quality Guidelines ◽  
Lake Maracaibo ◽  
Superficial Sediments

The evaluation of potential ecological risk of aquatic sediments associated with the presence of potentially toxic elements (PTE) determines its degree of danger on native biota. In this work, the potential ecological risk of V, Ti, Cr, Ni, Cu, Zn, As, Se, Cd, Sn, Hg and Pb in superficial sediments is explained in three different areas of Lake Maracaibo: El Tablazo Bay, Strait of Maracaibo and the lake itself, through a multi-guideline approach (elemental enrichment (enrichment factor, contamination degree, pollutant load index and geo-accumulation index), sediment quality guidelines and risk assessment code). The PTE levels ranged from < 0.025 to 176.722 mg·kg−1 DW, with an overall proportion of V > Ti > Pb > Zn > Cr > Cu > Ni > As > Cd > Se > Hg > Sn. The PTE concurrent effect on biota was El Tablazo Bay > lake > Strait of Maracaibo. The superficial sediments of Lake Maracaibo constitute a medium with a high potential ecological risk on estuarine biota. This is mainly due to the levels of As in El Tablazo Bay, Cd in the Strait of Maracaibo and Pb in the lake area. This represents a latent toxicity hazard for native biological communities and other associated organisms.

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