Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Leachate”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed2006

Behavior of B, Cr, Se, As, Pb, Cd, and Mo present in waste leachates generated from combustion residues during the formation of ettringite.

The behavior of B, Cr, Se, As, Pb, Cd, and Mo in the leachates generated from two combustion residues, coal-fired power plant fly ash and municipal solid waste incineration ash, during precipitation of ettringite is presented. Experiments also were performed using modeled waste leachates as well as controlled solutions containing all the investigated elements. Moreover, to determine the possible effect of pH, lime treatment was conducted using the waste and modeled leachates. Results indicated the removal of B, Se, and Cr from the leachates because of incorporation of their oxyanions in the ettringite structure. The removal of B could further be explained by considering the structure of ettringite and monosulfoaluminate. The removal of Pb also occurred, probably because of lime-induced precipitation of Pb(OH)2. Similarly, the removal of As was observed as a result of lime-induced precipitation of Ca3(AsO4)2 and incorporation into the ettringite structure. On the other hand, the precipitation of ettringite did not reduce the concentrations of Mo and Cd because of the complex nature of these elements in the leachates. The results also suggest that the presence of high amounts of constituents such as Cl-, an alkali metal in the solution, also affected ettringite precipitation behavior. Moreover, elemental speciations as well as the presence of other constituents in the solution affected the incorporation by ettringite.

Arsenic↗
PubMed1977

Metals in municipal landfill leachate and their health effects.

The leachate from five municipal landfills (containing no industrial waste or sewage sludge) was studied in 1975 by the U. S. Environmental Protection Agency (EPA). Copper was not present in concentrations above EPA standards. Zinc concentrations decreased with age of the site and were below standards. The amounts of cadmium and chromium appear to vary greatly from site to site. Lead, selenium, iron, and mercury were present at each site in concentrations above standards, regardless of site age. Although raw leachate contains concentrations of heavy metals in excess of the drinking water standards, it is not clear how likely it would be for these recorded levels to be found in drinking water supplies or for contamination to reach the human body. Before leachate reaches an aquifer, it is subject to the attenuating effect of the unsaturated zone. If municipal solid waste is placed directly into ground water, or if leachate is allowed to drain directly into surface water, severe damage to water quality can result. Further study of the environmental effects of leachate are being undertaken by the Environmental Protection Agency.

Humans↗
PubMed2001

Heavy metal removal from wastewater and leachate co-treatment sludge by sulfur oxidizing bacteria.

Heavy metal concentration in sludge is one of the major obstacles for the application of sludge on land. There are various methods for the removal of heavy metals in sludge. Using sulfur oxidizing bacteria for microbiological removal of heavy metals from sludges is an outstanding option because of high metal solubilization rates and the low cost. In this study, bioleaching by indigenous sulfur oxidizing bacteria was applied to sludges generated from the co-treatment of municipal wastewater and leachate for the removal of selected heavy metals. Sulfur oxidizing bacteria were acclimated to activated sludge. The effect of the high organic content of leachate on the bioleaching process was investigated in four sets of sludges having different concentrations of leachate. Sludges in Sets A, B, C and D were obtained from co-treatment of wastewater and 3%, 5%, 7% and 10% (v/v) leachate respectively. The highest Cr, Ni and Fe solubilization was obtained from Set A. Sulfur oxidizing bacteria were totally inhibited in Set D that received the highest volume of leachate.

Bioreactors↗
PubMed2002

[Experimental study on prediction model for leachate quality variation in MSW landfills].

The changing rule of leachate quality in Xiaping Sanitary Landfill was studied using pilot-scale leaching test for waste pollutants. And the parameters for Pollutants Leaching Model were determined using the data from the test by exponential regression method. Both the results from the test and the monitoring data in site indicated that the leachate concentration reached its maximum with COD of 31,581 mg/L after 75 days. Meanwhile, the accuracy of this prediction model was testified by comparing with the monitoring data in site, that means the model and its parameters achieved by leaching test for pollutants load can be used to predict the leachate quality variation in MSW landfills. Thus it provides a scientific numerical model and leaching test method for leachate quality prediction and basis for designing and managing leachate treatment facilities.

Models, Theoretical↗
PubMed2004

[Biodegradation characteristics of organic compounds in leachate in electrochemical oxidation and anaerobic process combined treatment system].

Degradation characteristics of typical organic compounds in landfill leachate were investigated by electrochemical oxidation and anaerobic process combined treatment system in this paper. In electrochemical oxidation system, degradation rate of polyphenolic, polyamide, benzothiazole, benzoquinone, quinoline and naphthalene compounds was higher than that of Exo-2-hydroxycineole and isoquinoline compounds, but that of the former was lower in anaerobic process. After electrochemical oxidation process, content of Volatile Fatty Acids (VFAs) markedly increased from 0.68% of raw leachate to 16.18% of effluent of electrochemical reactor. The results indicate that synergetic and antagonistic effects of complicated components on biotoxicity in leachate are notably decreased in such the combined treatment system, and biodegradability of systemic effluent is improved. These are key reasons to highly effectively treat landfill leachate by using such the combined treatment system, and can provide technical assistance to further investigate treatment technology of landfill leachate and large-scale development of electrochemical oxidation and anaerobic process combined treatment system.

Bacteria, Anaerobic↗
PubMed2005

Nitrogen losses through leachate and its distribution.

A column experiment was conducted to elucidate information on the nitrogen losses with clay loam and sandy clay loam soil collected from the farm of UPASI, Coonoor and UPASI, Valparai respectively with 5 levels of nitrogen viz., 0, 250, 375, 500 and 625 kg ha(-1) and two different rainfall intensities viz., i1 = 40 mm hr(-1) (medium rainfall intensity) and i2 = 60 mm hr(-1) (high rainfall intensity). The losses of nitrogen fractions through leachate were analyzed for a month period. The results indicated that the nitrogen application increased the concentration of NH4-N and NO3-N in the leachate collected under both the soils. The NH4-N concentration was high in the leachate collected under sandy clay loam soil (33.99 mg l(-1)) whereas N03-N concentration was high in the leachate collected under clay loam soil (17.75 mg l(-1)). Between the rainfall intensities, the NO3-N concentration was high in the leachate collected from clay loam soil under medium rainfall intensify and the reverse trend was observed under sandy clay loam soil. The distribution of NH4-N and NO3-N was higher in the clay loam soil than sandy clay loam soil. The NH4-N content increased with increase in the depth of soil column under both the soil. The N03-N distribution followed the similar trend under sandy clay loam soil. But in the clay loam soil, the highest N03-N content was detected at 14-21 cm depth under medium rainfall intensity.

India↗
PubMed2006

[Effects of dissolved organic matter in landfill leachate on soil Cd- and Pb bioavailability].

A pot experiment was conducted to study the effects of dissolved organic matter (DOM) in landfill leachate on ryegrass growth and its uptake of soil Cd and Pb. Fresh sample and Shuige leachate were collected from the municipal waste landfills established 0 and 12 years, respectively. The results showed that after the landfill leachate added, the average concentration of DOM remained in soil was 1.39 (fresh sample) and 1.47 (Shuige) times higher than the control (CK). The bioavailability of Cd and Pb in the soils treated with the two leachates was fluctuated in early period, and then raised. Compared with CK, the bioavailability of soil Cd was increased by 4.81% (fresh sample) and 48.97% (Shuige), and that of soil Pb was enhanced by 7.22% (fresh sample) and 18.99% (Shuige). The total concentrations of plant Cd and Pb in the treatments of fresh sample and Shuige were 19.59% and 104.4%, and 36.03% and 44. 66% higher than CK, respectively, while the total biomass of ryegrass was decreased by 14.03% to approximately 52.24%, in compared with CK. It could be inferred that the dissolved organic matter (DOM) in landfill leachate, especially in that from the landfills established for a longer time, could enhance the bioavailability of soil heavy metals and their accumulation in plant, and thus, suppress the growth of plants.

Cadmium↗
PubMed1989

Decontamination of landfill leachate by soil infiltration.

A soil column study was conducted to evaluate the efficiency of soil to attenuate pollutants in landfill leachate. It was found that more than 60% of the initial alkalinity, COD, and total nitrogen was removed after the leachate had percolated through the soil column. Lower efficiencies were observed for the removal of dissolved cations, ammonia nitrogen, and nitrate nitrogen. When previously percolated leachate was recirculated through the soil column, significant removal (93.6%) of ammonia nitrogen was achieved. Moreover, a further reduction in COD, total nitrogen, nitrate nitrogen, and potassium was evident. Bioassay tests of seed germination and root growth of Brassica chinensis were performed to compare the phytotoxicities of untreated, percolated, and recirculated leachates. The phytotoxicity was reduced by both treatments, with the greatest detoxification observed in the leachate recirculation treatment. The values of pH and Olsen phosphorus were significantly reduced (P less than 0.01) in the treated column soil, whereas significant increases (P less than 0.05) in electrical conductivity (EC), various forms of nitrogen, exchangeable sodium percentage (ESP), potassium, magnesium, zinc, and iron were observed. EC, ESP, potassium, magnesium, sodium, iron, and various forms of nitrogen accumulated at the soil surface (10 cm). On the other hand, manganese was deposited at 20 to 50 cm below the soil surface of the treated column.

Biological Assay↗
PubMed2004

Cytogenetic effects of leachates from tannery solid waste on the somatic cells of Vicia faba.

The contamination of surface- and groundwater by the leaching of solid wastes generated by industrial activities as a result of water runoff and rainfall is a matter of great concern. The leachates from tannery solid waste (TSW), a major environmental pollutant, were examined for their possible genotoxic effects on the somatic cells of Vicia faba. Leachates were prepared from solid wastes procured from leather-tanning industrial sites, and V. faba seedlings were exposed to three test concentrations, 2.5%, 5%, and 10%, through soil and aqueous media for 5 days. The root tips examined for cytogenetic damage revealed that leachate of TSW significantly inhibited the mitotic index and induced significantly frequent chromosomal and mitotic aberrations (CA/MA) in a dose-dependent manner. The chemical analysis of TSW samples revealed that the chief constituents were chromium and nickel, which may cause genetic abnormalities. The frequency of aberrations was found to be higher in the root meristematic cells of Vicia faba exposed through the aqueous medium than those exposed through the soil medium. The results of the present study indicated that contamination of potable water bodies by leachates of TSW may cause genotoxicity. For the biomonitoring of complex mixtures of toxicants with the V. faba bioassay, the use of the aqueous medium seems to be a more promising method than the use of the soil medium.

Chromosome Aberrations↗
PubMed1997

Toxicity of acid-sulfate soil leachate and aluminum to embryos of the Sydney Rock oyster.

The toxicity of leachate water from acid-sulfate soil to the early embryonic development of the Sydney Rock oyster, Saccostrea commercialis, was assessed. Concentrations of acid-sulfate soil leachate water as low as 3.3% in seawater were found to decrease the normal development of oyster embryos after 48 hr exposure, and this effect could not be attributed to any significant change in pH or salinity. An EC50 value for the acid-sulfate soil leachate water of 2.5 to 2.9% in seawater was obtained, and the no observed effect concentration was determined at a concentration of 2% in seawater. In tests conducted with aluminum added to seawater, a significant decrease in the percentage of embryos developed to the D-veliger stage occurred at concentrations of 150 micrograms/liter and greater, with no effects at 100 micrograms/liter. An EC50 of 225 micrograms/liter for the effect of added aluminum on embryo survival was obtained and all embryos showed developmental abnormalities at concentrations of 400 micrograms/liter and greater. A significant decrease in the embryonic development occurred when the fertilized eggs were incubated in pH-adjusted seawater at pH values < or = 6.75, but no significant effects were found at pH 7.0 or above. Since aluminum was present in high concentrations in the acid-sulfate soil leachate water, it was concluded that aluminum was the main toxicant in the acid-sulfate water that disrupted the oyster embryonic development.

Aluminum↗
PubMed2006

Determination of semi-volatile priority pollutants in landfill leachates and sediments using microwave-assisted headspace solid-phase microextraction.

The present work was focused on the development of a simple method aimed at the determination of 12 polycyclic aromatic hydrocarbons (PAHs) and 15 polychlorinated biphenyls (PCBs) in landfill leachates and sediments by adapting a domestic microwave oven to perform microwave-assisted headspace solid-phase microextraction (MA-HS-SPME) followed by gas chromatographic separation and tandem mass spectrometric detection. Good linearity was observed within the concentration range studied; detection limits ranged from 0.1 ng/l to 7 ng/l for PCBs and from 5 ng/l to 926 ng/l for PAHs. Concerning precision, the relative standard deviations obtained were, on average for the leachate and sediment samples analysed, 18% for PCBs and 20% for PAHs. Average recovery values were 37% and 76% for PCBs, and 58% and 48% for PAHs, respectively, for the leachate and reference sediment studied. The method allows the determination of PAHs and PCBs in landfill leachates and sediments, avoiding clean-up steps and the consumption of organic solvents.

Journal Article↗
PubMed1982

Chronic and reproduction studies in rats exposed to gasifier ash leachates.

Ash from the coal gasification process contains a broad spectrum of elements which through leaching (gasifier ash leachates) may enter into the environment. The health effect of such leachates i.e. complex mixtures of inorganic elements is insufficiently known. We investigated the effect of gasifier ash leachates in a chronic-(9-month) and in a three-generation reproduction study. The leachates were prepared weekly by water extraction of ash from a Lurgi coal gasification plant in Yugoslavia, and given to experimental animals instead of drinking water. In the chronic experiment exposed animals showed no changes in mortality rate, haematological findings, concentration of Fe, Zn, Mn in kidneys, liver, testicles and femur, as well as in femur composition and morphometry, gross pathology and organ histology. In the reproduction study the number of pregnancies, weight and number of newborns, and concentration of Fe, Zn, Mn in carcasses of sucklings were the same in control and experimental animals.

Animals↗
PubMed2004

Adsorbent supplemented biological treatment of pre-treated landfill leachate by fed-batch operation.

Biological treatment of landfill leachate usually results in low COD removals because of high chemical oxygen demand (COD), high ammonium-N content and presence of toxic compounds. Coagulation-flocculation with lime addition and air stripping of ammonia were used as pre-treatment in this study in order to improve biological treatability of the leachate. Pre-treated leachate was subjected to adsorbent supplemented biological treatment in an aeration tank operated in fed-batch mode. COD and NH(4)-N removal performances of powdered activated carbon (PAC) and powdered zeolite (PZ) were compared during biological treatment. Adsorbent concentrations varied between 0 and 5 gl(-1). Percent COD and ammonium-N removals increased with increasing adsorbent concentrations. Percent COD removals with PAC addition were significantly higher than those obtained with the zeolite. However, zeolite performed better than the PAC in ammonium-N removal from the leachate. Nearly 87% and 77% COD removals were achieved with PAC and zeolite concentrations of 2 gl(-1), respectively. Ammonium-N removals were 30% and 40% with PAC and zeolite concentrations of 5 gl(-1), respectively at the end of 30 h of fed-batch operation.

Adsorption↗
PubMed2004

The use of carbon and nitrogen isotope ratios to identify landfill leachate contamination: Green Island Landfill, Dunedin, New Zealand.

A study was undertaken to determine whether the isotopic ratios of C and N could be used to uniquely identify municipal solid waste landfill leachate as a source of contamination in the Kaikorai Estuary, Dunedin, New Zealand. Leachate samples were taken from the adjacent Green Island Landfill (GILF), and surface water samples were collected over an 8-month period from the stream and estuary, upstream and downstream of the landfill. Samples were analysed for delta(13)C-dissolved inorganic carbon (DIC), delta(15)N-NO(3)(-), delta(15)N-NH(4)(+), and particulate organic matter (POM) delta(13)C and delta(15)N. Plant material collected along the Kaikorai Stream was analysed for POM delta(13)C and delta(15)N. Leachate was found to have a distinct isotopic signature characterised by a highly enriched delta(13)C-DIC (as much as 16.11+/-0.23 per thousand ) and highly enriched delta(15)N-NH(4)(+) (as much as 27.42+/-0.90 per thousand ). Evidence of leachate contamination was found in the isotopic signatures of downstream delta(13)C-DIC, delta(15)N-NH(4)(+), and delta(13)C and delta(15)N of plant material POM. Other potential sources of enriched delta(13)C-DIC and delta(15)N-NH(4)(+) present in the study area, such as estuarine waters and livestock effluent, were eliminated on the basis of their isotopic characteristics.

Animals↗
PubMed2005

Spray irrigation of landfill leachate: estimating potential exposures to workers and bystanders using a modified air box model and generalised source term.

Generalised source term data from UK leachates and a probabilistic exposure model (BPRISC(4)) were used to evaluate key routes of exposure from chemicals of concern during the spraying irrigation of landfill leachate. Risk estimates secured using a modified air box model are reported for a hypothetical worker exposed to selected chemicals within a generalised conceptual exposure model of spray irrigation. Consistent with pesticide spray exposure studies, the key risk driver is dermal exposure to the more toxic components of leachate. Changes in spray droplet diameter (0.02-0.2 cm) and in spray flow rate (50-1000 l/min) have little influence on dermal exposure, although the lesser routes of aerosol ingestion and inhalation are markedly affected. The risk estimates modelled using this conservative worst case exposure scenario are not of sufficient magnitude to warrant major concerns about chemical risks to workers or bystanders from this practice in the general sense. However, the modelling made use of generic concentration data for only a limited number of potential landfill leachate contaminants, such that individual practices may require assessment on the basis of their own merits.

Aerosols↗
PubMed2004

Micronuclei induced by municipal landfill leachate in mouse bone marrow cells in vivo.

The induction of micronuclei (MN) in polychromatic erythrocytes (PCE) of mouse bone marrow by municipal landfill leachate was studied in vivo. Results showed that mouse exposure via drinking water containing various concentrations of leachate caused a significant increase of MN frequencies in a concentration (Chemical oxygen demand measured with potassium dichromate oxidation, COD(Cr))-dependent manner. MN induction in female and male mice was different at higher concentrations. This implies that leachate is a genotoxic agent in mammalian cells and that exposure to leachate in an aquatic environment may pose a potential genotoxic risk to human beings.

Animals↗
PubMed2004

Reactive transport modelling of biogeochemical processes and carbon isotope geochemistry inside a landfill leachate plume.

The biogeochemical processes governing leachate attenuation inside a landfill leachate plume (Banisveld, the Netherlands) were revealed and quantified using the 1D reactive transport model PHREEQC-2. Biodegradation of dissolved organic carbon (DOC) was simulated assuming first-order oxidation of two DOC fractions with different reactivity, and was coupled to reductive dissolution of iron oxide. The following secondary geochemical processes were required in the model to match observations: kinetic precipitation of calcite and siderite, cation exchange, proton buffering and degassing. Rate constants for DOC oxidation and carbonate mineral precipitation were determined, and other model parameters were optimized using the nonlinear optimization program PEST by means of matching hydrochemical observations closely (pH, DIC, DOC, Na, K, Ca, Mg, NH4, Fe(II), SO4, Cl, CH4, saturation index of calcite and siderite). The modelling demonstrated the relevance and impact of various secondary geochemical processes on leachate plume evolution. Concomitant precipitation of siderite masked the act of iron reduction. Cation exchange resulted in release of Fe(II) from the pristine anaerobic aquifer to the leachate. Degassing, triggered by elevated CO2 pressures caused by carbonate precipitation and proton buffering at the front of the plume, explained the observed downstream decrease in methane concentration. Simulation of the carbon isotope geochemistry independently supported the proposed reaction network.

Carbon Isotopes↗
PubMed2006

Recharge processes drive sulfate reduction in an alluvial aquifer contaminated with landfill leachate.

Natural attenuation of contaminants in groundwater depends on an adequate supply of electron acceptors to stimulate biodegradation. In an alluvial aquifer contaminated with leachate from an unlined municipal landfill, the mechanism of recharge infiltration was investigated as a source of electron acceptors. Water samples were collected monthly at closely spaced intervals in the top 2 m of the saturated zone from a leachate-contaminated well and an uncontaminated well, and analyzed for delta(18)O, delta(2)H, non-volatile dissolved organic carbon (NVDOC), SO(4)(2-), NO(3)(-) and Cl(-). Monthly recharge amounts were quantified using the offset of the delta(18)O or delta(2)H from the local meteoric water line as a parameter to distinguish water types, as evaporation and methanogenesis caused isotopic enrichment in waters from different sources. Presence of dissolved SO(4)(2-) in the top 1 to 2 m of the saturated zone was associated with recharge; SO(4)(2-) averaged 2.2 mM, with maximum concentrations of 15 mM. Nitrate was observed near the water table at the contaminated site at concentrations up to 4.6 mM. Temporal monitoring of delta(2)H and SO(4)(2-) showed that vertical transport of recharge carried SO(4)(2-) to depths up to 1.75 m below the water table, supplying an additional electron acceptor to the predominantly methanogenic leachate plume. Measurements of delta(34)S in SO(4)(2-) indicated both SO(4)(2-) reduction and sulfide oxidation were occurring in the aquifer. Depth-integrated net SO(4)(2-) reduction rates, calculated using the natural Cl(-) gradient as a conservative tracer, ranged from 7.5x10(-3) to 0.61 mM.d(-1) (over various depth intervals from 0.45 to 1.75 m). Sulfate reduction occurred at both the contaminated and uncontaminated sites; however, median SO(4)(2-) reduction rates were higher at the contaminated site. Although estimated SO(4)(2-) reduction rates are relatively high, significant decreases in NVDOC were not observed at the contaminated site. Organic compounds more labile than the leachate NVDOC may be present in the root zone, and SO(4)(2-) reduction may be coupled to methane oxidation. The results show that sulfur (and possibly nitrogen) redox processes within the top 2 m of the aquifer are directly related to recharge timing and seasonal water level changes in the aquifer. The results suggest that SO(4)(2-) reduction associated with the infiltration of recharge may be a significant factor affecting natural attenuation of contaminants in alluvial aquifers.

Biodegradation, Environmental↗