Household hazardous waste in municipal landfills: contaminants in leachate

Management of landfill leachate: The legacy of European Union Directives

Landfill leachate is the product of water that has percolated through waste deposits and contains various pollutants, which necessitate effective treatment before it can be released into the environment. In the last 30years, there have been significant changes in landfill management practices in response to European Union (EU) Directives, which have led to changes in leachate composition, volumes produced and treatability. In this study, historic landfill data, combined with leachate characterisation data, were used to determine the impacts of EU Directives on landfill leachate management, composition and treatability. Inhibitory compounds including ammonium (NH4-N), cyanide, chromium, nickel and zinc, were present in young leachate at levels that may inhibit ammonium oxidising bacteria, while arsenic, copper and silver were present in young and intermediate age leachate at concentrations above inhibitory thresholds. In addition, the results of this study show that while young landfills produce less than 50% of total leachate by volume in the Republic of Ireland, they account for 70% of total annual leachate chemical oxygen demand (COD) load and approximately 80% of total 5-day biochemical oxygen demand (BOD5) and NH4-N loads. These results show that there has been a decrease in the volume of leachate produced per tonne of waste landfilled since enactment of the Landfill Directive, with a trend towards increased leachate strength (particularly COD and BOD5) during the initial five years of landfill operation. These changes may be attributed to changes in landfill management practices following the implementation of the Landfill Directive. However, this study did not demonstrate the impact of decreasing inputs of biodegradable municipal waste on leachate composition. Increasingly stringent wastewater treatment plant (WWTP) emission limit values represent a significant threat to the sustainability of co-treatment of leachate with municipal wastewater. In addition, the seasonal variation in leachate production poses a risk to effective co-treatment in municipal WWTPs, as periods of high leachate production coincide with periods of maximum hydraulic loading in WWTPs.

Analyzing tree cores to detect petroleum hydrocarbon-contaminated groundwater at a former landfill site in the community of Happy Valley-Goose Bay, eastern Canadian subarctic

This research examines the feasibility of analyzing tree cores to detect benzene, toluene, ethylbenzene, and m, p, o-xylene (BTEX) compounds and methyl tertiary-butyl ether (MTBE) in groundwater in eastern Canada subarctic environments, using a former landfill site in the remote community of Happy Valley-Goose Bay, Labrador. Petroleum hydrocarbon contamination at the landfill site is the result of environmentally unsound pre-1990s disposal of households and industrial solid wastes. Tree cores were taken from trembling aspen, black spruce, and white birch and analyzed by headspace-gas chromatography-mass spectrometry. BTEX compounds were detected in tree cores, corroborating known groundwater contamination. A zone of anomalously high concentrations of total BTEX constituents was identified and recommended for monitoring by groundwater wells. Tree cores collected outside the landfill site at a local control area suggest the migration of contaminants off-site. Tree species exhibit different concentrations of BTEX constituents, indicating selective uptake and accumulation. Toluene in wood exhibited the highest concentrations, which may also be due to endogenous production. Meanwhile, MTBE was not found in the tree cores and is considered to be absent in the groundwater. The results demonstrate that tree-core analysis can be useful for detecting anomalous concentrations of petroleum hydrocarbons, such as BTEX compounds, in subarctic sites with shallow unconfined aquifers and permeable soils. This method can therefore aid in the proper management of contamination during landfill operations and after site closures.

Automated high-throughput in vitro screening of the acetylcholine esterase inhibiting potential of environmental samples, mixtures and single compounds

A high-throughput and automated assay for testing the presence of acetylcholine esterase (AChE) inhibiting compounds was developed, validated and applied to screen different types of environmental samples. Automation involved using the assay in 96-well plates and adapting it for the use with an automated workstation. Validation was performed by comparing the results of the automated assay with that of a previously validated and standardised assay for two known AChE inhibitors (paraoxon and dichlorvos). The results show that the assay provides similar concentration-response curves (CRCs) when run according to the manual and automated protocol. Automation of the assay resulted in a reduction in assay run time as well as in intra- and inter-assay variations. High-quality CRCs were obtained for both of the model AChE inhibitors (dichlorvos IC50=120µM and paraoxon IC50=0.56µM) when tested alone. The effect of co-exposure of an equipotent binary mixture of the two chemicals were consistent with predictions of additivity and best described by the concentration addition model for combined toxicity. Extracts of different environmental samples (landfill leachate, wastewater treatment plant effluent, and road tunnel construction run-off) were then screened for AChE inhibiting activity using the automated bioassay, with only landfill leachate shown to contain potential AChE inhibitors. Potential uses and limitations of the assay were discussed based on the present results.

Effects of sludge recirculation rate and mixing time on performance of a prototype single-stage anaerobic digester for conversion of food wastes to biogas and energy recovery

Food wastes have been recognized as the largest waste stream and accounts for 39.25 % of total municipal solid waste in Thailand. Chulalongkorn University has participated in the program of in situ energy recovery from food wastes under the Ministry of Energy (MOE), Thailand. This research aims to develop a prototype single-stage anaerobic digestion system for biogas production and energy recovery from food wastes inside Chulalongkorn University. Here, the effects of sludge recirculation rate and mixing time were investigated as the main key parameters for the system design and operation. From the results obtained in this study, it was found that the sludge recirculation rate of 100 % and the mixing time of 60 min per day were the most suitable design parameters to achieve high efficiencies in terms of chemical oxygen demand (COD), total solids (TS), and total volatile solid (TVS) removal and also biogas production by this prototype anaerobic digester. The obtained biogas production was found to be 0.71 m(3)/kg COD and the composition of methane was 61.6 %. Moreover, the efficiencies of COD removal were as high as 82.9 % and TVS removal could reach 83.9 % at the optimal condition. Therefore, the developed prototype single-stage anaerobic digester can be highly promising for university canteen application to recover energy from food wastes via biogas production.

In vivo micronucleus test in the assessment of cytogenotoxicity of landfill leachates in three animal models from various ecological habitats

The in vivo micronucleus (MN) test, a standard test for the genotoxicity screening of xenobiotics, was used to evaluate the cytotoxic and genotoxic activities of landfill leachates in Clarias gariepinus, Coturnix coturnix japonica and Rattus norvegicus. These organisms were exposed to various sub-lethal concentrations (1-50%) of Olusosun and Aba Eku landfill leachates. At post exposure, peripheral erythrocytes from catfish and quail, and bone marrow cells of quail and rat were subjected to MN analysis following standard protocols. The leachates induced significant increase in MN formation and total nuclear abnormalities (NAs) in the peripheral erythrocytes of catfish and quail. NAs occurred in the order; BN > BL > LB > NT in the catfish and BN > BudN > TLN > TN in quail. There was significant increase in MN formation in the bone marrow cells of quail, and micronucleated polychromatic erythrocytes and micronucleated normochromatic erythrocytes formation in the bone marrow of rats. The concentration dependent significant (p < 0.05) decrease in the PCE/NCE ratio in the bone marrow of the leachate treated rats suggest alterations in the bone marrow cell proliferation, leading to the suppression of immature erythrocytes (PCE). MN induction showed positive corrections with leachate concentrations in the test organisms; and it increased with exposure duration in the catfish. Indiscriminate disposal of solid waste generates leachates containing multiple xenobiotics that are capable of increasing genomic instability among vertebrates inhabiting various ecological habitats.

Luminescent ZnO quantum dots as an efficient sensor for free chlorine detection in water

Highly luminescent ZnO quantum dots (QDs) synthesizedviaa simple and facile route are used for the preparation of an optical sensor for the detection of free chlorine.

Sustainable production of valuable compound 3-succinoyl-pyridine by genetically engineering Pseudomonas putida using the tobacco waste

Treatment of solid and liquid tobacco wastes with high nicotine content remains a longstanding challenge. Here, we explored an environmentally friendly approach to replace tobacco waste disposal with resource recovery by genetically engineering Pseudomonas putida. The biosynthesis of 3-succinoyl-pyridine (SP), a precursor in the production of hypotensive agents, from the tobacco waste was developed using whole cells of the engineered Pseudomonas strain, S16dspm. Under optimal conditions in fed-batch biotransformation, the final concentrations of product SP reached 9.8 g/L and 8.9 g/L from aqueous nicotine solution and crude suspension of the tobacco waste, respectively. In addition, the crystal compound SP produced from aqueous nicotine of the tobacco waste in batch biotransformation was of high purity and its isolation yield on nicotine was 54.2%. This study shows a promising route for processing environmental wastes as raw materials in order to produce valuable compounds.

Use of Doehlert and constrained mixture designs in the development of a photo-oxidation procedure using UV radiation/H₂O₂ for decomposition of landfill leachate samples and determination of metals by flame atomic absorption spectrometry

This work proposes the use of photo-oxidation degradation with UV radiation/H2O2 as sample treatment for the determination of Fe, Zn, Mn, Ni and Co in municipal solid waste landfill leachate by flame atomic absorption spectrometry (FAAS). Three variables (pH, irradiation time and buffer concentration) were optimized using Doehlert design and the proportions of mixture components submitted to UV radiation (leachate sample, buffer solution and H2O2 30%, v/v) were optimized using a constrained mixture design. Using the experimental conditions established, this procedure allows limits of detection of 0.075, 0.025, 0.010, 0.075 and 0.041 µg mL-1, and the precision levels expressed as relative standard (%RSD, 0.5 µg mL-1) were 3.6, 1.8, 1.3, 3.3 and 1.7%, for Fe, Mn, Zn, Ni and Co respectively. Recovery tests were carried out for evaluation of the procedure accuracy and recoveries were between 92 and 106% for the studied metals. This procedure has been applied for the analysis of the landfill leachate collected in Jequié, a city of the southwestern region of the State of Bahia, Brazil. The results were compared with those obtained by acid digestion. There was no significant difference between the results obtained by the two methods based on paired t-test at 95% confidence level.

Household hazardous waste management: a review

This paper deals with the waste stream of household hazardous waste (HHW) presenting existing management systems, legislation overview and other relevant quantitative and qualitative information. European Union legislation and international management schemes are summarized and presented in a concise manner by the use of diagrams in order to provide crucial information on HHW. Furthermore, sources and types, numerical figures about generation, collection and relevant management costs are within the scope of the present paper. The review shows that the term used to refer to hazardous waste generated in households is not clearly defined in legislation, while there is absence of specific acts regulating the management of HHW. The lack of obligation to segregate HHW from the household waste and the different terminology used makes it difficult to determine the quantities and composition of this waste stream, while its generation amount is relatively small and, therefore, is commonly overlooked in waste statistics. The paper aims to cover the gap in the related literature on a subject that is included within the crucial waste management challenges at world level, considering that HHW can also have impact on other waste streams by altering the redox conditions or causing direct reactions with other non hazardous waste substances.

Public perception of hazardousness caused by current trends of municipal solid waste management

Municipal solid waste (MSW) piling up is becoming a serious problem in all developing countries (DC) as a result of inequitable waste collection and treatment. Citizens' collaboration is partly based on understanding their views and their active involvement in MSW planning; on the other hand the assessment of the perception of hazardousness related with MSW is considered rather important as well since the identification of the weak points of the applied MWM strategy is eased and the level of required training is determined. Researchers implemented a case study in the West Bank (WB) and Gaza Strip (GS) regions of Palestine, taking into consideration previous researches in other developing countries. They reached to safe and useful conclusions regarding the parameters which mean the greatest in the waste management field as far as DC are concerned. Lack of skilled manpower, irregular collection services, inadequate equipment used for waste collection, inadequate legal provisions, and resource constraints are additional factors that are confirmed to be challenging the waste management scenarios in all DCs today. The research takes those factors under consideration but focuses on the educational gap and the results revealed interesting trends a significant relationship between respondent's educational attainment and their awareness of hazardous waste (hazard perception); the results will indicate the measure taking required to avoid accidents occurred in those regions (burns from toxics, cuts from sharps, etc). National policy and legislation development based on the research outcomes will ensure equitable and accessible services are in place in order to move towards a healthier environment. Specialized health education and training programs on national scale are also needed to enhance awareness on hazardous waste.

Effect of organic fouling on micro-pollutant rejection in membrane bioreactor treating municipal solid waste landfill leachate

Effect of membrane fouling on the removal of micro-pollutants from municipal solid waste landfill leachate, i.e. 4-methyl-2,6-di-tert-butylphenol (BHT), bisphenol A (BPA), and bis(2-ethylhexyl)phthalate (DEHP), in membrane bioreactor (MBR) was investigated. Modifications of membrane surface properties were analyzed to determine their relationship with their removals. Membrane fouling was simulated with foulants of different particle sizes on cellulose acetate (CA) microfiltration membrane to investigate the effect of foulant characteristics on BHT, BPA, and DEHP retention in the filtration experiment. The rejection efficiencies of the organic micro-pollutants in the MBR were 82-97% by fouled membrane, and 70-90% by cleaned membrane. The fouled membrane provided higher rejection of micro-pollutants from about 5% for BPA and BHT to 19% for DEHP. These improvements were due to the modification of membrane surface characteristics in terms of surface morphology, and contact angle after membrane fouling. The degree of rejection was found to be dependent upon the characteristics of foulant deposited on CA membrane surface. Increasing foulant particle size and its density shifted the mechanism of micro-pollutant rejection from membrane pore narrowing to pore blocking and cake formation while increasing pollutant adsorption capacity onto the foulant layer.

Subcritical water treatment of landfill leachate: application of response surface methodology

CONTEXT

Leachate is the liquid formed when waste breaks down in the landfill and water filters through that waste. This liquid is highly toxic and can pollute the land, ground water and water ways. It is mandatory for landfills to protect against leachate in most countries worldwide. Controlling the pollutant loading, means reducing its quantity by containing or treating the waste to comply with certain discharge characteristics which are compatible with the receptor medium.

OBJECTIVE

This paper describes the reduction of the organic load of a mature landfill leachate using a novel experimental set-up that employs hydrogen peroxide under subcritical conditions and aims to establish this method as an effective alternative to currently used options. Response surface methodology was applied to optimize the treatment process and determine which of the following there parameters - temperature, residence time and hydrogen peroxide concentration - played the most important role.

METHOD

The method employed is based on the use of laboratory-scale, stainless steel reactors, filled with the leachate and appropriate quantities of hydrogen peroxide. Under subcritical conditions (temperature in the range of 100-374 °C and enough pressure to maintain the liquid state of water), hydrogen peroxide produces hydroxyl radicals which are highly reactive and oxidize the organic molecules of the leachate.

RESULTS

The highest COD decrease of 85% was experimentally observed at 300 °C, 500 mM H2O2 and 180 min residence time. It was determined that the combination of oxidant concentration and temperature is the rate-determining factor, whereas residence time has a lesser effect on the process.

CONCLUSIONS

A simple, quick, effective and environmentally-friendly method for the treatment of the organic load of landfill leachate was developed and optimized at laboratory scale.

Detection and drivers of exposure and effects of pharmaceuticals in higher vertebrates

Pharmaceuticals are highly bioactive compounds now known to be widespread environmental contaminants. However, research regarding exposure and possible effects in non-target higher vertebrate wildlife remains scarce. The fate and behaviour of most pharmaceuticals entering our environment via numerous pathways remain poorly characterized, and hence our conception and understanding of the risks posed to wild animals is equally constrained. The recent decimation of Asian vulture populations owing to a pharmaceutical (diclofenac) offers a notable example, because the exposure route (livestock carcasses) and the acute toxicity observed were completely unexpected. This case not only highlights the need for further research, but also the wider requirement for more considered and comprehensive 'ecopharmacovigilance'. We discuss known and potential high risk sources and pathways in terrestrial and freshwater ecosystems where pharmaceutical exposure in higher vertebrate wildlife, principally birds and mammals, may occur. We examine whether approaches taken within existing surveillance schemes (that commonly target established classes of persistent or bioaccumulative contaminants) and the risk assessment approaches currently used for pesticides are relevant to pharmaceuticals, and we highlight where new approaches may be required to assess pharmaceutical-related risk.

Household hazardous waste quantification, characterization and management in China's cities: a case study of Suzhou

A four-stage systematic tracking survey of 240 households was conducted from the summer of 2011 to the spring of 2012 in a Chinese city of Suzhou to determine the characteristics of household hazardous waste (HHW) generated by the city. Factor analysis and a regression model were used to study the major driving forces of HHW generation. The results indicate that the rate of HHW generation was 6.16 (0.16-31.74, 95% CI) g/person/day, which accounted for 2.23% of the household solid waste stream. The major waste categories contributing to total HHW were home cleaning products (21.33%), medicines (17.67%) and personal care products (15.19%). Packaging and containers (one-way) and products (single-use) accounted for over 80% of total HHW generation, implying a considerable potential to mitigate HHW generation by changing the packaging design and materials used by manufacturing enterprises. Strong correlations were observed between HHW generation (g/person/day) and the driving forces group of "household structure" and "consumer preferences" (among which the educational level of the household financial manager has the greatest impact). Furthermore, the HHW generation stream in Suzhou suggested the influence of another set of variables, such as local customs and culture, consumption patterns, and urban residential life-style. This study emphasizes that HHW should be categorized at its source (residential households) as an important step toward controlling the HHW hazards of Chinese cities.

Microbial adaptation to biodegrade toxic organic micro-pollutants in membrane bioreactor using different sludge sources

Biodegradation of toxic organic micro-pollutants in municipal solid waste (MSW) leachate by membrane bioreactor (MBR) was investigated. The MBR systems were seeded with different sludge sources, one was from a pilot-scale MBR system treating MSW leachate and the other was from an activated sludge sewage treatment plant. The biodegradation of BPA, 2,6-DTBP, BHT, DEP, DBP and DEHP, DCP and BBzP, by sludge from both reactors were found improved with time. However, enhanced biodegradation of micro-pollutants was observed in MBR operated under long sludge age condition. Bacterial population analyses determined by PCR-DGGE revealed the development of phenol and phthalate degrading bacteria consortium in MBR sludge during its operation.

Removals of phenolic compounds and phthalic acid esters in landfill leachate by microbial sludge of two-stage membrane bioreactor

Removals of bisphenol A (BPA), 2,6-di-tert-butylphenol (2,6-DTBP), 2,6-di-tert-butyl-4methylphenol (BHT), di-ethyl phthalate (DEP), di-butyl phthalate (DBP) and bis (2-ethylhexyl) phthalate (DEHP) were monitored in two-stage membrane bioreactor (MBR) by operating under no sludge wastage condition for 500 days. Those emerging contaminants were removed by 99.5%, 99.0%, 99.5%, 97.9%, 96.8% and 95.7% under long term operation in MBR without reaching maximum adsorption capacity of sludge. Biodegradation was the main mechanism for their removals in MBR systems and the microbial activities were enhanced by long sludge age operating condition. The removals of those compounds by microbial sludge in MBR by adsorption and combined (adsorption & biodegradation) mechanisms were well explained by pseudo-second order and first order kinetics, respectively.

Nitrogen removal via the nitrite pathway during wastewater co-treatment with ammonia-rich landfill leachates in a sequencing batch reactor

The biological treatment of ammonia-rich landfill leachates due to an inadequate C to N ratio requires expensive supplementation of carbon from an external carbon source. In an effort to reduce treatment costs, the objective of the study was to determine the feasibility of nitrogen removal via the nitrite pathway during landfill leachate co-treatment with municipal wastewater. Initially, the laboratory-scale sequencing batch reactor (SBR) was inoculated with nitrifying activated sludge and fed only raw municipal wastewater (RWW) during a start-up period of 9 weeks. Then, in the co-treatment period, consisting of the next 17 weeks, the system was fed a mixture of RWW and an increasing quantity of landfill leachates (from 1 to 10% by volume). The results indicate that landfill leachate addition of up to 10% (by volume) influenced the effluent quality, except for BOD5. During the experiment, a positive correlation (r(2) = 0.908) between ammonia load in the influent and nitrite in the effluent was observed, suggesting that the second step of nitrification was partially inhibited. The partial nitrification (PN) was also confirmed by fluorescence in situ hybridisation (FISH) analysis of nitrifying bacteria. Nitrogen removal via the nitrite pathway was observed when the oxygen concentration ranged from 0.5 to 1.5 mg O2/dm(3) and free ammonia (FA) ranged from 2.01 to 35.86 mg N-NH3/dm(3) in the aerobic phase. Increasing ammonia load in wastewater influent was also correlated with an increasing amount of total nitrogen (TN) in the effluent, which suggested insufficient amounts of assimilable organic carbon to complete denitrification. Because nitrogen removal via the nitrite pathway is beneficial for carbon-limited and highly ammonia-loaded mixtures, obtaining PN can lead to a reduction in the external carbon source needed to support denitrification.

Sorption and degradation of petroleum hydrocarbons, polycyclic aromatic hydrocarbons, alkylphenols, bisphenol A and phthalates in landfill leachate using sand, activated carbon and peat filters

Landfill leachates are repeatedly found contaminated with organic pollutants, such as alkylphenols (APs), phthalates and polycyclic aromatic hydrocarbons (PAHs) at levels exceeding water quality standards. It has been shown that these pollutants may be present in the colloidal and truly dissolved phase in contaminated water, making particle separation an inefficient removal method. The aim of this study was to investigate sorption and degradation of petroleum hydrocarbons (PHCs), selected APs, bisphenol A (BPA), phthalates and PAHs from landfill leachate using sand, granulated activated carbon (GAC) and peat moss filters. A pilot plant was installed at an inactive landfill with mixed industrial and household waste and samples were collected before and after each filter during two years. Leachate pre-treated in oil separator and sedimentation pond failed to meet water quality standards in most samples and little improvement was seen after the sand filter. These techniques are based on particle removal, whereas the analysed pollutants are found, to varying degrees, bound to colloids or dissolved. However, even highly hydrophobic compounds expected to be particle-bound, such as the PHCs and high-molecular weight PAHs, were poorly removed in the sand filter. The APs and BPA were completely removed by the GAC filter, while mass balance calculations indicate that 50-80% of the investigated phenols were removed in the peat filter. Results suggest possible AP degradation in peat filters. No evidence of phthalate degradation in the landfill, pond or the filters was found. The PHCs were completely removed in 50% and 35% of the measured occasions in the GAC and peat filters, respectively. The opposite trend was seen for removal of PAHs in GAC (50%) and peat (63%). Oxygenated PAHs with high toxicity were found in the leachates but not in the pond sediment. These compounds are likely formed in the pond water, which is alarming because sedimentation ponds are commonly used treatment techniques. The oxy-PAHs were effectively removed in the GAC, and especially the peat filter. It was hypothesized that dissolved compounds would adsorb equally well to the peat and GAC filters. This was not completely supported as the GAC filter was in general more efficient than peat.

Emerging organic contaminants in surface water and groundwater: a first overview of the situation in Italy

This paper provides the first review of the occurrence of 161 emerging organic compounds (EOCs) in Italian surface water and groundwater. The reported EOCs belong to the groups of industrials, pharmaceuticals, estrogens and illicit drugs. Occurrence of 137 pesticides was also reported. The reviewed research works have been published between 1997 and 2013. The majority of the studies have been carried out in Northern Italy (n. 30) and to a lower extent in Central Italy (n. 13). Only a limited number of research studies report EOC concentrations in water resources of Southern Italy. The EOCs that have been more frequently studied are in the following descending order, pesticides (16), pharmaceuticals (15), industrials (13), estrogens (7) and illicit drugs (2). Research activities investigating the EOC occurrence in surface water are more numerous than those in groundwater. This is consistent with the higher complexity involved in groundwater sampling and EOC detection. Among the reported EOCs, industrials and pesticides are those occurring in both surface water and groundwater with the highest concentrations (up to 15 × 10(6) and 4.78 × 0(5)ng L(-1), respectively). Concentrations of pharmaceuticals in surface water reach a maximum of 3.59 × 10(3)ng L(-1), whereas only the antimicrobial agent josamycin has been encountered in groundwater with a concentration higher than 100 ng L(-1). Both estrogens and illicit drugs appeared in surface water with concentrations lower than 50 ng L(-1). Groundwater concentrations for estrogens were measured to be below the detection limits, whereas illicit drugs have so far not been studied in groundwater. The present review reveals the serious contamination status of Italian surface water and groundwater especially by pesticides, industrials and to a lower extent by pharmaceuticals and the necessity to foster the research on EOC occurrence in Italian water resources, in particular in Southern Italy where a limited number of investigations currently exist.

Production of Biologically Activated Carbon from Orange Peel and Landfill Leachate Subsequent Treatment Technology

In order to improve adsorption of macromolecular contaminants and promote the growth of microorganisms, active carbon for biological wastewater treatment or follow-up processing requires abundant mesopore and good biophile ability. In this experiment, biophile mesopore active carbon is produced in one-step activation with orange peel as raw material, and zinc chloride as activator, and the adsorption characteristics of orange peel active carbon is studied by static adsorption method. BET specific surface area and pore volume reached 1477 m2/g and 2.090 m3/g, respectively. The surface functional groups were examined by Fourier transform infrared spectroscopy (FT-IR). The surface of the as-prepared activated carbon contained hydroxyl group, carbonyl group, and methoxy group. The analysis based on X-ray diffraction spectrogram (XRD) and three-dimensional fluorescence spectrum indicated that the as-prepared activated carbon, with smaller microcrystalline diameter and microcrystalline thickness and enhanced reactivity, exhibited enhanced adsorption performance. This research has a deep influence in effectively controlling water pollution, improving area water quality, easing orange peel waste pollution, and promoting coordinated development among society, economy, and environment.

Household hazardous wastes as a potential source of pollution: a generation study

Certain domestic wastes exhibit characteristics that render them dangerous, such as explosiveness, flammability, spontaneous combustion, reactivity, toxicity and corrosiveness. The lack of information about their generation and composition hinders the creation of special programs for their collection and treatment, making these wastes a potential threat to human health and the environment. We attempted to quantify the levels of hazardous household waste (HHW) generated in Mexicali, Mexico. The analysis considered three socioeconomic strata and eight categories. The sampling was undertaken on a house-by-house basis, and hypothesis testing was based on differences between two proportions for each of the eight categories. In this study, HHW comprised 3.49% of the total generated waste, which exceeded that reported in previous studies in Mexico. The greatest quantity of HHW was generated by the middle stratum; in the upper stratum, most packages were discarded with their contents remaining. Cleaning products represent 45.86% of the HHW generated. Statistical differences were not observed for only two categories among the three social strata. The scarcity of studies on HHW generation limits direct comparisons. Any decrease in waste generation within the middle social stratum will have a large effect on the total amount of waste generated, and decrease their impact on environmental and human health.

Review and prospect of emerging contaminants in waste--key issues and challenges linked to their presence in waste treatment schemes: general aspects and focus on nanoparticles

The presence in waste of emerging pollutants (EPs), whose behaviours and effects are not well understood, may present unexpected health and environmental risks and risks for the treatment processes themselves. EP may include substances that are newly detected in the environment, substances already identified as risky and whose use in items is prohibited (but which may be present in old or imported product waste) or substances already known but whose recent use in products can cause problems during their future treatment as waste. Several scientific studies have been conducted to assess the presence of EP in waste, but they are mostly dedicated to a single category of substance or one particular waste treatment. In the absence of a comprehensive review focused on the impact of the presence of EP on waste treatment schemes, the authors present a review of the key issues associated with the treatment of waste containing emerging pollutants. This review presents the typologies of emerging pollutants that are potentially present in waste along with the major challenges for each treatment scheme (recycling, composting, digestion, incineration, landfilling and wastewater treatment). All conventional treatment processes are affected by these new pollutants, and they were almost never originally designed to consider these substances. In addition to these general aspects, a comprehensive review of available data, projects and future R&D needs related to the impact of nanoparticles on waste treatment is presented as a case study.

Investigation on characteristics of leachate and concentrated leachate in three landfill leachate treatment plants

Concentrated leachate from membrane treatment processes is a potential pollution source for the surroundings. In this study, with comparison of the landfill leachate, chemical and microbial characteristics of concentrated leachate including biodegradability, amount of nitrogenous compounds and heavy metals, dissolved organic matter composition, and microbial community were investigated in three landfill leachate treatment plants. The results showed that hydrophilic (HyI) fraction was the major dissolved organic carbon in the landfill leachates, accounting for 54.6-60.7%, while humic substances including humic acid (HA) and fulvic acid (FA) were relatively higher in the concentrated leachates, ranging from 61.7% to 69.2%. Conjugated nitrogen existed mainly in FA and HyI in the concentrated leachates. The analysis of excitation emission matrix fluorescence spectroscopy, specific ultraviolet absorbance at 254nm (SUVA254) and GC/MS showed that aromatic compounds, long-chain hydrocarbons and halohydrocarbons were abundant in the concentrated leachates. During landfill leachate treatment processes, Cl(-), SO4(2-) and heavy metals were commonly accumulated in the concentrated leachates. NO3(-)N and/or NH4(+)N were the major nitrogenous compounds in the concentrated leachates. All the leachates from three landfill sites contained toluene in the range of 44.5-728.4μgL(-1). Ethylbenzene, chlorobenzene, and the phthalic acid esters including dibutyl phthalate, dimethyl phthalate and di-n-octyl phthalate were also detected in the concentrated leachates. Higher microbial diversity was observed in the concentrated leachate in comparison with landfill leachate.

Development of a screening method for the determination of xenobiotic organic pollutants in municipal landfill leachate using solvent extraction and comprehensive GCxGC-qMS analysis

In the present study, we propose a method for the evaluation of different classes of xenobiotic organic compounds enclosed in the municipal landfill leachate using comprehensive two-dimensional gas chromatography coupled with quadrupole mass spectrometry (GCxGC-qMS). Here we show that, due to high peak capacity of comprehensive two-dimensional gas chromatography, in a single run it is possible to separate compounds with different physical-chemical properties (such as aliphatic and aromatic compounds, polyaromatic hydrocarbons, phenols, phthalates, aldehydes, ketones, nitrogen containing compounds, organo-phosphoric flame retardants etc.), compounds which have proved to be endocrine disruptors, compounds that are persistent, bioaccumulative and toxic, carcinogenic, mutagenic, teratogenic, reprotoxic or harmful for the environment. Even though a solvent extraction method has been optimised, the extraction step still remains the main problem for a comprehensive characterization of all classes of organic toxicants enclosed in the municipal landfill leachate.

Uptake and translocation of organophosphates and other emerging contaminants in food and forage crops

Emerging contaminants in wastewater and sewage sludge spread on agricultural soil can be transferred to the human food web directly by uptake into food crops or indirectly following uptake into forage crops. This study determined uptake and translocation of the organophosphates tris(1-chloro-2-propyl) phosphate (TCPP) (log Kow 2.59), triethyl-chloro-phosphate (TCEP) (log Kow 1.44), tributyl phosphate (TBP) (log Kow 4.0), the insect repellent N,N-diethyl toluamide (DEET) (log Kow 2.18) and the plasticiser N-butyl benzenesulfonamide (NBBS) (log Kow 2.31) in barley, wheat, oilseed rape, meadow fescue and four cultivars of carrot. All species were grown in pots of agricultural soil, freshly amended contaminants in the range of 0.6-1.0 mg/kg dry weight, in the greenhouse. The bioconcentration factors for root (RCF), leaf (LCF) and seed (SCF) were calculated as plant concentration in root, leaf or seed over measured initial soil concentration, both in dry weight. The chlorinated flame retardants (TCEP and TCPP) displayed the highest bioconcentration factors for leaf and seed but did not show the same pattern for all crop species tested. For TCEP, which has been phased out due to toxicity but is still found in sewage sludge and wastewater, LCF was 3.9 in meadow fescue and 42.3 in carrot. For TCPP, which has replaced TCEP in many products and also occurs in higher residual levels in sewage sludge and wastewater, LCF was high for meadow fescue and carrot (25.9 and 17.5, respectively). For the four cultivars of carrot tested, the RCF range for TCPP and TCEP was 10-20 and 1.7-4.6, respectively. TCPP was detected in all three types of seeds tested (SCF, 0.015-0.110). Despite that DEET and NBBS have log Kow in same range as TCPP and TCEP, generally lower bioconcentration factors were measured. Based on the high translocation of TCPP and TCEP to leaves, especially TCPP, into meadow fescue (a forage crop for livestock animals), ongoing risk assessments should be conducted to investigate the potential effects of these compounds in the food web.

The occurrence and distribution of a group of organic micropollutants in Mexico City's water sources

The occurrence and distribution of a group of 17 organic micropollutants in surface and groundwater sources from Mexico City was determined. Water samples were taken from 7 wells, 4 dams and 15 tanks where surface and groundwater are mixed and stored before distribution. Results evidenced the occurrence of seven of the target compounds in groundwater: salicylic acid, diclofenac, di-2-ethylhexylphthalate (DEHP), butylbenzylphthalate (BBP), triclosan, bisphenol A (BPA) and 4-nonylphenol (4-NP). In surface water, 11 target pollutants were detected: same found in groundwater as well as naproxen, ibuprofen, ketoprofen and gemfibrozil. In groundwater, concentration ranges of salicylic acid, 4-NP and DEHP, the most frequently found compounds, were 1-464, 1-47 and 19-232 ng/L, respectively; while in surface water, these ranges were 29-309, 89-655 and 75-2,282 ng/L, respectively. Eleven target compounds were detected in mixed water. Concentrations in mixed water were higher than those determined in groundwater but lower than the detected in surface water. Different to that found in ground and surface water, the pesticide 2,4-D was found in mixed water, indicating that some pollutants can reach areas where they are not originally present in the local water sources. Concentration of the organic micropollutants found in this study showed similar to lower to those reported in water sources from developed countries. This study provides information that enriches the state of the art on the occurrence of organic micropollutants in water sources worldwide, notably in megacities of developing countries.

Landfills as a biorefinery to produce biomass and capture biogas

While landfilling provides a simple and economic means of waste disposal, it causes environmental impacts including leachate generation and greenhouse gas (GHG) emissions. With the introduction of gas recovery systems, landfills provide a potential source of methane (CH4) as a fuel source. Increasingly revegetation is practiced on traditionally managed landfill sites to mitigate environmental degradation, which also provides a source of biomass for energy production. Combustion of landfill gas for energy production contributes to GHG emission reduction mainly by preventing the release of CH4 into the atmosphere. Biomass from landfill sites can be converted to bioenergy through various processes including pyrolysis, liquefaction and gasification. This review provides a comprehensive overview on the role of landfills as a biorefinery site by focusing on the potential volumes of CH4 and biomass produced from landfills, the various methods of biomass energy conversion, and the opportunities and limitations of energy capture from landfills.

Partitioning of polycyclic aromatic hydrocarbons, alkylphenols, bisphenol A and phthalates in landfill leachates and stormwater

Partitioning of organic pollutants is essential to their fate, mobility and removal from water and soil. To study the partitioning behavior of selected alkylphenols, bisphenol A, phthalates and polycyclic aromatic hydrocarbons (PAHs), a method for separating the truly dissolved and colloidal phase of organic pollutants was developed, verified and applied to samples of landfill leachate and stormwater from urban areas and waste-sorting sites. Alkylphenols, bisphenol A, phthalates and PAHs were detected in all the untreated samples (total concentrations), most of the filtered samples and frequently in the colloid-bound phase. Concentrations of alkylphenols and PAHs in urban stormwater were one order of magnitude lower than in the landfill leachates and stormwater from waste-sorting sites. The difference between total, dissolved and colloid-bound concentrations in the water samples was not statistically significant for any phenols or phthalates, but for three of the PAHs; naphthalene (mostly dissolved), phenanthrene and fluoranthene (mostly particulate). These results indicate that in landfill leachates and stormwaters, organic pollutants are predominantly attached to colloids and/or truly dissolved in contrast to their expected strong sorption to particulate matter. Occurrence and concentrations of pollutants in dissolved and colloid-bound phases correlated negatively with the K(OW). However, even highly hydrophobic compounds were frequently detected in filtered samples, i.e. the dissolved phases, and it is suggested that the organic content in the colloids decreases the compounds' partition to particles. The results confirm that the K(OW) values of specific organic pollutants well describe the compounds partition-binding process to dissolved organic carbon (DOC) colloids. Our findings call for a re-assessment of the organic pollutants' mobility and associated risks. This knowledge can also serve as a base for selecting efficient treatment methods for stormwater and landfill leachates.

Mesophilic anaerobic co-digestion of pulp and paper sludge and food waste for methane production in a fed-batch basis

Co-digestion of pulp and paper sludge (PPS) and food waste (FW) in a batch-fed digestion system was conducted on a laboratory scale. Three reactors named A1, A2, and A3 were tested. PPS and FW mixed at different mass ratios of 1:3, 1:1, and 3:1, respectively, were loaded in the reactors. Bioconversion at high efficiency was obtained in the system. The accumulative methane yield of each reactor was 144mLg(-1)VSfed (A1), 256 mL g(-1) VSfed (A2), and 123 mL g(-1)VSfed (A3). The soluble chemical oxygen demand (COD) removal efficiencies reached 73.2% (Al), 93.9% (A2), and 79.6% (A3). A pH in the range 5.8-8.4 was obtained in the three reactors without adjustment due to the high buffer capacity of the mixing feedstock. No toxicity inhibitions of volatile fatty acids and NH3-N occurred in reactor A2. This study showed that it was good for co-digestion of PPS and FW in a mass ratio of 1:1 for methane production, which resulted in higher methane yield, a greater buffer capacity, a higher organics removal efficiency, and a more stable process.

Characterization and determination of the odorous charge in the indoor air of a waste treatment facility through the evaluation of volatile organic compounds (VOCs) using TD-GC/MS

Municipal solid waste treatment facilities are generally faced with odorous nuisance problems. Characterizing and determining the odorous charge of indoor air through odour units (OU) is an advantageous approach to evaluate indoor air quality and discomfort. The assessment of the OU can be done through the determination of volatile organic compounds (VOCs) concentrations and the knowledge of their odour thresholds. The evaluation of the presented methodology was done in a mechanical-biological waste treatment plant with a processing capacity of 245.000 tons year(-1) of municipal residues. The sampling was carried out in five indoor selected locations of the plant (Platform of Rotating Biostabilizers, Shipping warehouse, Composting tunnels, Digest centrifugals, and Humid pre-treatment) during the month of July 2011. VOC and volatile sulphur compounds (VSCs) were sampled using multi-sorbent bed (Carbotrap, Carbopack X, Carboxen 569) and Tenax TA tubes, respectively, with SKC AirCheck 2000 pumps. The analysis was performed by automatic thermal desorption (ATD) coupled with a capillary gas chromatography (GC)/mass spectrometry detector (MSD). One hundred and thirty chemical compounds were determined qualitatively in all the studied points (mainly alkanes, aromatic hydrocarbons, alcohols, aldehydes, esters, and terpenes), from which 86 were quantified due to their odorous characteristics as well as their potentiality of having negative health effects. The application of the present methodology in a municipal solid waste treatment facility has proven to be useful in order to determine which type of VOC contribute substantially to the indoor air odorous charge, and thus it can be a helpful method to prevent the generation of these compounds during the treatment process, as well as to find a solution in order to suppress them.

Toxic organic micro-pollutants removal mechanisms in long-term operated membrane bioreactor treating municipal solid waste leachate

The performance of two-stage membrane bioreactor (MBR) in term of toxic organic micro-pollutants removal was continuously monitored for 300 days under long sludge age condition. The phenolic compounds and phthalic acid esters (PAEs) in landfill leachate and treated water from MBR unit were quantified by solid phase extraction and gas chromatography-mass spectrometry. Priority pollutants in landfill leachate were phenolics and their degradation products i.e. 4-methyl-2,6-di-tert-butylphenol, bisphenol A at higher concentrations above 100 μg/l, PAEs i.e. dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, di-n-octyl phthalate, and di (2-ethylhexyl) phthalate. It was found that MBR could remove phenolic compounds and PAEs by 77-96%. Biodegradation and adsorption mechanisms were responsible for their removals in MBR. Additionally, the retention of compounds during filtration through the fouled membrane was also found significant. This research shows that the removal of organic micro-pollutants in landfill leachate was improved under higher biomass concentration and longer sludge age conditions.

Degradation of phenolic compounds in aerobic and anaerobic landfills: a pilot scale study

The aim of this study was to investigate the aerobic and anaerobic degradation of phenol and its derivatives in aerobic and anaerobic landfills. Phenolic compounds were extracted from leachate samples using the solid phase micro-extraction method. In this study, analysis of the 24 phenolic compounds included in the standard mixture and the change in the concentrations over time of 23 of the 24 compounds found in the calibration mix standard were determined in both aerobic and anaerobic landfill reactors. It can be concluded that faster and complete removal of phenol, chlorophenol, dichlorophenols, and trichlorophenol were achieved in the aerobic landfill while aerobic treatment was less effective on tetrachlorophenol and pentachlorophenol. In the anaerobic landfill, anaerobic reductive dechlorination probably occurred from all the highly chlorinated phenols and resulted in the accumulation of phenol and chlorophenol. The phenol could not be further degraded because the anaerobic methanogenic phase did not start during the 150 days of operation in an anaerobic landfill reactor. Nitrophenols can be degraded rapidly under aerobic conditions. These compounds are degraded to amino groups in the first step and then these amino groups are degraded to methane and CO(2) under anaerobic conditions. Although the degradation could not reach the methanogenic phase in anaerobic landfill reactor during the operational period, it is indicated that nitrophenol concentrations decreased in the anaerobic reactor. This is revealed as a result of the formation of the amino groups.

Chemical composition and genotoxicity assessment of sanitary landfill leachate from Rovinj, Croatia

Chemical analysis and an in vitro approach were performed to assess elemental composition and genotoxic effects of the samples of landfill leachate taken from Lokva Vidotto sanitary landfill the official landfill for Rovinj town, Croatia. Two samples of landfill leachate were collected and analyzed in order to evaluate macro, micro and trace elements by atomic absorption spectroscopy, energy dispersive X-ray spectrometry and colorimetry. Genotoxicity of sanitary landfill leachate was evaluated in human lymphocytes by the use of the micronucleus test and comet assay. Samples were characterized with relatively low concentrations of heavy metals while organic component level exceeded upper permissible limit up to 39 times. Observed genotoxic effects should be connected with high concentrations of ammonia nitrogen, which exceeded permissible limit up to 180 times. Leachate samples of both sanitary landfills increased the frequency of micronuclei, nucleoplasmic bridges and nuclear buds. Increase of DNA damage in human lymphocytes was also detected by virtue of measuring comet assay parameters. All parameters showed statistically significant difference compared to negative control. Increased micronucleus and comet assay parameters indicate that both samples of sanitary landfill leachate are genotoxic and could pose environmental and human health risk if discharged to an aquatic environment.

Degradation of nitrocellulose-based paint by Desulfovibrio desulfuricans ATCC 13541

Nitrocellulose is one of the most commonly used compounds in ammunition and paint industries and its recalcitrance to degradation has a negative impact on human health and the environment. In this study the capability of Desulfovibrio desulfuricans ATCC 13541 to degrade nitrocellulose as binder in paint was assayed for the first time. Nitrocellulose-based paint degradation was followed by monitoring the variation in nitrate, nitrite and ammonium content in the culture medium using Ultraviolet-Visible spectroscopy. At the same time cell counts and ATP assay were performed to estimate bacterial density and activity in all samples. Infrared spectroscopy and colorimetric measurements of paint samples were performed to assess chemical and colour changes due to the microbial action. Microscope observations of nitrocellulose-based paint samples demonstrated the capability of the bacterium to adhere to the paint surface and change the paint adhesive characteristics. Finally, preliminary studies of nitrocellulose degradation pathway were conducted by assaying nitrate- and nitrite reductases activity in D. desulfuricans grown in presence or in absence of paint. We found that D. desulfuricans ATCC 13541 is able to transform nitrocellulose as paint binder and we hypothesised ammonification as degradation pathway. The results suggest that D. desulfuricans ATCC 13541 is a good candidate as a nitrocellulose-degrading bacterium.

An assessment of the genotoxic effects of landfill leachates using bacterial and plant tests

Two bacterial tests (the Ames test and the umu-test) and the Allium test were used to assess the genotoxicity of aqueous leachates from municipal solid waste landfill sites in Southern Poland. A comparison of the sensitivity of the applied tests was performed. None of the tested samples revealed genotoxic activity in the umu-test and thus did not appear to be sensitive enough for evaluations of leachates. Two out of 22 leachates were described as genotoxic in the Ames test and 3 out of 6 leachates in the Allium test. All of the analyzed leachates samples affected cell divisions. Two of the tests applied, the Allium and Ames test, revealed the high genotoxicity of leachate 4. Among the bioassays used in these studies, the Allium test proved to be more sensitive than bacterial tests for the investigation of leachate toxicity. The results suggest that the Allium cytogenetic bioassay is efficient and simple for genotoxicity studies of leachates. The potential correlations between the chemical characteristics and genotoxic effects is discussed. The biological effects of selected appeared to be related to chemical parameters. Leachates have a genotoxic potential and pose a risk to human health and the environment. A combination of biotests and chemical analyses is the best approach for the assessment of the risk or impact of leachates.

Estimation of transport parameters of phenolic compounds and inorganic contaminants through composite landfill liners using one-dimensional mass transport model

One-dimensional (1D) advection-dispersion transport modeling was conducted as a conceptual approach for the estimation of the transport parameters of fourteen different phenolic compounds (phenol, 2-CP, 2-MP, 3-MP, 4-MP, 2-NP, 4-NP, 2,4-DNP, 2,4-DCP, 2,6-DCP, 2,4,5-TCP, 2,4,6-TCP, 2,3,4,6-TeCP, PCP) and three different inorganic contaminants (Cu, Zn, Fe) migrating downward through the several liner systems. Four identical pilot-scale landfill reactors (0.25 m3) with different composite liners (R1: 0.10+0.10 m of compacted clay liner (CCL), L(e) = 0.20 m, k(e) = 1 × 10(-8) m/s, R2: 0.002-m-thick damaged high-density polyethylene (HDPE) geomembrane overlying 0.10+0.10 m of CCL, L(e) = 0.20 m, k(e) = 1 × 10(-8) m/s, R3: 0.002-m-thick damaged HDPE geomembrane overlying a 0.02-m-thick bentonite layer encapsulated between 0.10+0.10 m CCL, L(e) = 0.22 m, k(e) = 1 × 10(-8) m/s, R4: 0.002-m-thick damaged HDPE geomembrane overlying a 0.02-m-thick zeolite layer encapsulated between 0.10+0.10 m CCL, L(e) = 0.22 m, k(e) = 4.24 × 10(-7) m/s) were simultaneously run for a period of about 540 days to investigate the nature of diffusive and advective transport of the selected organic and inorganic contaminants. The results of 1D transport model showed that the highest molecular diffusion coefficients, ranging from 4.77×10(-10) to 10.67 × 10(-10)m2/s, were estimated for phenol (R4), 2-MP (R1), 2,4-DNP (R2), 2,4-DCP (R1), 2,6-DCP (R2), 2,4,5-TCP (R2) and 2,3,4,6-TeCP (R1). For all reactors, dispersion coefficients of Cu, ranging from 3.47 × 10(-6) m(2)/s to 5.37 × 10(-2) m2/s, was determined to be higher than others obtained for Zn and Fe. Average molecular diffusion coefficients of phenolic compounds were estimated to be about 5.64 × 10(-10) m2/s, 5.37 × 10(-10) m2/s, 2.69 × 10(-10) m2/s and 3.29 × 10(-10) m2/s for R1, R2, R3 and R4 systems, respectively. The findings of this study clearly indicated that about 35-50% of transport of phenolic compounds to the groundwater is believed to be prevented with the use of zeolite and bentonite materials in landfill liner systems.

DNA and oxidative damage induced in somatic organs and tissues of mouse by municipal sludge leachate

Pollution by waste landfill leachate has prompted a number of studies on the toxic and potential health effects. This study assessed the genotoxicity of a municipal sludge leachate (MSL) in the somatic tissues (blood and bone marrow) and organs (liver, kidney, and spleen) of mice using the alkaline Comet assay. The possible cause of DNA damage via the study of antioxidant system (lipid peroxidation [LPO]; catalase [CAT]; reduced glutathione [GSH]; and superoxide dismutase [SOD]) responses in mouse liver was also investigated. Different concentrations (2.5%, 5%, 10%, and 15%) of the leachate were administered intraperitoneally for 5 consecutive days to male Swiss albino mice (4 mice/group). A significant (p < 0.05) increase in DNA damage in organs and tissues of treated mice compared to the negative control was observed as evident from the Comet assay parameters: olive tail moment (OTM, arbitrary units) and tail DNA (%). Bone marrow showed maximum DNA damage followed by liver > spleen > kidney > blood as evident by the OTM. A significant increase (p < 0.05) in the level of antioxidant enzymes (CAT and SOD) and LPO with a concurrent decrease in GSH in the liver of treated mice was also observed. Our finding demonstrates that the MSL induces DNA damage in the somatic tissues and organs of mouse as well as induces oxidative stress in the liver. These tissues and organs may be the potential targets in animal and human populations exposed to MSL. This is of relevance to public health; as such exposure could lead to adverse health effects via systemic genotoxicity.

Characterization and biodegradation of polycyclic aromatic hydrocarbons in radioactive wastewater

PAH degrading Pseudomonad and Alcaligenes species were isolated from landfill soil and mine drainage in South Africa. The isolated organisms were mildly radiation tolerant and were able to degrade PAHs in simulated nuclear wastewater. The radiation in the simulated wastewater, at 0.677 Bq/μL, was compatible to measured values in wastewater from a local radioisotope manufacturing facility, and was enough to inhibit metabolic activity of known PAH degraders from soil such as Pseudomonas putida GMP-1. The organic constituents in the original radioactive waste stream consisted of the full range of PAHs except fluoranthene. Among the observed PAHs in the nuclear wastewater from the radioisotope manufacturing facility, acenaphthene and chrysene predominated--measured at 25.1 and 14.2mg/L, respectively. Up to sixteen U.S.EPA priority PAHs were detected at levels higher than allowable limits in drinking water. The biodegradation of the PAHs was limited by the solubility of the compounds. This contributed to the observed faster degradation rates in low molecular weight (LMW) compounds than in high molecular weight compounds.

Cytogenotoxicity of sewage sludge leachate before and after calcium oxide-based solidification in human lymphocytes

Present study aimed to establish the chemical composition of sewage sludge leachate before/after calcium oxide-based solidification using energy dispersive X-ray fluorescence (EDXRF). The other aim was to determine leachate effects on human lymphocyte and DNA integrity in vitro using a battery of bioassays (DNA diffusion assay, micronucleus test and comet assay) to determine effects of those complex mixtures of elements on cell and DNA integrity. EDXRF showed that nickel concentration in the leachate of untreated sludge was 18.5 times higher than the upper permissible limit for inert waste landfills. Other elements were kept below the permissible values. After sludge solidification, leachate concentrations of Cr, Mn, Fe, Ni, Cu, Zn, and Pb dropped 1.6, 2.7, 37, 5.9, 3.2, 7.8, and 2.6 times, respectively. Untreated sludge leachate was cytogenotoxic to lymphocytes, and may lead to adverse effects on the exposed human populations, but calcium oxide-based solidification reduced these effects in significant manner.

Influence of a collapsed coastal landfill on metal levels in sediments and biota--a portent for the future?

In May 2008 a coastal landslide deposited landfill debris onto the shore near Lyme Regis, UK. Six months later, intertidal sediments and biota from the area were sampled to determine whether the landslip had affected distribution and bioavailability of metals in the area and if there were any biological effects. Highest sediment concentrations for the majority of metals occurred near the landslip zone and in several cases exceeded Threshold Effects or Probable Effects Levels (As, Cu, Hg, Ni, Pb, Zn). The 1 M HCl-extractable fraction of Cd, Pb and Zn in sediments also increased near the landslip. Metal bioaccumulation by intertidal biota showed variability between different species and metals, but there were several instances of increased accumulation near the landslip through increased availability from seawater, sediment and dietary sources. In most cases, metal concentrations in molluscs exceeded Oslo and Paris Commission (OSPAR) background concentrations (BCs) together with background assessment concentrations (BACs) at some sites. Kidney tissues in winkles (Littorina littorea) were measured for evidence of oxidative stress using the Total Oxyradical Scavenging Capacity (TOSC) assay. Responses to peroxynitrite, peroxyl and hydroxyl radicals suggested raised levels of TOSC in animals from the sites close to or east of the landfill waste. There have been very few studies of direct impact of landfills on the marine environment and this study could serve as a practical model for similar events driven by sea level rise.