Household hazardous waste in municipal landfills: contaminants in leachate

Removal of pollutants and reduction of bio-toxicity in a full scale chemical coagulation and reverse osmosis leachate treatment system

Removals of pollutants and toxic organic compounds and reduction in bio-toxicity of leachate along an operating full-scale leachate treatment system utilizing chemical coagulation, sand filtration, microfiltration (MF) and reverse osmosis (RO) membrane were evaluated. High pollutant removals were achieved mainly by coagulation and sand filtration. Major toxic organic pollutants, i.e. DEHP, DBP and bisphenol A were removed by 100%, 99.6% and 98.0%. Acute toxicity test using water flea, Nile Tilapia and common carp and genotoxicity (Comet assay) were conducted to determine toxicity reduction in leachate along the treatment. Ammonia was found to be the main acute toxic compounds in leachate as determined by LC(50) but the effect of organic substances was also observed. DNA damage in fish exposed to diluted raw leachate (10% of LC(50)) was found to be 8.9-24.3% and it was subsequently decreased along the treatment. Correlation between pollutants and its bio-toxicity was established using multivariable analyses.

Estimation of the environmental risk posed by landfills using chemical, microbiological and ecotoxicological testing of leachates

The leachates from 22 municipal solid waste (MSW) landfill sites in Southern Poland were characterized by evaluation of chemical, microbiological and ecotoxicological parameters. Chemical analyses were mainly focused on the identification of the priority hazardous substances according to Directive on Priority Substances, 2008/105/EC (a daughter directive of the WFD) in leachates. As showed, only five substances (Cd, Hg, hexachlorobutadiene, pentachlorobenzene and PAHs) were detected in the leachates. The compounds tested were absent or present at very low concentrations. Among them, only PAHs were found in all samples in the range from 0.057 to 77.2 μg L⁻¹. The leachates were contaminated with bacteria, including aerobic, psychrophilic and mesophilic bacteria, coliform and fecal coliforms, and spore-forming-bacteria, including Clostridium perfringens, and with filamentous fungi. From the analysis of specific microorganism groups (indicators of environmental pollution by pathogenic or opportunistic pathogenic organisms) it can be concluded that the landfill leachates showed sanitary and epidemiological hazard. In the ecotoxicological study, a battery of tests comprised of 5 bioassays, i.e. Microtox(®), Spirotox, Rotoxkit F™, Thamnotoxkit F™ and Daphtoxkit F™ magna was applied. The leachate samples were classified as toxic in 13.6%, highly toxic in 54.6% and very highly toxic in 31.8%. The Spirotox test was the most sensitive bioassay used. The percentage of class weight score was very high - above 60%; these samples could definitely be considered seriously hazardous and acutely toxic to the fauna and microflora. No correlations were found between the toxicity values and chemical parameters. The toxicity of leachate samples cannot be explained by low levels of the priority pollutants. It seems that other kinds of xenobiotics present in the samples at subacute levels gave the high aggregate toxic effect. The chemical, ecotoxicological and microbiological parameters of the landfill leachates should be analyzed together to assess the environmental risk posed by landfill emissions.

Environmental contamination associated with a marine landfill ('seafill') beside a coral reef

In Bermuda, bulk waste such as scrap metal, cars, etc., and blocks of cement-stabilized incinerator ash (produced from burning garbage) are disposed of in a foreshore reclamation site, i.e., a seafill. Chemical analyses show that seawater leaching out of the dump regularly exceeds water quality guidelines for Zn and Cu, and that the surrounding sediments are enriched in multiple contaminant classes (metals, polycyclic aromatic hydrocarbons, petroleum hydrocarbons, dioxins and furans, polychlorinated biphenyls and an organochlorine pesticide), i.e., there is a halo of contamination. When compared against biological effects-based sediment quality guidelines (SQGs), numerous sediment samples exceeded the low-range values (where biological effects become possible), and for Hg and Zn exceeded the mid-range value (where they become probable). A few metres away from the edge of the 25 acre dump lies a small coral patch reef, proposed here as most contaminated coral reef in the world.

Migration behavior of Cu and Zn in landfill with different operation modes

Cu and Zn were chosen to study the heavy metal migration behavior and mechanism in three simulated landfills with different operation modes, namely conventional landfill (CL), leachate directly recirculated landfill (RL) and leachate pre-treated bioreactor landfill (BL). It showed that Cu and Zn in refuse experienced periodic migration and retention gradually during decomposition, and the variation of Cu(II) and Zn(II) in leachate correspondingly reflected the releasing behavior of Cu and Zn in landfill refuse at different stabilization stages. Except for their accumulated leaching amounts, Cu(II) and Zn(II) concentrations in leachate from landfills with different operation modes had no significant difference. The accumulated leaching amounts of Cu and Zn from CL showed exponential increase, while those of RL and BL showed exponential decay. The operation of bioreactor landfill with leachate recirculation can obviously attenuate the heavy metal leaching than conventional operation. The introduction of methanogenic reactor (MR) in bioreactor landfill can further promote the immobilization of heavy metal in refuse than leachate recirculation directly.

Removal of heavy metal ions from municipal solid waste leachate using coal fly ash as an adsorbent

The purpose of this study was to investigate the possibility of the utilization of coal fly ash as a low cost adsorbent material for the adsorption of heavy metal ions (Zn, Pb, Cd, Mn and Cu) present in the municipal solid waste leachate. Batch experiments were conducted to determine the effect of contact time and fly ash dosage on adsorption of heavy metals. Experimental data were evaluated to find out kinetic characteristics of the adsorption process. The isothermal data could be well described by the Freundlich adsorption model. Kinetic parameters of adsorption such as the pseudo first-order constant, pseudo second-order constant and the intraparticle diffusion rate constant were determined. The fly ash concentration required to achieve maximum heavy metal removal was found to be 2g/L with the removal efficiencies of 39%, 28%, 74%, 42% and 71% for Cu, Mn, Pb, Zn and Cd respectively. The results of the study demonstrated that the fly ash could be used as an effective low cost adsorbent for the removal of heavy metal ions from municipal solid waste leachate.

Laboratory study on the leaching potential of spent alkaline batteries

Four different leaching tests were carried out with spent alkaline batteries as an attempt to quantify the environmental potential burdens associated with landfilling. The tests were performed in columns filled up with batteries either entire or cross-cut, using either deionized water or nitric acid solution as leachant. In a first set of tests, the NEN 7343 standard procedure was followed, with leachant circulating in open circuit from bottom to top through columns. These tests were extended to another leaching step where leachant percolated the columns in a closed loop process. Leachate solutions were periodically sampled and pH, conductivity, density, redox potential, sulphates, chlorides and heavy metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Tl and Zn) were determined in the samples. The results showed that the total amount of substances leached in tests with cross-cut batteries was higher than with entire ones; zinc and sulphates were the substances found the most in the leachate solutions. In general, the amount of substances dissolved in open circuit is higher than in closed loop due to the effect of solution saturation and the absence of fresh solution addition. Results were compared with metal contents in the batteries and with legal limits for acceptance in landfill (Decision 2003/33/CE and Decree-Law 152/2002). None of the metals were meaningfully dissolved comparatively to its content in the batteries, except Hg. Despite the differences in the experiment procedure used and the one stated in the legislation (mixing, contact time and granulometry), the comparison of results obtained with cross-cut batteries using deionized water with legal limits showed that batteries studied could be considered hazardous waste.

Releasing behavior of zinc in recirculated bioreactor landfill

The purpose of this research was to determine the releasing behavior of zinc in municipal solid waste (MSW) in landfill site with respect to refuse and leachate as an inseparable system. Two simulated bioreactor landfills, one with leachate recirculation and the other without, were operated in room temperature for 320 days. Results showed that the content of zinc in MSW could amount to 591.29+/-31.33-632.14+/-18.98 microg g(-1) dry weight(-1) (DW(-1)). It exceeded the set standard for "Environmental quality standard for soil" (< or =500 microg g(-1) DW(-1)) and had high potential environmental risk. The releasing behavior of zinc in refuse mainly experienced speciation of solid-Zn, Zn(2+), ZnHCO(3)(+), ZnCO(3), Zn(OH)(+), Zn(OH)(2), Zn(NH(3))(4)(2+), ZnS, etc. Zinc in refuse showed behaviors of staggered migration and retention, which corresponded with the degradation process of refuse in bioreactor landfill. The Zn(2+) concentration in leachate, which varied correspondingly with releasing behavior of zinc in refuse, were 0.75 mg L(-1) to 3.13 mg L(-1) and had no great difference in landfill with different operation modes (CL and RL). However, the amount of Zn(2+) leached out from refuse, which accounted for 28.70 mg and 130.67 mg after 320 day's operation, respectively. More attention should be paid to the inseparable system including refuse and leachate together.

Releasing behavior of copper in recirculated bioreactor landfill

The purpose of this study was to determine the releasing behavior of copper in municipal solid waste (MSW) in landfill with respect to refuse and leachate as an inseparable system. Two simulated bioreactor landfills, one with leachate recirculation and the other without, were operated in room temperature for 320 days. Copper in refuse showed behaviors of staggered migration and retention, which corresponded with the degradation process of landfill obviously. The significant different amounts of Cu2+ leached out from refuse into leachate of two landfills were 24.74 mg and 118.53 mg after 320 days' operation, respectively. It also reflected the releasing behavior of copper in landfill refuse at different stage accordingly. The results confirmed that the refuse in landfill had high potential of secondary pollution after closure.

Disposal practices for unwanted residential medications in the United States

The occurrence of trace levels of prescription and over-the-counter pharmaceuticals in the environment began to receive concerted attention nearly two decades ago. The public's growing awareness and concern over the presence of these chemicals, especially in drinking water, has served to catalyze considerable discussion and debate regarding the best practices for disposal of unused or unwanted medications. In the United States, the first federal guidance for consumers was issued in 2007. It recommends discarding unused pharmaceuticals to household trash, after taking precautions to mix the pharmaceuticals with an inert substance and conceal the contents from view. Providing the consumer with additional options for conscientious disposal are various community, city, and state collection events, ongoing programs, and government-funded pilot projects. These strategies include the opportunity to mail or bring unused medications to various collection points, such as pharmacies, for eventual destruction. All of these approaches to medication disposal play roles in reducing the introduction of pharmaceuticals to the environment.

Performance of a full-scale biofilter with peat and ash as a medium for treating industrial landfill leachate: a 3-year study of pollutant removal efficiency

Shredder residues of end-of-life vehicles and white goods are a complex waste stream, which nowadays most often is disposed of at industrial landfills. This paper describes the most important findings concerning the complex composition of the landfill leachate and its on-site, year-round treatment under cold-climate conditions. A 3-year investigation has confirmed that concentrations of different types of pollutants, most of them at low initial concentrations, can be simultaneously reduced in vertical-flow biofilters consisting of a mixture of peat and carbon-containing ash. For metals such as Mn, Cu, Sn, Cd, Pb, Fe and Ni the average removal was 73, 72, 66, 60, 55, 55 and 37%, respectively. An average reduction of NH(4)-N (45%), N(tot) (25%), total organic carbon (30%), dissolved organic carbon (28%) and suspended solids (38%) was also obtained. A good reduction was achieved for phenols (between 75 and 95%), polychlorinated biphenyls (between 22 and 99%), and gas chromatography-mass spectrometry amenable pollutants, considered at initial concentration above 50 microg L( -1) (between 80 and 100%). The performance of the biofilter system was good in spite of large variations of inlet concentration during the considered period.

In vitro assessment of genotoxic effects of electric arc furnace dust on human lymphocytes using the alkaline comet assay

In vitro genotoxic effects of leachates of electric arc furnace dust (EAFD) on human peripheral lymphocytes, assessed prior and following the treatment with a strong alkaline solution were investigated using the alkaline comet assay. Prior and following the treatment, lymphocytes were incubated with leachate of EAFD for 6 and 24 hours at 37 degrees C. Negative controls were also included. Mean values of the tail lengths established in the samples treated with the leachate stemming from the original dust for 6 and 24 hours, were 15.70 microm and 16.78 microm, respectively, as compared to 12.33 microm found in the control sample. Slight, but significant increase in the tail length was also found with the dust treated with a strong alkaline solution (13.37 microm and 13.60 microm). In case of high heavy metal concentrations (the extract of the original furnace dust), the incubation period was revealed to be of significance as well. The obtained results lead to the conclusion that alkaline comet assay could be used as a rapid, sensitive and low-cost tool when assessing genotoxicity of various waste materials, such as leachates of the electric arc furnace dust.

Bioassays for the evaluation of landfill leachate toxicity

This article reviews the application of bioassays for assessing the toxicity hazard posed by landfill leachate discharged to an aquatic environment. Landfill leachate is a complex mixture of chemicals; thus it is difficult to assess the risk posed to aquatic wildlife using standard chemical identification techniques, such as gas chromatography-mass spectroscopy (GC-MS). From this review it is clear that toxicity testing, using species that represent the different trophic levels, is a superior way to predict the risk posed by discharge than chemical analysis. Previous studies assessed leachate toxicity using bacteria, algae, plants, invertebrates, fish, and genotoxicity. Studies showed that leachate exhibits a wide range of toxicities to the species tested. Ammonia, alkalinity, heavy metals, and recalcitrant organics were identified to be the cause of adverse responses from the test organisms. Concentrations of these chemicals were found to depend upon the types of waste landfilled. As part of this review, Slooff analysis was applied to published results to calculate the sensitivity of test species. It was concluded that Lemna minor and Thamnocephalus platyurus were the most sensitive tests and, Vibrio fischeri (Microtox) was the least sensitive test available. Little is known about the sensitivity of each species to the different types of waste that might have been landfilled. A battery of tests needed for a more accurate assessment of landfill leachate is proposed. Some of the more common tests have been replaced by more sensitive tests that produce more relevant results for the industry and regulators.

Transmission electron microscopy (TEM) investigations of Mn-oxide rich cathodic material from spent disposable alkaline batteries

Transmission electron microscopy (TEM) techniques were used to investigate the spent cathodic material of a single common brand of disposable alkaline batteries. Mn-oxide particles are anhedral and irregular in shape and compose an estimated 99-95% of the < 10 microm size fraction of sample material. Diameters of particles vary widely and typically are between 50 nm and 3 microm; however, most particles are approximately 200-400 nm in diameter. Chemical composition varies for Mn-oxide particles with concentrations being SiO2 (0.00-1.52 wt%), TiO2 (0.49-4.58 wt%), MnO (65.85-92.06 wt%), ZnO (1.00-7.53 wt%), K2O (4.97-20.48 wt%) and SO3 (0.43-2.21 wt%). Discrete prismatic zinc crystals occur and vary from a maximum of approximately 0.8 microm long x 0.15 microm wide, to 100 nm long x 20 nm wide. Titanium metal was also observed in samples and composes approximately 0.25-1.0% of the < 10 microm size fraction of sample material. Results of this study suggest that battery components may be recycled in some special applications. Examples are low energy-low material requirement products such as paint pigments and Zn nanoparticles. This investigation provides detailed constraints on the nature of spent cathodic materials to improve existing recycling methods and develop new technologies.

Toxic potential of municipal solid waste leachates in transgenic Drosophila melanogaster (hsp70-lacZ): hsp70 as a marker of cellular damage

Municipal solid wastes (MSWs) are one of the major sources of environmental pollution. Leachates from these wastes might contaminate the water sources and affect quality of environment. The study was carried out to determine the possible toxic effects of leachates from MSW in transgenic Drosophila melanogaster (hsp70-lacZ). Third instar larvae exposed to 1.0-3.0% of these leachates at different time intervals were examined for hsp70 expression, oxidative stress enzyme activities, proteotoxicity, tissue damage along with effect on emergence and reproduction. Maximum hsp70 expression was observed in the larvae exposed to highly acidic leachates. Overwhelming of hsp70 expression in the exposed larvae caused a concomitant decline in total protein content and a significant elevation in oxidative stress enzymes and lipid peroxidation (LPO) product. The leachates caused a significant delay in emergence of flies and affected the reproductive performance of the flies at the tested concentrations. The present study highlights the toxic potential of MSW leachates and the advantage of Drosophila as a model to evaluate the impact of leachates at organismal and cellular levels, also advocating Hsp70 as the first tier indicator of toxicity.

Chemicals in household products: problems with solutions

The success of a regulatory regime in decreasing point-source emissions of some harmful chemicals has highlighted the significance of other sources. A growing number of potentially harmful chemicals have been incorporated into an expanding range of domestic household products and are sold worldwide. Tighter regulation has been proposed, and the European Commission has introduced the Regulation on the Registration, Evaluation, and Authorisation of Chemicals to address this concern. However, it is clear that in addition to the regulation, there is a potential to effect change through retailer and consumer attitudes and behaviours. Interviews were conducted with 7 key stakeholder groups to identify critical issues, which were then explored using a public survey questionnaire (1,008 respondents) and 8 subsequent focus groups. The findings demonstrated that the issue of chemicals in products is of concern to consumers for reasons of personal health rather than environmental protection. Key obstacles to the wider purchase of "green-alternative" products included perceived high cost and poor performance, lack of availability of products, and poor information concerning such products. Although improved regulation was seen as part of the solution, consumers must also play a role. It was clear from this study that consumers are not currently able to make informed choices about the chemicals they use but that they would be receptive to moving toward a more sustainable use of chemicals in the future if empowered to do so.

Characterisation of VOCs emitted by open cells receiving municipal solid waste

This study gives relevant information on the variation of concentrations of certain volatile organic compounds (BTEX, alkanes, organochlorides and terpenes) emitted by open cells receiving municipal solid waste. These compounds represent a large fraction of the total trace components present in landfill gas. The VOC measurements were carried out in the atmosphere of an open landfill cell as a function of time and meteorological parameters, but also as a function of the activity of trucks unloading waste and compaction vehicles, in order to identify the factors that influence VOC emissions. Comparisons were performed systematically between the surface of the open cell and the corresponding mechanical activity. The measurements carried out during the course of the day highlighted the influence of air temperature and waste composition on VOC emissions while measurements of activity showed that the activity of fresh waste compaction vehicles is responsible for the highest VOC emissions. Such information is essential since most of the data in the literature relate to analyses of VOC traces in the biogas network and not in the air of the open cells as a function of different parameters (i.e. meteorological parameters, activity on the site). The highest VOC concentrations (in microg/m3) in the area of an open cell were obtained for: tetrachloroethylene (9810), toluene (8230), limonene (4550), m-xylene (3980) and trichloroethylene (3680). The results showed that the TWA values (the time-weighted average concentrations for up to an 8-h workday) established by INRS/France for the personnel in the station were complied with on the site studied.

The effect of landfill leachate composition on organics and nitrogen removal in an activated sludge system with bentonite additive

A pre-denitrification activated sludge system (AS) without internal recycle was used in lab-scale studies of landfill leachate treatment. A bentonite supplement at a ratio of 1:4 (mineral : biomass) was used to ensure high sludge settling levels and to serve as a micro-organisms carrier. The system was operated within different parameters such as hydraulic retention time (HRT), ammonia loading rate (ALR) or external recycle ratio, which was adapted to treat varying leachate concentrations of COD and ammonia, ranging from 1020 to 2680 mgO(2)l(-1) and 400-890 mgNH(4)-Nl(-1) respectively. The nitrification was complete and ammonia oxidation reached 99%; this was obtained while the ALR did not exceed 0.09 g NH(4)(+)-Ng(-1)MLVSS d(-1) and HRT was not lower than 1 day (in the aeration reactor). The performance of denitrification was successfully improved by controlling the external recycle rate, when the BOD(5)/N ratio in the raw leachate was 4.1. Consequently, N-removal of up to 80% was achieved. A 10-fold decrease in the denitrification rate was obtained at a BOD(5)/N ratio of 0.5. The efficiency of COD removal varied significantly from 36% to 84%. The positive effect of bentonite addition was determined and is discussed based on preliminary studies. The experiments were carried out in fill-and-draw activated sludge with bentonite; the biomass ratio was 1:2. The activated sludge with bentonite was fed with a synthetic high ammonia and organic-free medium.

Bioaccumulation of metals and effects of landfill pollution in small mammals. Part I. The greater white-toothed shrew, Crocidura russula

Here we quantified the bioaccumulation of metals (lead, mercury, cadmium, iron, magnesium, zinc, copper, manganese, molybdenum, and chromium) and assessed several morphological (RI, relative weights) and genotoxic parameters as biomarkers of pollution from the landfill of Garraf (Barcelona, NE Spain). Specimens of Crocidura russula (Insectivora, Mammalia) from the landfill site showed increased Pb, Cd, Mg, Zn, Cu, and Cr concentrations in their tissues. Levels of mercury were below detection limits. Concentrations of Cd, Pb, and Cr varied significantly with age and no differences were found between males and females. While no differences were found in morphological parameters between shrews from the two sites, those from the polluted one showed more micronuclei in blood than those from reference site (1.786+/-0.272 vs. 0.088+/-0.045 per thousand; U=46.000, p<0.001). The considerable amounts of potentially toxic metals (Pb till 59.71 and Cd till 56.57microgg(-1) DW in kidneys) and the genotoxic effects indicate the harmful effect on biota. We consider necessary biomonitoring this landfill sited in a partially protected area.

Simultaneous sorption of benzene and heavy metals onto two organoclays

An experimental study was performed to determine the feasibility of using hexadecyltrimethylammonium bentonite clay (HDTMA-clay) and benzyltriethylammonium bentonite clay (BTEA-clay) for simultaneous sorption of benzene and one of four heavy metals (Pb, Cd, Zn and Hg). Specifically, the role of competition between benzene and each heavy metal was studied. The sorption of Pb, Cd, and Zn on both BTEA- and HDTMA-clay decreases in the presence of benzene relative to the sorption obtained without benzene present. This indicates that there is competition between Pb, Cd, and Zn and organic compounds during sorption onto both organoclays. On BTEA-clay, Cd, Pb and Zn sorption was reduced by 24, 37, and 51%, respectively. On HDTMA-clay, Cd, Pb, and Zn sorption was reduced by 25, 30, and 57%, respectively. Hg sorption was not affected either by the presence of benzene or by the organoclays used. The sorption of benzene onto BTEA-clay in the presence of Hg, Zn, Pb, and Cd was less than the sorption observed when no heavy metal was present. The presence of Hg resulted in the most significant decrease in sorption, causing a 59% reduction in benzene sorption. The presence of Zn, Pb, and Cd caused a 41, 35, and 31% reduction in benzene sorption, respectively. In general, sorption of benzene onto HDTMA-clay was not affected by the presence of the heavy metals, indicating there are no competitive effects observed with Zn, Cd, and Hg when HDTMA-clay was the sorbent. However, the presence of Pb did cause a 20% reduction in benzene sorption to HDTMA-clay. Both organoclays tested had dual sorptive properties for both heavy metals and an organic contaminant. While the competitive effects were greater for the BTEA clay, both organoclays are capable of simultaneously removing benzene and either Zn, Cd, Hg, or Pb from aqueous solution.

Household hazardous waste data for the UK by direct sampling

The amount of household hazardous waste (HHW) disposed of in the United Kingdom (UK) requires assessment. This paper describes a direct analysis study carried out in three areas in southeast England involving over 500 households. Each participating householder was provided with a special bin in which to place items corresponding to a list of HHW. The amount of waste collected was split into nine broad categories: batteries, home maintenance (DIY), vehicle upkeep, pesticides, pet care, pharmaceuticals, photographic chemicals, household cleaners, and printer cartridges. Over 1 T of waste was collected from the sample households over a 32-week period, which would correspond to an estimated 51,000 T if extrapolated to the UK population for the same period or over 7,000 T per month. Details of likely disposal routes adopted by householders were also sought, demonstrating the different pathways selected for different waste categories. Co-disposal with residual household waste dominated for waste batteries and veterinary medicines, hence avoiding classification as hazardous waste under new UK waste regulations. The information can be used to set a baseline for the management of HHW and provides information for an environmental risk assessment of the disposal of such wastes to landfill.

Household hazardous waste disposal to landfill: using LandSim to model leachate migration

Municipal solid waste (MSW) landfill leachate contains a number of aquatic pollutants. A specific MSW stream often referred to as household hazardous waste (HHW) can be considered to contribute a large proportion of these pollutants. This paper describes the use of the LandSim (Landfill Performance Simulation) modelling program to assess the environmental consequences of leachate release from a generic MSW landfill in receipt of co-disposed HHW. Heavy metals and organic pollutants were found to migrate into the zones beneath a model landfill site over a 20,000-year period. Arsenic and chromium were found to exceed European Union and US-EPA drinking water standards at the unsaturated zone/aquifer interface, with levels of mercury and cadmium exceeding minimum reporting values (MRVs). The findings demonstrate the pollution potential arising from HHW disposal with MSW.

Disposal of unwanted medicines from households in Kuwait

OBJECTIVE

To test the effectiveness of a simple educational intervention to encourage households to return unwanted medicines via a municipal collection program and to investigate the most common sources and types of unwanted medicines in the home.

SETTING

Households in Kuwait City, Kuwait.

METHOD

A convenience sample of 200 households in Kuwait received an educational letter and special plastic bags in which to place unwanted medicines to be collected by the municipality. They also completed a short self-administered questionnaire on medicine disposal habits. A second convenience sample of an additional 14 households in Kuwait received the same educational letter together with a face-to-face interview and assistance in collecting unwanted medicines. Returned medicines were categorized and their source and expiry dates noted.

MAIN OUTCOME MEASURE

Quantity and types of medicines returned.

RESULTS

No medicines were collected from the 200 households participating in the municipal collection scheme in spite of 45% of respondents agreeing that this was an appropriate method of disposal. 97% of the respondents said they currently disposed of their medication in the garbage. The second intervention yielded 123 medicines from 14 homes, a third of which were for the respiratory system (38% of these were cough and cold preparations). The majority of returned medications were for acute conditions, almost all were from government health centers and 52% were expired.

CONCLUSION

Simple collection of unwanted medicines by municipal authorities is unlikely to be effective. A multifaceted approach is more effective but resource intensive. Using local pharmacies as collection points in a reverse distribution system may be more cost-effective.

DNA damage induced in human peripheral blood lymphocytes by industrial solid waste and municipal sludge leachates

Exposure of humans to toxic compounds occurs mostly in the form of complex mixtures. Leachates, consisting of mixtures of many chemicals, are a potential risk to human health. In the present study, leachates of solid wastes from a polyfiber factory (PFL), an aeronautical plant (AEL), and a municipal sludge leachate (MSL) were assessed for their ability to induce DNA damage in human peripheral blood lymphocytes using the alkaline Comet assay. The leachates also were examined for their physical and chemical properties. Lymphocytes were incubated with 0.5-15.0% concentrations (pH range 7.1-7.4) of the test leachates for 3 hr at 37 degrees C, and treatment with 1 mM ethyl methanesulfonate served as a positive control. All three leachates induced significant (P < 0.05), concentration-dependent increases in DNA damage compared with the negative control, as measured by increases in Olive tail moment (arbitrary units), tail DNA (%), and tail length (mum). A comparison of these variables among the treatment groups indicated that the MSL induced the most DNA damage. Inductively coupled plasma emission spectrometry analysis of the leachates indicated that they contained high concentrations of heavy metals, viz. iron, manganese, nickel, zinc, cadmium, chromium, and lead. The individual, synergistic, or antagonistic effects of these chemicals in the leachates may be responsible for the DNA damage. Our data indicate that the ever-increasing amounts of leachates from waste landfill sites have the potential to induce DNA damage and suggest that the exposure of human populations to these leachates may lead to adverse health effects.

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.

Household disposal of pharmaceuticals and perception of risk to the environment

The presence of pharmaceuticals in the aquatic environment has become a cause for increasing concern in recent years. A wide range of pharmaceuticals have been discovered in fresh and marine waters and it has recently been shown that even in small quantities these compounds have the potential to cause harm to aquatic life. Their main pathway into the environment is through household use, and the disposal of unused or expired pharmaceuticals as manufacture is well-regulated. This work aimed to investigate the link between risk perception and household disposal. A survey was carried out, and around 400 householders, predominantly from the South-East of England, were interviewed. Information on when and how they disposed of unfinished pharmaceuticals was gathered. These responses were cross referenced with data on personal information and attitudes in order to determine the factors affecting the methods of disposal that are chosen. Although a link between perception of risk and the choice of disposal methods was not proved, findings demonstrated that perceived environmental awareness had an impact on the method of disposal chosen.

DNA damage in bone marrow and blood cells of mice exposed to municipal sludge leachates

Leachates of municipal solid waste from unsecured disposal sites contaminate sources of potable water and affect human health. In the present study, we have used the Comet assay to evaluate the DNA damage in mice exposed to municipal sludge leachates. Ten percent leachates were prepared from municipal sludge obtained from two different disposal drains. Male Swiss albino mice were treated daily with 0.1-0.4 ml of the leachates by oral gavage for 15 days, and the DNA damage was evaluated in bone marrow and blood using Olive tail moment, % tail DNA, and tail length as measures of DNA damage. Physicochemical and metal analysis of the leachates detected the presence of cadmium, chromium, copper, nickel, lead, and zinc, as well as elevated concentrations of sulfate and nitrate. Both of the leachates produced significant dose-responsive increases in DNA damage in both mouse tissues. There were no significant differences in the responses for any of the Comet endpoints between tissues (for the same leachate sample) or between leachate samples (for the same tissue). The results of this study indicate that municipal waste leachates produce DNA damage in vivo.

PCDD/DF in leachates from Korean MSW landfills

We analyzed levels of PCDD/DF in leachate liquid and solid from five Korean municipal solid waste landfills to investigate the relationship between PCDD/DF and dissolved organic carbon and suspended solids in raw leachate. The concentrations of PCDD/DF ranged from 173.2 to 1329.4 pg/l and 4.1 to 46.22 pg-TEQ/l. The range of PCDD/DF was 123.2-1161.3 pg/l in leachate solid and 50.0-383.3 pg/l in leachate liquid. Our results indicated that PCDD/DF in solid play a major role in determining their concentration levels, and the distribution of isomers in solid was almost the same as in liquid leachate. In addition, highly chlorinated PCDD/DF, such as HpCDD/DF and OCDD/DF, accounted for more than 70% of all isomers. Levels of PCDD/DF in liquid were strongly correlated with dissolved organic carbon concentrations, which increase the leachability (R2 = 0.92 in Korean leachate) of PCDD/DF from contaminant sources. Despite this high linearity between dissolved organic carbon and dissolved PCDD/DF, we observed no strong relationship between dissolved organic carbon and solid phase PCDD/DF (R2 = 0.001). Dissolved organic carbon scarcely affects dissolved PCDD/DF to be combined with solids. As a result, it is not appropriate for incinerated ash to be dumped with municipal solid wastes, as they have a large potential to result in high levels of organic matter, and therefore PCDD/DF, in leachate.

Practice and opinion towards disposal of unused medication in Kuwait

OBJECTIVES

The aim of this study was to measure the attitude and practice of Kuwaiti patients in Kuwait with regard to safe disposal of unwanted medicines.

SUBJECTS AND METHODS

Three-hundred patients or their family members waiting for prescriptions at public general hospitals in Kuwait completed a questionnaire soliciting their practice with regard to medication use and disposal, and their opinion of the best way to dispose of unwanted medicines.

RESULTS

Almost half of the respondents (45.4%) obtained medicines on prescription more than 3 times a year and almost all had unwanted medicines in the home. Reasons for possessing unused medication were mostly due to a change of medication by the doctor (48.9%), or self-discontinuation (25.8%). Their most common method of disposal was to throw unwanted medicines in the trash (76.5%) or flush them down the drain (11.2%). Half (54.0%) thought that a system of taking medicines to pharmacies for safe disposal would be favorable.

CONCLUSION

The study indicates that the need for an appropriate method for disposal of unwanted medication exists in Kuwait. Hence, guidelines on safe disposal of unwanted medicines are required and an organized method of collecting unused medication needs to be introduced.

Household disposal of pharmaceuticals as a pathway for aquatic contamination in the United kingdom

Pharmaceuticals are produced and used in increasingly large volumes every year. With this growth comes concern about the fate and effects of these compounds in the environment. The discovery of pharmaceuticals in the aquatic environment has stimulated research in the last decade. A wide range of pharmaceuticals has been found in fresh and marine waters, and it has recently been shown that even in small quantities, some of these compounds have the potential to cause harm to aquatic life. The primary pathway into the environment is the use and disposal of medicines; although much of the research in the area currently focuses on the removal of pharmaceuticals during sewage treatment processes, disposal via household waste might be a significant pathway requiring further research. To investigate the household disposal of unused and expired pharmaceuticals as a source of pharmaceutical compounds in the environment, we carried out a survey and interviewed members of 400 households, predominantly from southeastern England. We used the information on when and how they disposed of unfinished pharmaceuticals to construct a conceptual model to assess the pathways of human pharmaceuticals into the environment. The model demonstrated that disposal of unused pharmaceuticals, either by household waste or via the sink or toilet, may be a prominent route that requires greater attention.