Waste management health risk assessment: A case study of a solid waste landfill in South Italy

An integrated risk assessment study has been performed in an area within 5 km from a landfill that accepts non hazardous waste. The risk assessment was based on measured emissions and maximum chronic population exposure, for both children and adults, to contaminated air, some foods and soil. The toxic effects assessed were limited to the main known carcinogenic compounds emitted from landfills coming both from landfill gas torch combustion (e.g., dioxins, furans and polycyclic aromatic hydrocarbons, PAHs) and from diffusive emissions (vinyl chloride monomer, VCM). Risk assessment has been performed both for carcinogenic and non-carcinogenic effects. Results indicate that cancer and non-cancer effects risk (hazard index, HI) are largely below the values accepted from the main international agencies (e.g., WHO, US EPA) and national legislation (D.Lgs. 152/2006 and D.Lgs. 4/2008).     

Health risk assessment of air emissions from a municipal solid waste incineration plant--a case study

A health risk assessment of long-term emissions of carcinogenic and non-carcinogenic air pollutants has been carried out for the municipal solid waste incinerator (MSWI) of the city of Taranto, Italy. Ground level air concentrations and soil deposition of carcinogenic (Polychlorinated Dibenzo-p-Dioxins/Furans and Cd) and non-carcinogenic (Pb and Hg) pollutants have been estimated using a well documented atmospheric dispersion model. Health risk values for air inhalation, dermal contact, soil and food ingestion have been calculated based on a combination of these concentrations and a matrix of environmental exposure factors. Exposure of the surrounding population has been addressed for different release scenarios based on four pollutants, four exposure pathways and two receptor groups (children and adults). Spatial risk distribution and cancer excess cases projected from plant emissions have been compared with background mortality records. Estimated results based on the MSWI emissions show: (1) individual risks well below maximum acceptable levels, (2) very small incremental cancer risk compared with background level.     

Risk from exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans emitted from municipal incinerators

Incineration of wastes seems to be one of the major sources of PCDFs and PCDFs (dioxins). Their prevalence and extreme stability in the environment, bioavailability and bioaccumulation in the biota and human adipose tissues and breast milk are of much concern. 2,3,7,8-TCDD is one of the most toxic chemicals known and has been found to have teratogenic and carcinogenic activities in animals. Exposure to TCDD can result in chloracne, general weakness, drastic weight loss, hyperpigmentation of skin, hirsutism, porphyria cutanea tarda, liver damage, changes in activities of various liver enzymatic levels, abnormal lipid metabolism, abnormalities of the endocrine and immune systems, and possible teratogenic effects in humans. Moreover, chronic bioassay data indicate that TCDD is one of the most potent carcinogens known. It promotes liver and skin carcinogeneses, and is an initiator for various target organs in rodent test systems. There is only a limited number human epi-studies on carcinogenic outcome as a result of exposure to TCDD in isolated population.According to the classification system of the International Agency for Research on Cancer (IARC), the qualitative evidence for carcinogenicity of TCDD is considered to be “sufficient” in animals and “nadequate” in humans. Consequently, this chemical has been placed in IARC's 2B category. A modification of the multistage model is utilized for extrapolating high-dose, two-year animal cancer bioassay data to estimate human cancer risk for long-term, low-dose human exposure. The upper limit of incremental cancer risk is 3.3 × 10⁻⁵ for a continuous lifetime exposure to 1 pg m⁻³ of TCDD in ambient air. With the exception of 2,3,7,8-TCDD and a mixture of 1,2,3,6,7,8- and 1,2,3,7,8,9-HxCDDs, the chronic toxicity data on the rest of the 75 PCDD and 135 PCDF congeners are badly deficient. In the a absence of chronic bioassay data on other PCDFs and PCDFs, several TCDD equivalent approaches have been proposed for risk assessment on other congeners or mixtures. This paper compares the various approaches.     

Optimization of co-digestion of various industrial sludges for biogas production and sludge treatment: Methane production potential experiments and modeling

Optimal biogas production and sludge treatment were studied by co-digestion experiments and modeling using five different wastewater sludges generated from paper, chemical, petrochemical, automobile, and food processing industries situated in Ulsan Industrial Complex, Ulsan, South Korea. The biomethane production potential test was conducted in simplex-centroid mixture design, fitted to regression equation, and some optimal co-digestion scenarios were given by combined desirability function based multi-objective optimization technique for both methane yield and the quantity of sludge digested. The co-digestion model incorporating main and interaction effects among sludges were utilized to predict the maximum possible methane yield. The optimization routine for methane production with different industrial sludges in batches were repeated with the left-over sludge of earlier cycle, till all sludges have been completely treated. Among the possible scenarios, a maximum methane yield of 1161.53 m³ is anticipated in three batches followed by 1130.33 m³ and 1045.65 m³ in five and two batches, respectively. This study shows a scientific approach to find a practical solution to utilize diverse industrial sludges in both treatment and biogas production perspectives.     

Occupational hygiene in terms of volatile organic compounds (VOCs) and bioaerosols at two solid waste management plants in Finland

Factors affecting occupational hygiene were measured at the solid waste transferring plant at Hyvinkää and at the optic separation plant in Hämeenlinna. Measurements consisted of volatile organic compounds (VOCs) and bioaerosols including microbes, dust and endotoxins.The most abundant compounds in both of the plants were aliphatic and aromatic hydrocarbons, esters of carboxylic acids, ketones and terpenes. In terms of odour generation, the most important emissions were acetic acid, 2,3-butanedione, ethyl acetate, alpha-pinene and limonene due to their low threshold odour concentrations. At the optic waste separation plant, limonene occurred at the highest concentration of all single compounds of identified VOCs. The concentration of any single volatile organic compound did not exceed the occupational exposure limit (OEL) concentration. However, 2,3-butanedione as a health risk compound is discussed based on recent scientific findings linking it to lung disease.Microbe and dust concentrations were low at the waste transferring plant. Only endotoxin concentrations may cause health problems; the average concentration inside the plant was 425 EU/m³ which clearly exceeded the threshold value of 90 EU/m³. In the wheel loader cabin the endotoxin concentrations were below 1 EU/m³. High microbial and endotoxin concentrations were measured in the processing hall at the optic waste separation plant. The average concentration of endotoxins was found to be 10,980 EU/m³, a concentration which may cause health risks. Concentrations of viable fungi were quite high in few measurements in the control room. The most problematic factor was endotoxins whose average measured concentrations was 4853 EU/m³.     

Assessing detoxification and degradation of wood preserving and petroleum wastes in contaminated soil

This study was undertaken to evaluate in-situ soil bioremediation processes, including degradation and detoxification, for two types of wood preserving wastes and two types of petroleum refining wastes at high concentrations in an unacclimated soil. The soil solid phase, water soluble fractions of the soil, and column leachates were evaluated. Two bioassays, a mutagenic potential asay (Ames assay) and an aqueous toxicity assay (Microtox^™ assay) were used to evaluate detoxification; high performance liquid chromatography was used to evaluate chemical concentration and degradation for eight polynuclear aromatic hydrocarbons (PAHs). The group of non-carcinogenic PAHs studied demonstrated greater degradation, ranging from 54–90% of mass added for the four wastes; the carcinogenic group of PAHs studied exhibited degradation ranging from 24–53% of mass added. Although no mutagenicity was observed in waste/soil mixtures after one year of treatment, Microtox^™ toxicity was observed in water soluble fractions and in leachate samples. An integration of information concerning degradation of hazardous constituents with bioassay information represents an approach for designing treatability studies and for evaluating the effectiveness of in-situ bioremediation of contaminated soil/waste systems. When combined with information from waste, site and soil characterization studies, the data generated in treatability studies may be used in predictive mathematical models to: (1) evaluate the effectiveness of use of on-site bioremediation for treatment of wastes in soil systems; (2) develop appropriate containment structures to prevent unacceptable waste transport from the treatment zone; and (3) design performance monitoring strategies.     

Time allocation and recycling activities

Recycling is time consuming and the time available for housework may determine the intensity of recycling activities. In this study, we conducted a survey of 546 Japanese households and asked them their daily practice of five varieties of recycling activities: (1) choice of refill products, (2) use of own shopping bags, (3) sorting of recycled papers from burnable waste, (4) use of own drinking bottles when going out, and (5) use of recycle boxes prepared at the grocery store. We also asked households to record their behavior for two successive days. By combining recycling activity data and diary data, we estimate a multivariate probit model to empirically examine whether time available for housework determines the intensity of five varieties of recycling activities. The empirical result demonstrates that an individual that can allocate sufficient time for housework tends to purchase refill products. He or she also tends to bring their own shopping bags for grocery shopping. We also find that the size of house and the number of family members determine the likelihood of recycling. A housewife living with many family members in a large house is more likely to engage in time-consuming recycling activities.     

Inventory and treatment of compost maturation emissions in a municipal solid waste treatment facility

Emissions of volatile organic compounds (VOCs) from the compost maturation building in a municipal solid waste treatment facility were inventoried by solid phase microextraction and gas chromatography–mass spectrometry. A large diversity of chemical classes and compounds were found. The highest concentrations were found for n-butanol, methyl ethyl ketone and limonene (ppm_v level). Also, a range of compounds exceeded their odor threshold evidencing that treatment was needed. Performance of a chemical scrubber followed by two parallel biofilters packed with an advanced packing material and treating an average airflow of 99,300 m³ h^?1 was assessed in the treatment of the VOCs inventoried. Performance of the odor abatement system was evaluated in terms of removal efficiency by comparing inlet and outlet abundances. Outlet concentrations of selected VOCs permitted to identify critical odorants emitted to the atmosphere. In particular, limonene was found as the most critical VOC in the present study. Only six compounds from the odorant group were removed with efficiencies higher than 90%. Low removal efficiencies were found for most of the compounds present in the emission showing a significant relation with their chemical properties (functionality and solubility) and operational parameters (temperature, pH and inlet concentration). Interestingly, benzaldehyde and benzyl alcohol were found to be produced in the treatment system.     

Occupational hygiene in a Finnish drum composting plant

Bioaerosols (microbes, dust and endotoxins) and volatile organic compounds (VOCs) were determined in the working air of a drum composting plant treating source-separated catering waste. Different composting activities at the Oulu drum composting plant take place in their own units separated by modular design and constructions. Important implication of this is that the control room is a relatively clean working environment and the risk of exposure to harmful factors is low. However, the number of viable airborne microbes was high both in the biowaste receiving hall and in the drum composting hall. The concentration (geometric average) of total microbes was 21.8 million pcs/m3 in the biowaste receiving hall, 13.9 million pcs/m3 in the drum composting hall, and just 1.4 million pcs/m3 in the control room. Endotoxin concentrations were high in the biowaste receiving hall and in the drum composting hall. The average (arithmetic) endotoxin concentration was over the threshold value of 200 EU/m3 in both measurement locations. In all working areas, the average (arithmetic) dust concentrations were in a low range of 0.6-0.7 mg/m3, being below the Finnish threshold value of 5 mg/m3. In the receiving hall and drum composting hall, the concentrations of airborne microbes and endotoxins may rise to levels hazardous to health during prolonged exposure. It is advisable to use a respirator mask (class P3) in these areas. Detected volatile organic compounds were typical compounds of composting plants: carboxylic acids and their esters, alcohols, ketones, aldehydes, and terpenes. Concentrations of VOCs were much lower than the Finnish threshold limit values (Finnish TLVs), many of the quantified compounds exceeded their threshold odour concentrations (TOCs). Primary health effects due VOCs were not presumable at these concentrations but unpleasant odours may cause secondary symptoms such as nausea and hypersensitivity reactions. This situation is typical of composting plants where the workers are exposed to dozens of VOCs simultaneously. The odour units (OU/m3) were measured using olfactometer. The numbers were 23,000 OU/m3 at the output end of the composting drum and 6300 OU/m3 in the exhaust pipe. Inside the composting hall, the number of odour units was 500 and 560 OU/m3.     

Volatilization and Biodegradation of VOCs in Membrane Bioreactors (MBR)

Volatilization and biodegradation are major competitive volatile organic compound (VOC) removal mechanisms in biological wastewater treatment process, which depend on compound specific properties and system design/operational parameters. In this study, a mathematical model was used to determine major removal pathways at various organic loading rates (OLR), solids residence time (SRT) and dissolved oxygen (DO) concentrations in a biological process for vinyl acetate. Model results showed that biological treatment process should be designed with long SRT, high OLR and low DO concentrations to maximize biodegradation and minimize volatilization of VOCs. Unless a VOC is toxic to microorganisms under the given conditions, low VOC emission rates are an inherent advantage of MBRs, which operate at higher OLR and longer SRT compared to conventional activated sludge process. A lab scale membrane bioreactor (MBR) was operated at varying OLR to investigate the relative volatilization and biodegradation rates for acetaldehyde, butyraldehyde and vinyl acetate. Synthetic wastewater containing three VOCs was introduced to the MBR. The DO concentration and SRT was maintained at 2.0 mg L^{− 1} and 100 days, respectively. The overall VOC removal rate was more than 99.7% for three VOCs at all the OLR. For vinyl acetate, the biodegradation rate increased from 93.87 to 99.40% and the volatilization removal rate decreased from 6.09 to 0.59% as OLR was increased from 1.1 to 2.0 kg COD m^{− 3} d^{− 1}. It was confirmed that a MBR can be a promising solution to reduce VOC emissions from wastewater.     

Effects of volatile organic compounds on clay landfill liner performance

Clay borrow materials intended for use in a clay liner system were found to be contaminated by low concentrations of volatile organic chemicals (VOCs). The suspected source of contaminants was a nearby Superfund site where similar compounds were found in soil and groundwater. Based on these observations, questions were raised regarding the potential effects of VOCs on the performance of the clay materials as a landfill liner.Laboratory experiments were conducted to evaluate the effects of three levels of soil precontamination and two types of permeants. Atterberg tests showed that the precontaminations (acetone and m-xylene) and the simulated leachate (methylene chloride, trichloroethylene, and toluene), at the concentrations used, did not impact clay-pore fluid interaction. Sedimentation tests showed that the impact of methylene chloride, trichloroethylene, and toluene on sediment volume and rate of settlement was not detectable up to the maximum concentration level of 100 ppm for each chemical.From the permeation tests, acetone in the precontaminated samples was generally flushed out within three pore volumes but m-xylene was not detected (above the detection limit of 0.01 mg 1⁻¹) in the permeant effluent. The stabilized permeabilities of the specimens ranged from 0.2 × 10⁻⁷ to 3.0 × 10⁻⁷ cms⁻¹. It was found that precontamination of the clay at the levels studied did not affect organic chemical leachate transport/adsorption discernibly when compared with clean clay, and no measurable retardation or adsorption of VOCs in clay liners occurred in either clean clay or precontaminated clay.     

Sources and Variability of Indoor and Outdoor Gaseous Aerosol Precursors (O3, NOx and VOCs)

Measurements of indoor and outdoor aerosol concentrations and their gaseous precursors (O₃, NO and NO₂) as well as volatile organic compounds (VOCs) concentrations were performed at two houses in the Oslo metropolitan area. The variability of the concentration of gaseous compounds was studied in respect to their sources in the indoor and outdoor environments. Domestic heating during the winter and photochemical production during the summer were the main sources for outdoor NOx and O₃. In the indoor environment infiltration of outdoor air, candle burning, smoking and indoor chemical reactions were the main sources affecting their concentrations. The concentrations of VOCs outdoors were enhanced during the summer due to biogenic emissions whereas in the indoor environment their values were affected mostly by emissions from materials used during the recent refurbishing of the houses (>0.4 mg/m³).     

Baseline levels of bioaerosols and volatile organic compounds around a municipal waste incinerator prior to the construction of a mechanical-biological treatment plant

New waste management programs are currently aimed at developing alternative treatment technologies such as mechanical–biological treatment (MBT) and composting plants. However, there is still a high uncertainty concerning the chemical and microbiological risks for human health, not only for workers of these facilities, but also for the population living in the neighborhood. A new MBT plant is planned to be constructed adjacently to a municipal solid waste incinerator (MSWI) in Tarragona (Catalonia, Spain). In order to evaluate its potential impact and to differentiate the impacts of MSWI from those of the MBT when the latter is operative, a pre-operational survey was initiated by determining the concentrations of 20 volatile organic compounds (VOCs) and bioaerosols (total bacteria, Gram-negative bacteria, fungi and Aspergillus fumigatus) in airborne samples around the MSWI. The results indicated that the current concentrations of bioaerosols (ranges: 382–3882, 18–790, 44–926, and <1–7 CFU/m³ for fungi at 25 °C, fungi at 37 °C, total bacteria, and Gram-negative bacteria, respectively) and VOCs (ranging from 0.9 to 121.2 μg/m³) are very low in comparison to reported levels in indoor and outdoor air in composting and MBT plants, as well in urban and industrial zones. With the exception of total bacteria, no correlations were observed between the environmental concentrations of biological agents and the direction/distance from the facility. However, total bacteria presented significantly higher levels downwind. Moreover, a non-significant increase of VOCs was detected in sites closer to the incinerator, which means that the MSWI could have a very minor impact on the surrounding environment.     

石化企业固定顶储罐挥发性有机物排放量影响因素的分析

采用美国国家环保局推荐的储罐挥发性有机物(VOCs)排放量定量计算方法,以北京某石化企业轻柴油固定顶储罐为案例对象,计算了固定顶储罐的总损失。通过对不同参数进行调节,比较分析了各变量对损失量的影响程度,得出了影响固定顶储罐静置储藏损失和工作损失的关键参数和次要参数。并在此基础上,提出了降低固定顶储罐VOCs排放量的对应措施。实验结果表明:影响固定顶储罐静置储藏损失的关键参数为油品蒸气相对分子质量、日平均液体表面温度和液体存储高度,次要参数为日环境温差和罐漆太阳能吸收率;影响工作损失的关键参数为油品蒸气相对分子质量、日平均液体表面温度和年净周转量。     

Applications of life cycle assessment and cost analysis in health care waste management

The establishment of rules to manage Health Care Waste (HCW) is a challenge for the public sector. Regulatory agencies must ensure the safety of waste management alternatives for two very different profiles of generators: (1) hospitals, which concentrate the production of HCW and (2) small establishments, such as clinics, pharmacies and other sources, that generate dispersed quantities of HCW and are scattered throughout the city. To assist in developing sector regulations for the small generators, we evaluated three management scenarios using decision-making tools. They consisted of a disinfection technique (microwave, autoclave and lime) followed by landfilling, where transportation was also included. The microwave, autoclave and lime techniques were tested at the laboratory to establish the operating parameters to ensure their efficiency in disinfection. Using a life cycle assessment (LCA) and cost analysis, the decision-making tools aimed to determine the technique with the best environmental performance. This consisted of evaluating the eco-efficiency of each scenario. Based on the life cycle assessment, microwaving had the lowest environmental impact (12.64 Pt) followed by autoclaving (48.46 Pt). The cost analyses indicated values of US$ 0.12 kg^?1 for the waste treated with microwaves, US$ 1.10 kg^?1 for the waste treated by the autoclave and US$ 1.53 kg^?1 for the waste treated with lime. The microwave disinfection presented the best eco-efficiency performance among those studied and provided a feasible alternative to subsidize the formulation of the policy for small generators of HCW.     

包装印刷业VOCs污染特征分析

选取了北京市的14家大型包装印刷企业进行现场采样、监测,统计分析了生产工艺和原辅材料,识别了VOCs污染来源和排放节点。根据不同排放节点的特征搭建了相应的采样系统,并以此为基础考察了VOCs的排放特征、臭氧生成潜势和二次有机气溶胶(SOA)生成潜势。结果表明:包装印刷业所排放的VOCs以醇类和酯类为主;乙醇和异丙醇为主要的臭氧前体物,生产线和烘干集气系统排气口为主要的臭氧生成节点;烷烃和醇类为主要的SOA前体物,烘干集气系统排气口为首要的SOA生成节点。     

Occupational exposure in the fluorescent lamp recycling sector in France

The fluorescent lamp recycling sector is growing considerably in Europe due to increasingly strict regulations aimed at inciting the consumption of low energy light bulbs and their end-of-life management. Chemical risks were assessed in fluorescent lamp recycling facilities by field measurement surveys in France, highlighting that occupational exposure and pollutant levels in the working environment were correlated with the main recycling steps and processes.The mean levels of worker exposure are 4.4 mg/m³, 15.4 μg/m³, 14.0 μg/m³, 247.6 μg/m³, respectively, for total inhalable dust, mercury, lead and yttrium. The mean levels of airborne pollutants are 3.1 mg/m³, 9.0 μg/m³, 9.0 μg/m³, 219.2 μg/m³, respectively, for total inhalable dust, mercury, lead and yttrium. The ranges are very wide. Surface samples from employees’ skin and granulometric analysis were also carried out. The overview shows that all the stages and processes involved in lamp recycling are concerned by the risk of hazardous substances penetrating into the bodies of employees, although exposure of the latter varies depending on the processes and tasks they perform. The conclusion of this study strongly recommends the development of a new generation of processes in parallel with more information sharing and regulatory measures.     

SETTING DIOXIN EMISSION LIMITS FOR MSW INCINERATORS: A MULTIMEDIA EXPOSURE ASSESSMENT FRAMEWORK

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are emitted in trace amounts from municipal solid waste (MSW) incinerators. The exposure to PCDD/Fs experienced by an individual is dominated by the food chain pathway, which accounts for over 98% of the total uptake. Defining a target daily intake (the World Health Organization TDI of 10 pg I-TEQ kg.bw⁻¹day⁻¹) exposure assessment algorithms were then applied to arrive at the corresponding PCDD/F levels in air, soil, plants, food products, etc., which would allow the target intake to be met while retaining the balance of intake between the various exposure pathways. These concentrations were converted to an ambient air concentration of PCDD/Fs and ultimately, by defining criteria for acceptability, to a guide value for PCDD/F concentration in emissions from the MSW incinerator. This strategy was applied to PCDD/F emissions from MSW incinerators of various sizes against two illustrative criteria for acceptability: an “insignificant” release and a threshold above which the release may require further assessment for environmental effects and for control. Using the criteria developed in this paper, the current PCDD/F emission limit of 0.1 ng I-TEQ m⁻³results in an emission that is classed as “insignificant” for all plant sizes. However, higher emission concentrations can also be accommodated below the threshold for further assessment and control.     

Methane Fluxes from a Wetland using the Flux-Gradient Technique The Measurement of Methane Flux from a Natural Wetland Pond and Adjacent Vegetated Wetlands using a TDL-Based Flux-Gradient Technique

Methane emissions were measured from a bog andlake in the Experimental Lakes Area in Northern Ontario in 1992and 1993, prior to and following flooding. Bog fluxes were smallin 1992 (0.27 mg m^-2 d^-1) but increased 5-fold in 1993 afterflooding. Over the bog, there was a diel cycle of nighttimeemission and daytime uptake in 1992 in contrast to constantemission in 1993. Lake emissions decreased after flooding butwere much greater than bog emissions in both years (average = 7.3 mg m^-2 d^-1). Seasonally, the bog flux was correlated withground temperatures after flooding. In 1992, lake fluxes werecorrelated with air temperature on a daily basis. In contrast,seasonal lake fluxes were correlated with water and sedimenttemperatures in 1992, but only with sediment temperatures in1993. These results are explained with respect to the effects offlooding on lake and bog dynamics.