Hazardous Waste Sites Research Articles

Engineering practice of mechanical soil aeration for the remediation of volatile organic compound-contaminated sites in China: Advantages and challenges

In recent years, many industrial enterprises located in the urban centers of China have been relocated owing to the rapid increase in urban development. At the sites abandoned by these enterprises, volatile organic compounds have frequently been detected, sometimes at high concentrations, particularly at sites abandoned by chemical manufacturing enterprises. With the redevelopment of sites and changes in land-use type associated with these sites, substantial amounts of contaminated soils now require remediation. Since China is a developing country, soil remediation warrants the usage of techniques that are suitable for addressing the unique challenges faced in this country. Land shortage is a common problem in China; the large numbers of contaminated sites, tight development schedules, and limited financial resources necessitate the development of cost-effective methods for land reclamation. Mechanical soil aeration is a simple, effective, and low-cost soil remediation technique that is particularly suitable for the remediation of large volatile organic compound-contaminated sites. Its effectiveness has been confirmed by conducting laboratory studies, pilot tests, and full-scale projects. This study reviews current engineering practice and developmental trends of mechanical soil aeration and analyzes the advantages and disadvantages of this technology for application in China as an emerging soil remediation market. The findings of this study might aid technology development in China, as well as assist other developing countries in the assessment and implementation of costeffective hazardous waste site soil remediation programs. Open image in new window

Selectivity of Nano Zerovalent Iron in In Situ Chemical Reduction: Challenges and Improvements

Nano zerovalent iron (nZVI) is a promising remediation technology utilizing in situ chemical reduction (ISCR) to clean up contaminated groundwater at hazardous waste sites. The small particle size and large surface area of nZVI result in high reactivity and rapid destruction of contaminants. Over the past 20 years, a great deal of research has advanced the nZVI technology from bench-scale tests to field-scale applications. However, to date, the overall number of well-characterized nZVI field deployments is still small compared to other alternative remedies that are more widely applied. Apart from the relatively high material cost of nZVI and questions regarding possible nanotoxicological side effects, one of the major obstacles to the widespread utilization of nZVI in the field is its short persistence in the environment due to natural reductant demand (NRD). The NRD for nZVI is predominantly due to reduction of water, but other reactions with naturally present oxidants (e.g., oxygen) occur, resulting in situ conditions that are reducing (high in ferrous iron phases and H2) but with little or no Fe(0). This article reviews the main biogeochemical processes that determine the selectivity and longevity of nZVI, summarizes data from prior (laboratory and field) studies on the longevity of various common types of nZVI, and describes modifications of nZVI that could improve its selectivity and longevity for full-scale applications of ISCR. © 2016 Wiley Periodicals, Inc.

Hazardous waste and health impact: a systematic review of the scientific literature

Introduction: The impact of hazardous waste concerns public health at both national and international levels. Our aim was to conduct a systematic review to evaluate the evidence of the health impact of hazardous waste exposure, applying transparent and a priori defined methods. Methods: Bibliographic searches on population residing near hazardous waste sites were performed on Medline and Embase (1999-2015 publication period), using text words and descriptors to identify exposure and health outcomes. A priori criteria were defined for inclusion of papers. Selected articles reliability was evaluated, considering study design and risk of bias. Based on reliability of each study and results’ concordance, the overall evidence of association between each outcome and exposure was rated as sufficient/limited/inadequate. Results: 1,680 studies were found. Out of them, 219 abstracts of epidemiological studies on residents near hazardous waste sites were selected and 168 of them were found consistent with the a priori criteria. Several diseases were reported in excess, but the results were not always consistent. Evidence that exposure to oil industry waste releasing high concentrations of hydrogen sulphide causes acute adverse effects was evaluated as sufficient. The evidence was defined limited for several outcomes, namely: liver, stomach and lung cancer, acute respiratory infections, asthma and congenital anomalies of cardiovascular and urogenital systems. For most diseases the evidence was evaluated as inadequate. Discussion: Reviewed studies suffer from limitations mainly due to difficulties in exposure assessment, caused by diversity of exposure pathways and heterogeneity of contaminants. However, especially considering the more recent papers, the residence near hazardous waste sites was defined as associated with several diseases with different degrees of cogency.

When Does an Administrative Order Resolve CERCLA Liability Sufficiently to Trigger a § 113 Contribution Action?

ABSTRACTThis article discusses how parties who are negotiating administrative agreements with regulatory agencies regarding the remediation of inactive hazardous waste sites can best protect their right to bring a contribution action against other responsible parties. The article discusses the relevant statutory provisions and the case law, much of which holds that parties failed to preserve their contribution rights, and provides advice regarding specific language to include in such agreements.

Characterization of a locally deposited material on Arnela Beach (Galicia Coast, Spain)

The main objective of this paper is to identify and evaluate risks to Arnela beach coastal resources from hazardous waste sites and to develop remediation strategies to minimize those risks, using wastes as a secondary raw material. Research has been conducted on a material located on Arnela Beach, Muxía (A Coruña province, northwest Spain) due to its unknown nature not previously described or related to the geological context. This material can be seen mixed with sand and gravel, and its total chemical composition has been determined and mineralogically analyzed under XRF and XRD, respectively. The microstructure of this deposit on Arnela Beach has been investigated with optical and electron microscopy (SEM/EDS). After determining that it contains high proportions of silica (SiO2) and manganese, a complementary study has been carried out in order to evaluate its capability for the production of glasses and glass–ceramics. For this purpose, thermal transformations at high temperature have been followed by DTA/TG, as well as HSM. First results indicate that it is a metallurgical slag material with a vitreous character and unknown origin. Finally, this deposit is anthropogenic in origin with possible applications as a secondary raw material in the ceramic, glaze, and glass industries.

The Impacts of Sea-Level Rise on Tidal Flooding in Boston, Massachusetts

Kruel, S., 2016. The impacts of sea-level rise on tidal flooding in Boston, Massachusetts. In Boston, Massachusetts, chronic tidal flooding due to sea-level rise will occur in many developed parts of the city over the next several decades and beyond. This study examines the frequency and severity of tidal flooding due to increases in sea level of between 0.3 to 1.8 m (1.0 and 6.0 ft), as well as where flooding will generally occur. Local tide gauge data are compared to the National Weather Service's flood stage categories to determine how frequently they will be reached at high tide as sea level rises. GIS data are used to demonstrate where flooding is likely to occur, and U.S. Census data are used to identify assets that will be impacted. The study also depicts the relationships among the multiple datums currently used to measure water levels in Boston. Results of the analysis indicate that in the absence of any new flood barriers, the incidence of minor tidal flooding will increase to about 75 times per year within Boston Harbor with 0.3 m (1 ft) of sea-level rise. Nine-tenths of a meter (3 ft) of sea-level rise will result in about 30 occurrences of moderate flooding per year, and 1.2 m (4 ft) will bring that same frequency of major flooding incidents. Tidal flooding due to 1.8 m (6 ft) of sea-level rise will affect approximately 20% of the population and land, as well as housing, public facilities, transportation infrastructure, and hazardous waste sites. The study suggests that future conditions will require the development of nonemergency responses to flooding as well as a new approach to urban floodplain management.

Mitochondrial Dysfunction, Disruption of F-Actin Polymerization, and Transcriptomic Alterations in Zebrafish Larvae Exposed to Trichloroethylene.

Trichloroethylene (TCE) is primarily used as an industrial degreasing agent and has been in use since the 1940s. TCE is released into the soil, surface, and groundwater. From an environmental and regulatory standpoint, more than half of Superfund hazardous waste sites on the National Priority List are contaminated with TCE. Occupational exposure to TCE occurs primarily via inhalation, while environmental TCE exposure also occurs through ingestion of contaminated drinking water. Current literature links TCE exposure to various adverse health effects including cardiovascular toxicity. Current studies aiming to address developmental cardiovascular toxicity utilized rodent and avian models, with the majority of studies using relatively higher parts per million (mg/L) doses. In this study, to further investigate developmental cardiotoxicity of TCE, zebrafish embryos were treated with 0, 10, 100, or 500 parts per billion (ppb; μg/L) TCE during embryogenesis and/or through early larval stages. After the appropriate exposure period, angiogenesis, F-actin, and mitochondrial function were assessed. A significant dose-response decrease in angiogenesis, F-actin, and mitochondrial function was observed. To further complement this data, a transcriptomic profile of zebrafish larvae was completed to identify gene alterations associated with the 10 ppb TCE exposure. Results from the transcriptomic data revealed that embryonic TCE exposure caused significant changes in genes associated with cardiovascular disease, cancer, and organismal injury and abnormalities with a number of targets in the FAK signaling pathway. Overall, results from our study support TCE as a developmental cardiovascular toxicant, provide molecular targets and pathways for investigation in future studies, and indicate a need for continued priority for environmental regulation.

Applying a “Hard Science” Disciplined Approach to Identify and Verify Chemical Properties for Safe Response, Handling, and Disposal

Personnel who may have to deal with the uncertain nature and properties of unknown chemicals at an environmental incident, hazardous waste site, industry or in a laboratory need a way to identify the actual risks and hazards they may face. This applies whether the personnel are emergency responders, forensic researchers or waste clean-up crews. There is, however, a quick-check system to identify chemical properties of labeled, unlabeled, unknown or mixed chemicals. The system uses pH paper, starch paper and a source of flame such as a barbeque lighter or Bunsen burner. The basic test takes less than 60 seconds and will identify or verify high-risk properties such as whether substances are oxidizers or reactive to heat, air or water, their range of flammability and their corrosiveness. The test results provide vital information for responders to make critical decisions, whether dealing with a laboratory spill or a full-scale hazardous material emergency. Using hard science helps in dealing with time-critical issues, such as when, or whether, to add water to modify a chemical reaction when a bad situation could turn into a disaster. Whether working with laboratory or industrial chemicals or responding to a major emergency, hard science can provide the information needed to approach the scene, secure the area, and keep unprotected and unauthorized personnel out. It identifies the physical and chemical properties of known, unknown and newly formed substances and allows personnel to assess the risk, hazards and potential scales of impact including when it is safe to respond or take other appropriate action.

Indoor Air Contamination from Hazardous Waste Sites: Improving the Evidence Base for Decision-Making.

At hazardous waste sites, volatile chemicals can migrate through groundwater and soil into buildings, a process known as vapor intrusion. Due to increasing recognition of vapor intrusion as a potential indoor air pollution source, in 2015 the U.S. Environmental Protection Agency (EPA) released a new vapor intrusion guidance document. The guidance specifies two conditions for demonstrating that remediation is needed: (1) proof of a vapor intrusion pathway; and (2) evidence that human health risks exceed established thresholds (for example, one excess cancer among 10,000 exposed people). However, the guidance lacks details on methods for demonstrating these conditions. We review current evidence suggesting that monitoring and modeling approaches commonly employed at vapor intrusion sites do not adequately characterize long-term exposure and in many cases may underestimate risks. On the basis of this evidence, we recommend specific approaches to monitoring and modeling to account for these uncertainties. We propose a value of information approach to integrate the lines of evidence at a site and determine if more information is needed before deciding whether the two conditions specified in the vapor intrusion guidance are satisfied. To facilitate data collection and decision-making, we recommend a multi-directional community engagement strategy and consideration of environment justice concerns.

Modeling NAPL dissolution from pendular rings in idealized porous media

AbstractThe dissolution rate of nonaqueous phase liquid (NAPL) often governs the remediation time frame at subsurface hazardous waste sites. Most formulations for estimating this rate are empirical and assume that the NAPL is the nonwetting fluid. However, field evidence suggests that some waste sites might be organic wet. Thus, formulations that assume the NAPL is nonwetting may be inappropriate for estimating the rates of NAPL dissolution. An exact solution to the Young‐Laplace equation, assuming NAPL resides as pendular rings around the contact points of porous media idealized as spherical particles in a hexagonal close packing arrangement, is presented in this work to provide a theoretical prediction for NAPL‐water interfacial area. This analytic expression for interfacial area is then coupled with an exact solution to the advection‐diffusion equation in a capillary tube assuming Hagen‐Poiseuille flow to provide a theoretical means of calculating the mass transfer rate coefficient for dissolution at the NAPL‐water interface in an organic‐wet system. A comparison of the predictions from this theoretical model with predictions from empirically derived formulations from the literature for water‐wet systems showed a consistent range of values for the mass transfer rate coefficient, despite the significant differences in model foundations (water wetting versus NAPL wetting, theoretical versus empirical). This finding implies that, under these system conditions, the important parameter is interfacial area, with a lesser role played by NAPL configuration.

Applying A Community-Based Participatory Research Framework To Assess Soil Contamination Levels In North Charleston, South Carolina

Introduction: The Lowcountry Alliance for Model Communities (LAMC) neighborhoods host various hazardous waste sites, are surrounded by heavily trafficked roadways, and may be further impacted by the expansion of the Port of Charleston. The community developed the Charleston Area Pollution Prevention Partnership (CAPs) to assess environmental health disparities due to industrial and mobile sources of pollution. We conducted a baseline soil assessment to determine the magnitude of contamination in North Charleston, SC prior to the construction of the new Port terminal. Methods: Community members were recruited to collect soil samples in several LAMC neighborhoods. near heavily trafficked roadways, background and major industrial sites, brownfields, Superfund sites, schools, and community centers. Correlation and respective significance levels were estimated between pollutants and minimum and maximum concentrations were documented. Screening level data were downloaded from the EPA and matched by CAS number with pollutants measured in the samples. Results: Arsenic, barium, beryllium, cadmium, copper, iron, lead, magnesium, manganese, mercury, nickel, and zinc were found in soil samples. Only arsenic and lead had higher concentrations than the residential screening level in some stations. Arsenic measurements from all stations had a higher concentration than the residential screening level and 92% were higher than the industrial screening level. There were 5.7% of stations with a higher lead concentration than the residential screening level and 1.9% of stations had a higher lead concentration higher than the industrial screening level. Conclusion: The high concentration and array of contaminants identified in soil samples may be indicative of burden disparities and potential exposure and related health disparities for populations who live near environmental hazards in LAMC neighborhoods.

Hexachlorobenzene Contamination In An Austrian Alpine Valley

Introduction: In Austria, hexachlorobenzene (HCB) was used for agricultural purposes until 1992. In 2011, a cement factory located in a small valley was mandated to burn contaminated slaked lime from a hazardous waste site. When HCB levels exceeded legal standards for foodstuffs from that valley in 2014, concerned citizens sent blood samples and breast milk to Germany. Some were informed their HCB values exceeded German reference values. We were mandated to assess the risk, to establish Austrian reference values and to study routes of exposure. Methods: To establish Austrian reference values, stored blood samples from the Austrian Nutrition and Health Survey 2012 were analyzed. Possible routes of exposure were examined by analyzing samples (soil, air, food, Nordic spruce needles). Based on an individual assessment (e.g. food intake) local residents were invited to provide blood samples. Results: Austrian reference levels were similar to German values from approximately ten years ago. Out of 120 blood samples taken from residents in the exposed valley, 21 exceeded new established Austrian reference values. Highest concentrations were detected among those who mainly consumed food produced in the valley. Residents living closest to the factory had the highest blood HCB-concentrations. Air samples (up to 5.1 ng/m³) and spruce needles (30-50 ng/g dry weight) indicated high exposure in vicinity of the kiln over the last 10-13 months. Based on these findings, a direct route from air to the soil (up to 0.8 ng/g) and through the cattle feed and food for human consumption (esp. milk, meat) could well explain the variability in blood concentrations of HCB. Discussion: Despite the detection of high blood concentrations of HCB in 21 of 120 sampled, daily uptake over the course of one-year was determined to be well below the acceptable daily intake defined by WHO for lifelong exposure. Nevertheless, risk communication to concerned citizens remains a significant challenge.

Water Contamination, Land Prices, and the Statute of Repose

We examine how water contamination risk from an inactive hazardous waste site is capitalized into surrounding vacant land prices. After public knowledge of the first instance of off-site contamination, we find that shallow groundwater contamination potential is negatively capitalized into land prices, as is proximity to a known contaminated well. Public knowledge of off-site contamination and associated land price changes occur after the North Carolina’s 10-year statue of repose. Our findings raise questions concerning such statutes when environmental contamination has a long latency period, especially given a recent Supreme Court ruling that Superfund law does not preempt state statutes of repose.

Sustainable Social Work: An Environmental Justice Framework for Social Work Education

Environmental degradation is not experienced by all populations equally; hazardous and toxic waste sites, resource contamination (e.g., exposure to pesticides), air pollution, and numerous other forms of environmental degradation disproportionately affect low income and minority communities. The communities most affected by environmental injustices are often the same communities where social workers are entrenched in service provision at the individual, family, and community level. In this article, we use a global social work paradigm to describe practical ways in which environmental justice content can be infused in the training and education of social workers across contexts in order to prepare professionals with the skills to respond to ever-increasing global environmental degradation. We discuss ways for social work educators to integrate and frame environmental concerns and their consequences for vulnerable populations using existing social work models and perspectives to improve the social work profession's ability to respond to environmental injustices. There are significant social work implications; social workers need to adapt and respond to contexts that shape our practice, including environmental concerns that impact the vulnerable and oppressed populations that we serve.

Obsolete Pesticides in Saudi Arabia: Problems, Prevention and Disposal

Expired and deteriorated stocks of pesticides are present in most developing countries. Those products no longer can be used to control the intended target pests as recommended on the label. The existence of obsolete pesticides can be due to many reasons such as inadequate storage facilities or storage containers, in addition to poor stock management and record keeping. Banning the pesticides while in storage and poor assessment of pesticide requirements, such as inability to forecast pest outbreaks, may cause prolonged storage of products with short shelf lives. Furthermore, marketing systems with aggressive profit motive by vendors may lead to accumulation of expired pesticides. These stocks are often stored in poor conditions, which may cause damage and leaking of the containers with obsolete and dangerous pesticides that may pose a threat to human health and the environment. Disposal of obsolete pesticides in a safe and environmentally sound manner are only available in a few newly industrialized countries, but the developing countries do not have such facilities. Therefore, the recommended disposal method for stockpiles of obsolete pesticides in developing countries should systematically undergo various steps. These would include inventory, repackaging, safe guarding of the pesticides and then shipment of the pesticides to a country that has appropriate hazardous waste incineration facilities. This global environmental issue is a result of decades of mishandling. It is most dramatic in the developing world which lack the resources and funding for remediation of the hazardous waste sites and obsolete pesticides. Conservative estimates find well over 500,000 tons of obsolete pesticides in developing countries, with 50,000 to 100,000 tons just in Africa alone. The collaborative Programme on the Prevention and Disposal of Obsolete Pesticides, established by the Food and Agricultural Organization of the United Nations (FAO) in 1994, underlines the urgency and importance of a concerted international effort to solve this problem.

The NIEHS Superfund Research Program: 25 Years of Translational Research for Public Health.

BackgroundThe Superfund Research Program (SRP) is an academically based, multidisciplinary, translational research program that for 25 years has sought scientific solutions to health and environmental problems associated with hazardous waste sites. SRP is coordinated by the National Institute of Environmental Health Sciences (NIEHS). It supports multi-project grants, undergraduate and postdoctoral training programs, individual research grants, and Small Business Innovation Research (SBIR) and Technology Transfer Research (STTR) grants.ResultsSRP has had many successes: discovery of arsenic’s toxicity to the developing human central nervous system; documentation of benzene toxicity to hematologic progenitor cells in human bone marrow; development of novel analytic techniques such as the luciferase expression assay and laser fragmentation fluorescence spectroscopy; demonstration that PCBs can cause developmental neurotoxicity at low levels and alter the genomic characteristics of sentinel animals; elucidation of the neurodevelopmental toxicity of organophosphate insecticides; documentation of links between antimicrobial agents and alterations in hormone response; discovery of biological mechanisms through which environmental chemicals may contribute to obesity, atherosclerosis, diabetes, and cancer; tracking the health and environmental effects of the attacks on the World Trade Center and Hurricane Katrina; and development of novel biological and engineering techniques to facilitate more efficient and lower-cost remediation of hazardous waste sites.ConclusionSRP must continue to address the legacy of hazardous waste in the United States, respond to new issues caused by rapid advances in technology, and train the next generation of leaders in environmental health science while recognizing that most of the world’s worst toxic hot spots are now located in low- and middle-income countries.CitationLandrigan PJ, Wright RO, Cordero JF, Eaton DL, Goldstein BD, Hennig B, Maier RM, Ozonoff DM, Smith MT, Tukey RH. 2015. The NIEHS Superfund Research Program: 25 years of translational research for public health. Environ Health Perspect 123:909–918; http://dx.doi.org/10.1289/ehp.1409247

Water Contamination and Land Prices in a Mountainous Landscape

We examine how water contamination risk from an inactive hazardous waste site is capitalized into surrounding vacant land prices. After public knowledge of the first instance of off-site contamination, we find that shallow groundwater contamination potential is negatively capitalized into land prices, as is proximity to a known contaminated well. Public knowledge of off-site contamination and associated land price changes occur after the North Carolina’s 10-year statue of repose. Our findings raise questions concerning such statutes when environmental contamination has a long latency period, especially given a recent Supreme Court ruling that Superfund law does not preempt state statutes of repose.

A variance decomposition approach to uncertainty quantification and sensitivity analysis of the Johnson and Ettinger model

The Johnson and Ettinger (J&E) model is the most widely used vapor intrusion model in the United States. It is routinely used as part of hazardous waste site assessments to evaluate the potential for vapor intrusion exposure risks. This study incorporates mathematical approaches that allow sensitivity and uncertainty of the J&E model to be evaluated. In addition to performing Monte Carlo simulations to examine the uncertainty in the J&E model output, a powerful global sensitivity analysis technique based on Sobol indices is used to evaluate J&E model sensitivity to variations in the input parameters. The results suggest that the J&E model is most sensitive to the building air exchange rate, regardless of soil type and source depth. Building air exchange rate is not routinely measured during vapor intrusion investigations, but clearly improved estimates and/or measurements of the air exchange rate would lead to improved model predictions. It is also found that the J&E model is more sensitive to effective diffusivity than to effective permeability. Field measurements of effective diffusivity are not commonly collected during vapor intrusion investigations; however, consideration of this parameter warrants additional attention. Finally, the effects of input uncertainties on model predictions for different scenarios (e.g., sandy soil as compared to clayey soil, and “shallow” sources as compared to “deep” sources) are evaluated. Our results not only identify the range of variability to be expected depending on the scenario at hand, but also mark the important cases where special care is needed when estimating the input parameters to which the J&E model is most sensitive.Implications: The research described herein uses stochastic approaches to investigate the effect of individual input parameters on the J&E model. The results suggest that the J&E model is most sensitive to the building air exchange rate, regardless of soil type and source depth. Additional analysis reveals that chemical transport is more sensitive to effective diffusivity of the soil, rather than effective permeability of the soil. Accordingly, effective diffusivity and air exchange rates warrant additional attention when assessing vapor intrusion exposure risks at hazardous waste sites.

Indoor Air Contamination from Hazardous Waste Sites: Improving the Evidence Base for Decision-Making

Indoor Air Contamination from Hazardous Waste Sites: Improving the Evidence Base for Decision-Making

Resolving scientific controversy over smelter risks and neurodegenerative effects of metals

Although it is well known that metals pollution can cause neurotoxic effects, scientists are currently divided about the neurodegeneration hypothesis. That is, some scientists accept, while others fail to accept, the hypothesis that metals/metalloids, at exposure levels below those capable of causing neurotoxicity, can cause neurodegeneration—progressive or worsening neurological disease. Partly because of controversy over the neurodegeneration hypothesis, the US and other governments do not require cleanup of smelter-site metals, to the level (that many scientists say is) necessary to prevent site-caused neurodegenerative disease. The purpose of this review article is to help clarify and resolve conflict over the neurodegeneration hypothesis. This analysis (1) surveys the global problem of smelter-related metals pollution; (2) quickly gives an overview of metals pollution at one of the worst US Superfund or hazardous-waste sites, a former smelter in DePue, Illinois; (3) outlines the debate over the neurodegeneration hypothesis; and (4) assesses the current science on both sides of the neurodegeneration hypothesis by means of three classic methods of causal assessment: the mechanism, unification-coherence, and experimental-counterfactual methods. Using these classic methods, the authors (5) show that available scientific evidence argues for accepting the neurodegeneration hypothesis. This finding is significant because it suggests that much current science about smelters and metals' risks may be incomplete or flawed. It also shows that, as a result, there may be sound scientific reasons for strengthening environmental-metals standards.