Current and future solid waste management system in Northern Viet Nam with focus on Ha Noi: climate change effects and landfill management

The contribution investigates the solid waste management system in Ha Noi under consideration of the interrelation between climate change effects and landfill management by means of a cause-and-effect-analysis as well as water balances using the HELP 3.95 model and gas emission data, followed by a Strength, Weakness, Opportunities, Threats (SWOT) analysis. Even landfills are sources of methane (CH₄) emissions they are also impacted by climate change. The main effects on landfill sites are the change of climatic conditions, namely the regional water balance, extreme precipitation and storm events. The results of the water balance model results show that a geomembrane surface sealing can reduce the leachate formation significantly, a fact that is also valid for the climate change scenario with higher precipitation. The risk of flooding and erosion at the landfill sites increases, which will require a customized water management. In parallel landfill gas offers the opportunity for recovery of Greenhouse Gases (GHG) and the generation of renewable energy. Some further management options are wind turbines, photovoltaic systems or biomass for biogas conversion, which was grown on closed landfill sites. The inclusion of climate friendly management options of closed landfills in a “Good Landfill Aftercare Practice” is recommended.     

PCBs,PBDEs and dioxin-related compounds in floor dust from an informal end-of-life vehicle recycling site in northern Vietnam: contamination levels and implications for human exposure

Floor dusts from Vietnamese end-of-life vehicle (ELV)-processing households were investigated to elucidate the contamination levels and exposure risk of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and dioxin-related compounds (DRCs). The concentrations were in order of PBDEs (260–11,000, median 280 ng/g overall) > PCBs (19–2200, median 140 ng/g) > dioxin-like PCBs (8.8–450, median 22 ng/g) ? polybrominated dibenzo-p-dioxin/dibenzofurans (PBDD/Fs, 2000–28,000, median 8500 pg/g) > polychlorinated dibenzo-p-dioxin/dibenzofurans (PCDD/Fs, 440–4100, median 1800 pg/g) > MoBPCDD/Fs (1.9–1200, median 250 pg/g). Concentrations of PCBs and DRCs were higher than those reported for Vietnamese urban houses, indicating ELV processing as a significant source of these contaminants. Higher concentrations of PCBs relative to PBDEs suggest the abundance of old electrical capacitors/transformers in ELVs. The PBDD/F and PCDD/F profiles were indicative of DecaBDE-containing materials and combustion sources, respectively. PBDFs, PCDFs and DL-PCBs were the most important dioxin-like toxic equivalent (TEQ) contributors. The estimated PCB and TEQ intake doses from dust ingestion approached or exceeded the reference doses for children living in some ELV-processing households, indicating potential health risk. More comprehensive risk assessment of the exposure to PCBs and DRCs is required for residents of informal ELV recycling sites.     

Superfund site remediation by landfilling—overview of landfill design,operation, closure,and postclosure issues

This article discusses the appropriateness of using landfills as part of remediating hazardous chemical and Superfund sites, with particular emphasis on providing for true long‐term public health and environmental protection from the wastes and contaminated soils that are placed in the landfills. On‐site landfilling or capping of existing wastes is typically the least expensive approach for gaining some remediation of existing hazardous chemical/Superfund sites. The issues of the deficiencies in US EPA and state landfilling approaches discussed herein are also applicable to the landfilling of municipal and industrial solid “nonhazardous” wastes. These deficiencies were presented in part as “Problems with Landfills for Superfund Site Remediation” at the US EPA National Superfund Technical Assistance Grant Workshop held in Albuquerque, New Mexico, in February 2003. They are based on the author's experience in investigating the properties of landfill liners and the characteristics of today's landfills, relative to their ability to prevent groundwater pollution and to cause other environmental impacts. Discussed are issues related to both solid and hazardous waste landfills and approaches for improving the ability of landfills to contain wastes and monitor for leachate escape from the landfill for as long as the wastes in the landfill will be a threat. © 2004 Wiley Periodicals, Inc.     

Electroremediation: A study of the influence of buffering behavior in contaminated soils

This article presents the results of an experimental study conducted to evaluate the behavior of two types of andisol soils found in Tenerife, Canary Islands, Spain. The soils were evaluated in relation to their buffering capacity when confronted with acid and alkaline fronts generated during electroremediation treatment. The study was conducted using a cell, which established a continuous flow of distilled water through electrode chambers to remove H⁺ and OH^? generated during electrolysis. The results indicate that the soils had sufficient buffer capacity to support variations in pH independent of the maintenance of flow of solution in the electrode chambers. Although the mechanism of migration was not affected, the flow of water favored the movement of ions by diffusion monitoring of the electrolytic current allowed for a real‐time parameter to act as an indicator of the quantity of ions available in regions near the electrodes. © 2004 Wiley Periodicals, Inc.     

Progress toward remediation of the Sydney Tar Ponds: A major Canadian PCB/PAH “superfund” site

The Muggah Creek estuary in Sydney, Nova Scotia, received liquid and solid wastes from a steel mill and its associated coke ovens for approximately 100 years. This resulted in pollution of soils and sediments with polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), heavy metals, and other pollutants, including those in untreated domestic wastewaters. The Canadian federal and Nova Scotia provincial governments organized the Sydney Tar Ponds Agency (STPA) to develop a remediation approach for the Coke Ovens site soils and Sydney Tar Ponds sediments. The STPA developed a remediation approach for the Sydney Tar Ponds sediments, involving solidification/stabilization (S/S) through mixing cement and other materials into the sediments, and then capping them as a waste pile. High‐density polyethylene (HDPE) plastic sheeting vertical barriers are proposed to be used to divert groundwater and surface water from entering into the S/S‐treated sediments and to collect any water and associated pollutants released from the S/S‐treated sediments. The Coke Ovens site soils are proposed to be landfarmed to reduce some of the PAHs and other pollutants and then capped with a layer of soil. This remediation program is estimated to cost on the order of $400 million (CAN). This article presents a review of the significant potential problems with the STPA proposed remediation strategy of the Sydney Tar Ponds sediments and Coke Ovens site soils. © 2006 Wiley Periodicals, Inc.     

Two‐dimensional transport of lactate‐modified nanoscale iron particles in porous media

This study investigates the two‐dimensional transport of nanoscale iron particles (NIP) and lactate‐modified NIP (LMNIP) in homogeneous and heterogeneous porous media under typical pressurized groundwater flow conditions. A two‐dimensional bench‐scale test setup was developed and a series of experiments was conducted simulating homogeneous sand profile and two‐layer profile with two different sands. NIP and LMNIP at a concentration of 4 g/L were prepared in electrolyte simulating groundwater conditions and were injected at the inlet of the test setup under different pressure gradients (0.5. 0.8, 1, and 2 pounds per square inch). During the testing, effluent was collected and its volume and nanoiron concentrations were measured. At the end of the testing, soil cores were obtained at different distances from the inlet and were used to measure nanoiron concentrations and magnetic susceptibility values. Results showed that the transport of NIP and LMNIP was enhanced by increased pressure gradient. LMNIP transport occurred more uniformly as compared to bare NIP. The iron concentrations decreased with distance from the inlet to the outlet and increased from the top to the bottom of the test cell. The data indicate that, as the particles were transported, they underwent aggregation and sedimentation, which resulted in the observed non‐uniform spatial distribution of iron. The NIP and LMNIP transported through the high‐porosity and high‐permeability soil layer in the heterogeneous soil profile, implying that the transport occurred predominantly along the path of least resistance for the flow. Magnetic susceptibility values are found to have good correlation with the iron content in the soil and are helpful to characterize the transport of NIP and LMNIP. Overall, this study shows that the non‐uniform distribution of NIP and LMNIP occurs under two‐dimensional transport conditions and the soil heterogeneities can significantly impact the transport of NIP and LMNIP. The design of field delivery systems should consider such conditions and optimize the pressurized injection systems. © 2011 Wiley Periodicals, Inc.     

Temporary site selection and decision‐making methods: a case study of Tehran,Iran

Decisions on selecting an appropriate site for temporary shelter used to be taken in a limited amount of time after a disaster. The need for a systematic method in this area inspired the MADM (multi‐attribute decision making) for complex disaster management decisions. This research proposes a model for appropriate and systematic site selection for temporary shelters, before an earthquake, using a geographical information system and MADM based on an earthquake damage assessment. After the effective criteria for site selection of temporary shelters are determined, the geographical layers of these criteria are prepared for Municipal District No.1 of Greater Tehran, the capital of Iran. Given these attributes and the required shelter area (415–610 hectares), 14 zones are proposed initially. Various MADM methods are used for the final selection. The mean of the aggregated ranking results are determined, and 10 of the 14 initial zones are ranked.     

Classification of residential areas according to physical vulnerability to natural hazards: a case study of Çanakkale,Turkey

The selection of new settlement areas and the construction of safe buildings, as well as rendering built‐up areas safe, are of great importance in mitigating the damage caused by natural disasters. Most cities in Turkey are unprepared for natural hazards. In this paper, Çanakkale, located in a first‐degree seismic zone and sprawled around the Sartçay Delta, is examined in terms of its physical vulnerability to natural hazards. Residential areas are analysed using GIS (geographic information system) and remote‐sensing technologies in relation to selected indicators. Residential areas of the city are divided into zones according to an evaluation of geological characteristics, the built‐up area's features, and urban infrastructure, and four risk zones are determined. The results of the analysis show that the areas of the city suitable for housing are very limited. In addition, the historical centre and the housing areas near Sartçay stream are shown to be most problematic in terms of natural disasters and sustainability.     

Effects of lindane on Daphnia magna during chronic exposure

Abstract

Acute and chronic toxicity tests with lindane were conducted on Daphnia magna. The 24‐hr static LC50 was 1.64 mgL^‐1. The sublethal effects of 0.16, 0.25, 0.32, 0.60 and 0.80 mgL^‐1 lindane on the survival, reproduction and growth of D. magna were monitored for 21 days. The algae Nannochloris oculata (5 × 10⁵ cellsmL^‐1) was used to feed the daphnids. The parameters used to determined the effect of the pesticide on D. magna were:mean total young per female, mean brood size, days to first brood, intrinsic rate of natural increase (r), growth, and survival. Reproduction as well as survival was significantly reduced at lindane concentrations of 0.25 mgL^‐1 and higher. The intrinsic rate of natural increase (r) decreased with increasing concentrations of lindane. Growth, as measured by body length, was depressed significantly at 0.25 mgL^‐1 lindane and higher. The chronic data was used to formulate an acute/chronic ratio.     

Introduction

Abstract

Eight pairs of O‐methyl and O‐ethyl O‐(substituted‐phenyl) phenylphosphonothionates were evaluated with respect to their delayed neurotoxic activity in hens. O‐methyl compounds were in all cases more active than their O‐ethyl analogs. The neurotoxic potential of the O‐methyl phenylphosphonothionates was 2,5‐diCl >4‐NO₂ >2,4,5‐triCl and 2,4,6‐triCl >2,4‐diCl >2,5‐diCl‐4‐Br >4‐CN, when single oral doses were given. Both EPN‐ethyl and leptophos‐raethyl were more neurotoxic in multiple dermal than multiple oral dosing regimens. LD₅₀s for mice and flies were established.