Section G: Accidental and deliberate environmental contamination
The deliberate release of toxic materials to inflict injury or death is not a modern phenomenon. Indeed, it is likely that humans have utilized nature’s readily available bounty of poisons for nefarious purposes since time immemorial. However, a major development occurred during World War I. Prior to this, poisons based on simple inorganic chemicals or derivatives of toxic fauna and flora were mainly limited to weapons of assassination. The industrial capabilities of the main combatants in World War I, however, led to a rapid escalation in the complexity and effectiveness of chemical weapons on an immense scale: suddenly, it was possible to simultaneously expose thousands of individuals in an open environment to toxic concentrations of harmful substances. This led to great public opprobrium, and subsequently, a number of international agreements to ban such means of warfare were implemented (with varying degrees of success). The most significant development in recent times has been the willingness of certain factions to engage in activities that deliberately seek to expose unprotected members of the public to chemical, biological, radiological or nuclear (CBRN) hazards.
Chemical Grouting and Soil Stabilization
By Reuben H. Karol
By Reuben H. Karolin Chemical Grouting and Soil Stabilization
Advanced Soil Mechanics
By Braja M. Das
By Braja M. Dasin Advanced Soil Mechanics, Fifth Edition
Now in its fifth edition, this classic textbook continues to offer a well-tailored resource for beginning graduate students in geotechnical engineering. Further developing the basic concepts from undergraduate study, it provides a solid foundation for advanced study.
This new edition addresses a variety of recent advances in the field and each section is updated. Braja Das particularly expands the content on consolidation, shear strength of soils, and both elastic and consolidation settlements of shallow foundations to accommodate modern developments.
Real time monitoring of soil contamination with diesel fuel using photoionization detectors
Published in Arab Journal of Basic and Applied Sciences
Soil contamination is a very relevant environmental problem, which is directly connected with both groundwater and air contamination. Petroleum products represent often a major source of soil contamination. In this sense, leakage of diesel fuel can cause important environmental problems due to the persistence of it in contaminated soils and to its toxicity at low concentrations. Photoionization detectors (PID) have the ability to evaluate the ampleness of contamination by detection and quantification in real time of diesel fuel vapours. Finally, this achievement can lead to a rapid evaluation (in minutes) of soil contamination and will facilitate the application of most suitable remediation technologies. The purpose of this study was to simulate an accidental spill of diesel on the ground, with the aim to monitor the degree of volatilization of chemical compounds during six weeks. Thus, the reasons behind the low volatility of diesel fuel in the investigated soil samples, based on the trend of volatilization and on soil characteristics as well.
Schematic of the photoionization detector PID. The UV lamp, filled with Kr gas at low pressure, generates photons with the energy of 10.6 eV using a RF field that induces and sustains a glow discharge when applied onto a set of two opposite metallic plates placed externally to the lamp body. The lamp is a glass body (1/2” o.d. and ca. 4 cm length) with a soldered disc of material transparent to ultraviolet radiation (MgF2 for 10.6 eV lamps).
Level and Potential Risk Assessment of Soil Contamination by Trace Metal from Mining Activities
The trace metals in soil samples collected from a waste dump near eight kinds of mining sites included kaolin, gold, iron, clay, bauxite, bazan, construction stone, and antimony, located in Tay Nguyen region, Central highlands of Vietnam were investigated. The concentration of Cu, Pb, and Zn in soil were higher group compared to others heavy metal at almost mining areas in Tay Nguyen, Viet Nam. The highest concentration of Cu, Zn, Pb, Mo, B, As, Hg, and Cd was 120.46 mg/kg (Dak Drong antimony), 71.70 mg/kg (Tam Bo), 21.70 (Felspat Ea Kar), 17.33 (Trai Mat), 15.61 (Felspat Ea Kar), 8.87 (Trai Mat), 6.96 (Tan Rai), and 2.91 (Nhan Co), respectively. The content of trace metals was varying in different kinds of mining sites. Cd, Zn were mainly accumulated at waste dump from mining sites of clay, bauxite, and bazan; Pb was recorded at mining sites of clay, bazan, and construction stone while As and other trace metals were enriched at kaolin, gold, clay, and bazan. The calculated results of enrichment factor (EF) and pollution load index (PLI) indicate that almost the EF > 2 and PLI > 1 and the high contamination of trace metals for mining sites in Tay Nguyen due to human activities. The first spatial variations of trace elements in the central highlands region in Vietnam were demonstrated.
Soil contamination by Taenia solium egg DNA in rural villages in Kongwa district, Tanzania
Published in Infection Ecology & Epidemiology
A total of 192 pooled soil samples from five sampling points per household were examined by droplet digital Polymerase Chain Reaction (ddPCR) from 96 pig-keeping households both during the dry and rainy seasons. The pooled samples were first processed by a flotation-double sieving technique, followed by screening for worm DNA employing universal primers targeting the mitochondrial cytochrome c oxidase subunit I (cox1) gene of human taeniid species and some other helminths. All DNA positive samples were later confirmed by a specific ddPCR probe assay targeting the mitochondrial cox1 gene of T. solium. A total of 17.2% (n = 33) samples were positive with the universal ddPCR, whereas T. solium DNA was confirmed by the specific ddPCR only in 3.1% (n = 3) of the surveyed households. The detection of T. solium DNA in this study spells out a low risk of exposure to T. solium eggs from contaminated household soil. Based on our results, ddPCR seems to be a promising technology for screening T. solium eggs in soil. Graphical Abstract
Contamination and health risk assessment of trace elements in soil at play centers of urban low - income settings
Young children are considered critical receptors of potentially toxic trace elements (PTEs) by non-dietary ingestion of contaminated soil. The study assessed the potential enrichment of soil and the health risk of PTEs to 471 children less than seven years via non-dietary soil ingestion at six Early Childhood Development Centers (ECDCs) in urban low-income settings. The total concentrations of PTEs were determined by ICP-AES after wet acid digestion. The extent of soil contamination with PTEs and their source apportionment were assessed by the enrichment factor (EF). The US-EPA risk assessment model was used to determine the risk of PTE exposure by children. Multivariate statistical analyses and the EF suggested anthropogenic origin of PTEs in playgrounds and indoors, especially Cd and Pb from atmospheric deposition. Indoor floor dust at ECDCs was enriched (significant to extreme) with PTEs of anthropogenic origin imported from the outside environment.