Poster Session Brochures
ALS Environmental is frequently asked to present technical information on a variety of subjects for seminars and conferences in a poster session format. Below are just a few of the past offerings:
1,4-Dioxane is a manmade chemical used primarily as an industrial solvent or solvent stabilizer to prevent the breakdown of chlorinated solvents during manufacturing processes. In addition, 1,4-Dioxane can also be found in a host of household products, including shampoo, liquid and dishwashing soap, lotion, and cosmetic products. Due to its volatility and solubility in water, 1,4-Dioxane has a high potential for entering the environment and can facilitate the dispersal of spent chlorinated solvents into ground and surface water systems, as evidenced by its detection in surface waters throughout the United States.
Air sampling was conducted both at and adjacent to a facility that composts green waste (yard debris), blood and fat from chicken processing, fish carcasses, wood waste, gypsum and other wastes to identify the odorous airborne contaminants. The composting method was an outdoor turned windrow modified in a block configuration. The compounds of interest were those that are odorous at low levels and included amines, carboxylic acids (volatile organic/fatty acids), reduced sulfur compounds and odorous volatile organic compounds (VOCs). Carboxylic acids and amines were evaluated using two novel methods developed and validated by ALS Environmental's air quality laboratory.
Freeze Drying: Increasing Extraction Efficiency of Organic Contaminants from Solid Substrates Using Freeze Drying: A Case Study
The study presented here compares the extraction efficiency of freeze drying with that of sodium sulfate drying for analysis of Chlorinated Pesticides, PCBs, Organotins, Semivolatile Organics, and Polycyclic Aromatic Hydrocarbons. The study shows that extraction of freeze-dried samples consistently yields higher recoveries of analytes when compared with analytical results for chemically dried sediments.
Low-Level Determination of N-Nitrosodimethylamine by Chemical Ionization GC/MS with Large Volume Injection
N-Nitrosodimethylamine (NDMA) has been found to be a disinfection byproduct in water systems using chloramination and has also been detected in wastewater effluents. A method has been developed to detect NDMA at low part-per-trillion levels using a continuous extraction designed to minimize analytical interference.
Polybrominated Diphenyl Ethers (PBDEs) are a class of brominated flame-retardants that have been used over the past 30 years in the production of textiles, high impact plastics, and electronic circuitry. Recently PBDEs have gained increased attention as emergent chemicals because of their persistence in the environment and potential for bioaccumulation, as well as their similarity in structure to PCB’s, Dioxins and Furans. Because of the potential toxicity of these chemicals, various methods have been developed for the extraction and analysis of these compounds. For solid matrices such as tissues, sediments, and soils, a high degree of extraction efficiency for PBDEs can be achieved by automated Soxhlet extraction, while continuous liquid-liquid extraction techniques have been used for the efficient extraction from aqueous samples.
A procedure for analyzing a relatively wide range of trace metals in samples containing elevated levels of dissolved solids is discussed. The procedure incorporates a chemical separation to remove interfering matrix components so final analysis can be performed using inductively coupled plasma-mass spectroscopy (ICP-MS). The separation utilizes reduction of certain target analytes to the elemental state and precipitation of others as the boride, depending on reduction potentials and/or boride solubility. The precipitation is facilitated using elemental palladium plus iron boride as carriers. Once separated from the seawater matrix, the precipitate is dissolved and analyzed using ICP-MS. A number of modifications to the procedure have been made over the past 11 years to improve performance. The method meets general USEPA performance criteria.
The toxicity and environmental impact of organochlorine pesticides and Aroclors is well documented. Routine environmental analysis of these compounds has remained largely unchanged since the advent of the United States Environmental Protection Agency (USEPA) Methods 8081 and 8082. However, recent instrumental advances have allowed for significant improvements in detection limits. Using an Agilent Gas Chromatograph (GC) equipped with a micro-electron capture detector (micro-ECD) and a programmable temperature vaporizing (PTV) inlet along with a larger sample size, groundwater detection limits can be reduced ten to twenty-fold over nominal environmental laboratory limits.