Bruce E. Watkins

Treatment of solid wastes with molten salt oxidation

Abstract Molten salt oxidation (MSO) is a robust thermal treatment process that can be used to oxidatively and efficiently destroy the organic constituents of mixed and hazardous wastes, and energetic materials [1–7] . An integrated pilot-scale MSO demonstration facility has been installed and operated at Lawrence Livermore National Laboratory (LLNL). This facility, which has been operational since December 1997, was built to demonstrate the capability of processing organic feed at a commercially useful scale (5–7 kg/h). The integrated MSO treatment train consists of several subsystems:a primary MSO processor (reaction vessel), an off-gas conditioning system, a salt recycle system, and a ceramic final forms immobilization system. The MSO/off-gas system began operations in December 1997, while the salt recycle system and the ceramic final forms immobilization system were activated in May 1998 and September 1998, respectively. During FY98, we have successfully conducted tests in the MSO facility on a variety of liquid and solid organic feeds: chlorinated solvents, tributyl phosphate/kerosene mixtures, PCB-contaminated waste oils and solvents, shredded booties and coveralls, plastic pellets, ion-exchange resins, activated carbon, several radioactive-spike organics, and two well-characterized low-level liquid mixed wastes. This paper presents the results from the operation of the integrated pilot-scale MSO system for the treatmentof several solid feeds including activated carbon, ion exchange resin, plastic pellets, and shredded booties and gloves.

Development of an immunoassay for chlorinated dioxins based on a monoclonal antibody and an enzyme linked immunosorbent assay (ELISA)

Abstract A set of monoclonal antibodies to dioxin have been developed. These form the bases for a competition enzyme-linked immunosorbent assay capable of detecting 0.5 ng of 2,3,7,8-tetrachlorodibenzodioxin.

An immunoassay for chlorinated dioxins in soils

Abstract An immunoassay for chlorinated dioxins in soils is described. This immunoassay utilizes a competitive ELISA with a dioxin-specific monoclonal antibody and an avidin-biotin amplification system on aqueous solutions obtained after extraction of the matrix and an effective clean-up procedure. Its sensitivity has been shown on oil-soaked, composite California soils spiked with variable amounts of 2,3,7,8-tetrachlorodibenzodioxin.

Mutagens and carcinogens in cooked foods: Concentration, potency, and risk

The cooking of foods derived from muscle generates heterocyclic amines that are very potent bacterial mutagens and carcinogens in mice, rats, and monkeys. Presently 12 mutagenic compounds have been found in cooked foods derived from the Western Diet. Only 6 of these compounds have been definitely identified. Specifically designed monoclonal antibodies can detect nanogram amounts each of 2-amino-1-methyu1-6-phenylimidazo[4,5-f]pyridine(PhIP), 2-amino-3-methylimidazo[4,5f] quinoline(IQ), and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQx) in the meat matrix, but specific quantitation requires a prior HPLC separation before use of antibodies for identification. Modeling of PhIP (20 ppb in beef) formation under dry heating conditions using heavy isotope incorporation coupled with MS and NMR shows that all the C and N atoms in the PhIP are contributed by creatin(ine) and phenylalanine. PhIP is both a potent frameshift mutagen in Salmonella bacteria and a potent inducer of mutations, sister chromatid exchange and chromosomal aberrations in Chinese Hamster Cells in culture, and of chromosome damage in mouse bone marrow. Using accelerator mass spectroscopy, we can measure in a linear fashion one MeIQz DNA adduct per 1011nucleotides. N-OH-PhIP which is generated by both IA1 and IA2 forms of cytochrome P-450 appears to be a proximal mutagen.

Development and Characterization of a Fiber Optic Immuno-Biosensor

In this paper we describe preliminary results from the development and characterization of a fiber optic biosensor that utilizes a fluorescently-labeled monoclonal antibody to pyrethroid pesticides. A synthetic pyrethroid-like antigen was coupled to bovine serum albumin and immobilized on the surface of a stripped portion of the distal end of an optical fiber. Each fiber was individually calibrated for its optical response using standard solutions of fluoresceinamine. Binding of the antibody was detected via the evanescent wave of the fiber by use of a portable fiber optic fluorimeter. Initial binding rate and equilibrium levels of bound antibody showed a linear relationship with antibody concentrations between 7 nM and 25 uM. To test the reversibility of the biosensor, bound antibody was removed with protein denaturing agents and the same fibers were re-tested with similar concentrations of antibody. When re-immersed in antibody solution, binding of the antibodies was again observed. The results provide encouraging evidence that such a biosensor may be useful for the determination of small organic molecules in situ

Cooked-Meat Derived Aromatic Amine Mutagens and Their Immunoassay

Typical household cooking of meat produces a family of aromatic amine mutagens termed aminoimizodazaarenes (AIAs). This family contains among other members PhIP(2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), IQ (2-amino-3methylimidazo[4,5-f]quinoline), and MelQx (2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline). Along with the nitro-aromatics, these are some of the most mutagenic compounds ever tested in bacterial mutagenesis assays. Where tested, the AIAs are also carcinogens. Typical levels of AIAs in well-done cooked beef are 0.1, 1.0, and 10 ppb for IQ, MeIOx, and PhIP, respectively. This low level of presence in foods hampers analysis of AIAs in the diet. To facilitate AIA assay we have developed a set of monoclonal antibodies to the AIAs. Individual antibodies have been selected that react with IQ, MeIOx and PhIP. These antibodies are being used to quantify the levels of individual AIAs in various cooked meats. In addition, analysis of well-done beef shows the presence of other, currently unknown, structurally related compounds that immunochemically cross-react with the antibodies. The antibodies also recognize compounds present in the urine of people on diets of well-done beef, but not people eating vegetarian diets. These findings suggest that the antibodies may be useful as biochemical markers of human exposure to dietary meat mutagens. The antibodies also may provide a means of concentrating and purifying human metabolites of AIAs from urine.

Monoclonal Antibodies for Detection of Environmental Contamination: An Immunoassay for Dioxin

Environmental monitoring for chemical pollutants has traditionally been done using a variety of analytical techniques including gas chromatography and mass spectroscopy. These techniques, while very precise, are usually time-consuming, and require sophisticated equipment, dedicated laboratories, and highly trained personnel. All result in a costly analysis that is not amenable to automation. Alternative assays that detect specific chemicals and are less expensive, faster, and adaptable to automated systems are desirable. They also should be simple enough to be performed in mobile field laboratories by relatively untrained personnel.