An approach for comparing laboratory and field measures of bioaccumulation is presented to facilitate the interpretation of different sources of bioaccumulation data. Differences in numerical scales and units are eliminated by converting the data to dimensionless fugacity (or concentration-normalized) ratios. The approach expresses bioaccumulation metrics in terms of the equilibrium status of the chemical, with respect to a reference phase. When the fugacity ratios of the bioaccumulation metrics are plotted, the degree of variability within and across metrics is easily visualized for a given chemical because their numerical scales are the same for all endpoints. Fugacity ratios greater than 1 indicate an increase in chemical thermodynamic activity in organisms with respect to a reference phase (e.g., biomagnification). Fugacity ratios less than 1 indicate a decrease in chemical thermodynamic activity in organisms with respect to a reference phase (e.g., biodilution). This method provides a holistic, weight-of-evidence approach for assessing the biomagnification potential of individual chemicals because bioconcentration factors, bioaccumulation factors, biota-sediment accumulation factors, biomagnification factors, biota-suspended solids accumulation factors, and trophic magnification factors can be included in the evaluation. The approach is illustrated using a total 2393 measured data points from 171 reports, for 15 nonionic organic chemicals that were selected based on data availability, a range of physicochemical partitioning properties, and biotransformation rates. Laboratory and field fugacity ratios derived from the various bioaccumulation metrics were generally consistent in categorizing substances with respect to either an increased or decreased thermodynamic status in biota, i.e., biomagnification or biodilution, respectively. The proposed comparative bioaccumulation endpoint assessment method could therefore be considered for decision making in a chemicals management context.

Quantitative analyses of Cr, As, Se, Cd, Hg, and Pb in soil were performed using wavelength dispersive X‐ray fluorescence (WDXRF) spectrometry with pressed powder pellet and loose powder methods. Standard soil samples containing hazardous metals were prepared by adding appropriate amounts of aqueous standards to base soils and then drying and homogenizing them. Base soil powders ground to less than 12.5 µm of modal particle size were Tachikawa loam, brown forest soil, and weathered granite containing 17.9, 9.43, and 3.49 mass% of Fe2O3, respectively. Analytical lines were CrKα, AsKα, SeKα, CdKα, HgLα, and PbLβ, with accompanying corrections for overlapping of SeKβ to PbLβ and PbLα to AsKα. Specimens for XRF analysis were prepared using powder pellets pressed to 23 mm internal diameter of an Al ring with 300 kgf cm−2, and loose powder in a 31 mm internal diameter polyethylene cup covered with 6‐µm thickness of polypropylene film. Calibration curves drawn using the proposed standards showed good linearity under 3000 mg kg−1 for the five metals, and 300 mg kg−1 for Hg. Corrections with Compton scattering for AsKα, SeKα, CdKα, HgLα, and PbLβ, and with background scattering for CrKα were effective and produced identical inclinations of calibration curves. CdKα having larger critical depth in the loose powder specimen showed merely smaller inclination of calibration curve than that of the pressed powder specimen because of optical shading. The spike test for five analytes showed good recovery for gravel soil and pumice soil. Copyright © 2009 John Wiley & Sons, Ltd.

Standardized laboratory protocols for measuring the accumulation of chemicals from sediments are used in assessing new and existing chemicals, evaluating navigational dredging materials, and establishing site-specific biota-sediment accumulation factors (BSAFs) for contaminated sediment sites. The BSAFs resulting from the testing protocols provide insight into the behavior and risks associated with individual chemicals. In addition to laboratory measurement, BSAFs can also be calculated from field data, including samples from studies using in situ exposure chambers and caging studies. The objective of this report is to compare and evaluate paired laboratory and field measurement of BSAFs and to evaluate the extent of their agreement. The peer-reviewed literature was searched for studies that conducted laboratory and field measurements of chemical bioaccumulation using the same or taxonomically related organisms. In addition, numerous Superfund and contaminated sediment site study reports were examined for relevant data. A limited number of studies were identified with paired laboratory and field measurements of BSAFs. BSAF comparisons were made between field-collected oligochaetes and the laboratory test organism Lumbriculus variegatus and field-collected bivalves and the laboratory test organisms Macoma nasuta and Corbicula fluminea. Our analysis suggests that laboratory BSAFs for the oligochaete L. variegatus are typically within a factor of 2 of the BSAFs for field-collected oligochaetes. Bivalve study results also suggest that laboratory BSAFs can provide reasonable estimates of field BSAF values if certain precautions are taken, such as ensuring that steady-state values are compared and that extrapolation among bivalve species is conducted with caution.

Reaction between urea and hypobromite in alkaline solution was found to produce chemiluminescence with a maximum wavelength at 510 nm. A simple chemiluminescence detection method was used for the determination of urea in human urine and natural aqueous samples, which combined this chemiluminescence reaction with a flow injection analysis system. The relative standard deviation for 5 x 10(-7) mol dm-3 urea is 1.9% (n = 6), and the detection limit is 9.0 x 10(-8) mol dm-3 (3Sr). As this chemiluminescence reaction is very fast, a double concentric tube mixer connected directly to the chemiluminescence cell was used to mix urea solution and hypobromite solution. Alkylamines, carboxylic acids and most amino acids do not interfere in the determination. Ammonium ion interferes, but the sensitivity for ammonium ion is only 1% of that for urea. The interference from ammonium ion was removed sufficiently by using an on-line cation-exchange column.

No abstract

No abstract

The reaction kinetics, the chemiluminescence spectra, the products, and the lifetimes of emission species for the chemiluminescence reaction between hypobromite and ammonia or urea in an alkaline aqueous solution were investigated. Results show that the reaction mechanism for ammonia chemiluminescence is different from that for urea. The reaction of ammonia and hypobromite produces NO2 in the gaseous phase and NO2− in solution; however, the reaction of urea and hypobromite does not. For the reaction of ammonia and hypobromite, chemiluminescence intensity obeys 1.5 order kinetics for hypobromite concentration when ammonia is in excess, but the reaction of urea and hypobromite obeys second order kinetics for hypobromite when urea is in excess. The spectrum of the chemiluminescence from the ammonia and urea with hypobromite shows a maximum intensity at 710, and at 510 nm, respectively. The chemiluminescence lifetimes of the emission species were 0.056 and 0.092 s for the reaction of ammonia and the reaction of urea, respectively. The chemiluminescence species of the reaction between hypobromite and ammonia seems to be excited NO2, that for urea seems to be excited N2.

determined Cr(III) and Cr(VI) in river water and lake water with cation-and anion-exchange resin in batch experiments by ICP-AES. Sumida et al. 11,12 preconcentrated Cr(III) and Cr(VI) in tap water, river water, wastewater, and seawater with iminodiacetate chelating resin column by ICP-AES. Furusho et al. 13 developed an automated pretreatment system for the determination of Cr(III) and Cr(VI) in tap water, river water, and mineral drinking water with iminodiacetate chelating resin and synthesized chitosan resin columns by ICP-AES. In this way, the iminodiacetate chelating resin was often used for the speciation of Cr in water; however, the chelate-forming reaction 2010 © The Japan Society for Analytical Chemistry † To whom correspondence should be addressed. E-mail: tetsuo@meiji.ac.jp A simple method using solid-phase extraction combined with metal furnace atomic absorption spectrometry was developed for the determination of Cr(III) and Cr(VI) at sub-ppb levels in water. A 500-ml water sample was adjusted to pH 3 with nitric acid and then passed through an iminodiacetate extraction disk placed on a cation-exchange extraction disk at a flow rate of 20 -40 ml min -1 for concentrating Cr(III). The filtrate was adjusted to pH 10 with aqueous ammonia and then passed through an anion-exchange extraction disk at a flow rate of 2 ml min -1 for concentrating Cr(VI). The Cr(III) and Cr(VI) collected were eluted with 40 ml of 3 mol l -1 nitric acid for Cr(III) and 40 ml of 1 g l -1 diphenylcarbazide solution for Cr(VI). Each eluate was diluted to 50 ml with deionized water and injected into a U-type tungsten board on the metal furnace. The calibration curves of Cr(III) and Cr(VI) showed good linearity in the range of 0.1 -0.5 ng. The detection limits corresponding to three times the standard deviation (n = 5) of blank values were 8.1 pg for both Cr(III) and Cr(VI). The analytical value of total Cr (Cr(III) + Cr(VI)) in certified reference material of river water (JSAC 0302-3) was in good agreement with the reference value. The recovery test for 0.50 μg (1.00 μg l -1 ) of Cr(III) and Cr(VI) added to 500 ml of the water samples showed sufficient values (98.1 -106%), except for river water sampled downstream due to relatively higher CODMn value. The relative standard deviations (n = 5) were less than 5% for both Cr(III) and Cr(VI). Determination of Cr(III) and Cr(VI) at Sub-ppb Levels in