Samples from a hazardous waste site contaminated with lead and cadmium were analyzed by four independent laboratories, each using a different technique:  atomic absorption spectroscopy (AAS), X-ray fluorescence (XRF) spectroscopy, inductively coupled plasma−atomic emission spectroscopy (ICP-AES), and potentiometric stripping analysis (PSA). The four data sets were retrospectively analyzed to (1) establish the magnitudes of uncertainty in the measurements, (2) evaluate the comparability of the four instrumental methods, and (3) determine if any significant correlations existed between individual sets of data. In general, the four techniques gave comparable results for the analysis of lead and cadmium, with the best agreement between PSA and AAS. Concentrations determined by PSA were higher than those measured by ICP-AES, AAS, and XRF, while concentrations determined by XRF were lower than or equal to recoveries determined by ICP-AES and AAS. Principal component analysis determined that the two major principal components in the sample space of the data set were analyte concentration and sample preparation. The ICP-AES data were used to look for correlations among other elements in the samples. It was shown that concentrations of four of these elements (aluminum, zinc, iron, and calcium) were significantly higher than 19 other elements determined by ICP-AES. Principal component analysis on those 19 elements showed a first-component variation attributable to an analyte concentration effect and a second-component variation attributable to an analyst-day effect.

Air and water pollutant emissions were measured from two 9.9 HP outboard engines:  a two-stroke Evinrude and its four-stroke Honda counterpart. In addition to the measurement of regulated air pollutants, speciated organic pollutants and particulate matter emissions were determined. Aqueous samples were analyzed for MTBE (methyl tert-butyl ether) and BTEX (benzene, toluene, ethylbenzene, and xylene) emission rates. Compared to the four-stroke engine, the two-stroke had dramatically higher levels of toxic organic and particulate matter emissions. The organic material emitted from the two-stroke engine resembles the test gasoline due to the predominance of unburned fuel. Emission rates for PM10 (particulate matter with a diameter of 10 μm or less) are equal to those for PM2.5, implying that emitted particles are all in the respirable range. Aqueous emissions from the two-stroke are also higher:  the two-stroke's BTEX and MTBE emissions are, on average, 5 and 24 times higher, respectively, and 3−10% of the MTBE fed to the engine is emitted to the water. Aqueous emission rates, expressed in brake-specific units, tend to increase with decreasing engine load, as do the atmospheric emission rates.

A gas chromatograph/atomic emission detector (GC/AED) system has been evaluated for its applicability to environmental analysis. Detection limits, elemental response factors, and regression analysis data were determined for 58 semivolatile environmental contaminants. Detection limits for injected analytes ranged from 0.17 to 3.0 ng on the hydrogen 486-nm channel, from 1.0 to 5.0 ng on the nitrogen 174-nm channel, from 0.65 to 11.7 ng on the oxygen 777-nm channel, from 0.071 to 3.0 ng on the chlorine 479-nm channel, and from 0.023 to 0.038 ng on the sulfur 181-nm channel. Mean elemental response factors (ERFs) measured on these channels, relative to the carbon 496-nm channel, were hydrogen, 0.084 (mean %RSD = 6.6); nitrogen, 0.246 (mean %RSD = 19); oxygen, 0.459 (mean %RSD = 16); and chlorine, 0.417 (mean %RSD = 3.6). The higher precision obtained for hydrogen and chlorine, relative to that for nitrogen and oxygen, is attributed to the ability to scan these elemental channels in the same GC run as the carbon 496-nm channel (diode array wavelength range limitation of ∼40 nm/run). Mean ERFs of standard compounds were used to determine the molecular formulas of chlorinated hydrocarbons and chlorinated organosulfur compounds in a contaminated environmental soil sample. These formulas are in good agreement with the molecular weights and chlorine isotopic data obtained from low-resolution gas chromatography/mass spectrometry.

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