ADVANCES IN INDUCTIVELY COUPLED PLASMA OPTICAL EMISSION SPECTROMETRY FOR ENVIRONMENTAL ANALYSIS

Inductively coupled plasma optical emission spectrometry (ICP-OES) is a widely used method of elemental analysis because of its excellent analytical figures of merit and relative freedom from interferences. This review considers recent relative reviews, fundamental studies of the inductively coupled plasma, advances in other atom cells for atomic emission, and preconcentration methods. The focus of the article is on recent applications, illustrating the versatility of the instrumentation for practical analysis.     

DETERMINATION OF SELECTED METALS IN ALLIGATOR (Alligator mississippiensis) TISSUES BY INDUCTIVELY COUPLED PLASMA-OPTICAL EMISSION SPECTROMETRY

The results presented in this preliminary study show the concentrations of selected metals in the muscle and bone tissues from the tail of an alligator (Alligator mississippiensis) as determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). Cadmium and lead were not detected above the approximate detection limit of 0.5 µg/g for these two metals by ICP-OES, in either meat or bone tissues. Concentrations (µg/g) (mean ±standard deviation, range) for copper were 8.8 ± 3.8, 6.5–13.1 (meat), and 6.2 ± 3.5, 3.6–10.2 (bone); for iron were 41.9 ± 16.2, 28.8–59.9 (meat), and 26.4 ± 4.4, 21.3–29.0 (bone); and for zinc were 52.8 ± 7.4, 48.0–61.4 (meat), and 42.7 ± 9.0, 34.9–53.2 (bone). The results of copper, iron, and zinc levels were not considered to be potentially toxic to the alligator.     

DETERMINATION OF CADMIUM,CHROMIUM, COPPER,IRON, LEAD,AND ZINC IN OYSTERS FROM SOUTHWEST LOUISIANA BY INDUCTIVELY COUPLED PLASMA-OPTICAL EMISSION SPECTROMETRY

This article presents a follow-up, a more comprehensive and extensive study to a previous, but limited study on three metals in oysters from the West Cove area of Lake Calcasieu in Southwest Louisiana. Results from a two-sampling period in mid-October and mid-December 2009 showed concentrations levels in μg/g (mean of 15 oysters, ± standard deviation, and range) as determined by inductively coupled plasma-optical emission spectrometry (ICP-OES) of cadmium, 5.0, ±0.5, 4.0–6.3, and 3.0, ±0.5, 1.8–5.3; chromium, 3.1, ±0.6, 2.0–3.6, and 1.7, ±0.6, 0.7–3.0; copper, 125.0, ±115, 58–245, and 115, ±45, 76–228; iron, 224, ±66, 142–403, and 311, ±111, 160–559; lead, 3.4, ±0.7, 1.6–5.8, and 4.7, ±2.3, 0.7–13; and zinc, 1859, ±774, 740–3471, and 1578, ±783, 692–3056. These concentrations were lower by at least a factor of 10 from the previous study on cadmium and lead but similar to store-bought oysters. The two sampling period concentrations were not statistically different for the two sampling month periods. The lowering of the concentration was attributed to a cleaner (from metals) oyster beds. Results of the six metals from soils in six different sites in the oyster beds showed comparable or slightly higher concentrations than the oysters. Water samples from the six sites were low, or below the detection limit of the ICP-OES instrument.     

DETERMINATION OF COPPER,IRON, LEAD,MAGNESIUM, MANGANESE,AND POTASSIUM IN RICE FROM INDIA AND UNITED STATES BY INDUCTIVELY COUPLED PLASMA-OPTICAL EMISSION SPECTROMETRY

Rice from several regions in India and two areas of the U.S. were determined for selected metals following sample preparation using microwave technology for subsequent determination by inductively coupled plasma-optical emission spectrometry. Lead was not detectable in four of the rice samples and sub-part per million (ppm) for the remaining three rice samples. Concentrations of copper and manganese were in the ppm range, iron in the tens of ppm, and magnesium and potassium in hundreds to thousands of ppm.     

DETERMINATION OF ALUMINUM,CALCIUM, AND MAGNESIUM IN FRASER FIR (ABIES FOLIAGE) FOLIAGE AND SURROUNDING SOIL IN THE SOUTHERN APPALACHIANS

Located at high elevation sites in the Southern Appalachians, the Fraser fir (Abies fraseri) has suffered visible decline in recent years. This study involved the measurement of concentration levels of aluminum, calcium, and magnesium by inductively coupled plasma optical emission spectrometry to determine the contribution of acidic deposition to this decline. Calcium and magnesium are nutrients, and hence one would anticipate relatively high foliar concentrations of these elements in the absence of pollution. Conversely, aluminum is toxic to the trees, and one would expect higher foliar concentrations in polluted locations. Statistical comparisons of the metal concentrations did not demonstrate a causal relationship between the location or elevation of Fraser fir stands. However, compared to previous studies, the foliar concentrations of calcium and magnesium were higher than concentrations previously reported in the 1990s, suggesting pollution controls may have reduced atmospheric deposition.     

INVESTIGATION OF ACID DEPOSITION EFFECTS ON SOUTHERN APPALACHIAN RED SPRUCE (Picea rubens) BY DETERMINATION OF CALCIUM,MAGNESIUM, AND ALUMINUM IN FOLIAGE AND SURROUNDING SOIL USING ICP-OES

Red spruce (Picea rubens) are conifers found at high elevations (above 1370 m) sites in the Southern Appalachian Mountains. A decline of red spruce forests in the Southern Appalachian Mountains caused by atmospheric acid deposition has been reported since the 1970s. Acid deposition leaches essential nutrients (calcium and magnesium) out of the soil and increases the availability of toxic metals (aluminum) to plants. Acid deposition effects on red spruce forests were investigated by determining aluminum, calcium, and magnesium in foliage and surrounding soils using inductively coupled plasma optical emission spectrometry (ICP-OES). There was some correlation in nutrient or toxic metal concentrations found in the foliage or surrounding soils of red spruce trees with respect to elevation and geography of red spruce forests located in the Southern Appalachian Mountains. The majority of the results indicated that foliar nutrient or toxic metal concentrations from red spruce trees did not correlate with soil metal concentrations. Life stage of red spruces trees were independent of foliar or soil metal concentrations. A previously developed model using soil calcium/aluminum molar ratios suggested that almost all sample sites located in the Southern Appalachian Mountains are at high risk of adverse forests health effects. A comparison of red spruce sapling foliar calcium/aluminum ratios at Clingman's Dome, North Carolina/Tennessee, suggested a possible improvement since the 1980s in red spruce forest health. A comparison of sapling red spruce foliar calcium and magnesium concentrations with previous studies, which spanned 40 years, at Richland Balsam, North Carolina, suggested an improvement in red spruce health since 1994.