Elemental chemistry of four lichen species from the Apostle Islands,Wisconsin, 1987, 1995 and 2001

Four lichen species sampled three times over a 15-year time span at four of the Apostle Islands, Wisconsin were analyzed for 16 chemical elements in order to determine time trends and spatial patterns. Factor analyses of the data revealed that elements associated with soils (Al, Cr, Fe, Na, Ni and S) have increased over the study period, while nutrient and pollutant elements (Cu, K, P, Pb and Zn) have decreased. Four other elements (Ca, Cd, Mg and Mn) were unchanged over time. Cladina rangiferina, a terricolous species, contained the lowest concentrations of all elements, while the corticolous species Evernia mesomorpha was highest in soil elements, Hypogymnia physodes was highest in Ca, Cd, Mg and Mn, and Parmelia sulcata was highest in the nutritional elements. Lichens on islands within 3-4 km of the mainland were highest in soil elements, which decreased with distance from the mainland. Elements that were 18-43% greater on the nearest islands were significantly different between near and far islands. Eight elements (Al, Ca, Cd, K, Mg, Mn, P and S) exceeded enrichment levels for Hypogymnia physodes, suggesting possible contamination problems for this species. Although Pb has decreased significantly over the time period, other elements have increased in the lichens while decreasing in the atmosphere, suggesting that accumulation in the environment is continuing.     

Sex- and age-related variation in elemental concentrations of contemporary Japanese ribs

Twenty elements (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Sr, Ti, V, Zn, C and N) in 42 Japanese ribs (forensic medical autopsy cases) were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES), atomic absorption spectrometry (AAS) and carbon and nitrogen analysis to examine sex- and age-related variation in the concentrations of these elements. Bone Fe and Pb concentrations were significantly higher, while P concentrations were lower in males. Elements which showed age-related variation were Ca, P, Al, Fe, Mg, Na, Pb and Zn. Of these, Al, Fe, Pb and Zn linearly accumulate in bone with advancing age. The elements Na and Mg showed the lowest and highest concentrations in the youngest age group (0-19 years), respectively, and reached plateau levels in older age groups. The Ca and P concentrations were highest in the 20-39-year age group, gradually decreasing throughout older age groups, indicating that osteoporotic bone loss occurs in the older subjects. In addition, the results of correlation analysis indicated that the organic matter content of the bone, represented by C or N concentration, was a factor which contributed to the elemental variation of the bone.     

Mobility of trace metals in pore waters of two Central European peat bogs

Vertical peat profiles can only be used as archives of past changes in pollution levels if atmogenic elements are immobile after their burial. For mobile elements, similar pore-water concentrations can be expected at different peat depths. Concentrations of Pb, Cu, Zn, Cr, Mn, Fe, Co and Cd were determined in surface bog water and bog pore water 40 cm below surface in two Sphagnum-dominated peat bogs in the Czech Republic. Velke jerabi jezero (VJJ) is an upland bog located in an industrial area, Cervene blato (CB) is a lowland bog located in a rural area. Metal concentrations were monitored seasonally over 3 years (2002--2005) at both sites. Higher concentrations of Pb, Cu, Zn, Cr and Cd and lower concentrations of Mn, Fe and Co were found at the less polluted CB compared to VJJ. No clear-cut seasonality was observed in metal concentrations in bog waters, despite seasonal differences in industrial emission rates of pollutants (more coal burning in winter than in summer). This contrasts with an earlier observation of distinct seasonality in sulfate concentration and isotope composition in these stagnating bog waters. Peat substrate 40 cm below current bog surface represented pre-industrial low-pollution environment, yet pore waters at such depths contained the same metal concentrations as surface waters. The only exception was Pb, whose concentration in water solutes increased with increasing depth. Lack of vertical stratification in pore-water contents of Cu, Zn, Cr, Mn, Fe and Co indicated vertical mobility of these metals.     

The elemental composition and sources of house dust and street dust

The elemental compositions of house dust, street dust and soil have been determined for 26 elements on material collected in Christchurch, New Zealand. The elements Hf, Th, Sc, Sm, Ce, La, Mn, Na, K, V, Al and Fe may be considered to be soil-based and contribute about 45–50% to house dust and 87% to street dust. The elements which are enriched (>3 times) in the dusts relative to the levels found in local soils, are Br, Cu, Cl, Pb, Zn, Cr, Ca, Co, As and Sb in house dust, and Zn, Cr, Cu and Pb in street dust.     

Elemental composition of ancient Japanese bones

Excavated bones (rib) obtained from 50 sites in Japan were measured by ICP atomic emission spectrometry and atomic absorption spectrometry for concentration of 19 elements, including Al, B, Ca, Cd, Cr, Co, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Sr, Ti, V and Zn. One hundred and forty-one specimens were classified into five groups according to Japanese prehistoric and historic eras (Jomon, Yayoi, Kofun, Kamakura and Muromachi, and Edo). The elements, with concentrations which showed no significant change with era were Al, B and Cr. Average concentrations of Ca were in the range 2-2.5 X 10(-1) g g-1 and those of P ranged from 1.1 to 1.3 X 10(-1) g g-1, indicating a well-preserved bone mineral matrix. The Ca/P ratio (mol/mol) was lowest in the Edo group--1.48 as compared with 1.54-1.66 in the other groups. Among the elements which showed changes with era were Pb, Fe, Co and Mn, all of which showed remarkably elevated concentrations in the Edo group. In addition to this unique elemental composition of Edo bones, samples from the Kofun era showed a completely different composition from those of other periods, i.e. they had the highest concentrations of Cd, Zn and Mg, and the lowest concentrations of Cu, K, Ni and Sr. The cause of the elevated Pb concentration in Edo bones is discussed in relation to human activities which may have led to environmental Pb pollution.     

Spatial and seasonal variation in heavy metals in the sediments and biota of two adjacent estuaries, the Orwell and the Stour, in eastern England

A study was made of the concentrations of the elements As, Cd, Cu, Hg, Mn, Ni, Pb and Zn in the sediments and biota of two adjacent estuaries, the Orwell and Stour, in eastern England. The Orwell Estuary, with its urbanized head, was more contaminated with heavy metals than the Stour Estuary. Generally, in both estuaries, concentrations of metals were highest towards the head and the mouth. Saltmarsh sediments accumulated higher concentrations of most metals than mudflat sediments. Metal concentrations in the biota showed marked interspecific differences; Mytilus edulis had higher concentrations of Cd, Littorina littorea higher concentrations of Cu and Mn and Arenicola marina higher concentrations of Hg. Invertebrates from the Orwell had higher metal concentrations than those from the Stour. Algae had generally lower levels of metals than invertebrates. Metal concentrations were greatest and more variable in the top 10 cm of sediment. Metals were at greatest concentrations in winter and lowest in summer in sediments, algae and invertebrates. Mercury concentration increased with size in the three invertebrate species studied, but Cd and Zn generally were at higher concentrations in younger animals. Comparisons of sediments with average shale values indicated anthropogenic enrichment with several metals but it was considered that only Pb, at some sites, and possibly Hg posed potential threats to the ecology of the estuaries.     

Reference values for elemental concentrations in some human samples of clinical interest: A preliminary evaluation

Over 60 investigators, some of them with an outstanding international reputation as analysts, were requested to identify reliable data from their countries for elemental concentrations in normal adult human samples of clinical interest by contributing their own data as well as screening the literature information. A set of samples consisting of whole blood and its components, urine, milk, liver and hair were chosen and considered for 15 elements of biological significance: Zn, Cu, Fe, Se, Mn, Pb, Cd, Hg, As, Mo, Cr, Co, I, Ni and F. The results partly cover over 40 countries from the global regions of Africa, Asia, Europe, North, South and Central America, Australia and New Zealand.This survey has been useful in demonstrating certain trends of trace element picture around the world, at least qualitatively. Both diet and environment have a strong influence on the distribution pattern of several elements such as As, Cd, Mn, Pb, Se and Zn. A limited comparison of the available information on soil status of different countries revealed interesting associations for elements such as Mn and Zn.Importantly, this study revealed that only a few countries were in a position to supply a reasonable amount of data on samples requested here. In particular, for a number of countries, reliable data for even very essential elements such as Cu, Zn and Fe were not available. In view of the nutritional importance of several elements the time is ripe for international organizations to intervene and help produce some reference data for selected global regions which lack data of any kind.     

Elemental contamination of Japanese women's hair from historical samples

Japanese women's hair, which had been cut in the past and preserved was examined for the presence of 12 elements (Na, K, Mg, Ca, Sr, Mn, Fe, Cu, Zn, Hg, Pb and P). Elevated levels of Fe, Mn, Cu, Pb and Hg (inorganic mercury) were conspicuous in the samples cut in the period 1880-1929 and used as hair pieces (kamoji). The effects of washing on element concentration depended on both the method of washing and the type of element. The least effective was washing with acetone and water, compared with two other methods involving anionic or non-ionic surface active agents. The most resistant elements to washing were Pb, Hg, Cu and Zn. From the intercorrelation of element content and factor analysis, by examining the diminution of contents by washing and by comparing the detected levels with the values measured on contemporary Japanese women's hair, the contribution of exogenous contamination to hair levels was found to be very strong for Fe, Mn, Cu, Hg (inorganic mercury), and Pb, moderate for Na and Zn, and negligible for Ca, Mg, Sr, K, Hg (organic mercury), and P.     

Composition and sources of aerosols at Trombay, Bombay

Using energy dispersive X-ray fluorescence analysis, the concentrations of Si, S, Cl, K, Ca, Ti, Fe, Zn and Pb in aerosols, at Trombay (Bombay) have been measured. Factor analysis of the data showed that four sources other than seasalt are necessary to explain the observed aerosol composition. The levels in air of anthropogenic elements varied widely during diurnal cycles; the maximum variation, by a factor of 15, occurred for Pb concentrations. The local basalt weathered soil is suggested as the source material for the major elements of crustal origin measured in the aerosols.     

The influence of a city on element contents of a terrestrial moss (Hylocomium splendens)

Forty terrestrial moss (Hylocomium splendens) samples were collected along a 120-km-long south-north transect running through Norway's largest city Oslo. Concentrations of 29 chemical elements (Ag, Al, Au, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, Pt, S, Sb, Sr, Th, Ti, and Zn) and values for loss on ignition (475 degrees C) are reported. Silver (Ag), Al, Au, Bi, Cd, Co, Cr, Cu, Fe, Mo, Ni, Pb, Pt, Sb, Th, Ti, and Zn all show a characteristic Oslo peak when element concentrations are plotted against location of the sample site along the transect. Gold (Au) and Pt show the greatest relative enrichment of all elements in the city (ca. 10x "background"). Titanium (Ti), which is related to local minerogenic dust rather than anthropogenic emissions, shows a significant peak in Oslo. Loss on ignition, a measure of the amount of organic material in a sample, shows a negative peak in Oslo and at sites close to a known dust source. Input of fine dust thus appears to dominate many of the observed element concentrations in moss. The concentrations of Na are clearly influenced by the input of marine aerosols and show decreasing concentrations from south (near Oslo Fjord) to north (inland). The major plant nutrients Ca, K, Mg, P and S, as well as Hg, are the few elements displaying no spatial dependency along the transect. Element concentrations reach background variation levels at a distance of 20-40 km from the city centre.     

Trace element concentrations in skin of free-ranging bottlenose dolphins (Tursiops truncatus) from the southeast Atlantic coast

Concentrations of trace elements (Al, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Pb, Sb, Se, Sn, Tl, U, V, Zn) and total mercury (THg) were determined in skin samples collected from free-ranging bottlenose dolphin (Tursiops truncatus) populations. Dolphins were captured in the estuarine waters of Charleston (CHS), South Carolina (n=74) and the Indian River Lagoon (IRL), Florida (n=75) during 2003, 2004 and 2005. A subset of the skin tissue samples were used to determine methylmercury (MeHg) levels in CHS (n=17) and IRL (n=8) bottlenose dolphins. Distributions of trace element concentrations by age (adult vs. juvenile), gender (male vs. female) and study area (CHS vs. IRL) were examined. In general, higher elemental skin concentrations were found in CHS adult males than those of IRL adult males, except for THg and MeHg. For CHS dolphins, adult females showed significantly higher THg levels than juvenile females while higher Mn levels were found in juvenile females. For IRL dolphins, adult males showed significantly higher As concentrations than that in juvenile males and females while higher Co and V levels were found in juvenile males than adult males. Of all elements measured in this study, significantly higher levels of Fe, Se and Zn concentrations in skin tissue of both dolphin populations were similar to other studies reported previously. Percentage of MeHg/THg in skin tissue of CHS and IRL dolphin was about 72% and 73%, respectively. Dietary levels of trace elements may play an important role in contributing to concentration differences for As, Co, Mn, Sb, Se, THg and Tl between CHS and IRL dolphins. Total Hg concentrations were significantly correlated with the age of CHS dolphins, while an inverse relationship was detected for Cu, Mn, Pb, U and Zn. The only significant correlation found between trace element concentration and IRL dolphins' age was Mn. Geographic differences in several trace element concentrations (As, Co, Mn, Sb, Se, THg and Tl) in skin tissue may be potentially useful to discriminate between dolphin populations and is a possibility that warrants further investigation.     

Spatial heterogeneity of personal exposure to airborne metals in French urban areas

The spatial distribution of urban population exposures to ambient air particles was investigated as part of the Genotox'ER study conducted in four metropolitan areas (Grenoble, Paris, Rouen and Strasbourg) in France. In each city, 60 to 90 non-smoking adult and children volunteers were selected. Subjects lived in three different urban sectors: one highly exposed to traffic emissions, one influenced by local industrial sources, and a background urban environment. The Harvard Chempass multi-pollutant personal sampler was used to sample PM10 and PM2.5 particles during 48 h during two different seasons ('hot' and 'cold'). The elemental composition of the filters was analysed by Particle-Induced X-ray Emission (PIXE). Sixteen elements were found to be over the method detection limits: Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn and Pb. The relative concentrations of elements of crustal origin (Si, Al, Ca) were higher in the coarse fraction of PM10 filters, while elements associated with combustion processes (traffic emissions or industrial combustion) presented higher relative concentrations in the PM2.5 fraction (S, Ni, V, Pb). Spatial heterogeneity of elemental exposures by urban sector is substantial for some metals of health concern, with 20% to 90% greater exposure values, on average, in the traffic proximity or industrial sectors, compared to the background sector, for Fe, Zn, Cu, V and Cr. This spatial heterogeneity should not be overlooked in epidemiological or risk assessment studies.     

Evaluation of metal concentrations in edible vegetables grown in compost amended soil

Agricultural uses of compost usually have a positive effect on the yield of vegetable crops for human consumption. However, compost that contains heavy metals can transfer these components to soils and plants. To evaluate the contamination levels of metals in soil, compost, and edible vegetables, the Mn, Zn, Pb, Cd, Cu, and Ni total contents were measured. Metal availability in soils, as well as other variables – the pH, CEC (cation exchange capacity), total nitrogen, organic carbon, particle size distribution and mineralogy of the clay fraction – were examined in the soil samples. The analysed compost samples were produced from urban solid waste, cattle manure, and edible vegetable and tree pruning residues. The values of pH, CEC, total nitrogen, organic matter, exchangeable hydrogen and carboxylic groups were measured in the compost samples. Of the six metals examined in the soils, in general, Mn and Zn attained the highest concentrations, followed by Cu. Relatively high Mn, Zn, Cu, Cd and Pb concentrations were found in the soils. Metal concentrations extracted with DTPA were below the critical levels in soils, i.e. the levels above which toxicity is likely. In general, Zn, Pb, Cd, Cu and Ni concentrations in compost were lower than those reported by other workers, while Mn levels were within the range for this metal in compost. The results showed that there was an effect of the vegetable type (p < 0.01) for all the parameters examined. High Pb concentrations were found in lettuce and chive as compared with the tolerance limit for this metal in fresh vegetables in Brazil. Cadmium concentrations were also enhanced in the fresh vegetables compared with the typical concentrations of metals in plants. Zinc, Cu, Cd, and Ni concentrations were lower than the tolerance limits established for foods by the Brazilian legislation.     

Concentrations of heavy metals and plant nutrients in water, sediments and aquatic macrophytes of anthropogenic lakes (former open cut brown coal mines) differing in stage of acidification.

Concentration of heavy metals (Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V and Zn) as well as macronutrients (N, P, K, Ca, Mg, S) were measured in water, bottom sediments and plants from anthropogenic lakes in West Poland. The collected plants were: Phragmites australis, Potamogeton natans, Iris pseudoacorus, Juncus effusus, Drepanocladus aduncus, Juncus bulbosus, Phalaris arundinacea, Carex remota and Calamagrostis epigeios. Two reference lakes were sampled for Nymphaea alba, Phragmites australis, Schoenoplectus lacustris, Typha angustifolia and Polygonum hydropiper. These plants contained elevated levels of Cd, Co, Cr, Cu and Mn, and part of the plants contained in addition elevated levels of Mn, Fe, Pb, Ni and Zn. Analyses of water indicated pollution with sulfates, Cd, Co, Ni. Zn, Pb and Cu, and bottom sediments indicated that some of the examined lakes were polluted with Cd, Co and Cr. Strong positive correlations were found between concentrations of Co in water and in plants and between Zn in sediments and plants, indicating the potential of plants for pollution monitoring for this metal. Heavy metal accumulation seemed to be directly associated with the exclusion of Ca and Mg.     

Kidney and liver levels of some major, minor and trace elements in two Ontario communities

The contents of Ag, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, P, Pb, Se, Sr, Th, Ti and Zn in 143 autopsied liver and kidney specimens from two Ontario communities (Kingston and Ottawa) were determined using the techniques of inductively-coupled plasma--atomic emission spectrometry, and electrothermal atomization--atomic absorption spectrometry coupled with hydride evolution (As, Se), reduction--aeration (Hg), or solvent extraction (Pb). The majority of samples came from individuals older than 50 y. In general, the data for the various elements were independent of age or sex but showed some dependence on location for elements such as Cu, Fe, K, Mg, Mn, Na, P, Se and Zn. Despite these differences the elemental values of the liver and kidney samples from both the communities were within the normal range.     

Chemical composition of precipitation in tropical marine atmosphere around Indian subcontinent

Precipitation samples collected on board Indian Naval ships over the oceans surrounding peninsular India during MONEX-79 experimental programme of GARP, were assayed for Na, Cl, Mg, Ca, K, Sb, Th, Fe, Zn, Sc, Cr, Co and SO₄ concentrations. The Na/Cl and Mg/Cl distribution is observed to be in the same ratio as that found in sea water. SO₄/Na ratio in rain water also lies very close to sea water ratio of 0.25, unlike that reported for marine aerosols. K and Ca levels indicate an enrichment with reference to Na. Samples collected far away from the coast suggest enrichment of Ca in the sea salt aerosol and that from nearer the coast also gave high Ca excesses indicative of its contribution from the land. Major source of Fe and Sc appears to be of soil origin, while continental derived elements of anthropogenic origin such as Zn and Sb correlate with Rn concentrations and are useful as tracers for air mass movements.     

The use of lichen (Cetraria nivalis) and moss (Rhacomitrium lanuginosum) as monitors for atmospheric deposition in Greenland

Concentrations of Pb, Cd, Hg, Zn, Cu, Cr, Ni, As, V, Al and Fe are reported from soil, humus, moss (Rhacomitrium lanuginosum) and lichen (Cetraria nivalis) sampled at four locations in Greenland. For Al, Fe, Cr and V the levels in soil were highest followed by humus and R. lanuginosum and with the lowest levels in C. nivalis. The same was true for Pb, Cu and Ni but without as great a difference between medias. For Cd and Hg, the lowest levels were found in soil. For Zn and As, the media with highest levels differed between locality. Data were examined by a principal component analysis. Three principal components explained 87% of the total variation. The dominant elements in the first component were Fe, Al, V, Ni, Cr, Cu and Pb. This component is interpreted as a soil dust factor. The concentrations in R. lanuginosum and C. nivalis of these elements are believed to be highly influenced by soil dust. Pb concentrations in moss and lichen may also be influenced by other sources as Pb also had some correlation's with the third component. Zn and Cd and to a lesser extent. As were the dominant elements in the second component. The third component was highly dominated by Hg with a lesser influence of Pb and As, Zn, Cd and Hg concentrations in R. lanuginosum and C. nivalis are believed to be influenced by other sources than soil dust which may be long-range atmospheric transport. In general, both the within locality and the between locality variability in the values of the three components decreased in the order soil, humus, R. lanuginosum and C. nivalis. The lichen C. nivalis is looked at as an indicator with greater potential for monitoring atmospheric deposition of elements than the moss R. lanuginosum.     

Methods for processing aquatic mosses used as monitors of heavy metals

An evaluation is reported of methods used to prepare mosses for analysis when required for monitoring metal pollution. Fontinalis antipyretica and Rhynchostegium riparioides taken from the River Hoëgne, Belgium, were used for the study. The stages in preparation studied critically were the storage of the moss after it had been collected from the river, washing, choice of which particular fraction to use and the conditions for final drying prior to digestion. For any one particular treatment, the concentrations of metals analysed (Ca, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb) were usually lower in Fontinalis than Rhynchostegium. Metal concentrations found as a result of the various treatments differed markedly for some metals, including Zn, Cd and Pb. However no one sequence of methods is ideal for all purposes. Criteria that need to be considered when selecting methods include the time and facilities available and whether the moss is to be used for monitoring long-term or short-term pollution.     

Trace metals and water chemistry of forest lakes in northern Sweden

To study the influence of airborne pollutants on water quality, water samples were taken from 59 forest lakes in northern Sweden along a section of about 1000 km in length. Determinations were made of pH, water colour, conductivity, major ions, nitrogen and phosphorus, as well as the metals Fe, Mn, Al, Zn, Cu, Pb, Cd, Ni, Cr, Co, As and V.The lake waters were generally soft, with low levels of electrolytes. The pH values increased and the sulphate concentrations decreased from south to north. The lakes in the southern parts of the area showed evidence of increased deposition of acidifying substances, shown by higher Ca + Mg/alkalinity ratio.A geographical distribution pattern was observed from Zn and to some extent also for Pb and Cd, with the highest concentrations in the south. However, pH and water colour were of major importance for the distribution of trace metals. Mn, Al and Zn were negatively correlated to pH and Fe, Mn, Al, Pb and As were positively correlated to water colour. A multiple regression analysis showed that the distribution of Fe was influenced mainly by water colour, Zn mainly by pH, while Mn and Al were influenced both by pH and colour. Some of the lakes were sampled both in winter and summer and the concentration of metals was found to be around two-fold higher in winter than in summer.     

Metal phase associations in soils from an urban watershed, Honolulu, Hawaii

Soils of Manoa watershed, Hawaii, have received varying inputs of anthropogenic trace metals, with roadside soils primarily influenced by automobile contributions. A four-stage sequential extraction procedure was used to fractionate 13 topsoil (0-2.5 cm) and 13 subsoil (7.5-10.0 cm) samples into: (i) an adsorbed, exchangeable and carbonate (AEC) phase; (ii) a reducible phase; (iii) an oxidizable phase; and (iv) a residual phase. Phases (i)-(iii) were considered 'labile', with the residual fraction 'non-labile' under normal circumstances. An examination of eight elements (Al, Co, Cu, Fe, Mn, Ni, Pb and Zn) indicated that Pb was the trace metal most impacted by anthropogenic inputs. Roadside soil Pb enrichment was apparent with data from a 0.5 M HCI leach exhibiting a maximum concentration of 1000 mg/kg compared with a median background value of 12 mg/kg. Sequential extraction results indicated the following order with respect to phase dominance for Pb: reducible > residual > oxidizable > AEC. The identification of the reducible phase as the primary pool of available Pb supports previous work from temperate roadside soil environments. The reducible phase is characterized by hydrous Fe and Mn oxides and mobilization of fixed elements can occur with decreases in pH and redox potential. Iron was the least labile of the elements examined with only 5-6% of total Fe removed by the first three steps of the extraction procedure. Lead had the highest labile percentage with average values between 74 and 81%. Therefore, results from this study support earlier research in this watershed which identified Pb as the primary trace metal of concern from a contamination perspective.