Reduction of mercury pollution in the vicinity of a caustic soda plant in Thailand

Fish samples collected near the caustic soda factory of TACSCO in Thailand during November and December 1978 were found to contain 0.10 to 1.38 ppm Hg in flesh (on wet weight basis), whereas those of the control areas contained 0.01 to 0.30 ppm. The Hg content of the fish in the TACSCO area had decreased by more than half from the first investigation which took place during 1975–76. This decrease is obviously a result of the functioning of the waste-water-treatment system built by the factory in 1974. The bottom mud collected near the factory in 1978 contained 8.39 to 57.95 ppm Hg (on dry weight basis) as compared with the mean of 0.03 ppm in samples taken from the control area. The Hg content in fish-eating birds were low, 0.04 to 0.44 ppm in the muscles and 0.05 to 1.32 ppm in the livers (on wet weight basis).     

Phytosequestration of Metals in Selected Plants Growing on a Contaminated Okhla Industrial Areas, Okhla, New Delhi, India

Contamination of metal ions in soil and water represents more pressing threats to resources as well as human health. The present research was carried out to screen the phytosequester plants growing in industrial waste- and wastewater-affected industrial areas of Okhla, New Delhi, India. Accumulation trend of metal Fe, Zn, Cu, Cr, Pb, Cd, Hg, and As from soil and wastewater by plants were collected for study. Among aquatic plants Hydrilla verticillata, Marsilea quadrifolia, and Ipomea aquatica were found to be highest metals accumulator, Eclipta alba and Sesbania cannabina among terrestrial plant were highest accumulator of metals. Among the algal spp. Spirulina platensis and Phormidium papyraceum were the most efficient in accumulating Cd and Hg. The maximum bioconcentration factor (BCF) was recorded in Hygroryza aristata for the metals (Hg, Cd) in M. quadrifolia (Cd, Cr), in E. alba (Cr, Cu), and in S. platensis (Hg, Pb). However, the translocation factor (TF) of metals was found more in M. quadrifolia followed by I. aquatica than other plants. Among all the plants, H. verticillata showed high TF and low BCF values for toxic metals (Pb, Cr) and was suitable for phytostabilization of these metals. Our study showed that native plant species growing on contaminated sites may have a potential of phytosequestration of these metals.     

Phytoremediation Potential of <Emphasis Type="Italic">Helianthus annuus</Emphasis> and <Emphasis Type="Italic">Hydrangea paniculata</Emphasis> in Copper and Lead-Contaminated Soil

This study was conducted to assess the hyperaccumulation and phytoremediation potential of copper (Cu) and lead (Pb) in Hardy ‘Limelight’ Hydrangea (Hydrangea paniculata) and the common sunflower (Helianthus annuus). The study also investigated the capacity of these two plants to transpire the metals in a temperature-controlled greenhouse. Plants were grown for 4 weeks and periodically watered with known elemental concentrations of copper oxide nanoparticles, copper sulfate, and lead nitrate. Both H. annuus and H. paniculata accumulated significant amounts of Cu and Pb to be classified as hyperaccumulator species. H. annuus took up significant amounts of Cu in the shoots, specifically the leaves (Cu max.?=?1368 ppm), and easily translocated it from stem to leaf (translocation factor (TF) ranged from 2.7 to 81.0). Pb was not as easily taken up and translocated (TF?=?0.6) as Cu was by this species. H. paniculata took up Cu and Pb in high concentrations but preferentially stored more metals in the stems (Cu max.?=?1757 ppm; Pb max.?=?780 ppm) than in the leaves (Cu max.?=?126 ppm; Pb max.?=?35 ppm). The translocation ability of H. paniculata was much lower for both metals compared to H. annuus. Both Cu and Pb transpired from H. annuus at concentrations of 0.04 and 0.005 ppm, respectively.     

Common hydrophytes as bioindicators of nickel,chromium and cadmium pollution

Twelve Mediterranean hydrophyte species collected inLebanon were evaluated for their potential asbioindicator species for heavy metal pollution innutrient cultures enriched with 1 ppm Cr, Ni and Cd.These were: Nasturtium officinale R.Br, Apium nodiflorum L., Veronica beccabunga L., Veronica anagallis aquatica L., Veronicalysimachioides L., Veronica anagalloides L., Mentha longifolia L., Mentha aquatica L., Mentha pulegium L., Potentilla reptansL., Mentha sylvestris L., and Cardamine uliginosa L.. Large variability in responseto exposure to the heavy metals was observed. Growthrates remained high during the experimental period,indicating that the plants were little affected by thepresence of the metal at the experimentalconcentration. Metal accumulation and bioconcentrationvaried within at least one order of magnitude, andranged from less than 10 to over 200. Cr waspreferentially accumulated in the roots. All speciesbut M. pulegium, P. reptans and V. anagallisaquatica accumulated and bioconcentrated sufficientCr to qualify as bioindicator species. Five of thespecies that accumulated Cr also accumulated Ni, withthe same partitioning into the root. These were: N. officinale, C. uliginosa sp., M. longifolia, M. aquatica and M. sylvestris, all of which mayalso be used as bioindicators of Ni pollution. Onlyone species, M. aquatica, accumulated Cdsignificantly, and may, therefore, be used as abioindicator for all three metals.     

The influence of trophic level as measured by δ15N on mercury concentrations in freshwater organisms

The relationship between mercury (Hg) concentrations in freshwater biota and trophic position, as defined by stable nitrogen isotope ratios (δ¹⁵N), was examined in 6 lakes in northwestern Ontario. The heavier isotope of nitrogen (¹⁵N) increases an average of 3 parts per thousand (‰) from prey to predator and is used as a measure of an organism's trophic position. Dorsal muscle from lake trout, burbot, walleye, northern pike, white sucker, lake cisco, lake whitefish, and yellow perch was analyzed for Hg and δ¹⁵N using flameless atomic absorption and mass spectrometry respectively. Within each lake, log Hg was significantly related to δ¹⁵N (r ² ranged from 0.47 to 0.91,P<0.01). For four species, yellow perch, northern pike, lake cisco, and lake trout, log Hg was positively related to δ¹⁵N (r ² ranged from 0.37 to 0.47,P≤0.09) across all lakes. We also used δ¹⁵N measurements (assuming a 3‰ shift between an organism and its diet) and the developed within-lake regression equations to calculate a prey Hg for each individual fish. These food Hg values were then used to predict predator Hg using Norstromet al's bioenergetics model. Predicted results were strongly correlated to measured Hg concentrations (r=0.91,P<0.001), indicating that δ¹⁵N has potential to be used in modeling.     

Human exposure to mercury due to goldmining in the Tapajos River basin,Amazon, Brazil: Speciation of mercury in human hair,blood and urine

To obtain the basic information on human exposure to mercury (Hg) due to gold mining activities in Amazon, total mercury (T-Hg) and methylmercury (MeI Ig) were determined for human hair, blood and/or urine samples collected from populations living in gold mining area and fishing villages upstream of the Tapajos River basin. Abnormally high levels of T-Hg were observed in hair and blood from all fishing villages investigated and more than 90% of T-Hg was in the form of MeHg in both samples, whereas in goldrnining area the value were much lower and the %MeHg values varied widely (20–100%) with individuals even in blood samples. Urine from gold shop workers contained Hg mostly in inorganic form at 165μg/g creatinine on the average, with the range of 20 to 450μg/g creatinine. A good correlation between Hg in hair and blood was found in fishing villages and the ratios of hair Hg to blood Hg were very close to 250, generally established for MeHg. T-Hg and inorganic Hg levels in urine from gold shop workers were also significantly correlated with inorganic Hg in blood.     

Bioelectric potentials in the soil-plant system

A detailed study of the electric potentials in the soil-plant system was performed. It was found that the electric potential depends on the plant species and the soil properties. A theoretical interpretation of the obtained data was given. All the plants, independently from their species and their state, always had a negative electric potential relative to the soil. The electric potential of the herbaceous plants largely depended on the leaf area. In some plants, such as burdock (Arctium lappa) and hogweed (Heracleum sosnowskyi), the absolute values of the negative electric potential exceeded 100 mV. The electric potential was clearly differentiated by the plant organs: in the flowers, it was lower than in the leaves; in the leaves, it was usually lower than in the leaf rosettes and stems. The electric potentials displayed seasonal dynamics. As a rule, the higher the soil water content, the lower the electric potential of the plants. However, an inverse relationship was observed for dandelions (Taraxacum officinale). It can be supposed that the electric potential between the soil and the plant characterizes the vital energy of the plant.     

3D-laser scanning: A non-destructive method for studying above- ground biomass and growth of juvenile trees

Many experiments with juvenile trees require the non-destructive monitoring of plant biomass and growth which is most often conducted with allometric relationships between easy to measure morphological traits and plant biomass. In a growth experiment with potted juvenile Fagus sylvatica L. trees, we tested the practicability and accuracy of the portable 3D-laser scanner ZF Imager 5006 using the phase difference method for measuring total above-ground biomass (stems, twigs, leaves), the biomass of axes (stems and twigs), of leaves biomass and the leaf area of 63 experimental trees. The trees were scanned from 20 (or 21) different positions with an angular step width of 0.036° in horizontal and vertical direction and the 3D-point cloud of every tree was translated into a point cloud grid with defined distances between the data points to standardise the spatial resolution of the data. The validation of the laser scan data against traditional biomass harvest data gave good correlations for total above-ground biomass (green and woody plant material combined), leaf biomass and leaf area (obtained by measurements before and after leaf harvest), and the mass of stems and twigs (only woody compartments of the plants) with R²-values between 0.61 and 0.88, all significant with p < 0.001. Biomass estimates using allometric regressions between total plant height or total leaf number and above-ground biomass as alternative non-destructive methods were found to be weaker than laser scanning (R² 0.54-0.67) and required a similar calibration effort. Repeated scanning of the same plant can be used to monitor biomass increase over time. We conclude that 3D-laser scanning is a promising technique for the non-destructive monitoring of biomass and growth in experiments with juvenile trees.     

Arsenic accumulation and distribution in the tissues of inbred lines in maize (Zea mays L.)

We investigated arsenic (As) accumulation and distribution in four different tissues of maize, leaves, stems, bracts, and kernels. For these analyses, we used 122 elite inbred lines, which were grown in an As-contaminated area in China. The agricultural soil at the study site is highly As-contaminated (11.02?±?0.95?mg?As?kg?soil^?1) because of excessive use of As-rich surface water for irrigation. The As concentration in the leaves was significantly positively correlated with that in stems and kernels, and the As concentration in the stems was significantly positively correlated with that in the kernels. In the 122 inbred lines, the highest average As concentration was in the leaves, followed by the stems, the bracts, and then the kernels. The range of As concentrations in leaves, stems, bracts, and kernels of the 122 inbred lines was 0.13–1.48, 0.017–0.145, 0.013–0.131, and 0.0001–0.0408?mg?As?kg^?1, respectively. The inbred lines with low As concentrations in the kernels perhaps could be used as a parent to select an elite hybrid with low As concentration for decreasing the As damage for people and animal.     

Studies of toxic effects of Hg(II) on Pistia stratiotes

The uptake of Hg(II) and toxicity effect of the metal on some biochemical parameters in Pistia stratiotes L. were studied. The uptake of Hg(II) by the plants gradually increased with increase in concentration of Hg(II) in the culture medium. Maximum accumulation of Hg(II) was noted within 1 day. Maximum removal (about 90%) of Hg(II) was recorded below 20 ppm Hg(II). Accumulation of Hg(II) in roots was about four times higher than that in shoots. At 20 ppm, Hg(II) promoted senescence of Pistia plants by decreasing chlorophyll, protein, RNA, dry weight and activities of catalase and protease as well as increasing free amino acid content, peroxidase activity and the ratio of acid to alkaline pyrophosphatase activity over control values. At Hg concentrations below 20 ppm, these constituents were least affected.     

Population dynamics and nitrogen allocation of Sonchus arvensis L. in relation to initial root size

To develop better mechanical management strategies, more information on the impact of root partitioning on changes in the population dynamics of Sonchus arvensis is needed. Therefore, the effects of root fragmentation of S. arvensis on shoot height frequency distributions, biomass production and nitrogen allocation were studied in an outdoor experiment in Sweden in 2008. Three artificial populations of S. arvensis of different initial root lengths but with the same total root length per area were planted. Shoot heights were measured at the onset of flowering and dry weight and nitrogen content of leaves, stems, buds and roots were quantified twice during the season. Height frequency distributions of the populations were bimodal, indicating the existence of two generations distinctly different in height growth pattern. Shorter root fragments produced shoots with a lower mean height compared to longer fragments. Plants originating from longer root fragments had higher dry weight and more nitrogen compared to plants from shorter root fragments. Dry matter production per square meter did not differ between the populations. The proportion of dry matter and nitrogen allocated to the different plant components (leaves, stems, buds and roots) at harvest did not differ between the populations. Over time, nitrogen was reallocated from leaves and stems to roots. Our results show that initial root length of S. arvensis per square meter, rather than the number of root fragments per square meter, is a good predictor of biomass at harvest, and that the degree of root fragmentation does not affect nitrogen allocation patterns. Root fragmentation, however, leads to a lower average canopy height for S. arvensis, and thus may be an effective weed control measure in combination with a crop which is competitive for light.     

Mercury pollution in the soil and mosses around a geothermal plant

Samples of soils and mosses were collected near a geothermal power plant, which is located in one of the most active geothermal fields of the world (Southern Tuscany). High concentrations of Hg (up to 1.8 μg g^?1 d.w.) occur in mosses as far as 0.6 km from the geothermal plant, and the Hg uptake of mosses is unrelated to the species except for Bryum torquescens. The Hg in the soil was lower than in mosses, and the greatest concentrations in soil were near the Travale-22 well, which feeds the most powerful geothermal plant (30 MW) in the area. In addition, the concentrations of Hg detected in soil cores and in old bottom leaves of several specimens of Hypnum cupressiforme show that this element has been emitted into the air also in the past probably since the discovery of T-22 well in 1972.     

Variations in mercury and other trace elements contents in soil and in vine leaves from the Almadén Hg-mining district

Purpose

Vines (Vitis vinifera, L.) are a very important agricultural resource for Spain in general and for the Castilla-La Mancha region in particular, providing important productions of wines. Grapes and raisins are used for direct consumption too. In this work, we study analytical constraints regarding metallic trace elements uptake, focusing on Hg, from vines growing in the Almadén mercury mining district, the world's largest producer of this element, inactive nowadays.

Materials and methods

The study started with the analysis of these metals in soils and sets of vines leaves from seven sites located at different distances from the Almadén Hg mine. The samples of soils were dried at ambient temperature for 1 week. They were then sifted (<2 mm) and were stored for subsequent analysis. The leaves were dried and the leaf blade and petiole were separated. About 2 g of each sample were hand milled and analyzed using the same fluorescence spectrometer. Total mercury in soils and vine leaves were determined using a Lumex RA-915+ device, an atomic absorption spectrometer with a pyrolysis unit (RP-91c).

Results and discussion

Results show significant correlations between soil and leaves contents for total and organic mercury (R?=?0.934 and 0.984, respectively). Hg contents range in soil from 2,376 to 0.04 mg/kg in non-polluted places. For the organic fraction, the range varies between 197.49 and 3.15 mg/kg. Total Hg contents measured in leaves were from 5.14 mg/kg (close to dump zone of the mine) to 0.03 mg/kg in the proximity of Carrión de Calatrava, located some 100 km away from Almadén. Mercury reaches maximum in the proximity of known sources of the element: the mining and/or metallurgical areas of Almadén and Almadenejos.

Conclusions

Soils from the study area contain normal contents in trace metals, and these are conditioned by the local geology or urban locations of the area. Trace metals contents in leaves do not show a relationship with soil contents, possibly due to the low bioavailability of these elements in the soils investigated. Mercury is, as expected for this area, an exception to this trend, with very high concentrations that reach maximum values in the proximity of the known sources of the element: the proximity of mining and/or metallurgical areas in Almadén and Almadenejos.     

Impact of Seasonal Fluctuations on the Sediment-Mercury, its Accumulation and Partitioning in Halimione portulacoides and Juncus maritimus Collected from Ria de Aveiro Coastal Lagoon (Portugal)

The availability of metals to plants is a complex function of numerous environmental factors. Many of these factors are interrelated, and vary seasonally and temporally. The current study intended to understand the influence of seasonal fluctuations and the vegetation of salt marsh plants (SMPs; Halimione portulacoides, Juncus maritimus) on sediment??s mercury (Hg) and its pH and redox potential (Eh), as well as their cumulative effect on the plant??s Hg-accumulation and Hg-partitioning potential. The area selected for the study was Laranjo Basin at Ria de Aveiro lagoon (Portugal) where a known Hg gradient was existed due to chlor-alkali plant discharge. Three sampling sites (L1, L2 and L3) were selected along a transect defined by the distance from the main Hg source. Samples were also collected from the Hg-free site (R). Irrespective of the plant vegetation, Hg in sediments gradually increased with a decreasing distance towards Hg-point source. The sediment colonised by J. maritimus showed more Hg concentration compared with H. portulacoides irrespective of the season. As a whole, J. maritimus accumulated Hg more than H. portulacoides at all the sampling sites, whereas in root, stem and leaf, the concentration was ranked as: L1 > L2 > L3 in both the plant species and was differentially influenced by seasonal changes. Moreover, root of both plants exhibited highest Hg concentration compared with stem and leaf. In addition, the leaf of H. portulacoides exhibited more Hg than leaves of J. maritimus. Bioaccumulation and translocation factors and dry weight were differentially influenced by seasonal changes. Taking together the results, the physico-chemical properties of sediment especially the sediment-Eh seems to be influnced by the type of plant vegetation and seasonal changes which in turn may have influenced the chemistry of sediments; thus, it enfluences the bioavalability of Hg and the Hg-retention capacity of both salt marsh sediments (SMSs) and SMPs (bioaccumulation factor). Moreover, SMSs vegetated by J. maritimus exhibited a stronger capacity for the retention and phytostabilization of Hg belowground (in sediments and/or roots) than those dominated by H. portulacoides. Conversely, those SMSs extensively vegetated by H. portulacoides are expected to translocate more Hg to aboveground parts, acting as a potential source of this metal to the marsh ecosystem. Therefore, J. maritimus and H. portulacoides may be used repectively for phytostabilization (in rhizosediments) and phytoextraction (by accumulation in aboveground plant tissue for subsequent plant removal).     

Cadmium Phytoextraction Efficiency of Arum (Colocasia antiquorum), Radish (Raphanus sativus L.) and Water Spinach (Ipomoea aquatica) Grown in Hydroponics

Selection of a phytoextraction plant with high Cd accumulation potential based on compatibility with mechanized cultivation practice and local environmental conditions may provide more benefits than selection based mainly on high Cd tolerance plants. In this hydroponics study, the potential of Cd accumulation by three plant species; arum (Colocasia antiquorum), radish (Raphanus sativus L.) and water spinach (Ipomoea aquatica) were investigated. Arum (Colocasia antiquorum L.) plants were grown for 60 days in a nutrient solution with 0, 10 or 50 μM Cd, while radish and water spinach plants grew only 12 days in 0, 1.5, 2.5, 5 or 10 μM Cd. Growth of radish and water spinach plants decreased under all Cd treatments (1.5 to 10 μM), while arum growth decreased only at 50 μM Cd. At 10 μM Cd treatment, the growth of arum was similar to the control treatment indicating higher tolerance of arum for Cd than radish and water spinach. Cadmium concentrations in different plant parts of all plant species increased significantly with Cd application in the nutrient solution. Arum and water spinach retained greater proportions of Cd in their roots, while in radish, Cd concentration in leaves was higher than in other plant parts. Cadmium concentrations in arum increased from 158 to 1,060 in the dead leaves, 37 to 280 in the normal leaves, 108 to 715 in the stems, 42 to 290 in the bulbs and 1,195 to 3,840 mg kg^?1 in the roots, when the Cd level in the solution was raised from 10 μM Cd to 50 μM Cd. Arum accumulated (dry weight?×?concentration) 25 mg plant^?1 at 10 μM, while the corresponding values for radish and water spinach were 0.23 and 0.44 mg plant^?1, respectively. With no growth retardation at Cd concentrations as high as 166 mg kg^?1 measured in entire plant (including root) of arum at 10 μM Cd in the nutrient solution, arum could be a potential Cd accumulator plant species and could be used for phytoremediation.     

Salvinia natans — as the scavenger of Hg(II)

The plant, Salvinia natans L., was found effective in the removal of Hg(H) from wastewater. Maximum accumulation was noted within a day and maximum removal (about 90%) was recorded below 5 ppm of Hg(II). Accumulation of the metal occurred mainly in the roots. The senescence of the plant started at and above 5 ppm of Hg(H). The biochemical constituents like chlorophyll, Hill-activity, Protein, RNA, dry weight, and activities of catalase and protease decreased while free amino acid content, peroxidase activity and the ratio of acid to alkaline pyrophosphatase activity increased over control values at and above 5 ppm of Hg(H).     

Environmental fate of mercury discharged into the upper Wisconsin river

We studied the distribution of Hg in sediments, fish, and crayfish in a 60 km reach of the Upper Wisconsin River that formerly received Hg in discharges from pulp and paper mills. The most heavily contaminated strata of sediments were deposited during the 1950s and early 1960s and buried under subsequent deposits; however, surficial sediments remained substantially enriched at certain sites in 1981. Median concentrations of Hg in surficial sediments, adjusted for grain size, were at least 10-fold greater at the main study area than at an upstream reference site. Total concentrations exceeded 1.0 μg g^?1 wet weight in axial muscle tissue in only 2 of 173 fish analyzed from the study area; however, historical comparisons revealed that Hg contamination of fish (common carp Cyprinus carpio and walleye Stizostedion vitreum vitreum) and crayfish (Orconectes) in the river had not decreased since the early 1970s. The availability of Hg to biota in this system may be enhanced by rapid methylation of the metal in surficial sediments, despite burial of the most heavily contaminated sediments. Management practices for this river should be designed to prevent conditions favoring mobilization and methylation of Hg in sediments.     

Growth and Nutrient Absorption of Cape Gooseberry (Physalis Peruviana L.) in Soilless Culture

Cape gooseberry (Physalis peruviana L.) is a solanaceous plant. The growth and time-course of nutrient accumulation of the plant and its partitioning between roots, stems, leaves, and fruits were examined. The study was conducted analyzing two nutrient solutions in soilless culture under greenhouse conditions during two consecutive seasons. The macronutrient contents were analyzed. On average, the yield was 8.9 t·ha^?1. Growth of the plant until 90 d after transplanting obeys an exponential function of time and the relative growth rate for this period was determined. Nitrogen (N) was the element that showed the highest concentration, corresponding to leaves (4.67%), followed by potassium (K) in stems (4.46%). The highest accumulations of N, phosphorous (P), calcium (Ca), and magnesium (Mg) were found in leaves and of K in the stems. Potassium showed the highest nutrient accumulation (29 g·plant^?1) and the highest specific uptake rate.     

Heavy Metal Biosorption by Plant Biomass of the Macrophyte Ludwigia Stolonifera

Ludwigia stolonifera biomass of roots, floating roots and leaves were tested for their performance as heavy metal biofilters. Cadmium (Cd) and nickel (Ni) (50 ppm) solutions were filtered through 0.5–1.5 g packed columns with each biomaterial, to determine their metal removal efficiency. Root column was more efficient in removing Ni (as low as 6 ppb in the effluent) than of Cd (as low as to 22 ppb in the effluent). This tendency was also observed upon treatment of a mixed solution of both metals. Floating roots column reduced Cd content to the same level as the root column, but its metal binding capacity was higher; 93 mg Cd g^-1 DW in floating roots in comparison to 43 mg Cd g^-1DW in the roots biofilter. Leaf biomass column demonstrated the best metal binding capacity; 128 mg Cd g^-1 DW, and Cd concentration in the effluent was 17 ppb. Pectin content was 5, 8 and 10% W/W in roots, leaves and floating roots biofilters, respectively. It seems that ion exchange is the major mechanism by which the metal is biosorbed. Evidence for the exchange of the bound heavy metal ions against the discharge of light metal ions such as calcium (Ca), magnesium (Mg), potassium (K) and sodium (Na) was provided.     

Mercury exposure in humans through food consumption from the Everglades of Florida

In March 1989, The Florida Department of Health and Rehabilitative Services (HRS) issued a Health Advisory recommending the limited consumption of several fish species caught from the Everglades region of South Florida due to elevated methylmercury (MeHg) levels (average 2–3 ppm in fish meat). There were no reports of clinical MeHg poisoning in humans in Florida, although deaths of Florida panthers were attributed to mercury (Hg). poisoning. This study evaluated the extent of MeHg exposure in persons eating contaminated fish in the Everglades region. Populations at risk were identified including sport fishermen, Everglades Residents and subsistence fishermen. Over 1700 individuals were approached; those who had eaten fish or wildlife from the contaminated areas at least once/month for the prior three months were asked to participate. Three hundred and fifty (350) participants completed a brief questionnaire and provided a hair sample for Hg analysis. In 119 (36%) of individuals with levels above the limits of detection, the mean total Hg in hair was 3.62±3.0μg/g [± standard deviation] with a range of 1.28 – 15.57. The most at risk populations identified with respect to Hg levels were Blacks and men. Although the majority of the participants had fished in the Everglades for many years (>15 years), they reported relatively low intake of fish and had low hair Hg levels compared with similar populations in prior studies of other populations at risk. Although 71% of participants knew of the State Health Advisories concerning ingestion of Hg contaminated fish from the Everglades, this did not change their consumption habits. In addition, Blacks, individuals of lower income and of lower education levels were less likely to know about the Health Advisories. Given recent studies of neurologic effects from relatively low in utero MeHg exposure, the continuation of the Mercury Health Advisories and wildlife monitoring in the Everglades are warranted, especially for women of childbearing age and children. However, public education must be targeted for the populations at risk identified in this study in order to reach these populations more effectively.