Wolfgang C. Pfeiffer

Mercury and methylmercury in fish and human hair from the Tapajós river basin, Brazil

Mercury is being released in the Amazon in an abusive way due to goldmining activities. The Tapajós river basin was the first to be intensively exploited in the modern Amazon gold rush. Fish and hair samples as the best indicators of human methylmercury contamination were investigated in the main cities and villages along the Tapajós river basin. The upper basin has typical fish fauna with much larger carnivorous fish with higher mercury levels reaching an average value of 0.69 microgram.g-1 wet wt. in 43 fish. This was accompanied by high levels in hair of the human population living in the same area. The maximum hair value reach 151 micrograms.g-1 dry wt. with two villages presenting an average value close to 25 micrograms.g-1 dry wt. An analytical laboratory intercalibration exercise was performed between Japanese and Brazilian laboratories for total mercury analysis. Critical fish, areas, and more exposed human groups are identified.

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 methylmereury ~,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 goldmining area the value were much lower and the %MeHg value~ varied widely (20-100~ with individuals even in blood samples. Urine from gold shop workers contained Hg mostly in inorganic lbrm at 165 tLg/g creatinine on the average, with the range of 20 to 450 tlg/g creatinine. A good correlation between tlg in hair and blood was fotmd in fishing villages and the ratios of hair Hg to blood Hg were very close to 250, generally established for MeItg. T-IIg and inorganic Hg levels in urine from gold shop workers were also signilicantly correlated with inorganic Hg in blood. 1.Introduction Environmental mercury (Hg) pollution due to gold mining in theAmazonian region has become a m a t t e r o f worldwide concern in recent years. In the goldmining processes an enormous amount o f metallic Hg has been used and released in an abusive way into local ecosystems over the last 20 years. It is estimated that around 100 tons of Hg have been released annually, o f which 45% are discharged into river systems and 55% into the atmosphere (Preiffer and Lacerda, 1988). Owing to this metal, therefore, there i s a possibility of causing two types of health hazards in the Amazon river basin: First, occupational inorganic Hg poisoning by direct inhalation of r ig vapor during the processes of burning and re-burning Hg-Au amalgam. Secondly, a part o f Hg discharged into river systems is methylated and ultimately bio-accumulated to a significant level in fish. Thus, people living along the fiver and depending on riverine products are easily exposed to MeHg and may develop toxic levels through repeated consumption of these contaminated fish. The people living near gold mining areas may be contaminated with at least two forms of Hg inorganic Hg and MeHg simtlltaneously from surrounding air and diets. Though, in fact, high levels o f Hg in hair and fish from the main tributaries of Amazon river have Water, Air, and Soil Pollution 80: 85-94, 1995. 9 1995 Kluwer Academic Publishers. Printed in the Netherlands.

Methylmercury pollution in the Amazon, Brazil

In order to evaluate the extent of environmental mercury pollution due to goldmining activities in the Amazon, concentrations of total mercury and methylmercury were determined for human hair and fish samples from five fishing villages located mainly in the Tapajos river basin. Abnormally high levels of mercury were found in human hair from Jacareacanga and Brasilia Legal located near the main goldmining area as well as from Tres Bocas facing the lake in Amapa state, whereas the levels were much lower in Ponta de Pedras, a long way downstream. The values of male samples were about twice as high as females even in the same family. The predominant form of mercury in hair samples was methylmercury (average 90%), while high hair mercury observed in goldminers and workers in goldshops was mostly in the inorganic form. Longitudinal analyses of long hairs from people in fishing villages showed fairly constant and continuous exposure to methylmercury at least over the last few years with seasonal variations. Fish contained relatively high levels of mercury (up to 3.82 ppm) mostly in the form of methylmercury and most of the fish from upstream and some from downstream exceeded the allowable level of 0.5 ppm in Brazil.

Mercury inputs into the Amazon Region, Brazil

Abstract Mercury inputs into the Brazilian Amazon ecosystem due to goldmining activities are quantified based on data from various Brazilian Mineral and Environmental Agencies as well as field works. Total losses of Hg were estimated to be 1.32 kg Hg/kg Au from which 45% are released into rivers and 55% into the atmosphere. Total Hg input to the Amazon may contribute with up to 6% of the global anthropogenic Hg emissions to the atmosphere and the releases into the rivers are at the same order of magnitude as the inputs into the North Sea.

Trace metal accumulation by algae in Sepetiba Bay, Brazil.

Trace metal concentrations (Zn, Cd, Pb, Cr and Cu) were determined in some benthic algae from Sepetiba Bay, Brazil. This region has been modified by the increase of industrial activities during the last 30 years. Among species sampled the brown algae Padina gymnospora contained the greatest amount of Zn. The Bioconcentration Factor for Zn in P. gymnospora was found to be 10(4) under laboratory conditions. The absorption of (65)Zn depended on exposure time and increased with Zn concentrations in the medium. An insignificant amount of Zn desorbed from algae suggested a very high affinity with cellular binding sites. Zinc uptake by P. gymnospora is discussed by considering field and laboratory conditions.

Mercury concentrations in inland waters of gold-mining areas in Rondônia, Brazil

Total mercury concentrations in water, sediments and fish from the gold-mining areas of Brazil, especially the Amazon region, are presented. Mercury concentrations were variable among rivers, with the highest values found in samples from tributary forest rivers. Concentrations in water samples varied between 0.1 and 8.6 micrograms l-1, while in bottom sediments they reached 19,800 micrograms kg-1. Concentrations in edible parts of locally consumed fish reached up to 2700 micrograms kg-1 wet wt, surpassing by almost five times the Brazilian advisory level for human consumption.

An assessment of Hg pollution in different goldmining areas, Amazon Brazil

Abstract Metallic mercury used in gold prospecting is being dispersed over Amazon ecosystems through atmospheric emissions as well as directly to aquatic systems. Total mercury concentrations in the more representative environmental (air, soil, bottom sediments, fishes and plants) and human (hair and urine) indicators, collected in the last 7 years in different goldmining areas (garimpos) are presented and discussed. Critical exposure situations, pathways, areas and human groups are indicated. The goldminers (garimpeiros) that manipulate a major part of the Hg are not the critical group either from exposure to metallic mercury (Hg0) by inhalation or exposure to methylmercury by ingestion of contaminated fish. Results obtained from air and urine sampling show that people working in gold dealers shops are the critical group concerning Hg0 risk, while riverine communities are the risk group with respect to methylmercury.

Heavy metal distribution, availability and fate in Sepetiba Bay, S.E. Brazil

Abstract The total flux, distribution and fate of Cu, Cr, Cd, Zn, Mn and Pb were studied in Sepetiba Bay, Rio de Janeiro, SE Brazil. Metal contamination in the bay is of the same order of magnitude as historically contaminated areas of Europe and North America, inspite of the recent (15–20 years) contamination of the area. The estimated metal fluxes to the bay in tons per year are: Cu, 2.7; Cr, 10.9; Cd, 0.9; Zn, 11.5; Mn, 20.4; and Pb, 4.5. For most metals, transport to the bay is mainly by suspended particulate matter; for Cd and Cr 90 and 47% of the total flux was in dissolved forms. Most metals transported by suspended particulate matter were in weakly bound forms. Analysis of bottom sediments showed two groups of metals in relation to their distribution and source in the bay. Manganese and Cu showed higher concentration along the southern parts of the bay, showing no correlation with the other metals, and probably being derived from natural sources. The other metals were present at higher concentrations along the depositional area of fluvial sediments, at the northern part of the bay, and are derived from industrial and urban sources.

Mercury dispersal in water, sediments and aquatic biota of a gold mining tailing deposit drainage in pocone, Brazil

In the Pocone district, Brazil, Hg distribution was studied in a small watershed which drains tailings from a 10 yr old gold mining operation. Heavy regional rains are responsible for continuous weathering, thereby making it possible to transport Hg into the ecologically important Pantanal area. Mercury concentrations in creek sediments range from < 0.02 to 0.18 mg. kg−1. The highest concentrations occur close to the tailings deposit. Mercury concentrations in the water were always below the detection limit of the analytical method used (<0.04 µg. L−1). Suspended matter samples collected before, during and after a storm, showed a Hg peak value of 0.61 mg kg−1. about 30 min after the event. Dissolved Hg concentration still fell below the detection limit. Among the biota, molluscs accumulated moderately high concentrations of Hg, while macrophytes and fish did not. Mercury concentrations in molluscs were dependent on size, with larger animals presenting higher Hg concentration. We conclude that Hg present in the tailings shows low mobility and that its eventual transport into the drainage system is dependent on the erosion of fine material from the wastes during rains, resulting in a restricted contamination of the area and low Hg concentration in the biota.

Brown algae species as biomonitors of Zn and Cd at Sepetiba Bay, Rio de Janeiro, Brazil

Abstract In order to contribute to monitoring heavy metal contamination of Sepetiba Bay, Rio de Janeiro, Brazil, long term evaluation of Zn and Cd concentration was performed in two brown algae species, Padina gymnospora and Sargassum stenophyllum. In relation to Sepetiba Bay macroalgae community, these species were the most abundant in substrate cover. The algae metal concentration variation from 1990 to 1997 should be related to the inputs of metals released into the bay by industrial process of Zn production in the area. In situ uptake and release transplant experiments with Padina between Sepetiba Bay and a near uncontaminated area showed that the species could reflect the variation in metal environment availability. A lower reduction in metal concentration by plants transplanted to the uncontaminated area was observed. Analytical electron microscopy showed that the Zn in P. gymnospora from Sepetiba Bay was present as small deposits distributed in the cell walls.