Olaf Malm

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.

Trophic magnification factors: Considerations of ecology, ecosystems, and study design

Recent reviews by researchers from academia, industry, and government have revealed that the criteria used by the Stockholm Convention on persistent organic pollutants under the United Nations Environment Programme are not always able to identify the actual bioaccumulative capacity of some substances, by use of chemical properties such as the octanol-water partitioning coefficient. Trophic magnification factors (TMFs) were suggested as a more reliable tool for bioaccumulation assessment of chemicals that have been in commerce long enough to be quantitatively measured in environmental samples. TMFs are increasingly used to quantify biomagnification and represent the average diet-to-consumer transfer of a chemical through food webs. They differ from biomagnification factors, which apply to individual species and can be highly variable between predator-prey combinations. The TMF is calculated from the slope of a regression between the chemical concentration and trophic level of organisms in the food web. The trophic level can be determined from stable N isotope ratios (δ(15) N). In this article, we give the background for the development of TMFs, identify and discuss impacts of ecosystem and ecological variables on their values, and discuss challenges and uncertainties associated with contaminant measurements and the use of δ(15) N for trophic level estimations. Recommendations are provided for experimental design, data treatment, and statistical analyses, including advice for users on reporting and interpreting TMF data. Interspecies intrinsic ecological and organismal properties such as thermoregulation, reproductive status, migration, and age, particularly among species at higher trophic levels with high contaminant concentrations, can influence the TMF (i.e., regression slope). Following recommendations herein for study design, empirical TMFs are likely to be useful for understanding the food web biomagnification potential of chemicals, where the target is to definitively identify if chemicals biomagnify (i.e., TMF > or < 1). TMFs may be less useful in species- and site-specific risk assessments, where the goal is to predict absolute contaminant concentrations in organisms in relation to threshold levels.

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 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.

Hg methylation in sediments and floating meadows of a tropical lake in the Pantanal floodplain, Brazil

Potential net 203Hg methylation was assayed in different substrates and conditions in Fazenda Ipiranga Lake, 30 km downstream from gold mining fields near Pocone, Pantanal, Brazil, during the dry season. Samples and acidified controls of surface sediments and roots of dominant floating macrophytes (Eichhornia azurea, Salvinia sp.) were incubated in situ for 3 days with approx. 43 ng Hg.g−1 (dry weight), added as 203HgCl2. Methylmercury (Me203Hg) was extracted in toluene and measured by beta counting. Net methylation was about 1% in sediments under floating macrophytes, both at an open lake site and at a littoral site. Parallel incubations of sulphate or molybdate amended samples suggest that sulphate reducing bacteria may be important Hg methylators at both sites, and that their activity is sulphate-limited in particular at the littoral site. In laboratory experiments, net methylation in the same sediments was highest at temperatures in the 33–45°C range but was completely inhibited at 55°C. NaCl addition had a strong inhibiting effect on net methylation. In an intact open-lake sediment core, spiked with 203Hg in the overlying water and incubated for 3 days, total 203Hg was detectable down to a depth of 14–16 cm, coinciding with the depth reached by the galleries of chironomid larvae present in the core. Swimming insects caused 203Hg penetration down to 4 cm. Me203Hg was detected only in the upper layers (0–2 cm) of the sediment, with concentrations reaching 0.47–0.75% of total Hg. This suggests an important role for bioturbation in the exchange of Hg and MeHg between sediment and water. Methylation was up to nine times more intense in floating macrophyte roots than in the underlying surface sediments: an average of 10.4% of added Hg was methylated in samples of Salvinia sp. roots during the 3-day incubation, and 6.5% in E. azurea roots. This adds to previous findings on the role of such macrophyte stands, a distinctive feature of tropical rivers and lakes, as potentially important sites for the production of highly available MeHg.

Low dose of fine particulate matter (PM2.5) can induce acute oxidative stress, inflammation and pulmonary impairment in healthy mice

Air pollution is associated with morbidity and mortality induced by respiratory diseases. However, the mechanisms therein involved are not yet fully clarified. Thus, we tested the hypothesis that a single acute exposure to low doses of fine particulate matter (PM2.5) may induce functional and histological lung changes and unchain inflammatory and oxidative stress processes. PM2.5 was collected from the urban area of São Paulo city during 24 h and underwent analysis for elements and polycyclic aromatic hydrocarbon contents. Forty-six male BALB/c mice received intranasal instillation of 30 μL of saline (CTRL) or PM2.5 at 5 or 15 μg in 30 μL of saline (P5 and P15, respectively). Twenty-four hours later, lung mechanics were determined. Lungs were then prepared for histological and biochemical analysis. P15 group showed significantly increased lung impedance and alveolar collapse, as well as lung tissue inflammation, oxidative stress and damage. P5 presented values between CTRL and P15: higher mechanical impedance and inflammation than CTRL, but lower inflammation and oxidative stress than P15. In conclusion, acute exposure to low doses of fine PM induced lung inflammation, oxidative stress and worsened lung impedance and histology in a dose-dependent pattern in mice.

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.

First Determination of UV Filters in Marine Mammals. Octocrylene Levels in Franciscana Dolphins

Most current bioexposure assessments for UV filters focus on contaminants concentrations in fish from river and lake. To date there is not information available on the occurrence of UV filters in marine mammals. This is the first study to investigate the presence of sunscreen agents in tissue liver of Franciscana dolphin (Pontoporia blainvillei), a species under special measures for conservation. Fifty six liver tissue samples were taken from dead individuals accidentally caught or found stranded along the Brazilian coastal area (six states). The extensively used octocrylene (2-ethylhexyl-2-cyano-3,3-diphenyl-2-propenoate, OCT) was frequently found in the samples investigated (21 out of 56) at concentrations in the range 89-782 ng·g(-1) lipid weight. São Paulo was found to be the most polluted area (70% frequency of detection). Nevertheless, the highest concentration was observed in the dolphins from Rio Grande do Sul (42% frequency of detection within that area). These findings constitute the first data reported on the occurrence of UV filters in marine mammals worldwide.

Anthropogenic and naturally-produced organobrominated compounds in marine mammals from Brazil

Liver samples from 51 cetaceans, comprising 10 species, stranded between 1994 and 2006 in a highly industrialized and urbanized region in Southeast Brazil, were analyzed for polybrominated diphenyl ethers (PBDEs) and methoxylated-PBDEs (MeO-PBDEs). A concentration range of PBDEs (3-5960ng/g lw) similar to that observed in Northern Hemisphere dolphins was found. MeO-PBDE concentrations in continental shelf (CS) dolphins from Brazil are among the highest detected to date in cetaceans (up to 250microg/g lw). Higher SigmaMeO-PBDE concentrations were measured in CS and oceanic dolphins than in estuarine dolphins. The SigmaPBDE/SigmaMeO-PBDE ratio varied significantly ranging from a mean value of 7.12 to 0.08 and 0.01 for estuarine, CS and oceanic species, respectively. A positive correlation was observed between SigmaPBDE and year of stranding of male estuarine dolphins (Sotalia guianensis), which suggests temporal variation in the exposure. Placental transfer of organobrominated compounds was also evidenced in S. guianensis.