Organic mercury levels among the Yanomama of the Brazilian Amazon Basin

The Catrimani River basin in northern Brazil is the home of the Yanomama and has been the site of renegade gold mining since 1980. Gold-mining operations release inorganic mercury (Hg) into the environment where it is organified and biomagnified in aquatic ecosystems. Ingestion of mercury-contaminated fish poses a potential hazard to fish-eating populations such as the Yanomama. We surveyed Hg levels in Yanomama villagers living near mined and unmined rivers in 1994 and 1995, and analyzed Hg levels in piranha caught by villagers. In 1994, 90 Yanomama Indians from 5 villages and in 1995, 62 Yanomama Indians from 3 villages participated in the studies. Four villages surveyed in 1994 were located directly on the Catrimani River, approximately 140-160 km downstream from past gold-mining activities. The other village surveyed in 1994 was situated on the unmined Ajaraní River. In 1995, 2 of the Catrimani River villages were revisited, and a third Yanomama village, on the unmined Pacu River, was surveyed. Blood organic mercury levels among all villagers surveyed ranged from 0 to 62.6 microg L(-1) (mean levels in each village between 21.2 microg L(-1) and 43.1 microg L(-1)). Mercury levels in piranha from the mined Catrimani River ranged from 235 to 1084 parts per billion (ppb). Nine of 13 piranhas, measuring 30 cm or longer had total mercury levels which exceeded mercury consumption limits (500 ppb) set by both the World Health Organization and the Brazilian Ministry of Health. Unexpectedly, high mercury levels were also observed in fish and villagers along the unmined Ajaraní and Pacu Rivers suggesting that indirect sources may contribute to environmental mercury contamination in the Amazon basin.     

Polychaete feeding guilds from Georges Bank,USA

Based on 408 quantitative samples distributed over two seasons (winter and spring) and 42 stations, from Georges Bank, New England, USA, the feeding guild classification presented by Fauchald and Jumars was examined. Hypotheses involving the association of particular feeding guilds with environmental variables were posed and tested. In this study, herbivore, motile, jawed (HMJ); filtering and surface deposit feeding, sessile or discretely motile, and tentaculate (F-SD-SDT); burrowing, sessile, non-jawed (BSX); surface deposit feeding, motile, non-jawed (SMX); carnivore, motile, jawed (CMJ), and filter feeding, discretely motile, non-jawed (FDT) were the major feeding guilds of polychaetes. There were more significant associations between feeding guilds and depth, dissolved oxygen, and mean phi and gravel than any other environmental variables. Some significant relationships between feeding guilds and depth, fine-grained sediment, nutrition in sediment (carbon, nitrogen, bacterial biomass, and microbial biomass) emerged. Burrowing, motile, non-jawed (BMX), surface deposit feeding, discretely motile, tentaculate (SDT) and FDT increased with depth. BMX, BSX, and FDT increased with carbon, microbial biomass, and nitrogen, respectively. Some preliminary polychaete feeding surfaces were posed. Nantucket Shoals and Georges Bank were characterized by HMJ and F-SD-SDT; Northern Slope by FDT; Southern Slope by FDT and HMJ; Southwestern Slope by HMJ, SMX, BMX; and the Gulf of Maine by F-SD-SDT, SDT and surface deposit feeding, sessile, tentaculate (SST).     

Chemical Plume Tracing

Environmental Fluid Mechanics -     

Differential attraction of females to dominant males: Olfactory discrimination and mating preference in the brown lemming (Lemmus trimucronatus)

Summary This study investigated differential attraction of estrous brown lemmings (Lemmus trimucronatus) to conspecific males recently exposed to each other for a 10-min agonistic encounter. In tests conducted 5 min, 1 h and 24 h after agonistic encounters, females preferred the oder of dominant males to that of defeated males when both odors were presented simultaneously in a Y-maze olfactometer. Defeat in an agonistic encounter did not reduce the propensity of male lemmings to initiate sexual behavior. In one-male, one-female tests conducted 5 min after agonistic encounters, dominant males achieved higher mount and thrust scores while defeated males obtained higher scores for attempted mounts. The sexual behavior of dominant and defeated males did not differ significantly in similar tests conducted 1 h and 24 h later. In contrast, females readily mated with dominant males and tended to avoid defeated males in two-male tethering tests conducted 5 min after agonistic encounters. In these tests, females still showed a preference for dominant males 1 h and 24 h after male agonistic encounters.     

Prevention of dioxins de novo formation by ethanolamines

Two inhibitors, triethanolamine (TEA) and monoethanolamine (MEA), were tested for their ability to prevent the de novo formation of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) on sinter plant fly ash. The amounts of both PCDDs and PCDFs, formed by thermal treatment of the fly ash, decreased when inhibitors were added. Up to 90% reduction of the PCDD/Fs formation was reached when 2 wt % monoethanolamine was mixed with fly ash. The temperatures tested, 325 and 400 °C, did not affect the inhibition activity. However, a longer reaction time, 4 h instead of 2 h, gave higher percentages of PCDD/Fs reduction. The laboratory results show that ethanolamines reduce the dioxins formation on sinter plant fly ash under various conditions of temperature and reaction time. Moreover, factory tests performed in parallel at a sinter plant are in good agreement with the laboratory experiments, thus confirming that the use of ethanolamine inhibitors is an appropriate technique for the prevention of dioxins emissions from sintering processes. Electronic Publication     

Preliminary assessment of cement kiln dust in solidification and stabilization of mercury containing waste from a chlor-alkali unit

Journal of Material Cycles and Waste Management - A low-level mercury containing hazardous waste with a mercury concentration of 22.0 ± 5.00 ppm generated at a...     

Does phylogenetic inertia explain the evolution of ineffective antipredator behavior in a sunfish-salamander system?

The streamside salamander, Ambystoma barbouri, exhibits ineffective antipredator behavior (high emergence rate from refuge, and high activity while out of refuge) and thus suffers heavy predation in stream pools with sunfish. A. barbouri evolved relatively recently from an ancestor that closely resembled a sister species, A. texanum, which breeds in fishless, ephemeral ponds. Sunfish thus represent a relatively new selection pressure for A. barbouri. Phylogenetic inertia predicts that (1) A. texanum should be very poor at coping with fish and (2) because it has only recently been exposed to fish, A. barbouri should still be poor at avoiding fish, but due to its recent exposure to fish, A. barbouri should be better than A. texanum at coping with sunfish. Experimental results provided mixed support for these predictions. As predicted, A. texanum suffered heavy sunfish predation. Compared to A. texanum, A. barbouri showed a greater tendency to initiate alarm moves that enhanced escape success from fish. However, in both the presence and absence of fish, A. barbouri showed higher emergence rates from refuge and higher movement while out of refuge than A. texanum. These behaviors tend to increase exposure to sunfish, i.e., for these key behaviors, A. barbouri apparently evolved in the wrong direction as far as fish predation is concerned. Due to these offsetting effects (increased exposure to fish, increased escape success), A. barbouri is no better at surviving with sunfish than A. texanum. A possible explanation for the high activity of A. barbouri is its use of highly ephemeral habitats (relative to A. texanum) that favor the evolution of higher activity, feeding, and developmental rates for A. barbouri relative to A. texanum. Received: 15 May 2000 / Revised: 3 August 2000 / Accepted: 18 August 2000