Evidence of mercury biomagnification in the food chain of the cardinal tetra Paracheirodon axelrodi (Osteichthyes: Characidae) in the Rio Negro, central Amazon, Brazil.

In this study, nitrogen stable isotope (δ(15) N) and total mercury (THg) analyses were conducted on algae, submersed and emergent macrophytes, shrubs and trees, Macrobrachium sp. and Paracheirodon axelrodi collected in three streams that drain a large interfluvial region in the middle Rio Negro, Amazonas State, Brazil. Samples were collected during different hydrological periods over 12 months in lower stream reaches and their headwaters; the latter being characterized by shallow, open-canopy swamps. Additionally, δ(15) N values and mercury concentrations of Paracheirodon simulans and Cichla spp. from the middle Rio Negro were analysed to demonstrate THg biomagnification in the food web. The highest mercury levels of P. axelrodi were found in small individuals, which were collected principally in the low water period. The log10 THg-δ(15) N relationship of vascular plants and algae, Macrobrachium sp., Paracheirodon spp. and Cichla spp. showed significant mercury biomagnification among trophic levels, with regression slopes of 0·15 and 0·25 for the entire food web and heterotrophs-only food web, respectively. The mean ± s.d. THg concentrations for Macrobrachium sp., P. axelrodi, P. simulans and Cichla spp. were 63·6 ± 23·7, 104·5 ± 40·0, 112·3 ± 31·4 and 418·5 ± 188·1 ng g(-1) wet mass, respectively. Elevated levels of mercury found in Paracheirodon spp. and top predators such as Cichla spp. in a remote area far from anthropogenic inputs provide evidence that high mercury concentrations occur naturally in Rio Negro aquatic food webs.

Factors influencing the structure and spatial distribution of fishes in the headwater streams of the Jaú River in the Brazilian Amazon / Fatores influenciando a estrutura e distribuição espacial dos peixes nos Igarapés de cabeceira do Parque Nacional do Jaú, Amazônia Central

The aim of this study was to investigate the influence of spatial variation in river channels and habitats on the distribution of fish communities in the headwater streams of the Jaú River System, a blackwater tributary of the Negro River. Collections and measurements were made in 34 headwater streams during the period of November- December, 1998. Fish were captured with fish traps and hand nets along standard reaches of two meanders. Data on benthic habitat structure, stream depth and width were collected along lateral transects in each sample reach. A total of 66 fish species from 24 families were collected and classified into seven trophic guilds: allocthonous insectivore, autochthonous insectivore, general insectivore, piscivore, detritivorous planktivore, detritivorous insectivore and insectivorous piscivore. Variations in the distribution and diversity of bottom substrates were important factors influencing fish community structures in these systems. Also, variation in stream size explained the observed variability in fish communities.(AU)

O objetivo desse estudo foi investigar a influência da variação espacial de características físicas do canal dos igarapés e habitats na distribuição das comunidades de peixes em igarapés de cabeceira no sistema do rio Jaú. O rio Jaú é um tributário de águas pretas do rio Negro. Coletas e medidas foram realizadas em 34 igarapés de cabeceira durante os períodos de novembro a dezembro de 1998. Os peixes foram capturados com armadilhas e puçás ao longo de dois meandros em cada local. Um total de 66 espécies de peixes de 24 famílias foram coletados e classificados em sete guildas tróficas: insetívoro alóctone, insetívoro autóctone, insetívoro em geral, piscívoro, detritívoro algívoro, detritívoro insetívoro e insetívoro piscívoro. Variações na distribuição e diversidade do substrato de fundo foram importantes fatores influenciando a estrutura da comunidade nesses sistemas. Sendo assim, variações no tamanho dos igarapés mostraram reflexos nas comunidades de peixes.(AU)

Factors influencing the structure and spatial distribution of fishes in the headwater streams of the Jaú River in the Brazilian Amazon.

The aim of this study was to investigate the influence of spatial variation in river channels and habitats on the distribution of fish communities in the headwater streams of the Jaú River System, a blackwater tributary of the Negro River. Collections and measurements were made in 34 headwater streams during the period of November- December, 1998. Fish were captured with fish traps and hand nets along standard reaches of two meanders. Data on benthic habitat structure, stream depth and width were collected along lateral transects in each sample reach. A total of 66 fish species from 24 families were collected and classified into seven trophic guilds: allocthonous insectivore, autochthonous insectivore, general insectivore, piscivore, detritivorous planktivore, detritivorous insectivore and insectivorous piscivore. Variations in the distribution and diversity of bottom substrates were important factors influencing fish community structures in these systems. Also, variation in stream size explained the observed variability in fish communities.

Effects of an oil spill and discharge of domestic sewage on the insect fauna of Cururu stream, Manaus, AM, Brazil.

Assemblages of aquatic and edaphic insects in three streams in Central Amazonia were used to evaluate the impact on one of the streams (Cururu) caused by an oil spill that occurred in August 1999. The Cururu stream had already been impacted by domestic sewage. These three streams were evaluated during four different periods of the regional hydrological cycle (falling-, low-, rising- and high-water), from September 2000 to May 2001. An Eckman dredge, an aquatic entomological net and a manual auger were used to collect insects, which were used to estimate the taxonomic richness (at the family level) and insect density in each stream. Anoxic and eutrophic conditions were determined in each stream based on the mean concentration of dissolved oxygen, total nitrogen and phosphorus. Richness and abundance of insect fauna were higher in the Cristalino stream (not impacted) than in the Bom Jardim stream (impacted by domestic sewage) and in the Cururu stream, with the exception of samples collected along the stream banks (littoral fauna). The mean dissolved oxygen was lower in the Cururu stream than in the other two, while the mean concentrations of total nitrogen and phosphorus were higher. These elements showed intermediate values in the Bom Jardim stream, while the opposite pattern was observed in the Cristalino stream, with higher concentrations of dissolved oxygen and lower concentrations of total nitrogen and phosphorus. The concentrations of these variables reflect the modifications resulting from anthropogenic eutrophication caused by the discharge of domestic sewage into Bom Jardim and Cururu and by the oil spill in Cururu, which negatively affected the richness and abundance of insects in these streams.

Effects of an oil spill and discharge of domestic sewage on the insect fauna of Cururu stream, Manaus, AM, Brazil

As assembléias de insetos aquáticos e edáficos de três igarapés da Amazônia Central foram utilizadas para avaliar o impacto sofrido por um deles (igarapé Cururu), após um vazamento de óleo derivado de petróleo, ocorrido em agosto de 1999. O igarapé Cururu já era impactado pelo despejo de esgoto doméstico. A avaliação desses sistemas foi realizada em quatro diferentes períodos do ciclo hidrológico da região (vazante, seca, enchente e cheia), entre setembro de 2000 e maio de 2001. Os insetos foram coletados com draga Eckman, rede entomológica aquática e trado, e utilizados para estimar a riqueza taxonômica (nível de família) e a densidade de insetos em cada sistema. Os efeitos de anóxia e os efeitos da eutroficação foram mensurados pelas médias de concentração de oxigênio dissolvido, nitrogênio total e fósforo total, estimadas nos três sistemas. A riqueza e abundância da fauna de insetos foram maiores no igarapé Cristalino (não impactado) do que nos igarapés Bom Jardim (impactado pelo despejo de esgoto) e Cururu, com exceção das amostragens de insetos litorâneos. A concentração do oxigênio dissolvido no igarapé Cururu foi menor do que nos outros dois sistemas, enquanto as concentrações de nitrogênio total e fósforo total no igarapé Cururu foram maiores. Esses elementos tiveram valores inversos no igarapé Cristalino e intermediários no igarapé Bom Jardim. As concentrações de oxigênio dissolvido, nitrogênio total e fósforo total refletem as modificações provocadas pela eutroficação antropogênica nos sistemas Bom Jardim e Cururu. Isso ocorreu devido à liberação de efluentes domésticos pelas comunidades locais e pelo óleo introduzido no igarapé Cururu, influenciando negativamente a riqueza e abundância de insetos nesses igarapés.

Effects of an oil spill and discharge of domestic sewage on the insect fauna of Cururu stream, Manaus, AM, Brazil

Assemblages of aquatic and edaphic insects in three streams in Central Amazonia were used to evaluate the impact on one of the streams (Cururu) caused by an oil spill that occurred in August 1999. The Cururu stream had already been impacted by domestic sewage. These three streams were evaluated during four different periods of the regional hydrological cycle (falling-, low-, rising- and high-water), from September 2000 to May 2001. An Eckman dredge, an aquatic entomological net and a manual auger were used to collect insects, which were used to estimate the taxonomic richness (at the family level) and insect density in each stream. Anoxic and eutrophic conditions were determined in each stream based on the mean concentration of dissolved oxygen, total nitrogen and phosphorus. Richness and abundance of insect fauna were higher in the Cristalino stream (not impacted) than in the Bom Jardim stream (impacted by domestic sewage) and in the Cururu stream, with the exception of samples collected along the stream banks (littoral fauna). The mean dissolved oxygen was lower in the Cururu stream than in the other two, while the mean concentrations of total nitrogen and phosphorus were higher. These elements showed intermediate values in the Bom Jardim stream, while the opposite pattern was observed in the Cristalino stream, with higher concentrations of dissolved oxygen and lower concentrations of total nitrogen and phosphorus. The concentrations of these variables reflect the modifications resulting from anthropogenic eutrophication caused by the discharge of domestic sewage into Bom Jardim and Cururu and by the oil spill in Cururu, which negatively affected the richness and abundance of insects in these streams.

As assembléias de insetos aquáticos e edáficos de três igarapés da Amazônia Central foram utilizadas para avaliar o impacto sofrido por um deles (igarapé Cururu), após um vazamento de óleo derivado de petróleo, ocorrido em agosto de 1999. O igarapé Cururu já era impactado pelo despejo de esgoto doméstico. A avaliação desses sistemas foi realizada em quatro diferentes períodos do ciclo hidrológico da região (vazante, seca, enchente e cheia), entre setembro de 2000 e maio de 2001. Os insetos foram coletados com draga Eckman, rede entomológica aquática e trado, e utilizados para estimar a riqueza taxonômica (nível de família) e a densidade de insetos em cada sistema. Os efeitos de anóxia e os efeitos da eutroficação foram mensurados pelas médias de concentração de oxigênio dissolvido, nitrogênio total e fósforo total, estimadas nos três sistemas. A riqueza e abundância da fauna de insetos foram maiores no igarapé Cristalino (não impactado) do que nos igarapés Bom Jardim (impactado pelo despejo de esgoto) e Cururu, com exceção das amostragens de insetos litorâneos. A concentração do oxigênio dissolvido no igarapé Cururu foi menor do que nos outros dois sistemas, enquanto as concentrações de nitrogênio total e fósforo total no igarapé Cururu foram maiores. Esses elementos tiveram valores inversos no igarapé Cristalino e intermediários no igarapé Bom Jardim. As concentrações de oxigênio dissolvido, nitrogênio total e fósforo total refletem as modificações provocadas pela eutroficação antropogênica nos sistemas Bom Jardim e Cururu. Isso ocorreu devido à liberação de efluentes domésticos pelas comunidades locais e pelo óleo introduzido no igarapé Cururu, influenciando negativamente a riqueza e abundância de insetos nesses igarapés.

Effects of an oil spill and discharge of domestic sewage on the insect fauna of Cururu stream, Manaus, AM, Brazil

Assemblages of aquatic and edaphic insects in three streams in Central Amazonia were used to evaluate the impact on one of the streams (Cururu) caused by an oil spill that occurred in August 1999. The Cururu stream had already been impacted by domestic sewage. These three streams were evaluated during four different periods of the regional hydrological cycle (falling-, low-, rising- and high-water), from September 2000 to May 2001. An Eckman dredge, an aquatic entomological net and a manual auger were used to collect insects, which were used to estimate the taxonomic richness (at the family level) and insect density in each stream. Anoxic and eutrophic conditions were determined in each stream based on the mean concentration of dissolved oxygen, total nitrogen and phosphorus. Richness and abundance of insect fauna were higher in the Cristalino stream (not impacted) than in the Bom Jardim stream (impacted by domestic sewage) and in the Cururu stream, with the exception of samples collected along the stream banks (littoral fauna). The mean dissolved oxygen was lower in the Cururu stream than in the other two, while the mean concentrations of total nitrogen and phosphorus were higher. These elements showed intermediate values in the Bom Jardim stream, while the opposite pattern was observed in the Cristalino stream, with higher concentrations of dissolved oxygen and lower concentrations of total nitrogen and phosphorus. The concentrations of these variables reflect the modifications resulting from anthropogenic eutrophication caused by the discharge of domestic sewage into Bom Jardim and Cururu and by the oil spill in Cururu, which negatively affected the richness and abundance of insects in these streams.

As assembléias de insetos aquáticos e edáficos de três igarapés da Amazônia Central foram utilizadas para avaliar o impacto sofrido por um deles (igarapé Cururu), após um vazamento de óleo derivado de petróleo, ocorrido em agosto de 1999. O igarapé Cururu já era impactado pelo despejo de esgoto doméstico. A avaliação desses sistemas foi realizada em quatro diferentes períodos do ciclo hidrológico da região (vazante, seca, enchente e cheia), entre setembro de 2000 e maio de 2001. Os insetos foram coletados com draga Eckman, rede entomológica aquática e trado, e utilizados para estimar a riqueza taxonômica (nível de família) e a densidade de insetos em cada sistema. Os efeitos de anóxia e os efeitos da eutroficação foram mensurados pelas médias de concentração de oxigênio dissolvido, nitrogênio total e fósforo total, estimadas nos três sistemas. A riqueza e abundância da fauna de insetos foram maiores no igarapé Cristalino (não impactado) do que nos igarapés Bom Jardim (impactado pelo despejo de esgoto) e Cururu, com exceção das amostragens de insetos litorâneos. A concentração do oxigênio dissolvido no igarapé Cururu foi menor do que nos outros dois sistemas, enquanto as concentrações de nitrogênio total e fósforo total no igarapé Cururu foram maiores. Esses elementos tiveram valores inversos no igarapé Cristalino e intermediários no igarapé Bom Jardim. As concentrações de oxigênio dissolvido, nitrogênio total e fósforo total refletem as modificações provocadas pela eutroficação antropogênica nos sistemas Bom Jardim e Cururu. Isso ocorreu devido à liberação de efluentes domésticos pelas comunidades locais e pelo óleo introduzido no igarapé Cururu, influenciando negativamente a riqueza e abundância de insetos nesses igarapés.

Quality assurance of a diarrhoea control programme in northeastern Brazil.

In this study quality assurance methods were used in an evaluation of a programme for Control of Diarrhoeal Diseases (CDD) in northeastern Brazil. Seventy-eight randomly selected public primary care facilities in four states were assessed by trained surveyors. Problems observed in the facilities were lack of information on target population and coverage, lack of equipment to permit rehydration in the premises, and frequent unavailability of trained professionals. Health workers showed deficiencies in history taking, physical examination and knowledge on diarrhoea management. Many caretakers had difficulties in recalling information given to them in the health facilities. Eighty-four percent of the cases were treated with oral rehydration, but 90% were sent home immediately and not kept in the facilities to practice rehydration under guidance as recommended by the national CDD programme. An overuse of the medical treatment was observed. More than two-thirds of health professionals gave wrong indications for use of antibiotics. The study showed that oral rehydration therapy is well established in the government health services in the region but that the CDD programme needs to take early action to correct deficiencies in logistics, case management and health education.

PIP: The 9 states in the northeast of Brazil were divided into 4 groups based on population size and geographical distribution. In the capital cities of each state, 5-8 health units treating children with diarrhea were chosen at random. Overall, 78 health care units were studied. University-trained nurses evaluated each health care unit regarding diarrhea management and conducted interviews using questionnaires for the data collection. The survey team was split into groups of 4, each group covering 1 state. The field-work was carried out in May 1989 and took 4-6 weeks to complete. 88% of facilities surveyed were health centers, while the rest were outpatient departments in hospitals. In 40% of the facilities, the number of monthly consultations of children was known, while only 22% had information on the number of children attending for diarrhea each month. 62% of facilities had a special oral rehydration therapy (ORT) place for children. Utensils for administration of ORT were available in only half of the facilities. In 1/5 of the facilities the sugar-salt-solution packets were never or seldom available. In 32 of 65 facilities, the most recent shipment of ORS packets had arrived in the last month. 10 facilities had not received ORS for more than 6 months. In 67 facilities (86%) a physician, and in 9 a health auxiliary, was responsible for managing childhood diarrhea. 75 visits for childhood diarrhea were observed in 42 health facilities. 58 of the attendances (77%) were managed by doctors, 12 by health auxiliaries, and 5 by nurses. 90% of the patients were sent home, while the rest were treated. In 84% of cases oral rehydration therapy was prescribed, usually oral rehydration salts (ORS). Antimicrobial drugs were prescribed in 21% of the cases. Other drugs like metochlopramide, caolin-pectin, aspirin and vitamins were prescribed in 41% of the cases.

Management of childhood diarrhoea at the household level: a population-based survey in north-east Brazil.

The management of childhood diarrhoea at the household level was studied in a population-based survey in four states in north-east Brazil. Of a representative sample of 6524 children under 5 years of age, 982 (15.1%) had diarrhoea on the day of the interview or had had diarrhoea at some time during the previous 15 days. A total of 66% of the children were not taken for treatment, while government health services were used by 14%, private doctors by 1%, and traditional healers (rezadeiras) by 24%. Oral rehydration therapy was given to 24.3% of the children as follows: solutions of oral rehydration salts (ORS) were received by 6.8%, salt-and-sugar solutions by 14.7%, and solutions of commercial ORS brands by 4.3%. Although 95% of the caretakers knew about rehydration solutions, only 18% prepared them correctly, the most common error being the use of insufficient water. Of the rehydration solutions used, 39% had a sodium concentration that was potentially dangerous (greater than 120 mmol/l), and 8% had a sodium concentration that was very low. Of those solutions prepared using ORS, 38% had too high a sodium concentration, while 14% of the salt-and-sugar solutions prepared using either the "scoop-and-pinch" approach or a plastic spoon were too concentrated. However, potentially the most dangerous were the salt-and-sugar solutions prepared using nonstandard recipes. More than half of these had an unacceptably high sodium concentration or osmolarity.