Mercury distribution in a mangrove tidal creek affected by intensive shrimp farming.

In this study, the Hg distributions in water and sediments from a mangrove creek that receives intensive shrimp farming effluents were determined. The average dissolved and particulate Hg concentrations in the water varied from 3.1 to 9.2 ng L(-1) and from 4.4 to 9.4 ng L(-1), respectively. However, the Hg concentrations in the suspended particulate matter and the bottom sediments varied from 95.4 to 115.7 ng g(-1) and from 1.6 to 10.3 ng g(-1), respectively. A Ward quadratic distance cluster analysis based on the Hg concentrations and hydro- and geochemical parameters (oxygen, salinity, temperature, pH, and organic matter and aluminum content) showed the effects of shrimp farming effluents on the Hg distribution pattern. Furthermore, these results were supported by the Hg distribution in the sediment cores. This study emphasizes the necessity of including Hg as a potential pollutant when monitoring the environmental impacts of intensive shrimp farming.

Mercury emission factors from intensive shrimp aquaculture and their relative importance to the Jaguaribe River Estuary, NE Brazil.

This study estimated Hg emission factors (EFs) and total Hg loading to the Jaguaribe Estuary, NE Brazil, from intensive shrimp farming, and compares this with other local anthropogenic activities. The EF reached 83.5 mg ha(-1) cycle(-1) (about 175 mg ha(-1) year(-1)), resulting in an annual Hg load to the estuary of 0.35 kg. The calculated EF is comparable to Hg EFs from urban wastewaters (200 mg ha(-1)) and solid waste disposal (400 mg ha(-1) year(-1)) from cities located in the estuary's basin. However, due to the smaller area of aquaculture (2,010 ha), total annual loads are much lower than from these other sources (75 and 150 kg year(-1), respectively). Since shrimp farming effluents are released directly into the estuary, the estimated high EF raises environmental concerns with this expanding industry, suggesting the inclusion of this element in ongoing environmental monitoring programs.

Mercury accumulation and metallothionein expression from aquafeeds by Litopenaeus vannamei Boone, 1931 under intensive aquaculture conditions.

This study describes the accumulation of Hg and metallothionein gene expression in Litopenaeus vannamei Boone, 1931 with aquafeeds as the major source of Hg. Trials were conducted under controlled conditions in experimental tank facilities with high (indoor tanks) and low (outdoor tanks) Hg aquafeeds concentrations. Aquafeeds were the sole source of Hg for the shrimps and concentrations varied from 5.4 to 124 ng.g-1 d.w.. In the three animal fractions analysed; muscle (6,3 - 15,9 ng.g-1); hepatopancreas (5,1 - 22,0 ng.g-1) and exoskeleton (3,0 - 16,2 ng.g-1), Hg concentrations were significantly lower in the outdoor trials submitted to Hg-poor aquafeeds. Maximum shrimp muscle Hg concentrations were low (36.4 ng.g-1 w.w.) relative to maximum permissible concentrations for human consumption and Hg content in muscle and hepatopancreas were significantly correlated with Hg content in aquafeeds. Highest Hg concentrations in the exoskeleton of animals exposed to Hg-richer aquafeed, suggested that a detoxification mechanism is taking place. On the other hand the metallothionein suffered no variation in its relative expression in any of the experiments, meaning that the contact with feed containing the observed Hg concentrations were not sufficient to activate gene transcription. It was not possible, under the experimental design used, to infer Hg effects on the biological performance of the animals.

Soroprevalência de brucelose canina na cidade de Alfenas, MG. dados preliminares / Serum prevalence of canine brucellosis in Alfenas city MG, Brazil, Preliminary data

One hundred and two blood serum samples from dogs referred to the Veterinary Teaching Hospital of Alfenas University, were submitted to the agarose immune diffusion and to the fast serum-agglutination tests addressed to find antibodies anti-Brucella canis and B. abortus, respectively. Five samples (4.9 percent) were positives for B.canis and none for B. abortus. This prevalence is considered by some as an alert for an epidemiologic and public healthy problems, considering the serious zoonotic aspect of canine brucellosis

The effect of the dressing in the tissue reactions following apical plugging of the root canal of dog's pulpless teeth with dentin chips / Efeito do curativo de demora na reaçäo tecidual de dentes de cäes após o emprego de plug de raspas de dentina em casos de necropulpectomia

O objetivo deste trabalho foi observar se o curativo de demora tem alguma influência no processo de reparo após o emprego de um plug de raspas de dentina em casos de necropulpectomia. Dentes de cäes foram submetidos à pulpectomia e os canais deixados expostos ao meio oral até que lesöes periapicais fossem detectadas radiograficamente. Os canais radiculares foram a seguir preparados e obturados com cones de guta-percha e cimento de óxido de zinco e eugenol, após a confecçäo de um plug apical de raspas de dentina, em sessäo única, ou depois da aplicaçäo de dois curativos de demora com para-monoclorofenol-canforado. Seis meses após o tratamento, a análise histológica mostrou melhores resultados no grupo onde se empregou o curativo de demora