ABSTRACT
The trahira Hoplias aff. malabaricus is a top predator in pampean shallow lakes and is highly appreciated by recreational anglers and artisanal fishermen. Trahira growth from Yalca shallow lake was determined by lepidological analysis and age validated by marginal increment. When growth was fitted to the von Bertalanffy model, annual classes exhibited a bimodal pattern as a result of the presence of spring and summer annual cohorts associated with a three month spawning season, each period in turn showing different growth patterns. The trahira population-age structure at Yalca shallow lake showed a truncated profile with very low numbers of large adults and few individuals older than three to four years, thus producing an unbalanced length-structure population. Growth parameters and growth performance were similar to the corresponding parameters estimated for other shallow pampean lakes of the region, but strongly diverged from the data for those populations inhabiting subtropical and tropical environments. Such differences could be accounted for by dissimilarity in metabolic rates associated with thermal differences accompanying seasonal variability among latitudes as well as by the development of adaptive physiologic and demographic responses to cope with the high thermal amplitude and hydrologic instability observed in pampean lakes.
A traíra Hoplias aff. malabaricus é um predador de topo encontrado em lagoas rasas nos Pampas, muito apreciada nas pescas comerciais e esportivas. O crescimento da traíra no lago Yalca foi determinado através de análises lepidológicas, validadas a partir do incremento marginal. O crescimento foi ajustado ao modelo de von Bertalanffy, sendo que as classes de tamanho anuais apresentaram padrão bimodal devido à presença de coortes de primavera e verão, associadas à uma longa estação reprodutiva com diferentes padrões de crescimento. A estrutura etária da traíra do lago Yalca apresentou um perfil truncado, com um número pequeno de adultos de maior porte e poucos indivíduos com mais de três ou quatro anos, produzindo uma estrutura em tamanho desbalanceada. Os parâmetros e a performance de crescimento foram similares aos estimados para outros lagos rasos da região, mas fortemente divergentes de populações encontradas em ambientes tropicais e subtropicais. Tais diferenças podem estar relacionadas à diferentes taxas metabólicas associadas à variação térmica sazonal entre latitudes e ao desenvolvimento de respostas adaptativas fisiológicas e demográficas em resposta aos padrões termais altamente variáveis e instabilidade hidrológica observados nos lagos da região dos Pampas.
Subject(s)
Animals , Growth , Fishes/anatomy & histology , MetabolismABSTRACT
This study was conducted to evaluate the relationships between the environmental exposure and biological monitoring among workers exposed to metallic mercury. We interviewed each workers to get the medical history including previous hazardous occupational history we measured the respiration rate and tidal volume of each worker in order to calculate the 8-hour inhaled mercury of workers. And we wanted to evaluate the effect of exposure duration to mercury concentrations in blood and urine as biologic exposure indices of metallic mercury. The regression and correlation analysis were done to the relationships of 8-hour inhaled mercury are mercury in blood and urine. The results were as follows; 1. The subjects were 35 fluorescent lamp manufacturing workers. The mean age of subjects was 24.8 years old, and the mean work careers of workers was 1.19 years. 89% of the total was consisted man. 2. The correlation coefficients between 8-hour inhaled mercury and mercury in blood and urine were higher than that of only considered air mercury concentration. 3. The correlation coefficients of 8-hour inhaled mercury and mercury in blood and urine were above 0.9 in workers who had exposed to mercury more than 1 year. 4. The R-square value and -value of regression analysis between the 8-hour inhaled mercury and mercury inn blood and urine was also higher in workers who had exposed to mercury over 1 year than in workers who had less than 1 year working experience. The important results or this study were that relationships between the 8hr-inhaled mercury and mercury in blood and urine was very high than that with air mercury concentration only. And the results were very apparent when considering workers 1 year or more. Therefore we concluded that the work career and respiratory volume of each individuals should be considered in evaluation the results of biological monitoring of workers exposed to metallic mercury.
Subject(s)
Environmental Exposure , Environmental Monitoring , Inhalation , Respiratory Rate , Tidal VolumeABSTRACT
In this study, we measured the activity of the erythrocyte pyrimidine 5'-nucleotidase(P5N) for 83 workers exposed to lead in their workplace, and analyzed the correlation of the activity with other biological exposure indices of lead. The measurement was performed by using a high performance liquid chromatography (HPLC) with a reverse phased ODS column. The results are as follows; 1. The correlation of the erythrocyte P5N activity with the concentration of blood lead(PbB) was shown to be statistically significant (r=-0.71, p=0.0001). 2. For a group of subjects whose PbB was less than 10microgram/dl, the erythrocyte P5N activity was 14.9+/-1.5 micromole uridine/h/g Hb. 3. For medical surveillance, this study suggests the erythrocyte P5N activity of 12 micromole uridine/h/g Hb is equivalent to 40 microgram/dl of PbB. 4. The correlation coefficients of the erythrocyte P5N activity with other biological exposure indices of lead such as PbB, ZPP, ALA-U, PBU, CP-U, ALAD, and log ALAD were -0.71, -0.64, -0.57, -0.51, -0.50, 0.46 and 0.64, respectively. 5. The correlation coefficients of the PbB with other biological exposure indices of lead for ALAD, P5N, ZPP, PBU, CP-U, and ALA-U were -0.76, -0.71, 0.68, 0.59, 0.42, and 0.41, respectively. The erythrocyte P5N activity can be used as a reliable biological exposure index of lead.