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91.
Albatrosses and petrels (Procellariiformes) are migratory oceanic birds of considerable conservational interest. Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were assessed in the subcutaneous fat, liver and muscle of 100 birds belonging to eight species of Procellariiformes collected during their migration period in southern Brazil, one of the most important feeding areas for these species. Although the profiles of PCBs and OCPs were similar among the individuals, with predominance of penta, hexa and heptachlorobiphenyls and pp-DDE, organochlorine concentrations exhibited a high degree of intra-species variability. The influence of body condition during the migration period in the distribution of organochlorine contaminants was also evaluated, showing that it is a significant factor in the variation and redistribution of these compounds in the tissues of these birds. The intense use of lipid reserves associated to the contamination from organochlorine compounds could be a troubling factor for seabirds with extended breeding periods and that spend most of their lives at sea migrating long distances, such as most of Procellariiformes. Studies on contamination are necessary to improve the knowledge of the threats to these birds and their populations as well as to contribute with information about persistent organic pollutants in the South Atlantic marine environment.  相似文献   
92.
This paper describes the phenotypic and genotypic diversity of a Gram-positive, aerobic bacterial population isolated from the chlorine tank of a wastewater treatment plant. A total of 12 sporeforming, rod-shaped isolates were identified using 16S rRNA gene sequencing and biochemical tests. Pairwise genetic comparisons revealed the identity among sequences obtained from isolates varied from 92.6 to 100%. Similarity searches on GenBank showed that five strains were closely related (99 to 100% identity) to Bacillus subtilis and two were almost identical (99%) to B. megaterium and B. licheniformis. Because the five remaining strains were either closely related (97 to 99% identity) or identical to B. cereus, B. thuringiensis, and B. anthracis, they were classified as belonging to the B. cereus group. Apart from one strain, all clades in the phylogenetic tree were identical to clusters formed in the dendrogram based on biochemical tests results. According to the biochemical profiles, all isolates were characterized as different strains. In addition to chlorine resistance, all isolates were found to be resistant to at least one of five antibiotics tested. These results identify the potential risk of spreading antibiotic resistance genes in the environment by chlorine-resistant strains of Bacillus.  相似文献   
93.
Perchlorate contamination was investigated in groundwater and surface water from Sivakasi and Madurai in the Tamil Nadu State of South India. Sensitive determination of perchlorate (LOQ?=?0.005 μg/L) was achieved by large-volume (500 μL) injection ion chromatography coupled with tandem mass spectrometry. Concentrations of perchlorate were <0.005–7,690 μg/L in groundwater (n?=?60), <0.005–30.2 μg/L in surface water (n?=?11), and 0.063–0.393 μg/L in tap water (n?=?3). Levels in groundwater were significantly higher in the fireworks factory area than in the other locations, indicating that the fireworks and safety match industries are principal sources of perchlorate pollution. This is the first study that reports the contamination status of perchlorate in this area and reveals firework manufacture to be the pollution source. Since perchlorate levels in 17 out of 57 groundwater samples from Sivakasi, and none from Madurai, exceeded the drinking water guideline level proposed by USEPA (15 μg/L), further investigation on human health is warranted.  相似文献   
94.
The aim of this study was to estimate the risk for caries and fluorosis in a desertification area, applying the calcium/fluoride concentration ratio of underground water and the quality of water in a selected geographical region. This study was performed in the municipality of São João do Rio do Peixe, located in the tropical semiarid lands of Brazil. A total of 111 groundwater samples were collected. Fluoride concentration varied from 0.11 to 9.33 mg/L. Thirty percent of all samples analyzed showed values above 1.5 mg/L, while 64 % were above the ideal limit of 0.7 mg/L. Mean calcium concentration was 47.6 mg/L, and 14.4 % of all samples presented values above the WHO acceptable limits. The proportional value of calcium/fluoride in water showed that only 12 % of the samples were suitable for dental caries prevention with minimal risk for dental fluorosis. Mapping of the fluoride distribution indicated that approximately 2,465 people could be affected by dental fluorosis and 1,057 people might be affected by skeletal fluorosis. It can be concluded that, in addition to fluoride, many water parameters were not suitable for the drinking water. Mapping out calcium/fluoride ratio may indicate areas of water suitability for caries control, whereas the fluoride concentration solely can indicate the areas with the risk for fluorosis. This approach can be relevant for health authorities for identifying communities where dental caries or dental fluorosis is prevalent.  相似文献   
95.
96.
Environmental Science and Pollution Research - In this work, for the first time, Cordia trichotoma sawdust, a residue derived from noble wood processing, was applied as an alternative biosorbent...  相似文献   
97.
Environmental Science and Pollution Research - We analyze potential Late Holocene metal contamination along a sediment core collected in the distal zone of Ria de Vigo (North Spain). Statistical...  相似文献   
98.
Geographical Range Size and the Conservation of Mexican Mammals   总被引:2,自引:0,他引:2  
Range was estimated for the 423 noninsular mammals of Mexico to identify those species with more restricted distributions and to detect priority areas for conservation based on the presence of such species. Thirty-eight percent of nonvolant mammals and 15.4% of bats are restricted in Mexico to areas of less than 114,000 km2. Restricted species were defined as those occurring in ranges smaller than the median for bats and for nonvolant species. Following this criterion, most nonvolant species with restricted distribution in Mexico are either endemic to the country or are shared with the United States, whereas endemic chiropteran species are few, and most Mexican bats with restricted distribution also occur in South America. Nonvolant mammals with restricted distribution in Mexico tend to be of small body size, herbivore or granivore, and fossorial or semifossorial. Among bats, gleaners are significantly more restricted than aerial insectivores. Species with restricted distribution are inadequately represented in the current official list of endangered species, particularly in the case of nonvolant mammals. Similarly, some areas of Mexico that harbor several species with restricted distribution are not represented in the Mexican system of protected areas. Therefore, rarity, in this case measured by the area of distribution, should be included as an additional criterion for conservation of the Mexican mammal fauna.  相似文献   
99.
Marine reserves can help in maintaining biodiversity and potentially be useful as a fishery management tool by removing human-mediated impacts. Intertidal, soft-sediment habitats can often support robust recreational and commercial shellfish harvests, especially for clams; however, there is limited research on the effects of reserves in these habitats. In San Juan County, Washington, several reserves prohibit recreational clam digging. We examined the effects of these reserves on infaunal community composition through comparison with non-reserve beaches during a 6-week period. Clam abundance, overall species richness and total polychaete family richness were greater on reserve beaches compared to non-reserve beaches. Additionally, an experiment within a reserve demonstrated negative impacts of digging on non-target infauna. These effects probably resulted from local disruption and disturbance of the sediment habitat and not from increased post-digging predation, which was controlled. Intertidal reserves could play an important role in sustaining local and potentially regional biodiversity.  相似文献   
100.
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