Lead traceability along soil-melliferous flora-bee family-apiary products chain

Indirect measures were considered to study the lead transfer along the soil-melliferous flora-bee family-apiary products food chain. The concentrations of total and bioavailable lead in the soil were first investigated. Next, the lead level in different organs of melliferous flora and subsequently in the bee family and apiary products was measured. The results indicate a decrease in contamination as follows: honeybees > drones > propolis > wax > bee larvae > honey > royal jelly. The statistical analysis highlights the "lead pollution bioindicator" role of honeybees, honey and propolis. The risk factor parameter allows the prediction of the most impacted month and the least impacted of the melliferous season.     

Enzyme-based resource allocated decomposition and landscape heterogeneity in the Florida Everglades

Enzyme catalyzed reactions are generally considered the rate-limiting step in organic matter degradation and may be significantly influenced by the structure and composition of plant communities. Changes in these rates have the potential to effect long-term peat accumulation and influence the topography of a wetland ecosystem. To determine habitat influences on enzyme activities, we examined slough and sawgrass plots within enriched and reference phosphorus (P) sites in the Everglades. Assays were performed for the enzymes involved in carbon (C), nitrogen (N), and P cycling and lignin depolymerization. Enzyme activities were normalized and analyzed in terms of a resource allocation strategy. Plant composition was found to significantly alter the allocation of enzymatic resources due to varying substrate complexities. Potential decomposition in the slough was less influenced by lignin than in the sawgrass habitats. Additionally, an index relating hydrolytic and oxidative enzymes was significantly greater in the slough habitats, whereas C/N ratios were significantly lower. These indices suggest more favorable decomposition conditions and thus slower peat accretion within the slough communities, which may contribute to the development of elevation differences within the sawgrass ridge and slough topography of the Everglades.     

A probabilistic hazard and risk assessment of exposure to metals and organohalogens associated with a traditional diet in the Indigenous communities of Eeyou Istchee (northern Quebec,Canada)

Environmental Science and Pollution Research - Hunting, trapping, and fishing are part of an Indigenous lifestyle in subarctic Canada. However, this lifestyle may be a route of exposure to...     

Ecological Status of Beaucarnea gracilis, an Endemic Species of the Semiarid Tehuacán Valley, México

We present a demographic analysis and suggestions for the conservation of Beaucarnea gracilis, a species endemic to the Tehuacán Valley, Puebla, México. The species is dioecious, it flowers every year, and the breeding system and floral display are typical of a generalist mode of pollination. The density of B. gracilis in the study plot was 16.7 individuals/ha. Distribution of trunk diameter size classes fits a normal distribution (n = 404), but the smaller sizes were not found (<0.7 m). The inflorescences were visited by 46 insect species. Over 2600 seeds are produced per inflorescence; 27–30% are damaged by parasites, and the rest germinate readily (90–100%). Survival of seeds and seedlings is very low. We found 313 seedlings in a 12-ha area, all (94.24%) of which were at the base of nurse plants; particularly Mimosa luisiana and Castela tortuosa. The ecological status of the population of Beaucarnea gracilis is relatively good for adult individuals. In addition to low recruitment, (whether natural or human influenced), past extraction of seedlings for commerce, grazing by goats, and land clearing for corn cultivation, highway construction, and urbanization, are a real threat to the survival and establishment of seeds and seedlings. Conservation of this slow-growing, long-lived species should be promoted because (1) ecologically, it is a feeding center for many insect species, an important host for many Bromeliaceae, and part of the highly rich and endemic flora of Tehuacán and (2) economically, it helps low income people in the area (seedlings raised for commerce). Protection of nurse plants, regulation of grazing by goats, a halt to illegal extraction, and conservation of areas of the Tehuacán valley will help the survival of this species in nature.     

Subarachnoid cyst with hydrocephalus–a complication of mid-trimester amniocentesis

We report a child with a subarachnoid cyst with hydrocephalus following a mid-trimester amniocentesis. Although fetal trauma is a rare complication, it is important to stress the need to perform amniocentesis under ultrasound control. Children with neurological disease or convulsions of unknown origin in early infancy who are born to mothers who have had midtrimester amniocentesis should have a CT scan as part of the investigations to exclude this rare but nevertheless important complication.     

Further 237Pu experiments with the plaice Pleuronectes platessa: Subcellular distribution of plutonium in the liver

The subcellular distribution of ²³⁷Pu in the livers of the plaice Pleuronectes platessa has been studied by differential and isopycnic gradient centrifugation. It has been shown that the ²³⁷Pu is particularly accumulated in pellets sedimenting out at 3000 and 6000 g which, by deduction from marker enzyme tests, contain a mixture of mitochondria and lysosomes. Separation of lysosomes from mitochondria was achieved by using a non-lytic detergent injected into the fish 3 d prior to removal of the livers; it was found that ²³⁷Pu was associated with the lysosomal fraction. In this respect, the metabolism of plutonium of the plaice resembles that of the rat.