Geochemical and man-made sources of lead and human health.

Multiple sources of Pb have been identified for human populations, but there is little agreement as to their relative significance. Marked regional geochemical anomalies in the distribution of Pb have been identified and, in one district, their impact on rural communities has been determined. The absorption of ingested Pb is modified by its chemical and physical form, by interaction with dietary minerals and lipids and by the nutritional status of the individual. Studies on children of various ethnic groups have demonstrated differences in soft tissue Pb burdens which may in part have a nutritional basis. Erythrocyte protoporphyrin determinations suggest that metabolic disturbances attributable to Pb may occur at soft tissue burdens previously regarded as acceptable. The problem of defining an adverse health effect in relation to environmental sources of Pb is discussed.     

浙江省玄武岩母质发育的土壤的地球化学特征及其资源生态学意义

研究结果表明,发育于玄武岩母质的土壤具独特的地球化学优势,其生态系统能量转换率为其它母质发育的土壤的1.39—3.46倍,钾素供应和土壤结构并非尤其不良,是一种被长期忽视的重要土壤资源。但是,不同地球化学演化阶段形成的土壤,能量转换率相差可达77.86％,其中弱富铁铝化土壤具更大的开发利用潜力。土壤氧化铁富集与转化特征,由不同地质层位和不同玄武岩类型导致的土壤地球化学变异,对多种农业生态学过程有特殊影响。因此认为,从地球化学角度研究土壤资源生态学可望是有效的途径之一。     

森林生态学的任务及面临的发展问题

森林生态学是生态学的一个分支学科 ,也是林学的一个分支学科 .2 0世纪 90年代 ,国家自然科学基金委员会曾先后组织我国许多科学家研究和编写出版了一系列自然学科发展战略调研报告 ,其中包括了“生态学发展战略”和“林学发展战略” ,森林生态学为它们的重要分支学科 .“生态学发展战略”由已故的马世骏先生主持 ,由中国生态学会组织科学家们完成 .它相当全面地、系统地和深刻地总结了生态学发展历史 ,提出了发展预测和今后的重要研究领域 .它正确地指出 ,当前的生态学已由经典的生态学任务 ,即研究阐明生物及其环境的相互关系的科学 ,发展…     

Geochemical surveys in the United States in relation to health.

Geochemical surveys in relation to health may be classified as having one, two or three dimensions. One-dimensional surveys examine relations between concentrations of elements such as Pb in soils and other media and burdens of the same elements in humans, at a given time. The spatial distributions of element concentrations are not investigated. The primary objective of two-dimensional surveys is to map the distributions of element concentrations, commonly according to stratified random sampling designs based on either conceptual landscape units or artificial sampling strata, but systematic sampling intervals have also been used. Political units have defined sample areas that coincide with the units used to accumulate epidemiological data. Element concentrations affected by point sources have also been mapped. Background values, location of natural or technological anomalies and the geographic scale of variation for several elements often are determined. Three-dimensional surveys result when two-dimensional surveys are repeated to detect environmental changes.     

Occupational health problems among migrant and seasonal farm workers.

Migrant and seasonal farm workers are one of the most underserved and understudied populations in the United States. The total US population of such farm workers has been estimated at 5 million, of whom about 20% live or work in California. Farm workers perform strenuous tasks and are exposed to a wide variety of occupational risks and hazards. Low socioeconomic status and poor access to health care also contribute to existing health problems in this population. Potential farm work-related health problems include accidents, pesticide-related illnesses, musculoskeletal and soft-tissue disorders, dermatitis, noninfectious respiratory conditions, reproductive health problems, health problems of children of farm workers, climate-caused illnesses, communicable diseases, bladder and kidney disorders, and eye and ear problems. Few epidemiologic studies exist of these occupational health problems. No comprehensive epidemiologic studies have assessed the magnitude of occupational health problems among migrant and seasonal farm workers and their dependents. Although the migratory nature of this population makes long-term studies difficult, the development of standardized data collection instruments for health consequences and scientific assessment of farm work exposures and working conditions are vital to characterize and reduce the occupational health risks in farm workers.     

Geochemistry and ecology.

This paper discusses the importance of geochemistry as a determining factor in the evolutionary development of plant assemblages. Three contrasting examples of geochemical systems are described and considered in relation to their effects on plant growth and development. Soils derived from serpentines may contain elevated and sometimes toxic concentrations of Cr and Ni depending on mineral composition and weathering processes. These conditions have so modified plant growth during the past few million years that specialized floras have evolved on particular sites. Extensive areas throughout the world contain high concentrations of Se but these have not always been accompanied by the development of specific floras. Geochemistry can help explain how Se-specific floras have developed in several Western States of America but are absent on Se-rich sites in the Republic of Ireland. Pronounced effects of As toxicity in plants have been recognized in recent years especially from areas polluted by smelter waste and fallout. As-tolerant genotypes have developed during the past 100 years and may still be evolving at the present time.     

Microbial ecology of the intestines in health and in pathology

Bifidoflora constitute 85--95 per cent of the large intestine microbiocenosis in children under 1 year of age. Bacteroides are not specific of children under 6 months of age. Lactobacilli, lactic acid streptococci, colon bacilli, enterococci and staphylococci (saprophytic, epidermal) constitute not more than 15 per cent. The predominating group peculiar of eubiosis in adults includes bifidobacteria and bacteroides. Changes in human autoflora are often induced by such factors as impaired ecology, stress, uncontrolled use of antibacterial drugs, radio- and chemotherapy, etc. Dysbacteriosis (first of all lower quantitative contents of bifidoflora) has an unfavourable effect on the intestine secretory function, absorption and certain indices of protein, lipid and mineral metabolism, vitamin synthesizing and fermentative functions and leads to disfunction of the gastrointestinal tract. It is a cause of persisting and relapsing infections in children and adults. High and optimal levels of bifidoflora in the intestine usually prevent the pathogenic action of pathogens. Lysozyme of digestive secretion and secretory immunity with immunoglobulin A prevalence also play an important role in the complicated mechanism of the protective barrier. The use of bacterial preparations such as bifidumbacterin, lactobacterin or bifilact for stabilization and recovery of high bifidoflora levels is indicated in all the cases with impaired microbiocenosis of the intestine.     

Nutritional ecology and diachronic trends in Paleolithic diet and health

Modern nutritional studies have found that diverse diets are linked to lower infant mortality rates and longer life expectancies in humans. This is primarily because humans require more than fifty essential nutrients for growth and cell maintenance and repair; most of these essential nutrients must come from outside food sources rather than being manufactured by the body itself; and a diversity of food types is required to consume the full suite of essential nutrients necessary for optimal human health. These principles and their related affects on human adaptations and demography are the hallmarks of a theoretical paradigm defined as nutritional ecology. This essay applies concepts derived from nutritional ecology to the study of human evolution. Principles of nutritional ecology are applied to the study of the Middle‐to‐Upper Paleolithic transition in order to broadly illustrate the interpretive ramifications of this approach. At any stage in human evolution, those hominid populations that chose to diversify their subsistence base may have had a selective advantage over competitors who restricted their diet principally to one food type, such as terrestrial mammals.     

Biomarkers of animal health: integrating nutritional ecology,endocrine ecophysiology,ecoimmunology, and geospatial ecology

Diverse biomarkers including stable isotope, hormonal, and ecoimmunological assays are powerful tools to assess animal condition. However, an integrative approach is necessary to provide the context essential to understanding how biomarkers reveal animal health in varied ecological conditions. A barrier to such integration is a general lack of awareness of how shared extraction methods from across fields can provide material from the same animal tissues for diverse biomarker assays. In addition, the use of shared methods for extracting differing tissue fractions can also provide biomarkers for how animal health varies across time. Specifically, no study has explicitly illustrated the depth and breadth of spacial and temporal information that can be derived from coupled biomarker assessments on two easily collected tissues: blood and feathers or hair. This study used integrated measures of glucocorticoids, stable isotopes, and parasite loads in the feathers and blood of fall‐migrating Northern saw‐whet owls (Aegolius acadicus) to illustrate the wealth of knowledge about animal health and ecology across both time and space. In feathers, we assayed deuterium (δD) isotope and corticosterone (CORT) profiles, while in blood we measured CORT and blood parasite levels. We found that while earlier migrating owls had elevated CORT levels relative to later migrating birds, there was also a disassociation between plasma and feather CORT, and blood parasite loads. These results demonstrate how these tissues integrate time periods from weeks to seasons and reflect energetic demands during differing life stages. Taken together, these findings illustrate the potential for integrating diverse biomarkers to assess interactions between environmental factors and animal health across varied time periods without the necessity of continually recapturing and tracking individuals. Combining biomarkers from diverse research fields into an integrated framework hold great promise for advancing our understanding of environmental effects on animal health.