Chromium accumulation,transport and toxicity in plants∗

The predominant pathway for human exposure to chromium in non‐occupationally exposed individuals is via food with a daily intake of around 30–100 μgd^–1, with vegetables providing a major contribution. Unlike reports of chromium essentiality to man and animals, plants appear not to require chromium in spite of some early reports of a stimulatory growth effect.

Most reports on chromium in plants have been concerned with their growth on soils amended with sewage sludge, pF‐ash, tannery waste, or on ultra basic soils, which contain extreme concentrations of the element. Experimental studies with plants grown in hydroponic solution have often been undertaken at unrealistically high concentrations to examine the uptake of chromium in various forms, either as CrIII or CrVI at different pHs. In most cases, reports on chromium in plants deal with element concentrations and plant/soil relationships rather than detailed biochemical and physiological processes.

In general, chromium is largely retained in the roots of plants, although the oxidation state of chromium, pH, presence of humates and fulvates and plant species, affect plant uptake and transport. Leaves usually contain higher concentrations than grains. The uptake of CrIII is largely a passive process, whereas CrVI uptake is a metabolically mediated process via the sulphate pathway and is thus readily transported around the plant. The presence of a compound similar to trioxalate CrIII has been recorded while little chromium has been reported to be associated with cell organelles or soluble proteins.     

Integrating archaeology and ancient DNA analysis to address invasive species colonization in the Gulf of Alaska

The intentional and unintentional movement of plants and animals by humans has transformed ecosystems and landscapes globally. Assessing when and how a species was introduced are central to managing these transformed landscapes, particularly in island environments. In the Gulf of Alaska, there is considerable interest in the history of mammal introductions and rehabilitating Gulf of Alaska island environments by eradicating mammals classified as invasive species. The Arctic ground squirrel (Urocitellus parryii) is of concern because it affects vegetation and seabirds on Gulf of Alaska islands. This animal is assumed to have been introduced by historic settlers; however, ground squirrel remains in the prehistoric archaeological record of Chirikof Island, Alaska, challenge this timeline and suggest they colonized the islands long ago. We used 3 lines of evidence to address this problem: direct radiocarbon dating of archaeological squirrel remains; evidence of prehistoric human use of squirrels; and ancient DNA analysis of dated squirrel remains. Chirikof squirrels dated to at least 2000 years ago, and cut marks on squirrel bones suggested prehistoric use by people. Ancient squirrels also shared a mitochondrial haplotype with modern Chirikof squirrels. These results suggest that squirrels have been on Chirikof longer than previously assumed and that the current population of squirrels is closely related to the ancient population. Thus, it appears ground squirrels are not a recent, human‐mediated introduction and may have colonized the island via a natural dispersal event or an ancient human translocation.     

Gastrointestinal Bacterial Transmission among Humans,Mountain Gorillas,and Livestock in Bwindi Impenetrable National Park,Uganda

Abstract: Habitat overlap can increase the risks of anthroponotic and zoonotic pathogen transmission between humans, livestock, and wild apes. We collected Escherichia coli bacteria from humans, livestock, and mountain gorillas (Gorilla gorilla beringei) in Bwindi Impenetrable National Park, Uganda, from May to August 2005 to examine whether habitat overlap influences rates and patterns of pathogen transmission between humans and apes and whether livestock might facilitate transmission. We genotyped 496 E. coli isolates with repetitive extragenic palindromic polymerase chain reaction fingerprinting and measured susceptibility to 11 antibiotics with the disc‐diffusion method. We conducted population genetic analyses to examine genetic differences among populations of bacteria from different hosts and locations. Gorilla populations that overlapped in their use of habitat at high rates with people and livestock harbored E. coli that were genetically similar to E. coli from those people and livestock, whereas E. coli from gorillas that did not overlap in their use of habitats with people and livestock were more distantly related to human or livestock bacteria. Thirty‐five percent of isolates from humans, 27% of isolates from livestock, and 17% of isolates from gorillas were clinically resistant to at least one antibiotic used by local people, and the proportion of individual gorillas harboring resistant isolates declined across populations in proportion to decreasing degrees of habitat overlap with humans. These patterns of genetic similarity and antibiotic resistance among E. coli from populations of apes, humans, and livestock indicate that habitat overlap between species affects the dynamics of gastrointestinal bacterial transmission, perhaps through domestic animal intermediates and the physical environment. Limiting such transmission would benefit human and domestic animal health and ape conservation.     

Variable transfer of detoxified metals from snails to hermit crabs in marine food chains

In any polluted marine environment, different invertebrate species contain markedly different concentrations of heavy metals. Primary producers take metals from seawater, but animals take additional metals from diets of animals, plants and detritus. Metals in a dietary organism of a food chain have varying reactivities and they follow different biochemical pathways. Excess metals are bound by ligands to form insoluble compounds within cytological compartments. These metabolic systems prevent the disruption of normal biochemical reactions by metals. The present work on Mediterranean invertebrates, initiated in Greece in 1993, used digestive glands from three species of marine snail,Monodonta mutabilis (Philippi),Cerithium vulgatum (Bruguière), andMurex trunculus (Linnaeus) as prey tissue, and hermit crabsClibanarius erythropus (Latreille) as predators; the digestive glands and faecal pellets from all animals were analysed by atomic absorption spectroscopy and x-ray microanalysis. Most metals detoxified by the snails are unavailable to the crabs and they pass straight through the gut and appear in the faecal pellets. This applies to significant proportions of the manganese, nickel, copper, zinc and silver which are bound electrostatically to phosphate or covalently to sulphur within membrane-bound intracellular compartments. Cadmium and chromium are transferred to the crabs. In digestive glands of snails, cadmium is bound to soluble highsulphur protein in the cytosol; the cytology of chromium in these animals is not known.     

Dental fluorosis linked to degassing of Ambrym volcano, Vanuatu: a novel exposure pathway

Ambrym in Vanuatu is a persistently degassing island volcano whose inhabitants harvest rainwater for their potable water needs. The findings from this study indicate that dental fluorosis is prevalent in the population due to fluoride contamination of rainwater by the volcanic plume. A dental survey was undertaken of 835 children aged 6–18 years using the Dean’s Index of Fluorosis. Prevalence of dental fluorosis was found to be 96% in the target area of West Ambrym, 71% in North Ambrym, and 61% in Southeast Ambrym. This spatial distribution appears to reflect the prevailing winds and rainfall patterns on the island. Severe cases were predominantly in West Ambrym, the most arid part of the island, and the most commonly affected by the volcanic plume. Over 50 km downwind, on a portion of Malakula Island, the dental fluorosis prevalence was 85%, with 36% prevalence on Tongoa Island, an area rarely affected by volcanic emissions. Drinking water samples from West Ambrym contained fluoride levels from 0.7 to 9.5 ppm F (average 4.2 ppm F, n = 158) with 99% exceeding the recommended concentration of 1.0 ppm F. The pathway of fluoride-enriched rainwater impacting upon human health as identified in this study has not previously been recognised in the aetiology of fluorosis. This is an important consideration for populations in the vicinity of degassing volcanoes, particularly where rainwater comprises the primary potable water supply for humans or animals.     

Comments on the Carcinogenicity and Mutagenicity of metals and their compounds†

The carcinogenicity of metals has received extensive study, both epidemiologically and in the laboratory. These have included case reports of occasional human occurrence or clusters of cancer cases as well as extensive epidemiologic studies; in addition, there has been significant laboratory research on the whole animals and in vitro systems. This body of information will be examined selectively.

I will not in this paper attempt a comprehensive review of the mutagenicity and carcinogenicity of metals and their compounds. Rather, I will attempt to set forth some historical perspectives, and to comment on some current gaps and needs.

Other papers in this workshop have presented thorough and very current reviews of most of the topics briefly noted in this presentation and do not require repetition here.

The cancer issue has been studied and reported on far more extensively than that relating to heritable mutations. There has been in recent years increasing interest in the use of short term tests for mutagenicity and cell transformation. These, however, are primarily with respect to their relationship to cancer production rather than to germ cell injury. Interest in cancer from metal compounds goes back a long time; in fact, one of the earliest reports was on the carcinogenicity of arsenic not many decades after the pioneering report of Sir Perceval Pott on cancer in chimney sweeps. Since then cancer has been definitely associated in humans with chromium compounds, nickel, and with less assurance but probably definitely with beryllium and cadmium. The confirmation of these findings in laboratory animals has been uneven. In the case of arsenic, for example, there has been only limited success in the production of cancer in laboratory animals with arsenic.

Many other metals have been found in laboratory studies to produce cancer, although with most of these, evidence of production of cancer in humans is either absent or extremely uncertain.

The extensive body of recent information relating to the testing of metals with a variety of short term tests will be briefly reviewed.     

Spatial analysis of chromium in southwestern part of Iran: probabilistic health risk and multivariate global sensitivity analysis

This study was concerned with chromium as a potential carcinogenic contaminant in 64 wells located in five aquifers, southwest of Iran. A probabilistic health risk assessment indicated a high risk to the local residents including adults and children in the study area. A sequential sensitivity analysis and a novel approach known as multivariate global sensitivity analysis using both principal component analysis and B-spline were applied to investigate the behavior of health risk model along time considering four independent input parameters in the risk equation. In this context, based on the results of sensitivity analysis, concentration of chromium in drinking water (C_w) and body weight (W) were the most influential parameters. Random forest (RF) was used as a variable selection method to choose the most influential parameters for the prediction of chromium. Five parameters, among 13 water quality variables, including phosphate, nitrate, fluoride, manganese and iron were selected by RF as the most important parameters for spatial prediction. Hybrid methods of RF and ordinary kriging (RFOK) and RF and inverse distance weighting (RFIDW) were then applied for spatial prediction of Cr using the secondary variables. The RFOK and RFIDW were more efficient than that of ordinary kriging (OK) with respect to a cross-validation algorithm. For instance, in terms of relative root mean squared error, the performance of OK was improved from 31.72 to 23.21 and 23.61 for RFOK and RFIDW, respectively.

     

Statistical aspects of inhalation toxicokinetics

The statistical analysis of dynamic processes is a useful tool to learn how environmental and ecological systems work and how they respond to disturbances. In the context of human risk assessment of potentially harmful chemicals, many complex dynamic processes in terms of kinetics have to be taken into account. Thorough research of direct influence of chemicals to humans depends on investigations with animalsin vivo andin vitro. However, when animals serve as models of human systems, one critical step is the extrapolation from the risk observed in the experimental animals to the risk associated with the human organism. To extrapolate the observed risk in this case, the detailed knowledge of the relevant kinetic processes as well as their differences between species is fundamental. On the other hand experimental tools for these processes are quite restrictive. Based on simple experimental designs a statistical method is proposed for characterizing such kinetic processes using the well-known compartmental analysis tool and non-linear regression. The methodology is then exemplified by non-invasive toxicokinetic inhalation experiments with rats.     

钴在土壤和植物系统中的迁移转化行为及其毒性

钴是人与动植物必需的微量元素,但土壤环境中过量的钴可通过土壤-粮食/蔬菜-人与动物等途径进入人体或动植物体内,对其产生危害,因此有必要了解土壤中钴的含量,应该将钴纳入必须检测与掌控的指标。然而,我国目前对于土壤中钴的含量却没有一个明确的评价体系,致使无法有效地对土壤中钴的含量进行评价和管控,从而给土壤以及人和动植物的健康都带来一定的风险。本文通过整理近20多年的国内外文献资料,综述了钴的特点、应用、形态、含量、毒性、评估方法,指出了现行对土壤中钴污染风险评估体系中存在的问题,并提出了今后的研究方向。     

Toward an integrative molecular approach to wildlife disease

Pathogens pose serious threats to human health, agricultural investment, and biodiversity conservation through the emergence of zoonoses, spillover to domestic livestock, and epizootic outbreaks. As such, wildlife managers are often tasked with mitigating the negative effects of disease. Yet, parasites form a major component of biodiversity that often persist. This is due to logistical challenges of implementing management strategies and to insufficient understanding of host–parasite dynamics. We advocate for an inclusive understanding of molecular diversity in driving parasite infection and variable host disease states in wildlife systems. More specifically, we examine the roles of genetic, epigenetic, and commensal microbial variation in disease pathogenesis. These include mechanisms underlying parasite virulence and host resistance and tolerance, and the development, regulation, and parasite subversion of immune pathways, among other processes. Case studies of devil facial tumor disease in Tasmanian devils (Sarcophilus harrisii) and chytridiomycosis in globally distributed amphibians exemplify the broad range of questions that can be addressed by examining different facets of molecular diversity. For particularly complex systems, integrative molecular analyses present a promising frontier that can provide critical insights necessary to elucidate disease dynamics operating across scales. These insights enable more accurate risk assessment, reconstruction of transmission pathways, discernment of optimal intervention strategies, and development of more effective and ecologically sound treatments that minimize damage to the host population and environment. Such measures are crucial when mitigating threats posed by wildlife disease to humans, domestic animals, and species of conservation concern.     

A critical exploration of blood and environmental chromium concentration among oral cancer patients in an oral cancer prevalent area of Taiwan

The growing incidence of oral cancer (OC) in Taiwan has become a crucial public health concern. In particular, Changhua, a county in central Taiwan, carries persistently high OC incidence rate, with an alarmingly high male/female ratio of OC incidence. Previous epidemiological studies had found that the incidence is spatially correlated with the level of soil content to certain heavy metals in the central Taiwan area. Soil and the human body both intake environmental heavy metals, which can be absorbed through various ways. The soil metal concentration is an index of possible environmental exposure to heavy metal, and the blood metal concentration somewhat reflects the level of the exposure on the human body. Metallic carcinogen is likely to generate free radicals and play a role in many cancers, and many studies had reported that environmental exposure to heavy metals is an important risk factor for developing cancer. Studies on animals showed that chronic intake of chromium (Cr) could induce OC. This study aims to explore the association between the Cr concentration in the farm soil and in the blood of OC patients. We recruited 79 OC patients from Changhua County, with their lifestyle being adjusted in regression analysis. The results showed that the Cr concentration in the blood of OC patients is significantly higher than the background value, and is positively associated with the Cr concentration in the soil surrounding their residence (p-value < 0.023). Because Changhua County is only with moderate prevalence of the known OC habitual risk factors, an environmental factor related to heavy metal Cr exposure is suspected. Future investigations may verify the causal relation between Cr and OC.     

Cetacean DNA fingerprinting using the oligonucleotide (GGAT)4 as a probe

Since the discovery in 1985 of hypervariable minisatellite regions in human DNA, DNA fingerprinting has been widely used in animals and plants. Although many different probes have been developed recently, most investigators still use 33.15 and 33.6 human polycore minisatellites for hybridization studies of cetaceans. This animal order shows considerably less variability than humans, and thus some limitations have to be taken into account when using these probes. The present study demonstrates that the short repetitive tandem oligonucleotide (GGAT)₄ hybridizes with cetacean (Globicephala macrorhynchus andGrampus griseus) DNA, yielding individual-specific patterns of bands or DNA fingerprints. Freedom of design and shorter hybridization times of oligonucleotides allow an increase in the number of usable probes used, helping to overcome some of the problems found when only human polycore minisatellites are used.     

Intraspecific Chromosome Number Variation: a Neglected Threat to the Conservation of Rare Plants

Abstract: The effectiveness of rare plant conservation will increase when life history, demographic, and genetic data are considered simultaneously. Inbreeding depression is a widely recognized genetic concern in rare plant conservation, and the mixing of genetically diverse populations in restoration efforts is a common remedy. Nevertheless, if populations with unrecognized intraspecific chromosome variation are crossed, progeny fitness losses will range from partial to complete sterility, and reintroductions and population augmentation of rare plants may fail. To assess the current state of cytological knowledge of threatened and endangered plants in the continental United States, we searched available resources for chromosome counts. We also reviewed recovery plans to discern whether recovery criteria potentially place listed species at risk by requiring reintroductions or population augmentation in the absence of cytological information. Over half the plants lacked a chromosome count, and when a taxon did have a count it generally originated from a sampling intensity too limited to detect intraspecific chromosome variation. Despite limited past cytological sampling, we found 11 plants with documented intraspecific cytological variation, while 8 others were ambiguous for intraspecific chromosome variation. Nevertheless, only one recovery plan addressed the chromosome differences. Inadequate within‐species cytological characterization, incomplete sampling among listed taxa, and the prevalence of interspecific and intraspecific chromosome variation in listed genera, suggests that other rare plants are likely to have intraspecific chromosome variation. Nearly 90% of all recovery plans called for reintroductions or population augmentation as part of recovery criteria despite the dearth of cytological knowledge. We recommend screening rare plants for intraspecific chromosome variation before reintroductions or population augmentation projects are undertaken to safeguard against inadvertent mixtures of incompatible cytotypes.     

Effects of Trophy Hunting on Lion and Leopard Populations in Tanzania

Abstract: Tanzania holds most of the remaining large populations of African lions (Panthera leo) and has extensive areas of leopard habitat (Panthera pardus), and both species are subjected to sizable harvests by sport hunters. As a first step toward establishing sustainable management strategies, we analyzed harvest trends for lions and leopards across Tanzania's 300,000 km² of hunting blocks. We summarize lion population trends in protected areas where lion abundance has been directly measured and data on the frequency of lion attacks on humans in high‐conflict agricultural areas. We place these findings in context of the rapidly growing human population in rural Tanzania and the concomitant effects of habitat loss, human‐wildlife conflict, and cultural practices. Lion harvests declined by 50% across Tanzania between 1996 and 2008, and hunting areas with the highest initial harvests suffered the steepest declines. Although each part of the country is subject to some form of anthropogenic impact from local people, the intensity of trophy hunting was the only significant factor in a statistical analysis of lion harvest trends. Although leopard harvests were more stable, regions outside the Selous Game Reserve with the highest initial leopard harvests again showed the steepest declines. Our quantitative analyses suggest that annual hunting quotas be limited to 0.5 lions and 1.0 leopard/1000 km² of hunting area, except hunting blocks in the Selous Game Reserve, where harvests should be limited to 1.0 lion and 3.0 leopards/1000 km².     

Influence of uraniferous black shales on cadmium,molybdenum and selenium in soils and crop plants in the Deog-Pyoun-g area of Korea

The influence of naturally occurring uraniferous black shales on cadmium, molybdenum and selenium concentrations in soils and plants is examined. The possible implications of element concentrations to animal and human health are considered for the Deog-Pyoung area. Geochemical surveys have been undertaken within 13 river tributary valleys in the area underlain by uraniferous black shales and black slates or grey chlorite schists. Sampling of rocks, soils and plants has been carried out along transect lines within each valley. Samples were analysed for trace elements by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) and for uranium by Neutron Activation Analysis (NAA). Soil pH, cation exchange capacity, loss on ignition and particle size distribution have been measured for selected samples. Average trace element concentrations of the Okchon uraniferous black shales were 6.3 μg g⁻¹ Cd, 136 μg g⁻¹ Mo and 8.6 μg g⁻¹ Se. Soils derived from these rocks tend to reflect their extreme geochemical composition. Trace element concentrations in alluvial soils derived in part from these black shales averaged 1.2 μg g⁻¹ Cd, 20 μg g⁻¹ Mo and 1.5 μg g⁻¹ Se. Trace element concentrations in plants were found to be influenced by those of soils. Cadmium accumulated in tobacco leaves up to 46 μg g⁻¹ (D.M.) and leafy plants such as lettuce contain up to 0.5 μg g⁻¹ Se (D.M.). In addition to total concentrations in soils, soil pH is a major factor influencing uptake of Mo into crop plants and soil texture for Se. Concentrations of trace elements in plants also varied between plant species. The relative concentrations of Cd were found to vary in the order tobacco > lettuce > red pepper > rice grain. Elevated concentrations of Cd in crop plants and in tobacco may possibly have deleterious effects on human health in this area. The low Cu:Mo ratio in rice stalk of 2.65:1 may be associated with disturbed Cu metabolism in ruminant animals which regularly consume this material.     

贵州万山汞矿地区耐汞野生植物研究

在贵州万山地区废弃汞矿堆和矿山附近,受长期高剂量汞暴露的影响经过的自然选择,该地区出现了一些能耐受汞毒性的生态型植物。对汞耐受及汞富集植物的筛选对于汞污染土壤的植物修复具有一定的现实意义。通过对万山梅子溪地区汞污染土壤及汞耐受植物采样调查发现,该区域采样土壤中汞的含量均在50 mg·kg-1以上,达到重度汞污染水平。对该地区野生植物的采样分析发现,蔷薇科植物悬钩子不仅数量较多,单株植物生物量较大,表现出很强的耐汞毒性的能力,而且植株内可以很大程度地富集汞,在其植株中汞的含量可达20 mg·kg-1左右,属于汞富集植物,另外发现野蒿对汞也具有较强的富集能力,其植株中汞的含量可达10 mg·kg-1以上。该类型植物的发现将为植物的汞耐受以及汞富集机理研究提供新的素材,为汞污染土壤的植物修复技术提供新的植物类型,也为进一步开发汞污染土壤处理技术提供了一种可能。     

A brief and critical review on hydrofluorosis in diverse species of domestic animals in India

India is one of the fluoride-endemic countries where the maximum numbers of ground or drinking water sources are naturally fluoridated. In India, a total of 23, out of 36 states and union territories have drinking water contaminated with fluoride in varying concentration. In the present scenario, especially in rural India, besides the surface waters (perennial ponds, dams, rivers, etc.), bore wells and hand pumps are the principal drinking water sources for domestic animals such as cattle (Bos taurus), water buffaloes (Bubalus bubalis), sheep (Ovis aries), goats (Capra hircus), horses (Equus caballus), donkeys (Equus asinus) and dromedary camels (Camelus dromedarius). Out of 23 states, 17 states, namely Andhra Pradesh, Assam, Bihar, Chhattisgarh, Gujarat, Haryana, Jharkhand, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Odisha (Orissa), Punjab, Rajasthan, Telangana, Uttar Pradesh and West Bengal, have fluoride beyond the maximum permissible limit of 1.0 or 1.5 ppm in drinking water. This situation is a great concern for the animal health because fluoride is a slow toxicant and causes chronic diverse serious health hazards or toxic effects. Despite the fact that domestic animals are the basic income sources in rural areas and possess a significant contributory role not only in the agriculture sector but also in the strengthening of economy as well as in sustainable development of the country, research work on chronic fluoride intoxication (hydrofluorosis) due to drinking of fluoridated water in domestic animals rearing in various fluoride-endemic states is not enough as compared to work done in humans. However, some interesting and excellent research works conducted on different aspects of hydrofluorosis in domesticated animals rearing in different states are briefly and critically reviewed in the present communication. Author believes that this review paper not only will be more useful for researchers to do some more advance research work on fluoride-induced toxicosis in different species of animals but will also be helpful in the making of health policy for domestic animals at state and national level for the mitigation of hydrofluorosis in India.     

Glucosinolates and other metabolites in the leaves of <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> from natural populations and their effects on a generalist and a specialist herbivore

Because many secondary metabolites in plants act as defense against herbivores it has been postulated that these compounds have evolved under selective pressure by insect herbivores. One explanation for the within-species variation in metabolite patterns in a particular species is that different populations are under selection by different herbivores. We tested this hypothesis, using Arabidopsis thaliana plants that originated from dune and inland areas. We analyzed Arabidopsis thaliana leaves using NMR spectroscopy and multivariate data analysis. Major differences in chemical composition were found in water-methanol fractions and were due to higher concentrations of sinigrin and fumaric acid in dune plants. Inland plants showed lower levels of glucose. Quantitative analysis of glucosinolates was performed with HPLC. Individual plants and populations demonstrated differences in glucosinolate composition and concentration. In growth chamber experiments, the generalist herbivore, Spodoptera exigua grew significantly better on the inland plants, while the specialist herbivore Plutella xylostella performed equally well on plants of both origins. Aliphatic glucosinolate as well as total glucosinolate concentrations negatively correlated with larval mass of Spodoptera exigua. No significant correlations, however, were found between larval mass of Plutella xylostella and glucosinolates in the leaves. A specialist and a generalist herbivore were responding differently to plant secondary chemistry, as was also found in several other studies. This is an important indication that differences in glucosinolate concentrations among populations may result from differential selection by different guilds of herbivores.     

Influence of Care of Domestic Carnivores on Their Predation on Vertebrates

Abstract: Domestic dogs (Canis familiaris) and cats (Felis catus) are the most abundant mammalian carnivores worldwide. Given that domestic carnivores rely on human‐provided food, their densities are usually independent of prey densities. Nevertheless, underfed pets may need to hunt to meet their energetic and nutritional requirements. We explored the effects of different levels of care (provision of food) of dogs and cats on their predation rates on wild vertebrates in 2 areas of southern Chile. We interviewed cat and dog owners and analyzed prey remains in scats of pets to examine how domestic dogs and cats were managed and to gather information on the wild vertebrates killed and harassed by pets. We used logistic regression to examine the association between pet care and the frequency of wild vertebrate remains in scats. The probability of a dog preying on vertebrates was higher for poorly fed than for adequately fed dogs (odds ratio = 3.7) and for poorly fed than for adequately fed cats (odds ratio = 4.7). Domestic dogs and cats preyed on most endemic and threatened mammals present in the study sites. Our results provide support for the hypothesis that the less care domestic animals receive from owners the higher the probability those animals will prey on wild vertebrates.     

Relationships between distributions of longevous population and trace elements in the agricultural ecosystem of Rugao County,Jiangsu, China

Soil, plant, and water, as well as trace elements they contain, can influence human health through the food chain. A survey was conducted on distributions of trace elements in soils, plants, and drinking water in Rugao County, Jiangsu Province, China, an agricultural area with a high level of centenarians and nonagenarians. The ratio of people over 90 years old per 100,000 inhabitants (90-rate) based on village (about 4,000 residents in 4 km²) was correlated with trace elements in soil, drinking water, and rice by means of correlation analysis and/or principal component analysis. Although the average 90-rate in the whole area was as high as 277, the rates were not uniform across the entire region. The 90-rate in the area of loamy and strongly-developed Anthrosols and Cambosols was about 330, significantly higher than the 255 in the areas of sandy and strongly-developed Cambosols and of clayey and weakly-developed Cambosols. The concentrations of available Se, B, Ni, and Mo in soils of the area with the high 90-rate were markedly greater than those in the area with the low 90-rate. This was demonstrated by highly positive correlations between the 90-rate and available Se (r = 0.33), B (r = 0.21), Ni (r = 0.17) and Mo (r = 0.17) at the p < 0.01 level and high loadings of available Se (0.851), B (0.535), Ni (0.594) and Mo (0.394) in the longevous factor. Similar relationships between the available elements in soils and elements in water and rice were found. These results suggest that: (1) the available forms of elements in soil were more crucial to elemental bio-availability in the ecosystem and human health than total elements in soil; and (2) the element association above might have affected the 90-rate positively and could be an important environmental geochemical factor influencing the longevity of humans.