Abstract:Heavy metal(loid)s and organic contaminants are two major groups of pollutants in soils. The fate and exposure of such pollutants in soil depends on their chemical properties, speciation, and soil properties. Soil properties and processes that control the toxicological aspects of pollutants include temperature, moisture, organic matter, mineral fractions, and microbial activities. These processes are vulnerable to climate change associated with global warming, including increased incidences of extreme rainfall, extended dry periods, soil erosion, and a rise in sea level. Here we explain evidence that relates to the effects of climate change-driven soil processes on the mobility, transport, and storage of pollutants in soil. The review found that changes in climate could increase human exposure to soil contaminants mainly due to processes involving soil organic carbon (SOC), surface runoff, redox state, and microbial community. However, uncertainties remain in relation to the extent of contaminant toxicity to human health, which is linked to global change drivers.Keywords: soil contaminants; soil process; climate changes; ecotoxicity of pollutants
Hydroxyapatite is not used as widely as would be expected for augmentation of facial shape given its proven qualities of safety, versatility, and long-term use. A possible reason for this lack of popularity may be the absence of conclusive data regarding the long-term maintenance of the augmented volume. To evaluate the long-term fate of porous hydroxyapatite granules used in augmentation of the facial skeleton, a prospective radiologic study was performed over a 2-year follow-up period using thin-slice CT scans.
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In contrast to the explosive increase of a population following biological invasion, natural dispersal, i.e., when a population disperses from its original range into a new range, is a passive process that is affected by resources, the environment, and other factors. Natural dispersal is also negatively impacted by genetic drift and the founder effect. Although the fates of naturally dispersed populations are unknown, they can adapt evolutionarily over time to the new environment. Can naturally dispersed populations evolve beneficial adaptive strategies to offset these negative effects to maintain their population in a stable state?
The expansion of a population from its original habitat to a new area forms the basis for the development of, and changes in, phylogeographic patterns and biological dispersal behavior. Natural dispersal usually takes a significant period of time, and stable or even differentiated populations might form. However, in other cases, the naturally dispersed population might gradually reduce and disappear in fluctuating ecosystems. This uncertainty has aroused the interest of researchers to explore the fate of naturally dispersed populations [1]. By contrast, the ecological effect of redispersal behavior after biological invasion is easier to determine and has become a research focus in both ethology and ecology. For example, Wang et al. (2018) revealed the taxonomic diversity indices of plant communities significantly decreased under moderate and heavy degree of Solidago canadensis invasion conditions [2]. In another research, the existing geographical distribution of invasive cane toads (Rhinella marina) which formed after the redispersal in Australia was consistent with the central marginal hypothesis predictions, that is, the genetic diversity of the marginal population was lower than that of the central population [3]. Biedrzycka et al. (2014) inferred invasion routes through the study of the existing genetic structure of species [4]. It has been proposed that biological invasion and natural dispersal are essentially the same [5], although we consider them to be very different. Most invasive populations result from human-mediated extra-range dispersal events or other factors and spread rapidly after invading the new area, forming a population with a stable genetic structure in a short time frame. By contrast, natural dispersal is usually achieved by the gradual spread of a population from its original to a new range, or through a suitable habitat corridor. The natural dispersal of a population is a complex process, which is affected by resource competition and environmental change, and the time between the occurrence of dispersal behavior to the formation of a new species distribution pattern is significant [6]. In addition, such dispersal provides a prerequisite for the evolution of adaptive traits (e.g. behavioral phenotypes). Different from the rapid expansion of population after the biological invasion, if the naturally dispersed population need to form a stable geographical pattern, it will inevitably experience genetic drift, the founder effect, inbreeding depression and many other evolutionary processes that may lead to population decline [7, 8]. Then, can the naturally dispersed population evolve adaptive strategies that offset these negative effects to maintain a stable or even differentiated population?
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Every day we fail to act is a day that we step a little closer towards a fate that none of us wants -- a fate that will resonate through generations in the damage done to humankind and life on earth. Our fate is in our hands. 2ff7e9595c
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