• Osborn Dalby posted an update 6 months, 4 weeks ago

    Location of river-groundwater exchange zones and biodiversity hotspot is essential for a river management plan, especially for Mediterranean karstic rivers. This location is often difficult and time-consuming when long river sectors are considered. We studied a 13 km-long sector of the Cèze River (Southern France) located in a karstic canyon. We compared five indicators of river-groundwater exchanges longitudinal profiles of temperature, electrical conductivity and 222Rn concentrations in the surface water of the river, chemical characteristics of the hyporheic water and hyporheic biodiversity. Upwelling zones occurred downstream of geomorphological heterogeneities (here at the tail of gravel bars). Surface water chemistry, especially electrical conductivity and 222Rn concentrations, clearly traces large scale gaining sections, which were not associated to valley narrowing but with lateral springs, suggesting a crucial role of the geological structuration of the karstic plateau of Méjanne-le-Clap. Hyporheic water chemistry fits with the large-scale hydrological pattern, but with a high variability corresponding to local heterogeneities. The stygobite fauna (obligate groundwater organisms) and benthic EPTC (Ephemeroptera, Plecoptera, Trichoptera and Coleoptera) occurred preferentially in the gaining sections fed by groundwater, likely because of oligotrophic water and cooler temperature. The spatial distribution of river-groundwater exchange zone and hyporheic biodiversity may be thus predicted using changes in surface water chemistry, especially for electrical conductivity and 222Rn concentrations.The neonicotinoid insecticide acetamiprid is applied widely for pest control in agriculture production. However, little is known about the effects of acetamiprid on the foraging behavior of nontarget pollinators. This study aims to investigate effects of sublethal acetamiprid doses on lifespans and foraging behaviors of honey bees (Apis mellifera L.) under natural swarm conditions. Newly emerged worker bees of each treatment received a drop of 1.5 μL acetamiprid solution (containing 0, 0.5, 1, and 2 μg/bee acetamiprid, diluted by water) on the thorax respectively. Bees from 2-day-old to deadline were monitored on foraging behaviors involving the age of bee for first foraging flights, rotating day-off status and the number of foraging flights using the radio frequency identification (RFID) system. We found that acetamiprid at 2 μg/bee significantly reduced the lifespan, induced precocious foraging activity, influenced the rotating day-off status and decreased foraging flights of worker bees. The abnormal behaviors of worker bees may be associated with a decline in lifespan. This work may provide a new perspective into the neonicotinoids that accelerate the colony failure.Europe’s largest copper ore tailings impoundment has been considered a potential source of risk for human health, thus leading to the elimination of agricultural production in the surrounding area and its subsequent afforestation. The aim of this study was to analyse the level, spatial distribution and temporal changes in soil and edible plant contamination with trace elements around the impoundment, taking into account the local soil properties. The mean concentrations of Zn, Pb and As (31.5, 19.3 and 3.9 mg kg-1, respectively) were found to be higher than median values in soils of Poland, but they do not indicate soil pollution or enrichment when assessed using the relative geochemical index (Igeo) and enrichment factor (EF). The Cu concentration (mean 25.6 mg kg-1) was significantly higher than the median value for Polish soils, indicating moderate to high pollution/enrichment. A relationship between Cu concentration in topsoil and distance to the impoundment, in particular in its eastern forefield, indicates that this landfill site may be considered the source of soil contamination with Cu. However, both the mean and maximum concentrations of all elements under study, including Cu, were below the legal intervention levels. Long-term topsoil monitoring, although high data variability on permanent plots, has documented stable concentration or slow decrease of element concentration over a period 1995-2016. Cu and Zn concentrations in vegetables from home gardens do not differ from typical values in commercially available products, whereas higher than typical concentrations of Pb and As may result from other local sources of contamination. Low level and stable soil and plant contamination with trace metals justifies continuation of crop production and no need for the further conversion of arable lands into forests. The relatively little negative impact of the tailings impoundment, despite its large dimensions, results probably from implemented effective anti-emission measures.Perfluorooctane sulfonate (PFOS) is a synthetic substance with a great number of applications. However, it persists in the environment and is potentially toxic to organisms. Although China has been the main manufacturer and consumer for PFOS, the national pollution level and potential risk of this chemical are yet to be determined. This study aimed to provide an overview of PFOS contamination in surface and drinking water across China and to assess the potential ecological and health risks. Available monitoring data for PFOS in surface and drinking water were evaluated. PFOS was found to be ubiquitous in China, but the overall level of contamination was low compared with that in other countries. The southeast coastal area of China, with major PFOS-related companies, was characterized by relatively high PFOS exposure concentrations. learn more The most sensitive effects was screened and applied to assess the ecological risk using the joint probability curve method. The probability of exceeding the growth and development toxicity for 5% of aquatic species was 0.65% in Chinese surface waters, while the highest probability of 0.90% was in Tai Lake in east China. Considering the average daily dose (ADD) for the Chinese population, the health risk posed by PFOS through drinking water ranged from 1.31 × 10-4 to 13.91. Besides the relatively high health risk existed in east China, most health risks in China were acceptable.

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