浅析环境监测QC/QA过程的采样环节

对环境监测布点采样中的QC/QA以及由采样引起的误差来源做了简要分析,并对监测采样过程中QC/QA的操作提出了一些设想。     

False-negative prenatal exclusion of Wiskott-Aldrich syndrome by measurement of fetal platelet count and size

The study of the fetal platelet count and size can, according to the literature, be used for the prenatal diagnosis of the Wiskott-Aldrich syndrome (WAS). So far, no affected fetuses have been identified by this method. All pregnancies in which this method had been applied to resulted, as correctly predicted, in the birth of normal children. Here we report on a familial case of WAS where the haematological parameters failed to reveal the affected second child. Hence we assume that the platelet count and size of platelets remain normal in fetuses with WAS to the gestational age of 22 weeks and cannot be used for prenatal diagnosis.     

Evaluation of Clostridium perfringens as a tracer of sewage contamination in sediments by two enumeration methods

A traditional method of enumerating Clostridium perfringens using membrane filtration (MF) as an indicator of fecal contamination was compared to recently developed rapid method using Rapid Fung Double Tube (RFDT) in an evaluation to characterize the extent of sewage contamination in sediments of the Great Lakes. Evaluation of these two methods included determining C. perfringens concentrations and recovery efficiencies from sewage, sewage-spiked sediments, and water (surface and bottom) and sediment samples collected from two Great Lakes. The RFDT method proved to be a superior method for identifying C. perfringens in lake sediments compared to MF, as it had higher recovery efficiency and was more rapid, reliable, simple, and effective. This study provides biological evidence of the long-term deposition and movement of sewage particulates in the Great Lakes environment and demonstrates the potential usefulness of C. perfringens as a tracer for sewage contamination using a reliable enumeration method.     

The cost of tolerance: sensitivity of stream benthic communities to UV-B and metals.

The ability to tolerate disturbance is a defense strategy that minimizes the effects of damage to fitness and is essential for sustainability of populations, communities, and ecosystems. Despite the apparent benefits of tolerance, there may be an associated cost that results in a deficiency of a system to respond to additional disturbances. Aquatic ecosystems are often exposed to a variety of natural and anthropogenic disturbances, and the effects of these compound perturbations are not well known. In this investigation, we examine whether tolerance to one stressor, metals, results in a cost of increased sensitivity to an additional stressor, ultraviolet-B (UV-B) radiation. Heavy metal pollution is recognized as a major environmental problem in Rocky Mountain streams. These high-elevation, typically clear streams may be at particular risk to elevated UV-B levels associated with reduced levels of ozone. Microcosm experiments were conducted using natural stream benthic communities collected from a reference site and a site with a long-term history of heavy-metal pollution. Direct and interactive effects of heavy metals and UV-B radiation on structural and functional characteristics of benthic communities were evaluated among four treatments: control, UV-B, metals, and metal and UV-B. Communities from the metal-polluted site were more tolerant of metals but less tolerant to UV-B compared to reference communities. Increased mayfly drift and reduced metabolism in response to metal exposure were observed in reference communities but not in the metal-polluted communities. In contrast to these results, UV-B radiation significantly reduced community metabolism, total macroinvertebrate abundance, and abundances of mayflies, caddisflies, and dipterans from the metal-polluted site, but had no effects on benthic communities from the reference site. ANOSIM results demonstrated that community responses differed among treatments at both sites. Metals had the largest impact on community differences at both sites, while UV-B had greater impacts at the metal-polluted site. This research demonstrates the need to account for potential costs associated with tolerance and that these costs can result in behavioral, structural, and functional impacts to benthic communities.     

探究条纹贻贝过滤率的最佳钙和温度条件以作为物种入侵的潜在预测因子

条纹贻贝（Dreissena rostriformis burgensis）是一种对北美具有高度入侵性的水生物种,能够过滤大量的水并造成严重的生态和经济影响。自20世纪80年代首次入侵五大湖以来,它们的活动范围一直在扩大。为了预测条纹贻贝的活动范围,了解有助于它们活动范围扩大的环境参数至关重要。影响它们分布的两个因素可能是钙和温度。在其它环境条件有利的情况下,这些因素对贻贝的适宜性最佳时其过滤率有可能被最大化,从而使贻贝发挥其生长潜力。偏离最佳条件可能导致过滤率的改变。我们探究了贻贝对两个浮游植物物种—条纹贻贝的常见食物来源之一Ankistrodesmus facaltus和一种不太可口的食物Microcystis icthyoblabe具有最大过滤率时的钙浓度和温度。实验室实验的温度范围为2~30℃,钙浓度在0~180 mg/L之间时,条纹贻贝过滤24小时后,通过细胞计数测定钙浓度和温度条件下的过滤率。使用响应面法,得出碳酸钙浓度为137 mg/L和26℃时达到最大过滤率,为22 mL/mg/h。该信息可用于预测具有较高入侵可能的淡水生境。