van Lieverloo J Hein M, Bosboom Dick W, Bakker Geo L, Brouwer Anke J, Voogt Remko, De Roos Josje E M
Kiwa Water Research, Nieuwegein 3430 BB, P.O. Box. 1072, The Netherlands.
Water Res. 2004 Mar;38(5):1101-12. doi: 10.1016/j.watres.2003.11.021.
Water utilities in the Netherlands aim at controlling the multiplication of (micro-) organisms by distributing biologically stable water through biologically stable materials. Disinfectant residuals are absent or very low. To be able to assess invertebrate abundance, methods for sampling and quantifying these animals from distribution mains were optimised and evaluated. The presented method for collecting invertebrates consists of unidirectionally flushing a mains section with a flow rate of 1 ms(-1) and filtering the flushed water in two separate flows with 500 microm and 100 microm mesh plankton gauze filters. Removal efficiency from mains was evaluated in nine experiments by collecting the invertebrates removed from the mains section by intensive cleaning immediately subsequent to sampling. Of 12 taxa distinguished, all except case-building Chironomidae larvae (2%) and Oligochaeta (30%) were removed well (51-75%). Retention of invertebrates in 100 microm filters was evaluated by filtering 39 filtrates using 30 microm filters. Except for flexible and small invertebrates such as Turbellaria (13%), Nematoda (11%) and Copepoda larvae (24%), most taxa were well retained in the 100 microm filters (53-100%). During sample processing, the method for taking sub-samples with a 10 ml pipette from the suspension of samples with high sediment concentrations was found to perform well in 75% of the samples. During a 2-year national survey in the Netherlands and consecutive investigations, the method appeared to be very suitable to assess the abundance of most invertebrate taxa in drinking water distribution systems and to be practicable for relatively inexperienced sampling and lab technicians. Although the numbers of small, less abundant or sessile taxa were not accurately assessed using the method, these taxa probably should not be the primary focus of monitoring by water utilities, as consumer complaints are not likely to be caused by these invertebrates. The accuracy of quantifying small invertebrates was further improved, however, by filtering the 100microm filtrate with a 30microm mesh plankton gauze filter.
荷兰的水务公司旨在通过生物稳定材料输送生物稳定的水来控制（微）生物的繁殖。消毒剂残留量不存在或非常低。为了能够评估无脊椎动物的数量，对从配水管网中采集和量化这些动物的方法进行了优化和评估。所提出的收集无脊椎动物的方法包括以1米/秒的流速单向冲洗一段管网，并将冲洗后的水分别通过500微米和100微米网目的浮游生物纱网过滤器进行过滤。在九个实验中，通过在采样后立即对管网段进行强化清洗来收集从管网段中去除的无脊椎动物，从而评估从管网中的去除效率。在区分出的12个分类单元中，除了筑巢摇蚊幼虫（2%）和寡毛纲动物（30%）外，其他所有分类单元的去除效果都很好（51%-75%）。通过使用30微米的过滤器过滤39份滤液来评估100微米过滤器对无脊椎动物的截留情况。除了像涡虫纲（13%）、线虫纲（11%）和桡足类幼虫（24%）等柔软且小型的无脊椎动物外，大多数分类单元在100微米的过滤器中截留效果良好（53%-100%）。在样品处理过程中，发现在75%的样品中，用10毫升移液管从高沉积物浓度样品悬浮液中取子样品的方法效果良好。在荷兰进行的为期两年的全国性调查及后续调查中，该方法似乎非常适合评估饮用水分配系统中大多数无脊椎动物分类单元的数量，并且对于经验相对不足的采样和实验室技术人员来说是可行的。尽管使用该方法无法准确评估小型、数量较少或固着的分类单元的数量，但这些分类单元可能不应成为水务公司监测的主要重点，因为消费者投诉不太可能由这些无脊椎动物引起。然而，通过用30微米网目的浮游生物纱网过滤器过滤100微米的滤液，进一步提高了对小型无脊椎动物量化的准确性。
