Arimoro Francis O, Osakwe Emeka I
Department of Zoology, Delta State University, Abraka, Nigeria. fransarimoro@ yahoo.com
Chem Biodivers. 2006 May;3(5):578-92. doi: 10.1002/cbdv.200690061.
The impact of sawmill wood wastes on the distribution of benthic macroinvertebrates at the Sapele section of Benin River, Niger Delta, Nigeria, was investigated from March 2005 to August 2005. A total of 434 individuals were collected by kick-sampling method, representing 21 taxa of benthic macroinvertebrates. Three stations, 1, 2, and 3, were selected from upstream of the site, receiving wood wastes discharge, the impacted site and its down stream, respectively. Among the water quality variables, conductivity, dissolved oxygen, biochemical oxigen demand (BOD(5)), nitrate-nitrogen, phosphate-phosphorus, transparency, and alkalinity were significantly different (P<0.05) among the stations. Orthogonal comparison by Duncan's multiple range test showed that station 2 (the impacted site) was the cause of the difference. More sensitive species such as Ephemeroptera or Plecoptera were completely absent from station 2, the impacted site. Species abundance was similar in station 1 and 3, indicating that the wood wastes must have adversely affected the distribution of these macroinvertebrates, especially the intolerant species. The wood waste discharge not only altered the water chemistry, but also stimulated the abundance of less-sensitive macroinvertebrate species.
2005年3月至2005年8月，对尼日利亚尼日尔三角洲贝宁河萨佩莱河段锯木厂木材废料对底栖大型无脊椎动物分布的影响进行了调查。通过踢网采样法共采集到434个个体，代表21种底栖大型无脊椎动物类群。分别从该场地的上游、接收木材废料排放的受影响场地及其下游选取了1号、2号和3号三个站点。在水质变量中，各站点之间的电导率、溶解氧、生化需氧量（BOD(5)）、硝酸盐氮、磷酸盐磷、透明度和碱度存在显著差异（P<0.05）。通过邓肯多重极差检验进行的正交比较表明，2号站点（受影响场地）是造成差异的原因。在受影响的2号站点，蜉蝣目或襀翅目等更敏感的物种完全不存在。1号和3号站点的物种丰度相似，这表明木材废料一定对这些大型无脊椎动物的分布产生了不利影响，尤其是不耐受的物种。木材废料的排放不仅改变了水化学性质，还刺激了对污染不太敏感的大型无脊椎动物物种的丰度。
