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Effect of Multiple Stressors on Water Quality and Macroinvertebrate Assemblages in an Effluent-Dominated Stream

“…Multivariate analysis divides macroinvertebrate communities upstream and downstream WWTP discharges along Axis 1, as shown also in Couceiro et al (2007), but the worst EBI and Shannon's D Index values, indicating the poorer biotic communities, are confined in clusters influenced by the simultaneous presence of the worst water quality (Mattei et al 2006), given by ammonia nitrogen spills, and of recurring floods. Thus, while the effluent-dominated section of the stream obviously presents a worse macroinvertebrate assemblage structure if compared with the reference site (lower Taxa Richness, Shannon's D Index and EBI values), the worst impacts affecting the stream ecology are not given by WWTP treated effluents, but are caused by untreated discharges (mainly due to sewer overflows), according to literature (Rueda et al 2002;Gücker et al 2006), and altered hydrology. Samples related to such extreme conditions show not only a worse quality in taxa sensitivity (no Plecoptera, only tolerant Ephemeroptera and Tricoptera), typical for all the samples in the effluent-dominated portion of the stream, but also a significantly lower taxa richness, caused by the absence of even some tolerant taxa, and density.…”

Influence of Treated Sewage Discharge on the Benthos Ciliate Assembly in the Lowland River

“…It can be argued that the composition of prevailing in the number of ciliated protozoa and other organisms was similar as in the activated sludge from the advanced biological nutrient removing wastewater treatment plant Hajdow, Lublin [44,45]. Despite the fact that the activated sludge in WWTP Sumy was of high-quality, the introduction of energetic subsidies as additional quantities of primarily nitrogen and phosphorus compounds was not limited, which was recorded in the increased levels in the receiving river below sewage discharge, as well as by the increased BOD 5 . Accordingly, such conditions caused the observed difference in the composition of benthic ciliate assemblage above and below the sewage discharge.…”

“…The processes triggered by sewerage inflow often result in the reduction of oxygen concentration or in appearance of the deoxygenated zones [4,5]. Herewith, the deterioration of aquatic environment results in changes of structure and functions of the aquatic communities [1,[6][7][8].…”

The Influence of Sawmill Wood Wastes on the Distribution and Population of Macroinvertebrates at Benin River, Niger Delta Area, Nigeria

“…Monitoring the changes of water quality in streams and rivers can be performed through studies of the organisms living in it [1]. Resident biota in a water body are natural monitors of environmental quality and can reveal the effects of episodic as well as cumulative pollution and habitat alteration [2]. The focus on urban impacts upon waterways has been recently expanded to include the structure and function of the aquatic biota [3], and typically macroinvertebrate fauna as a key indicator for stream condition [3].…”

“…It is generally believed that low species biomass and low dominance in an aquatic environment could be indicative of an ecologically unfavorable environment. Simlarly, Rueda et al [2], and Newall and Walsh [5] stated that a stressed biological population is characterized by reductions in diversity and population size. The low species richness and low diversity recorded at the sawmill wood-waste site may be due largely to the sawdust emanating from the sawmill industries, which leads to low transparency occasioned by colored turbid effluence of the wood waste as well as the high suspended material load.…”