Engineering and Technology Journal

Within Al-Najaf lake, that is one of the important shallow lakes in Iraq, the lake facing tremendous pressure due to encroachments, discharge of untreated domestic and industrial waste, drainage water from cultivated orchards, dumping of solid waste and illegal diversion of water and currently it's still suffering from these problems and neglect. The study aimed to evaluate the eutrophication status. Eutrophication is a grave problem in lakes, a knowledge about the eutrophic state help in providing a make efficient realization of the eutrophic problem.
This study conducted to assess the Eutrophication level with a scale 0 – 100 depending on the trophic state index (TSI) and (CTSI) calculation by measuring (Chl-a), (TP), (TN) and (TSS), also measured the parameters (Tw), (Pb), (TDS), (pH), (EC), (MPN) and (COD). The least significant difference (LSD) and ANOVA analysis were performed by using the Genstat statistical program. Lake can be classified according to the Carlson index as eutrophic (CTSI > 80) most hegemony of blue-green algae, extensive macrophyte troubles. Adding, according to Trophic State Index classification (TSItotal was ranged between 88.104-89.49 depending on TP, TSS, TN, P/N and Chl-a concentrations), were classified as the lake as extremely hypereutrophic and algal scums.

The producing composite materials of dual reinforcement in which the matrix material is aluminum reinforced with two types of ceramic particles : which are Alumina (50μm

Keywords

composite materials; wear test ; Al2O3; SiC: Al

The term "eutrophic" refers to system rich in nutrients, and hence Eutrophication
means nutrient enrichment, particularly by increasing levels of nitrogen and
phosphorus [1]. In lakes, phosphorus is generally regarded as the limiting nutrient for
primary production [2] implying that increasing phosphorus concentrations will result
in increasing production of phytoplankton and benthic algae. Excessive amounts of
phytoplankton cause low Secchi depths and may consequently wipe out the benthic
flora by shading the light [3]. Toxic cyanobacteria tend to bloom when nutrient levels
are high [4]. Apart from being a nuisance in their own right, settling phytoplankton
may cause anoxia in hypolimnetic waters as their decomposition consumers oxygen
[5], and this may result in extinction of the benthic fauna [6] and fish feeding on such
animals. Altogether, these Eutrophication effects threaten the foundations of aquatic
ecosystems. The low oxygen levels in hypolimnetic waters associated with
Eutrophication may also cause mobilization of phosphorus in the sediments, thus
inducing a feedback mechanism where already high nutrient levels increase even more.