Aquatic pollution

Burullus Lake is one of most important lakes in north Delta of Egypt. It is exposed to huge amounts of serious pollutants especially heavy metals. The sediments within the lake aid in the dispersion of these metals. The main objectives of this research were to evaluate and map the spatial distribution of heavy metals in Burullus Lake sediments. Accordingly, 37 locations were randomly distributed within the lake. Sediment samples were taken from these locations. These samples were analyzed for seven metals including Fe, Cu, Zn, Cr, Co, Cd and Pb. Also, five indices were used to identify the status of metal pollutants in the Lake. These indices are: enrichment factor (EF), contamination factor (CF), degree of contamination (DC), pollution load index (PLI) and geo-accumulation index (Igeo). Ordinary Kriging was used to interpolate the spatial distribution of the studied elements within the lake. The obtained results indicated that cadmium was the most enriched element in the lake sediments due to industrial and agricultural wastes drained into the lake. The Igeo index revealed that Cd and Pb were the common pollutants in lake sediments. The DC values ranged between low (near El-Boughaz) and moderate (near drainage areas). The spatial distribution of pollutants within the lake indicated that the highly polluted areas are located close to the drains, whereas as the less polluted areas were close to El-Boughaz.

Aquatic continental ecosystems are among the most threatened on the planet. They are constantly exposed to runoff carrying residues of fertilizers and pesticides to its waters, the routine spill of sewage and industrial waste, the introduction, intentionally or by accident, of species that have become invasive, and the effects of the global climate change. For that reason a method of evaluation that allows early detection of environmental stressors that threaten the ecological health of these ecosystems is necessary. Recently, the use of fish as bioindicators has gained importance due to various reasons. 1) Their sensitivity to environmental stressors that makes them to respond quickly to disturbances in their environment. 2) Their wide geographical distribution allow us to compare data between populations. 3) Their presence in virtually the entire trophic chain allow us to know the impact of environmental stressors on the biota in each of the trophic levels. 4) The relative simplicity of fish taxonomic identification facilitates the estimation of their abundance and diversity in the ecosystem of interest. 5) Their easiness of adaptation to captivity allow us to evaluate the effect of environmental stressors under controlled conditions. Behaviour is a labile attribute of organisms; therefore several environmental stressors can alter it. The significance of these changes is that reliably reflect the physiological condition of the organisms and directly affect their survival and adaptation. Throughout the chapter we discuss the advantages and disadvantages of using fish behaviour as biomarker of the presence of environmental stressors. We then describe the most relevant behaviours for assessing the ecological health of these ecosystems and explain how to carry out this assessment.

The study was aimed to find out the present status and causes of fish and shellfish diversity reduction in the Rupsa River of Bangladesh. Studies were conducted for a period of 6 months from July to December 2016. Focus group discussions (FGD), questionnaire interviews (QI) and key informant interviews (KII) were done to collect appropriate data from the local fishers and resource persons. A total of 62 species of fish and shellfish from 23 families were found in the river and 9 species disappeared in last 10 years. The species availability status was remarked in three categories and obtained as 14 species were commonly available, 28 species were moderately available and 20 species were rarely available. The highest percentage of fishes was catfishes (24.19%). There was a gradual reduction in the species diversity from previous 71 species to present 62 species with 12.68% declined by last 10 years. Average fish catch per fishermen per day reduced from 8.35 kg to 2.95 kg in last 10 years. Combined effects of some manmade and environmental factors are responsible for the loss of biodiversity. Majority of the respondents (90%) agreed that two manmade factors namely overfishing and navigation are mainly responsible for the loss of fish and shellfish diversity in the river followed by use of illegal fishing gears (86%), pollution (72.5%) and urbanization (64%). During the survey, 93.25% respondents reported water depth reduction as the main environmental factor followed by siltation and sedimentation (91%), temperature (61.75%) and turbidity (56%). The present work recommends preventing water pollution, maintaining fishing gears, increasing fishers’ awareness, implementing fisheries laws and establishing fish sanctuary to conserve finfish and shellfish diversity in the river. Moreover, counter and random surveys are also recommended to crosscheck the fishes’ status and decline causes for ensuring their proper management and conservation.

The present study was undertaken to evaluate the chemical profile of the water and to determine heavy metal concentrations in water and muscles of certain freshwater fish and crayfish species of Rupsha River, Bangladesh. The concentrations of heavy metals were determined in six fish and crayfish species: Peneaus monodon, Macrognathus aculeatus, Gudusia chapra, Channa punctatus, Glossogobius giuris and Barilius bola. Fish and crayfish samples as well as chemical parameters of water were measured in three different sampling stations for six months during the year of 2010. Three sampling stations in the Rupsha River were - main industrial discharge site (S1), river site close to effluents from fish processing plants, brick yards and agricultural runoff (S2), and apparently low industrial waste discharge point but rich in sewage and municipal wastes admixing with Fe compounds from Ship breaking yard (S3). The heavy metals concentrations were determined by Atomic Absorption Spectrophotometer. Among the water quality parameters, the values of Dissolved oxygen (DO), Nitrate-Nitrogen (NO3-N) and Ammonia Nitrogen (NH3-N) were detected beyond the acceptable limit whereas pH and alkalinity were within the permissible limits, respectively. DO levels below and NO3-N levels beyond suitable limits indicated a low water quality of Rupsha River and therefore, a habitat unfavorable for fish and other aquatic animals. Heavy metals measured from the river water were Pb, Zn, Fe and Mn, and those from fish and crayfish muscles were Fe, Cu, Zn, Pb, Cr, Mn and Ni. The heavy metal concentrations in Rupsha River water were found within the permissible limits except for Fe. The mean Fe concentrations were recorded to be 0.68±0.48, 0.77±0.38 and 0.67±0.35 mgL-1 at sampling points S1, S2 and S3, respectively. The accumulations of heavy metals in fish and crayfish muscles were found within the permissible limits. However, bioaccumulation factor (BAF) for metals in fish and crayfish muscles showed unacceptable concentrations for Zn, Pb and Mn. BAF results indicate that consumption of fish and crayfish species from Rupsha River is likely to exert health hazards for human being.

Se determinó la toxicidad aguda de los plaguicidas Malation 500 ® y Tyson 4E ® , los cuales tienen como ingrediente activo al malatión y al clorpirifós etil respectivamente, empleando como organismo de prueba a Capitella sp. recolectado en la Bahía de Che-tumal y aclimatado en condiciones de laboratorio. Para ello se realizaron bioensayos de toxicidad de tipo estático por 48 h utilizando cinco concentraciones nominales distri-buidas con una escala logarítmica, tres réplicas por concentración y un control por cada cámara de bioensayos; se emplearon 10 organismos por réplica en cristalizadores con sedimento tratado, solución salina y su respectivo volumen del plaguicida. Se registró la mortalidad y se determinó la concentración letal media (CL50) mediante el análisis Probit con un intervalo de confianza de 95 %. Los valores de CL50 obtenidos fueron de 27.79 ± 2.67 mg/L para el malatión y 7.46 ± 1.59 mg/L para el clorpirifós etil; por lo tanto, se comprueba que este último fue el más tóxico. El análisis estadístico ANDEVA demostró que existen diferencias significativas entre las distintas concentraciones (p < 0.05). Malation 500 ® se clasificó como ligeramente tóxico y Tyson 4E ® como mo-deradamente tóxico para Capitella sp. Los cocientes de riesgo de ambos plaguicidas (CR < 1) indican que su riesgo ecológico es despreciable.

Burullus Lake is one of most important lakes in north Delta of Egypt. It is exposed to huge amounts of serious pollutants especially heavy metals. The sediments within the lake aid in the dispersion of these metals. The main objectives of this research were to evaluate and map the spatial distribution of heavy metals in Burullus Lake sediments. Accordingly, 37 locations were randomly distributed within the lake. Sediment samples were taken from these locations. These samples were analyzed for seven metals including Fe, Cu, Zn, Cr, Co, Cd and Pb. Also, five indices were used to identify the status of metal pollutants in the Lake. These indices are: enrichment factor (EF), contamination factor (CF), degree of contamination (DC), pollution load index (PLI) and geo-accumulation index (Igeo). Ordinary Kriging was used to interpolate the spatial distribution of the studied elements within the lake. The obtained results indicated that cadmium was the most enriched element in the lake sediments due to industrial and agricultural wastes drained into the lake. The Igeo index revealed that Cd and Pb were the common pollutants in lake sediments. The DC values ranged between low (near El-Boughaz) and moderate (near drainage areas). The spatial distribution of pollutants within the lake indicated that the highly polluted areas are located close to the drains, whereas as the less polluted areas were close to El-Boughaz.