Mercury in the Izmir Bay: An assessment of contamination

The levels of mercury in suspended particulate matter, sediment, plankton and fish were investigated in Izmir Bay (Eastern Aegean). The study aimed to assess the level of mercury in different environmental compartments of the Izmir Bay. Seasonal (dry and wet season) and spatial variations in suspended particulate Hg concentrations showed that pluvial transport is the major pathway to the bay. Suspended particulate matter was the main vehicle for carrying mercury from land based sources to the bay. Gediz River and inactive mining sites (Karaburun) were the most important inputs of mercury to the outer bay. Hg concentrations ranged from 0.70 to 28.7 nmol g(-1) (dry weight) in suspended particulate, from 0.60 to 3.19 nmol g(-1) (dry weight) in plankton, from 0.20 to 3.14 nmol g(-1) (dry weight) in sediment and from 0.05 to 4.54 nmol g(-1) (wet weight) in organisms. Plankton, sediment Hg concentrations and its organic matter contents increased from outer bay to middle-inner bays. Based on the correlation matrix obtained for mercury data, organic matter was the dominant factor controlling Hg distribution in the sediment. There was a correlation between fish length and Hg (muscle tissue) concentrations in Mullus barbatus and Merluccius merluccius. In the other species these were not related to fish length. The maximum permissible mercury limit accepted by WHO for edible parts of marine organisms is 3.5 nmol g(-1) (wet weight); our results indicated that Merlangius merlangus and Pagellus erythrinus exceed this limit. (c) 2006 Elsevier B.V

DISTRIBUTION OF NUTRIENTS AND CHLOROPHYLL-A IN THE AEGEAN SEA

The distributions of inorganic nutrients and phytoplankton chlorophyll-a were investigated in relation to the hydrography of the Aegean Sea. The data were collected during cruises in May and October 1992, February, May and October 1993 and July 1994, in the framework of a National Marine Measurement and Monitoring Programme for the Aegean Sea. Concentrations of nitrate +nitrite+ammonia nitrogen and phosphate phosphorus were lower than those previously reported for the Black Sea; generally lowest at the surface, they increased with depth. The highest nutrient values were in the northern part of the Aegean Sea, and may have resulted from water originating from the Black Sea. Both phosphates and silicates increased with depth to maxima of 0.16 and 4.7 mu M, respectively. The concentration of chlorophyll-a ranged from 0.03 to 0.70 mg m(-3). Elemental ratios (N/P and Si/P) were calculated to be 13.6 - 36.8 and 14.0 - 48.0, respectively

Dissolved and dispersed petroleum hydrocarbons in the aegean sea

The distribution and transportation of Dissolved and Dispersed Petroleum Hydrocarbon (DDPH) were investigated in the Aegean Sea with the hydrodynamics of the water masses of the region. It is clear that distribution of this pollutant is strongly affected by physical dynamics of environment. The data were collected during cruises in November 1994, in the framework of National Marine Measurement and Monitoring Programme in the Aegean Sea. In the present study additionally the Chlorophyll-a was measured fluorometrically and there is good correlation between petroleum hydrocarbon and chlorophyll-a in the Aegean Sea. DDPH data was used to search origin of hydrocarbons: biogenic or non biogenic. © 1995, Taylor & Francis Group, LLC. All rights reserved

Trace metal concentrations in edible fishes from Izmir Bay, Eastern Aegean

Radiative corrections to processes that involve the production and subsequentdecay of unstable particles are complex due to various theoretical andpractical problems. The so-called double-pole approximation offers a way out ofthese problems. This method is applied to the reaction e^{+}e^{-} \toW^{+}W^{-} \to 4 fermions, which allows us to address all the key issues ofdealing with unstable particles, like gauge invariance, interactions betweendifferent stages of the reaction, and overlapping resonances. Within thedouble-pole approximation the complete \OO(\alpha) electroweak correctionsare evaluated for this off-shell $W$-pair production process. Examples of theeffect of these corrections on a number of distributions are presented. Thesecomprise mass and angular distributions as well as the photon-energy spectrum

Elemental composition of particulate matter and nutrient dynamics in the Izmir Bay (Eastern Aegean)

Izmir Bay (38 degrees 41 '-38 degrees 21 ' N, 26 degrees 30 '-27 degrees 08 ' E) is one of the great natural bays of the Aegean Sea. Temporal variations and regional distribution of particulate organic matter, dissolved nutrients and chlorophyll-a were investigated seasonally in the bay. The data were collected during four cruises of R/V K. Piri Reis between March 2000 and January 2001 at selected sampling points within the framework of the "Izmir Bay Marine Research Project". The composition of particulate matter was determined and evaluated together with physical parameters in Izmir Bay. Due to the atmospheric and land-based nutrient inputs, the levels of nutrients are lower in the outer part than the middle and inner parts of the bay. The particulate concentrations varied between 3.2 and 23 for POC, 0.32 and 2.1 for PON, 0.02 and 0.21 mu M for PP in the outer and 12 and 197 for POC, 1.7 and 30 for PON, 0.11 and 1.9 mu M for PP in the middle-inner bays. The elemental mean ratios of particulates (POC:PON:PP) from the individual measurements were 166:16:1 and 127:17:1 for the outer and middle-inner bays, respectively. The ratios, derived from the slopes of linear regressions, are quite comparable with the ratio from the preformed nutrient data. Atomic ratios of particulate matter from the regression equations were similar to off-shore Mediterranean Sea and lower than near-shore Black Sea in the outer bay. POC:PON:PP ratios were mostly greater than the Black Sea in the middle and inner bays. Mean DIN:DIP ratios in the water column were 14 and 3.5 in the outer and middle-inner bays, respectively, which are lower than the Redfield ratio. (c) 2005 Elsevier B.V. All rights reserved

EUTROPHICATION IN IZMIR BAY, EASTERN AEGEAN

The polluted waters of Izmir Bay were studied to measure the variations of biochemical and physical characteristics monthly or three monthly. The spatial and temporal changes of nutrients (nitrate, nitrite, and ortho phosphate) and chlorophyll-a, in the bay were monitored during the period of February 1990-December 1992. Eutrophication of the inner bay has already started, spreading progressively to the rest of the Bay. The degree of eutrophication in the Bay was assessed. The concentration of nutrients ranged between 0.21-2.51, 0.44-4.20, 0.11-3.50 mug-at/l for PO4-P, NO3-N, NO2-N respectively. Chlorophyll-a concentration is between 0.7-39.1 mug/l and estimated primary productivity in the bay is 7-10 time higher than the offshort production in the region. Tha main reason for high primary production is the high terrestrial input. As expected total suspended solids concentrations is high, so that the water is turbidit having extremely low penetration, the average depth of secchi disk is between 2-10 m

Trace metal and organochlorine residue levels in red mullet (Mullus barbatus) from the eastern Aegean, Turkey

The levels of trace metals and organochlorine residue were determined in red mullet (Mullus barbatus) in the framework of a MED-POL II Project for the Aegean Sea during 1991-1998. Samples were analyzed seasonally from July 1994 to January 1998. The concentrations of trace metals found varied with Hg: 16-200 mug kg(-1), Cd: 0.57-4.5 mug kg(-1) and Pb: 40-207 mug kg(-1) wet weight. The order of trace metal concentrationn found in Mullus barbatus was Pb > Hg > Cd. Correlation coefficients were calculated between Hg, Cd, and Pb concentrations and fork lengths to be Hg:0.5852, Cd:-0.081, Pb:0.5823, respectively. Cadmium levels are lower than the results in fish tissues reported from Mediterranean regions. The results of organochlorine residues measured varied between Aldrin: 0.10 and 0.61 mug kg(-1) t-DDD: 0.86 and 4.5 mug kg(-1) and t-DDE: 10 and 18 mug kg(-1) wet weight. Correlation coefficients for measured organochlorine residues and fork lengths are Aldrin: 0.6422, t-DDD: 0.2237 and t-DDE: 0.5484. The levels of mercury, lead and organochlorine residues are similar to the results in fish from Mediterranean countries. (C) 2001 Elsevier Science Ltd. All rights reserved

Monitoring of eutrophication and nutrient limitation in the Izmir Bay (Turkey) before and after Wastewater Treatment Plant

The distribution of inorganic nutrients and phytoplankton chlorophyll-a was investigated and N/P ratios were determined in Izmir Bay during 1996-2001. The average concentrations showed ranges of 0.01-0.19 and 0.01-10 muM for phosphate-phosphorus; 0.11-1.8 and 0.13-27 muM for (nitrate + nitrite)-nitrogen, 0.30-4.1 and 0.50-39 muM for silicate and 0.02-4.3 and 0.10-26 mug l(-1) for chlorophyll-a in the outer and middle-inner bays, respectively. The results are compared with the values obtained from the relatively unpolluted waters of the Aegean Sea. The N/P ratio is significantly lower than the assimilatory optimal (N/P = 15:1) in conformity with Redfield's ratio NIP = 16:1. Nitrogen is the limiting element in the Izmir Bay. Phosphate, which originates from detergents, is an important source for eutrophication in the bay, especially in the inner bay

Determination of nontoxic concentrations of piperacillin/tazobactam for intravitreal application - An electroretinographic, histopathologic and morphometric analysis

Background: To investigate the highest nontoxic intravitreal dose of piperacillin/tazobactam in rabbits. Material and Methods: Forty New Zealand white albino rabbits were used in this study. The rabbits were divided into four equal groups ( 10 rabbits in each) and the right eyes were treated with 0.1 ml intravitreal injections of 1,000 mug piperacillin/tazobactam in group 1, 500 mug in group 2, 250 mug in group 3, and 100 mug in group 4. The left eyes served as controls and were injected with 0.1 ml of saline solution. Ganzfeld electroretinogram ( ERG) was performed on all eyes before and after 4 weeks of intravitreal injections. Then, the rabbits were killed and the eyes were enucleated for histopathological evaluation of the retina. Retinal sections were evaluated by morphometric analyses on cell counts of ganglion cell layer and thickness of the various retinal layers. Results: Baseline ERGs were similar among the groups (p > 0.05). After 4 weeks of injection, there were a reduction of the b-wave amplitude and extension of the b-wave implicit time in photopic and scotopic ERGs in group 1 and group 2 when compared with controls (for each, p 0.05). After morphometric analysis of retinal sections in all groups, there were no statistically significant differences in the mean number of surviving ganglion cells, thickness of the whole retina and the inner plexiform layer compared with controls (p > 0.05). Conclusion: 250 mug/0.1 ml piperacillin/tazobactam is the highest nontoxic dose to the normal retinas of adult albino rabbits as intravitreal injection. Piperacillin/tazobactam may be a new, potentially important drug in the treatment of endophthalmitis as it has a broad antimicrobial spectrum. Copyright (C) 2004 S. Karger AG, Basel