Assessment of seawater pollution by heavy metals (lead & cadmium) in the Qeshm rocky shore: use of the sea urchin, Echinometra mathaei, as a bioindicator

The general purpose of this study is to investigate the degree of heavy metal accumulation in hard and soft tissue of sea urchin, and determining these tissues as the most suitable bioindicator for lead and cadmium in the environment of the sampling stations. The way of doing this assessment was MOOPAM. Samples were prepared and classified according to sea urchin organ (soft tissue, hard tissue, Tube feet, Test, Lantern Structure and spines) and then lead and cadmium were measured in them. Result of this study shows that hard tissue is a better index of lead and cadmium than soft tissue. The result of bioaccumulation of lead in the related tissue was found to be in the following order: Soft tissue=21, hard tissue=28.1, Test=20.8, Lantern Structure=20.5 and spines=23.9. The result of bioaccumulation of cadmium in the related tissue was found to be in the following order: Soft tissue=9. 7, hard tissue=5.01, Test=4.2, Lantern Structure=4.06 and spines=5.53.

Seasonal changes of heat and moisture fluxes from the Caspian Sea surface and its effect on synoptic systems with heavy rainfalls in southern shores of the sea during 2005-2010

Caspian Sea with its unique characteristics is a significant source to supply required heat and moisture for passing weather systems over the north of Iran. Investigation of heat and moisture fluxes in the region and their effects on these systems that could lead to floods and major financial and human losses is essential in weather forecasting. Nowadays by improvement of numerical weather and climate prediction models and the increasing need to more accurate forecasting of heavy rainfall, the evaluation and verification of these models has been become much more important. In this study we have used the WRF model as a research-practical one with many valuable characteristics and flexibilities. In this research, the effects of heat and moisture fluxes of Caspian Sea on the synoptic and dynamical structure of 20 selective systems associated with heavy rainfall in the southern shores of Caspian Sea are investigated. These systems are selected based on the rainfall data gathered by three local stations named: Rasht, Babolsar and Gorgan in different seasons during a five-year period (2005-2010) with maximum amount of rainfall through the 24 hours of a day. In addition to synoptic analyses of these systems, the WRF model with and without surface flues was run using the two nested grids with the horizontal resolutions of 12 and 36 km. The results show that there are good consistencies between the predicted distribution of rainfall field, time of beginning and end of rainfall by the model and the observations. But the model underestimates the amounts of rainfall and the maximum difference with the observation is about 69%. Also, no significant changes in the results are seen when the domain and the resolution of computations are changed. The other noticeable point is that the systems are severely weakened by removing heat and moisture fluxes and thereby the amounts of large scale rainfall are decreased up to 77% and the convective rainfalls tend to zero.

Three dimensional modeling of contaminants transportation (oil spill) in Caspian Sea

Nowadays, Caspian Sea is in focus of more attentions than past because of its individualistic as the biggest lake in the world and the existing of very large oil and gas resources within it. Very large scale of oil pollution caused by development of oil exploration and excavation activities not only make problem for coastal facilities but also make severe damage on environment. In the first stage of this research, the location and quality of oil resources in offshore and onshore have been determined and then affected depletion factors on oil spill such as evaporation, emulsification, dissolution, sedimentation and so on have been studied. In second stage, sea hydrodynamics model is offered and tested by determination of governing hydrodynamic equations on sea currents and on pollution transportation in sea surface and by finding out main parameters in these equations such as Coriolis, bottom friction, wind and etc. this model has been calculated by using cell vertex finite volume method in an unstructured mesh domain. According to checked model; sea currents of Caspian Sea in different seasons of the year have been determined and in final stage different scenarios of oil spill movement in Caspian sea on various conditions have been investigated by modeling of three dimensional oil spill movement on surface (affected by sea currents) and on depth (affected by buoyancy, drag and gravity forces) by applying main above mentioned depletion factors.

Survey of past, present pollutants via sediment cores analysis in the coastal trend of Caspian Sea

This is especially well supported by down core variation Zn concentration. As Caspian Sea water intrudes into the Bay, it may be concluded that some part of pollution has sea origin. The geochemical index (Igeo) was reformulated for the area of study using chemical partitioning as well as Pb-210 results. The newly developed geochemical index is indicative of low to medium pollution intensity in the Bay of Gorgan. Thus, any additional pollution into the area of study may leave adverse effects on the aquatic ecology of Bay of Gorgan. Further, lithogenous and non-lithogenous inputs of metals into the Bay were assessed. For this purpose and through chemical partitioning, association of metals with different sedimentary phases was determined. The overall results show that about 114th total metal concentration have been added into the Bay of Gorgan through human activities.