PCBs in N.W. Mediterranean coastal waters

The world wide occurrence of polychlorinated biphenyls is well established, but very few data are available for the Mediterranean Sea. Results of sea water analysis for samples taken from eleven stations off the northwestern Mediterranean coast give an overall average PCB concentration of 13 ng/l.     

The establishment of the national gravity standard base net of Egypt (N.G.S.B.N.-77)

The earliest gravity measurements in Egypt were carried out by the Anglo-Egyptian Oil Company using Holweck-Lejay pendulum in the period 1937–1940.The measurement comprised few stations (about 41) in restricted areas along both the Western and Eastern coasts of the Gulf of Suez.During the period 1950–1951 Prof. G. Woolard made 21 gravimetric measurements in Egypt as a part of the world-wide gravity base net. Thi was refeered to Potsdam absolute value which was considered as the World Gravity Datum.In 1974, a new world-wide gravity net was published (I.G.S.N.71) which introduced a new concept for the world gravity reference datum, and consequently has replaced the Potsdam System. Since then, it was recommended that a national gravimetric network of base stations in Egypt on the basis of the I.G.S.N.-71 be established within the frame of establishing a gravity map of Egypt.In the period from January 1975, The General Petroleum Company carried out 624 gravity observations throughout the country. These measurements have been combined with the I.G.S.N.-71 values to form 65 gravity base points which in turn from the N.G.S.B.N. (Fig. 1).     

Trace metals in mussels from the N.W. Mediterranean

A coastal survey in the northwestern Mediterranean region was initiated to measure existing levels of selected trace metals in mussels. For most metals the highest values were found in samples from port cities and areas in the vicinity of river discharge. Marked seasonal variation for many metals was evident; an overall increase in metal concentration in mussels from most stations during March 1974 was attributed to high precipitation and attendant run-off rather than to local pollution. Data comparison indicates that average metal levels in northwestern Mediterranean mussels do not differ markedly from those measured in similar species from different localities throughout the world.