Hidrológiai Közlöny 1971 (51. évfolyam)

1. szám - Dr. Bolberitz Károly: Természetes vizekben előforduló mikroszennyező anyagok fajtái és hatásai

34 Hidrológiai Közlöny 1971. 1. sz. Special Conference Number, Szebellédy, L. organism and the changes therein—especially in the case of micro-pollution—appear already, before functional disorders in other organs become observable. The investigation is performed using the ingenious "labyrinth" test deseribed in the paper. From the results of the mathematical evaluation it appears that much may be expected from this method in the future. For studying chronie constitutional damages 48 rats were given suitably diluted solutions of the standard solution to drink for 3 months, during which their weight and blood count was checked regularly, while at the end of the test the rats were slughtered and their heart, lung, liver, kidneys, adrenal gland, thyroid gland and sexual organ weighed, accompained by histological examinations on all. Most reliable results are obtained by the twoyear tests on cancerogeneous materials. The duration is justified by the long latency of such substances. A piece of plastic is implanted under the skin of 25 males, 25 females and the same number of reference specimens and after one year the animals are given to drink water containing substances dissolving from the same plastic for another year. Not unless this test yields alsó a negative result and no tumour growth is observable Gan it be ascertained with any degree of reliability that no substances detrimental to health are dissolved from the particular plastic. Studies performed on six different plastic products have shown only one, containing a tar-derivative, tobeofpotential cancerogeneous effect, the rest having been found harmless in this respect. From a combined evaluation of such investigations limit values can be determined. Changing to the second sphere of subjects, there appears tőbe generál agreement on the necessity of more sophisticated, reliable and sensitive analytical methods, as a prerequisite for the successful completion of investigations and research. It is easy to understand that in the case of micro-pollution the sensitivity of earlier analytical methods had to be increased sometimes as much as thousandfold, and no successful research was possible until such methods became available. Continuous efforts are undertaken to improve the extensively used chromatographic methods, especially gas-chromatography, flame photometry, atom adsorption, infra-red spectroscopv, micro-wave fluorescence and various radiometric methods and new procedures are expected to become available in the future. However, besides methodology, measurements raise other problems as well, and for the time being these are more severe than those related to the analytical methods. This is the problem of sampling, which is alsó divided into two parts, namely the method of sampling, which makes reliable work sometimes difficult, the second being associated with the location, time and frequency of sampling. Of the papers submitted, in the one by Mrs. Szebellédy and P. Literáthy mention is made of sampling devices which proved successful for taking samples from both the surface oil film and subsurface water layers. For determining the oil content they developed a method involving the use of anadsorbent material available on the markét under the trade name Ekoperl. A method serving for the measurement of oil pollution is mentioned alsó in the paper by Sz. Papp. In his measurements the oil content of the water sample is separated as a precipitate with ferri-hydroxide. This precipitate is. then extracted with hexane and the oil is measured directly, by gravimetry. Certain problems related to the determination of íluorine with zircon-alizarine are dealt with in the paper by M. Hadek. In his paper on the fluorine treatment of drinking water the experiences gained with checking tests are related. The allowable aluminium ion eoncentration in drinking water was found to have no disturbing effect on this method of determination. The third subject treated in the papers submitted is that of surveys, practical measurements and observations aimed at the determination of various micro-pollutants in surface waters for estimating the extent and frequency of pollution caused by them. These are the investigations where the results of fundamental research are utilized in practice. A report on extensive similar investigations is presented in the paper by Sz. Papp, who performed —together with his co-workers—observations on the pollution caused in the surface waters of Hungary by oil, phenoles, detergents, copper- and zinc ion, DDT, DDE and Lindane. Data on lowest, highest and average pollution are given on the basis of the three-year study for each component, arranged according to orderof magnitude. A visual picture is thus presented on the watercourses which are most highly polluted by the individual substances under consideration. The highest extent of oil pollution has been encountered, obviously, in the vicinity of oil refineries and in the region of oil fields, but considerable oil was found alsó in Danube downstream of the capital. Pollution due to phenoles and heavy metals has been observed primarily in industrial regions. Synthetic detergents have been encountered in the water of minor watercourses with low rates of streamflow, which act as the recipient for the wastes of major settlements. The pesticides considered in this study have been encountered in varying quantities in practically every watercourse (recipient) around which agricultural operations exist. The extent ánd result of major interest of the investigation conducted at the Research Institute for Water Resources Development are deseribed in the paper by Mrs. Szebellédy and P. Literálhy. According to these investigations 30 to 60% of the micro-organisms present in the Hungárián reach of the Danube are detrimental to taste and odour. Tests have shown the twater of the Danube to be very little polluted by the different pesticides. Studies on the oil pollution in the Danube have revealed most of the oil content to be carried in the top layer of about 50 cm thickness and to decrease downward. It was concluded further that whereas the oil in the top layer is present in emuisi-