INUNDATION OF THE LABE-RIVER - A SOURCE O F XENOBIOTIC SUBSTANCES IN SOIL

The meadow inundated by the Labe river is situated on the right bank o f this stream, near the village Valy, the Pardubice district. It has a boundary with it on one side. It is at a distance of 6 km from the si te of the discharge of waste waters from the company Synthesia Pardubi ce-Semtin, which is a dominant polluter of the Labe river by organic x enobiotic substances. The content of xenobiotic substances in soil in this meadow has been compared with their content in soil in two meadow s non-inundated by Labe in the Pardubice district. One of them is loca ted in the cadastre of the village Plch and the second one is in the c adastre of the village Dritec. In the meadow inundated by Labe seven s oil samples were taken, in meadows of the cadastre of the villages Plc h and Dritec four samples from each were taken. Each sample was taken from the sod horizon, from a depth of 0 to 20 cm, 20 to 30 by the punc tures made by the probe bar. The total content of As, Hg, Cd, Pb, Cr, Ni, Cu and Zn (decomposition of the mixtures HNO3, HClO3 and HF) was d etermined in each taken soil sample from potentially hazardous element s, and except Hg also in the extract 2M HNO3, of organic xenobiotic su bstances PCB (congeners by the nomenclature IUPAC No. 28, 52, 101, 118 , 138, 153, 180 and the total content - Delor 103 + Delor 106), chlori nated pesticides, PAU, chlorinated and nitrated phenols, triazines and in 1996 in the soil inundated by Labe also strippable nonpolar volati le substances, aromatic amines and nitroaromates. The same hazardous e lements and organic xenobiotic substances like in soil were determined also in the hay samples. The number of analyzed hay samples from each meadow was identical with the number of soil samples. The soil inunda ted by Labe contains the higher number of all hazardous elements than the soils non-inundated by this stream (Tab. I). In the soils non-inun dated by Labe the content of none of the hazardous elements exceeds th e limit of soil contamination, in the soil inundated by Labe this limi t is exceeded by the content of Cd, As, Cr, Ni and Zn in 2M HMO3 extra ct and the total content of Cd and Zn. Content of Cd, Zn and As in 2M HNO3 extract and the total content of Cd and Zn in inundated soil exce eds also their maximum permitted content (the limit of soil intoxicati on). The differences between the content of hazardous elements in the soil inundated and non-inundated by the Labe river are usually statist ically very significant or significant. When compared with the soils n on-inundated by the Labe river, the soil inundated by this river is al so stronger contaminated by some organic xenobiotic substances (Tab. I I). Among them are such as: particularly PCB and PAU. Of PAU substance s they contain most of benzo(a)anthracene, phenanthrene, fluoroanthene and pyrene. The differences in the content of most of PAU substances in the soil inundated and non-inundated by the Labe river are statisti cally very significant or significant. Inundated soil contains differe nt volatile hydrocarbons (toluene in the greatest amount) and aniline of aromatic amines. The content of PCB, toluene, DDE and except dibenz o(a,h)anthracene and naphthalene, of all the other measured PAU in thi s soil is greater than the limit of soil contamination. This limit is exceeded also by the content of PCB and DDE in the soil in meadow in P lch and DDE in the soil in meadow in Dritec, that is in soils non-inun dated by the I,abe, river. Unlike hazardous elements the content of no ne of measured organic xenobiotic substances exceeds the values E of t he Netherlands guidelines, i.e, the values of soil intoxication. Despi te the fact that the soil in the meadow inundated by the Labe river is strong-contaminated by hazardous elements, the content of no hazardou s element in the hay harvested in this meadow in 1995 and 1996 exceede d its highest permitted content in feeds. The same was the situation w ith the content of PCB and chlorinated pesticides. Of other organic xe nobiotic substances for which the highest permitted content in feeds w as not settled, in the hay from inundated meadow in 1995 PAU substance s were found, particularly phenanthrene (138.2 mu g.kg(-1) dry matter) and fluoranthene (79 mu g.kg(-1) dry matter). In 1996, however, the c ontent of all measured PAU substances in hay was lower than the limit of determinability (10 mu g.k(-1) of dry matter). The presence of anil ine in the hay from the meadow inundated by the Labe river, in which i ts content in soil was relatively high, was not confirmed. Contaminati on of Labe by hazardous elements and organic xenobiotic substances in 1996, i.e. when the common sewage treatment plant of the town Pardubic e and Synthesia Pardubice-Semtin, started to work, is evident from Tab . III.