SQL & PL/SQL

I've got procedure which basicaly transforms one xml structure into other xml structure and then inserts that other into clob column.
I'm using xmlParser.parser , xmlDom.DomDocument .
After every iterations of procedure my PGA grows .
I'm using xmldom.freeDocument(doc) xmldom.freeDocument(document) xmlparser.freeparser(parser) and dbms_lob.freetemporary .
So have no idea what could cause the memory leak .
Is DBMS_LOB.CALL duratino solution to my problem ?
Default is session long DBMS_LOB.SESSION .

wynik        CLOB;
  v_xc         CLOB;
  doc          xmldom.DOMDocument
 
BEGIN
 
    dbms_lob.createtemporary(wynik,true);
    INSERT INTO tabxml   
      (id_xml, dane)
    VALUES
      (XML_ID, empty_clob())
    RETURNING dane into v_xc;
    xmldom.writeToClob(doc, wynik);
    dbms_lob.copy(v_xc,wynik, dbms_lob.getlength(wynik));
   dbms_lob.freetemporary(wynik);
END;

DB 9.2.0.8
Regards.
Greg