Utilization of data below the analytical limit of quantitation in pharmacokinetic analysis and modeling: promoting interdisciplinary debate

Traditionally, bioanalytical laboratories do not report actual concentrations for samples with results below the LOQ (BLQ) in pharmacokinetic studies. BLQ values are outside the method calibration range established during validation and no data are available to support the reliability of these values. However, ignoring BLQ data can contribute to bias and imprecision in model-based pharmacokinetic analyses. From this perspective, routine use of BLQ data would be advantageous. We would like to initiate an interdisciplinary debate on this important topic by summarizing the current concepts and use of BLQ data by regulators, pharmacometricians and bioanalysts. Through introducing the limit of detection and evaluating its variability, BLQ data could be released and utilized appropriately for pharmacokinetic research

Content of metals in soil and groundwater of military polygon of Ādaži

Darbā apkopota literatūra par galvenajiem piesārņojuma avotiem militārās teritorijās, tai skaitā lodēm; izstudētas literatūras avotos aprakstītās piesārņojuma likvidācijas metodes citviet pasaulē. Izanalizēta literatūra par analīžu metodēm un iekārtām (to uzbūvi un darbības pamatprincipiem) augsnes un gruntsūdens ķīmiskā satura analizēšanai. Darbā tika analizēti augsnes un gruntsūdens paraugi, kas ievākti Ādažu militārā poligona mazkalibra kājnieku ieroču šautuves teritorijā. Kvantitatīvais metālisko elementu saturs augsnē un gruntsūdeņos noteikts ar viļņu dispersijas rentgenfluorescences, induktīvi saistītās plazmas masspektrometrijas un liesmas atomabsorbciometrijas metodēm. Veikta rezultātu salīdzināšana starp dažādām analīzes metodēm, augsnes paraugu ņemšanas vietām. Metālisko elementu saturs augsnē un gruntsūdeņos izvērtēts pamatojoties uz Latvijas Republikas Ministru kabineta izdotajiem noteikumiem Nr.804. un Nr.118.In this thesis literature about main pollution sources in military grounds (for example, bullets) were summarized, and possible ways to reduce pollution were researched. Analytical chemistry methods of soil and groundwater analysis and mechanical equipment, their structure and working principles were described. Soil and groundwater samples from polygon of Ādaži, small weapon (small-calibre) shooting-ground were analyzed. Quantitative concentration of zinc, copper and lead in soil and groundwater were determinated with wavelength disperse x-ray fluorescence, inductively coupled plasma mass spectrometry and flame atomic absorption spectroscopy. Results were compared and analysed between different methods of analyses and sampling places. Results were comapred with the Cabinet of Ministers of the Republic of Latvia regulations No. 804. and No.118