The paper presents a synthesis of results obtained by long-term international collaboration in the field of applying nuclear and atomic analytical techniques for the quantification of heavy metals and trace elements in soil material. The multistage research aimed at the development of a system of complex monitoring heavy metals, trace elements, rare earths and radionuclides in Lower Danube Euroregion in order to control the state of the environment, to provide rational use of natural resources and to prevent hazardous impacts on human and animals, health of the main anthropogenic sources. Accurate monitoring of metal concentrations in environmental samples is of great importance in order to minimize health hazards resulting from exposure to such a large spectrum of toxic substances. For this purpose, it is essential to employ different high sensibility and precision methods of elemental analysis.The concept was based on: i) assessment of concentrations of heavy metals (HMs) and trace elements in selected industrially developed areas, agricultural and protected areas and their sources, ii) assessment of HM contamination level of the environment and ecological risk over the territories affected by their impact using combined pollution indices, and iii) mapping the pollution in target areas using GIS technology. The following analytical methods were employed in collaborating institutions from Romania, Moldova, Ukraine, Greece and Russian Federation, and used in complementarity for elemental determination in soils sampled from Romania (about 50 chemical elements of the Periodic Table): X-ray fluorescence analysis with energy dispersion (ED-XRF), including portable technique (p-XRF); instrumental neutron activation analysis (INAA); atomic absorption spectrometry (AAS), including High Resolution Continuum Source (HR CS-AAS) technique, inductively-coupled plasma mass spectrometry (ICPMS); ion beam techniques Particle-Induced X-ray (PIXE) and Gamma-ray (PIGE) Emission using accelerated proton beams, and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). The accuracy and precision of the results were evaluated by measuring certified reference samples of similar matrix and organizing several intercomparison exercises between research laboratories. The elements examined were: Ag, Al, As, Au, B, Ba, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Eu, F, Fe, Hf, Hg, I, K, La, Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Rb, S, Sb, Sc, Se, Si, Sm, Sr, Ta, Tb, Ti, Tm,Th, U, V, Yb, Zn. From them, the main toxic elements of interest are: As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Se, W, Zn, and Zr. Supplementary measurements of radioactive isotopes from the natural series of U and Th and of 40K, as well as artificial radioisotope 137Cs in several industrial soils in Galati area, Romania, were performed by low background gamma spectrometry. Merits and drawbacks of each analytical technique employed are discussed, as well as the possibility of the assessment of toxicants, impact upon human health using a risk calculator, developed in the frame of MONITOX partnership. The results emphasize the fact that the parallel use of different analytical techniques could extend the palette of measured elements, and also provides a quality control for the common elements determined by different techniques. Environmental complex studies proved to be very useful for the identification of a large series of trace elements, some of them being toxic for living organisms and humans and others contributing to the elemental cycling in natural environments. Results could be correlated with those obtained for a certain region using biological indicators of atmospheric pollution. Acknowledgement: We acknowledge the funding from ENI project eMS code BSB27 MONITOX (2018-2021), Joint Operational Programme Black Sea Basin 2014-2020;Romania-JINR Dubna Projects nos. 63 and 64/2019; Romania-JINR Dubna Grants no. 24/2016 and 21/2019 and ENPI project MIS ETC 1676 (20132015), Joint Operational Programme Romania-Ukraine-Republic of Moldova 2007-2013. The paper is dedicated to the celebration in 2019 of the International Year of the Periodic Table of Chemical Elements.