**4. The results of health risks assessment in floodplain soils in the Czech Republic**

Since the magnitude of the total estimation for human health risks on individual sampling localities was calculated (Equations 1–3) and cartographically represented (see **Figure 2**), the regional differentiation of potential human health impacts of complex soil pollution can be determined for floodplains soils in the Czech Republic. An increase of human health risk estimation was recorded for the Elbe River below the industrial centres (Opatovice, Pardubice, Neratovice, the Ohře River inflow) confirming the spatial patterns of pollution of various environmental compartments in the Elbe basin reported by previous studies [38, 39]. The high PAHs contributions together with an above-average RISKHUMAN were surprisingly found in the upper reaches of the Elbe River and Morava River. This could only be explained by a high propensity of PAHs to atmospheric transport resulting in high concentration of airborne POPs in remote and unpolluted freshwater ecosystems [40]. The higher magnitude of RISKHUMAN was recorded in a consequence of some well-known hot spots in the Berounka catchment (the Litavka stream inflow [41, 42] or the influence of Ag-Pb-Zn deposit in Stříbro). Similarly, the elevated RISKHUMAN followed the Odra River with the regional rising near the Ostrava agglomeration where the long-term airborne pollution resulted in a higher PAHs and Cd contamination of agricultural soils [43]. The elevated level of quantified human risks was also recorded in soil samples near the confluence of the Morava and Dřevnice River below the Otrokovice-Zlín agglomeration as a regional centre of industry that involves especially plastic and rubber manufacturing and historically established chemical industries for secondary manufacturing (shoemaking tradition). Several local contamination rising were detected in a consequence of spatially confined pollution sources (industrial centre of Mladá Boleslav or the Svitava River near Boskovice). A cluster analysis was processed for the transformed data matrix of relative contributions of each analyte to the total estimation of human health risk to reveal patterns of pollution profiles of floodplain samples in the Czech Republic. The results proved high cophenetic correlation coefficient (r = 0.92) with the optimal number of 11 clusters in the cluster analysis. One substantial cluster (covered 71 from 100 sampling localities) and several regional pollution abnormalities were detected in our analysis (see **Figure 1**). The dominant cluster was formed by the localities characteristic in a high contribution of polycyclic aromatic hydrocarbons (and especially benzo(a)pyrene, benzo(a)anthracene and benzo(b)flu‐ oranthene) and in an elevated contribution of lead to total estimation of health risks. Some regional pollution abnormalities were connected to higher contribution of organochlorine pesticides (the Berounka and Ohře River), elevated contribution of PCBs (the Elbe River), or geochemical anomalies connected to local metallogenic zones (deposits). When combining both the magnitude of estimated RISKHUMAN and structural characteristics of pollution profiles (the cluster analysis results), the highest estimated humanotoxicological risks proved only several localities with a high content of polycyclic aromatic hydrocarbons accompanied by higher lead contents (there are depicted the predominant pollution profiles for the localities with the elevated total RISKHUMAN hazard index in **Table 7**). The results of human risk assessment well correspond with the exceedance of indication limit values for human protec‐ tion. The indication limits of human health protection for PAHs and Pb contents were exceeded for several localities of floodplain soils in our study.

**Figure 1.** Similarity of the soil pollution profiles (relative contribution of pollutants to overall estimation of human risks—RISKHUMAN) of individual floodplain samples in a cluster analysis presented by the heatmap and a projection of dominant cluster in our dataset. *Note—the more intense red color the more similar samples.*

**Figure 2.** Spatial differentiation of magnitude of human health risks quantified using total RISKHUMAN (Equations 1–3) and visualisation of the regional hot spots (where RISKHUMAN > 1.5).


Notes

B(a)P—benzo(a)pyrene; B(a)A—benz(a)anthracene; B(b)F—benzo(b)fluoranthene; In(cd)P—Indeno(1,2,3-cd)pyrene; DiB(ah)A – Dibenz(a,h)anthracene, Pb – lead.

\*Exceeding of indication limit of human health protection for particular pollutant and locality.

**Table 7.** Priority pollutants for floodplain samples with topmost estimation of human health risks (RISKHUMAN > 1.5) and their pollution profiles (predominant pollutant concentrations and their relative contribution to RISKHUMAN).

## **5. Conclusion**

The proposed system of hierarchical limit values helps to protect soil environment, food chain, and human health against the contamination and will improve the current version fundamentally. The currently valid principle of maximally tolerable values presenting no ac‐ tual risk (but selected agricultural soils on two categories—useful and non-useful by the ex‐ istence of one limit value level) will be replaced by the system of hierarchical limit values referred to an individual level of the risks and followed by appropriate measures in the cas‐ es of limit exceeding. The case study of floodplains research proved the operability of the established methodology and verified relevancy of the human health limits (indication lim‐ its of human health protection) in Czech proposal of soil protection legislation. The estab‐ lished methodology helped to reveal the areas where the soil does not meet the soil quality standards and where the human health risks were elevated. The characteristic pollution pro‐ files of floodplain soils with elevated human health risks were defined on the basis of the results.
