**1. Introduction**

In 2016, the total waste generated in the EU-28 by all economic activities and households amounted to 2538 million tons, being 100.7 million tons classified as hazardous waste (HW), which means 4% of the total [1]. According to EU statistics, in the period 2010–2016 there was an increasing trend of around 5% in the generation of HW in the EU-28. Although landfilling is still the most predominant practice used to manage HW in the EU, recycling is also relatively important, as up to 37.8% of the total amount was recycled. Other alternatives include backfilling and incineration, either with or without energy recovery. The percentages of HW that is incinerated vary across the EU, with Norway, Denmark and Portugal presenting the highest rates (34%, 19% and 12%). In contrast, the contribution of incineration to HW managemen<sup>t</sup> in countries, such as Malta, Greece or Bulgaria is nominal.

In 2016, only 3.6% of the HW generated in Spain was incinerated. Currently, Spain counts with only one HW incinerator (HWI), which is located in Constantí (Tarragona, Catalonia, Spain). This facility has been continuously operating for 20 years since 1999, when it started its regular operations. In the 1996–1998 period, a pre-operational surveillance program was conducted to assess potential temporal changes that could occur regarding the exposure to environmental pollutants potentially emitted by the plant. The baseline survey included the analysis of polychlorinated dibenzo-*p*-dioxins and dibenzofurans (PCDD/Fs) and a number of trace elements, two groups of pollutants of high concern for the population, and whose levels in stack air must be periodically controlled [2]. The contents of PCDD/Fs and trace elements were determined in a wide range of environmental and biological samples [3–9]. Because diet is the most important route of exposure to these chemicals [10–12], the dietary intake by the local population was also evaluated [13,14]. The biomonitoring was based on the analysis of 11 trace elements in samples of hair from schoolchildren, blood from general population, as well as samples of autopsy tissues from individuals who had been residing near the plant for at least the last 10 years [3–5]. Since then, the concentrations of the same chemicals in the same matrices have been updated every 5 years [15–17]. Recently, we have reported the levels of As and a number of metals in human hair and blood of the population living in the neighborhood of the HWI [18,19].

In the present study, the concentrations of trace elements were determined in samples of autopsy tissues collected in 2019 from subjects who had been living near the HWI of Constantí. The temporal trends in the pollutant levels were also established by comparing the current results with those found in the baseline (1998) and the previously performed (2002–2007–2013) studies. Finally, the concentrations of these elements in autopsy tissues were correlated with those found in other biomonitors (human hair and blood) from non-occupationally exposed individuals living in the same area.

#### **2. Materials and Methods**
