# Natural Versus Anthropic Influence on North Adriatic Coast Detected by Geochemical Analyses
## 4 Discussion
### Anthropic Signal  
The Zn and Pb concentrations found in well dated sediment cores collected at several locations along the western Adriatic Sea were successfully used to reconstruct the anthropogenic influence in the past [7,8,10].  
In samples from S1 site, Zn and Pb values fall far beyond the Holocene reference field, corresponding to the pre-industrial concentrations [10,41,42] (Table 2). The investigate time interval is limited (only the last nine years), however it is interesting to evidence that the observed decline over recent time of Pb and Zn concentrations (Figure 7) is in line with the historical trend reconstructed using data reported in the literature [59,60] (Table 5 and Appendix B) in the same area. Perhaps this is the result of the application of the Merli Italian Law 319, adopted in 1976, that regulates the concentrations of contaminants in wastewaters for environmental protection. The same assumption was suggested to explain the low content of trace metals observed in the sediments from the River Po delta [10]. Additionally, the Pb content reduction may be in response to the implementation of anti-pollution policies on automotive Pb in the second half of the 1980s in Western Europe [61].  
At the E1 site, the longer time interval sampled (see Section 4.1) provides the history of contamination during the last 100 years. The E1 normalized depth profiles of Pb and Zn (Figure 7) display a gradual increasing accumulation trend from the 1940s with a peak from 1980 to 2000 in particular for Pb concentration.  
Figure 7: Down-core variability of geochemical proxies (Pb/Al\({}_{2}\)O\({}_{3}\) and Zn/Al\({}_{2}\)O\({}_{3}\)) in S1 (red line) and E1 (green line) measured in ANOC16 cores.  
The detected major presence of these elements in the area around the mid-1940s is probably related to the gradual industrialization of the region after World War II. It is worth noting that, in Italy, the time interval of 1945-1963, known as \"Economic Miracle\", experienced a strong industrial development with an increase of the mechanical, chemical and ceramics industries [7].  
The observed increase in trace metals is consistent with what was found in previous investigations carried out along the coast between Cattolica and the mouth of the Rubicone River [62]. The strong increase from the 1980s (Figure 7, E1 site) correlates in time with marine dumping off Comacchio from 1986 to 1990, used as the disposal sites for dredged materials from the Ravenna port [7; 63]. In our opinion, the dumping influenced directly or indirectly the surrounding environment since the activity can destroy and/or degrade habitats for species as well as cause coastal pollution. The documented high accumulation of Pb and Zn may be explained with the southward dispersion of contaminated sediments under the influence of the WAC (Figure 1) from the dumping site to the E1 site located approximately 60 nautical miles away. The recent decrease of Zn and Pb observed since the early 2000s may be related to the application of the Italian Law 319/76 as mentioned above for S1 site.