chemical-physical analysis for all sites

In particular, the possibility of managing these materials as by-products and not as waste has been the subject of numerous regulatory interventions over the last decade, until the entry into force of the new Regulation containing the simplified discipline of the management of excavated earth and rocks (22 August 2017), contained in Presidential Decree no. 120 of 13 June 2017, which repealed all previous regulations (Ministerial Decree no. 161/2012, art. 184-bis, paragraph 2bis of the Consolidated Environmental Act, as well as art. 184-bis, paragraph 2bis of the Consolidated Environmental Act, as well as art. 184-bis, paragraph 2bis of the Consolidated Environmental Act, as well as art. 184-bis, paragraph 2bis of the Consolidated Environmental Act, as well 120, which repealed all previous regulations (Ministerial Decree no. 161/2012, art. 184-bis, paragraph 2bis of the Consolidated Act on the Environment, as well as arts. 41, para. 2 and 41-bis of Legislative Decree no. 69/2013).

Essentially, this Decree is currently the only applicable regulatory instrument that allows the use of excavation materials (excavated soil and rocks and backfill) from small and large construction sites, including those for the construction or maintenance of networks and infrastructures, as by-products.

The legislation dictates the criteria for the qualification of soil and rock as by-products, including, in addition to the demonstration that the contamination threshold concentration (CTC) values are not exceeded, two important new features:

• The methodology for the quantification of anthropogenic materials (they cannot exceed the maximum quantity of 20%), reported in Annex 10
• The criteria for assimilating backfill materials into excavated soil and rock (compliance with the transfer test, according to the methods in Annex 3 to the Ministerial Decree of 5 February 1998, with the exclusion of the asbestos parameter and comparison with the legal limits for groundwater).

The sampling procedures to be followed for environmental characterisation for plans for the use of excavated soil and rocks in large construction sites are also defined.

 

So what changes in the context of reusing excavated materials?

Whereas previously operators and supervisory bodies were free to assess the environmental quality of the soil, the current regulations eliminate this discretionary power. To be classified as by-products, excavated soil and rock, for all construction sites, must meet the criteria established by art. 184-bis of Legislative Decree no. 152/2006, compliance with which is assessed according to the procedural methods established by art. 4 of the new Regulation: these requirements are certified and demonstrated after carrying out a chemical-physical characterisation according to the methods defined in Annex 4, therefore through laboratory analysis.
It should be noted that the producer must demonstrate that the threshold concentration values in columns A and B, Table 1, Annex 5, Title V, of Part IV, of Legislative Decree No. 152 of 3 April 2006 are not exceeded.

In particular, Annex 4 shows the characteristics of the soil samples to be subjected to chemical laboratory analysis and the criteria for the definition of the analytes to be researched, establishing a minimum analytical set to be considered, shown in Table 4.1, which includes the determination of the following parameters: Arsenic, cadmium, cobalt, nickel, lead, copper, zinc, mercury, hydrocarbons C>12, total chromium, chromium VI, asbestos, BTEX, PAH. BTEX and PAH should be analysed if the excavation area is located within 20 metres of major road infrastructure and settlements that may have influenced the characteristics of the site through atmospheric emissions.
With regard to the methods for verifying environmental requirements, if there is evidence of contamination by human activity, including of the overburden (for example, in the presence of asbestos), the analytical determinations are conducted on the entire sample, including the particle size fraction larger than 2 cm, and the concentration is referred to the same.
In the case of earth and rock from excavations in solid rock, in order to verify compliance with the environmental requirements of Article 4 of the Regulation in question, the environmental characterisation is carried out after porphyrization of the entire sample.
If reuse on the same site is envisaged in a project subject to Environmental Impact Assessment, the operator must prepare a preliminary utilisation plan that integrates the environmental impact study. This plan must be integrated with the results of the sampling (to be sent to the authorities before work begins) and must include the volumes to be excavated and reused, the location and duration of the deposits, and the final location of the excavated soil and rocks.

Furthermore, a series of activities can be carried out on the excavated earth and rocks that fall within ‘normal industrial practices’, that make their reuse more effective and that are clearly specified in Presidential Decree 120/17. In this case, the earth may contain other materials (with no percentage limits, except for fillers) such as: concrete, bentonite, PVC, fibreglass, cement mixtures and additives for mechanised excavation, provided that the concentrations of pollutants are within the limits set out in columns A and B, Table 1 Annex 5 Legislative Decree 152/06.
These operations can only be carried out after demonstrating that the material is a by-product and not waste, otherwise it constitutes an illegal activity.
The experience gained by Tecno Piemonte Spa in the field of excavated earth and rocks, also in the face of the complexity of the regulatory scenario, underlines the fundamental role of the environmental analysis laboratory in providing technical-scientific support to the companies proposing and carrying out the work.

The highly qualified personnel of the Tecno Piemonte Spa environmental laboratory are available to prepare sampling plans and the subsequent analytical characterisation of excavated soil and rock.