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EOX is a useful parameter in the estimation of exposure to POPs in environmental samples from different sources

The environmental quality of aggregates

Moral Alicia Santa - Olalla, Centre of studies and experimentation of public works (yields)
Other authors:
Ignacio Rieiro (University of Castilla - La Mancha)
Mayte Larrea (CENIM)
Amalia Cerdá (TIRME)

17/03/2011

on March 17, 2011

Aggregates use artificial in the construction of roads in place of those from natural sources is a measure that may favorably impact the industrial symbiosis of activities that are involved. Reduces demand for arid natural in the construction of road infrastructure and restricted the flow of materials going to landfill deposit. The valorisation of artificial aggregates is conditioned, among other requirements, the satisfaction of the technical and environmental specifications.

Artificial aggregates is a material which is derived from industrial by-products and that has a defined usage pattern. Secondary sources of aggregates included indicate slag of electric furnace steel, slag from municipal waste incineration, the sands of moulding, etc. Given that the origin of artificial aggregates is different from the natural hopefully a different composition in what refers to minority components and trace. That is why these materials are subject to the assessment of the release of substances which could endanger human health and the environment.

The environmental dynamics of bioaccumulation, biomagnification and toxicity that exhibit Polihalogenados organic compounds such as PCBs and dioxins and furans requires control of the presence of these in artificial aggregates. In both cases it's families of compounds which bring together species of similar chemical behavior, but whose toxicity is extremely variable. Why it for practical purposes is of interest the use of critical parameters such as the EOX (extractable organohalogen compounds) prior to the identification and quantification of each possible PCB, dioxin or furan present, once exceeded a certain threshold of EOX in artificial aggregates. PCBs grouped theoretically to a family of about 209 Members and 75 and 135, in the case of dioxins and furans, respectively.

Table 1: concentration of EOX in environmental samples.

This technical communication shows the results obtained in the quantification of EOX in aggregates derived from incineration slag samples. Describes the procedure followed for the quantification and contrasted the levels found with those present in the literature.

The content of EOX as an indicator of the presence of POPs in secondary materials

The use of the secondary materials in the construction of roads is a measure that may favorably impact the industrial symbiosis of activities that are involved: the construction of road infrastructure and industrial processes that are sources of arid artificial. Artificial aggregates is a material derived from industrial by-products and which has a usage pattern. It is subject to the satisfaction of the technical and environmental requirements making it suitable for certain applications. Depending on the type of source, it will be necessary to assess the presence in these materials of persistent organic compounds (POPs).

The use of the secondary materials in the construction of roads is a measure that may favorably impact the industrial symbiosis

The term COP brings together families of compounds chemically diverse (PCBs, dioxins and furans and organochlorine pesticides), but with a common environmental dynamics: the persistence, bioaccumulation and potential for transport to long distance, as well as being toxic at low concentrations. Molecular characterization of the compounds present in different environmental matrices organohalogen, usually not quantitative so the use of parameters as the EOX collects double interest. Firstly, ecotoxicological, i.e. reporting of total content, that is related to exposure to organohalogen compounds (table 1). Second, policy: requirement to meet by the arid artificial derived from secondary sources according to German standard, set at 3 mg Cl/kg.

Figure 1a: procedure for extraction and analysis of organohalogen compounds.

Materials and methods

We analysed samples of arid artificial (AA) derived from slag incineration of waste urban (EIRU) from plants that operate with different combustion technology. The procedure of extraction (4) and quantification, is shown in Figure 1.a. Data processing and statistical treatment of the same (5 and 6) are detailed in Figure 1b. Figure 2 the obtained results are presented and compared to levels present in the literature (7 and 8).