Characterization and Determination of the Toxicological Risk of Biochar Using Invertebrate Toxicity Tests in the State of Aguascalientes, Mexico  
[PERSON]  
1 Institut fur angewandtes Stoffstrommanagement (IfaS), Umwelt-Campus Birkenfeld, Hochschule Trier, 55761 Birkenfeld, Germany; [EMAIL_ADDRESS]  
[PERSON]  
2 Facultad de Ingenieria, Universidad Panamericana, Josemaria Escriva de Balaguer 101, Aguascalientes, Aguscalientes 20290, Mexico 2  
[PERSON]  
3 Centro de Ciencias Basicas, Departamento de Quimica, Universidad Autonoma de Aguascalientes, Avenida Universidad 940, Aguascalientes, Aguascalientes 20131 C.P., Mexico; [EMAIL_ADDRESS] (D.R. be tremendously different produced from a broad range of different types of biomass and thus serve different purposes and trigger unwanted effects [5; 6; 7]. Within the last six years, considerable progress has been made with regard to standardization, pyrolysis techniques, quality, and sustainability control of BC. In 2012 the European Biochar Foundation established an accredited control system (ACS) for BC named European Biochar Certificate (EBC) that certifies the compliance with quality parameters and thresholds for contaminants, the use of accredited analytical methods and the sustainability of production [8]. Together with the United States (US) induced International Biochar Initiative (IBI) [9], EBC led to considerable improvements in BC quality and the sustainability of its production and hazard-free application for environmental safety, both in agriculture and livestock feed. The certification under the EBC (as the US counterpart IBI) solicits, in addition to technology-related requirements (e.g., heat recovery, complete combustion of the pyrolysis gases, etc. ), compliance with certain limit values of predefined physical and chemical parameters of the products. The physical parameters serve primarily to classify the coals affiliation or category (e.g., pyrolytic coal, hydrochar, BC, etc.) and quality (e.g., degree of inertization and recalcitrance (molar elemental ratios), surface area, density, storage capacity, etc.). The chemical parameters are used to determine the hazard potential of char-bounded contaminants (e.g., polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-\(p\)-dioxins and furans (PCDD/Fs), fluorine, polychlorinated biphenyls (PCBs), and heavy metals). Heavy metals are either already contained in the feedstock or not and become concentrated by the thermochemical process. Aromatic and polychlorinated toxicants instead emerge during carbonation, reduction, and aromatization phases [8; 10; 11; 12]. Potential contamination of soils when using BC in agriculture, as well as possible intoxications when used as animal feed, should be avoided as far as possible by adhering to the limit values specified by the current standard. The hazard potential of BC is generally limited, as the hazardous substances contained in BC are strongly bound, due to the high adsorption potential caused by the porous structure and increased redox potential [7; 13]. In addition aforementioned hazardous substances are very hydrophobic, exhibit low biological availability and are hardly metabolizable, as they are incorporated into the aromatic benzene ring skeleton [14; 15]. The concentration of PAHs is strongly dependent on feedstock, temperature, and design of the pyrolysis unit [13]. However, even if the strong adsorption capacity of BCs limits the noxiousness, mineralization and metabolization processes propelled by microfauna could potentially trigger a bioavailable release of pollutants. [PERSON] et al. [16] state, that pollutants in BC can result in toxicity to organisms during environmental application of BC. When toxic potencies of BC were assessed by different methods, a significant correlation between concentrations of PAHs and toxicity was observed. Re-condensation of volatile organic compounds (VOCs) during pyrolysis can result in BC containing compounds that are bioavailable and phytotoxic [17].