# Key Properties for the Toxicity Classification of Chemicals:
## 3 Chemical Properties and Safety Assessment Tests Required under the REACH  
With the aim of determining the toxicity of a substance and its potential danger, as well as establishing the conditions of safe use and other issues such as safety pictograms, for example, it is important to carry out different studies. First of all, it is important to determine the quantities per year of the substance to be analyzed, this is essential to determine what type of tests must be done. Once this has been determined, a human health, physicochemical, and environmental hazard assessment should be realized. Additionally, persistent, bioaccumulative and toxic, and very persistent and very accumulative assessments have to be conducted ([[https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX](https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX)]([https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX](https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX)): 32006R1907&from=ES accessed on 8 November 2022).  
Bearing this in mind, the physicochemical properties and the safety study (ecotoxicological and toxicological) required by REACH are presented. The necessary studies to be carried out, depending on the tons of substances that are marketed, are shown in Table 1. These studies are presented in detail below.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Tons/Year** & **Physicochemical Properties** & **Ecotoxicological Information** & **Toxicological Information** \\ \hline \multirow{8}{*}{\(>\)1000} & - & Degradation (biotic, & \\  & - & further testing) & \\  & - & Fate and behavior in the & \\  & & environment & - & Reproductive toxicity \\  & & (further information) & (developmental, one species) \\ \cline{3-4}  & - & Effects on terrestrial organisms: & - & Reproductive toxicity \\  & & - & invertebrates, plants (long term) & (two generations, one species) \\  & & - & Effects on sediment organisms & - & Carcinogenicity study \\  & & - & (long term) & \\  & & - & Effects on birds (long term & \\  & & or reproductive) & \\ \hline \multirow{8}{*}{\(100-1000\)} & \multirow{8}{*}{-} & \multirow{8}{*}{Stability in organic solvents and identity of relevant degradation products (if substance stability is considered to be critical)} & - & Aquatic toxicity in invertebrates \\  & - & Dissociation constant & - & Degradation (biotic, soil, \\  & - & Sediment, and identification of & & one species) \\  & & identity of relevant degradation products & degradation products) & - & Repeated dose toxicity (90 days, \\  & & products (if substance stability is considered to be critical) & - & Fate and behavior in the environment (adsorption/ \\  & - & Dissociation constant & desorption screening, \\  & - & Viscosity & - & desorption screening, \\  & - & & bioaccumulation in \\  & & Viscosity & - & aquatic species) \\  & & - & Effects on terrestrial organisms & \\  & & & (short term: invertebrates, plants, \\  & & & and soil microorganisms) & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Physicochemical properties and ecotoxicological and toxicological information proposed by REACH to classify a chemical.