All chemicals form non-extractable residues (NER) to various extents in environmental media like soil, sediment, plants and animals. NER can be quantified in environmental fate studies using isotope-labeled (such as ¹⁴C or ¹³C) tracer compounds. Previous NER definitions have led to a mismatch of legislation and state of knowledge in research: the residues are assumed to be either irreversibly bound degradation products or at least parts of these residues can be released. In the latter assumption, soils and sediments are a long-term source of slowly released residues. We here present a conceptual experimental and modeling approach to characterize non-extractable residues and provide guidance how they should be considered in the persistence assessment of chemicals and pesticides. Three types of NER can be experimentally discriminated: sequestered and entrapped residues (type I), containing either the parent substance or xenobiotic transformation products or both and having the potential to be released, which has indeed been observed. Type II NER are residues that are covalently bound to organic matter in soils or sediments or to biological tissue in organisms and that are considered being strongly bound with very low remobilization rates like that of humic matter degradation rates. Type III NER comprises biogenic NER (bioNER) after degradation of the xenobiotic chemical and anabolic formation of natural biomolecules like amino acids and phospholipids, and other biomass compounds. We developed the microbial turnover to biomass (MTB) model to predict the formation of bioNER based on the structural properties of chemicals. Further, we proposed an extraction sequence to obtain a matrix containing only NER. Finally, we summarized experimental methods to distinguish the three NER types. Type I NER and type II NER should be considered as potentially remobilizable residues in persistence assessment but the probability of type II release is much lower than that of type I NER, i.e., type II NER in soil are “operationally spoken” irreversibly bound and can be released only in minute amounts and at very slow rates, if at all. The potential of remobilization can be evaluated by chemical, physical and biological methods. BioNER are of no environmental concern and, therefore, can be assessed as such in persistence assessment. The general concept presented is to consider the total amount of NER minus potential bioNER as the amount of xenoNER, type I + II. If a clear differentiation of type I and type II is possible, for the calculation of half-life type I NER are considered as not degraded parent substance or transformation product(s). On the contrary, type II NER may generally be considered as (at least temporarily) removed. Providing proof for type II NER is the most critical issue in NER assessment and requires additional research. If no characterization and additional information on NER are available, it is recommended to assess the total amount as potentially remobilizable. We propose our unified approach of NER characterization and evaluation to be implemented into the persistence and environmental hazard assessment strategies for REACH chemicals and biocides, human and veterinary pharmaceuticals, and pesticides, irrespective of the different regulatory frameworks.

中文翻译：

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对于包括持久性的评估化学品和农药的非抽提残余物（NER）的统一方法。

所有的化学品形成非可萃取残余物（NER）在像土壤，沉积物，植物和动物的环境介质中的各种程度。NER可以在环境命运研究使用同位素标记的（如被量化¹⁴ C或¹³C）示踪剂化合物。上一页NER定义导致了法律和知识的状况在研究的不匹配：残留物被认为是要么不可逆结合降解产物，或者至少这些残留的部分可以被释放。在后一种假设，土壤和沉积物中缓慢释放残基的长期来源。在这里，我们提出一个概念上的实验和建模方法表征非可萃取残余物，并提供指导他们应该如何在化学品和农药的持久性评估考虑。三种类型的NER可以实验鉴别：螯合和包埋的残基（I型），包含任一母体物质或异生素转化产物或二者并具有确实已经观察到要释放的潜力。II型NER是共价结合的有机物质在土壤或沉积物或生物组织中的生物和被认为是非常低的再活化率这样的腐殖质降解率被强烈地结合残留。III型NER包括所述生物外源性化学品的降解和生物分子天然等氨基酸和磷脂，和其它生物质的化合物的合成代谢后形成生物NER（bioNER）。我们开发的微生物周转到生物量（MTB）模型来预测bioNER的基于化学物质的结构特性的形成。此外，我们提出了一种提取序列，以获得仅含有NER的矩阵。最后，我们总结实验方法来区分三种类型NER。I型NER和II型NER应被视为持久性评估潜在remobilizable残基，但II型释放的概率比I型NER的要低得多，也就是说，请在土壤II NER是“操作上说出”不可逆结合和CAN发布仅是微量，并在很慢的速度，如果在所有。再迁移的潜力可以通过化学，物理和生物方法进行评估。BioNER没有环境问题，因此，可以评定为这种持久性的评估。提出的总体思路是考虑NER负电位bioNER总量为xenoNER的数量，类型I + II。如果类型的明确区分I和II型是可能的，半衰期I型NER的计算被认为是不降解的母体物质或转化产物（S）。相反，II型NER通常可被认为是（至少暂时地）除去。提供II型NER的证据是NER评估中最关键的问题，需要进一步的研究。如果没有表征和上NER附加信息是可用的，则建议的总量评估潜在remobilizable。我们提出我们的统一NER鉴定和评价的方法来实现成REACH化学品和生物杀灭剂，人用和兽用药品和杀虫剂持久性和环境危害评估策略，不论不同的监管框架。如果没有表征和上NER附加信息是可用的，则建议的总量评估潜在remobilizable。我们提出我们的统一NER鉴定和评价的方法来实现成REACH化学品和生物杀灭剂，人用和兽用药品和杀虫剂持久性和环境危害评估策略，不论不同的监管框架。如果没有表征和上NER附加信息是可用的，则建议的总量评估潜在remobilizable。我们提出我们的统一NER鉴定和评价的方法来实现成REACH化学品和生物杀灭剂，人用和兽用药品和杀虫剂持久性和环境危害评估策略，不论不同的监管框架。