Sulphur mustard (HD) was the most widely produced chemical warfare agent (CWA) in the history of chemical warfare (CW). Simultaneously, the loads of HD account as by far the largest fraction of the sea-dumped CW. Nowadays its presence in the marine ecosystems recognized as a serious threat for marine users and maritime industries. Although, during over a decade of research much has been done to assess the environmental threats linked with underwater chemical munitions. There are, however, essential gaps in scientific knowledge including scarce information about the aquatic toxicity thresholds of HD and its degradation products.

Standardized biotests were performed according to the Organisation for Economic Co-operation and Development (OECD) Test No. 202: Daphnia sp. Acute Immobilisation Test guidelines. Obtained results provide a solid foundation for comparison and categorisation of threats of HD and its degradation products. With the D. magna LC₅₀ aquatic acute toxicity threshold at as low as 224 ± 12 μg × L⁻¹, 1,2,5-trithiepane is very toxic, being one of the most toxic CWA degradation products that have been investigated up to date. It exhibits stronger effects than 1,4,5-oxadithiepane and diluted HD that turn out to be toxic. In total, the toxicity of 7 compounds has been estimated. Whenever possible, toxicity thresholds were compared with previously existing data originating from different biotests and mathematical modelling.

芥菜（HD）是化学战（CW）历史上生产最广泛的化学战剂（CWA）。同时，HD的负荷是迄今为止海上抛弃式CW的最大部分。如今，它在海洋生态系统中的存在已被视为对海洋使用者和海洋产业的严重威胁。尽管在十多年的研究中，已经做了很多工作来评估与水下化学弹药有关的环境威胁。但是，科学知识方面存在重大缺陷，包括关于HD及其降解产物的水生毒性阈值的信息不足。

根据经济合作与发展组织（OECD）第202号测试：Daphnia sp。进行了标准化的生物测试。急性固定测试指南。获得的结果为HD及其降级产品的威胁进行比较和分类提供了坚实的基础。与大型溞LC ₅₀在尽可能低的水生急性毒性阈值作为224±12微克×L ^-11,2,5-三乙pan具有极高的毒性，是迄今已被研究的毒性最高的CWA降解产物之一。它显示出比1,4,5-恶二硫烷和稀释的HD更强的作用，后者证明是有毒的。总体上，已经估计了7种化合物的毒性。只要有可能，就将毒性阈值与源自不同生物测试和数学模型的现有数据进行比较。