RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 61137, Brno, Czech Republic.
RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 61137, Brno, Czech Republic.
Environ Pollut. 2022 Jun 1;302:119050. doi: 10.1016/j.envpol.2022.119050. Epub 2022 Feb 23.
Contamination with hydrophobic organic compounds (HOCs) such as persistent organic pollutants negatively affects global water quality. Accurate and globally comparable monitoring data are required to understand better the HOCs distribution and environmental fate. We present the first results of a proof-of-concept global monitoring campaign, the Aquatic Global Passive Sampling initiative (AQUA-GAPS), performed between 2016 and 2020, for assessing trends of freely dissolved HOC concentrations in global surface waters. One of the pilot campaign aims was to compare performance characteristics of silicone (SSP) and low-density polyethylene (PE) sheets co-deployed in parallel under identical conditions, i.e. at the same site, using the same deployment design, and for an equal period. Individual exposures lasted between 36 and 400 days, and samples were collected from 22 freshwater and 40 marine locations. The sampler inter-comparability is based on a rationale of common underlying principles, i.e. HOC diffusion through a water boundary layer (WBL) and absorption by the polymer. In the integrative uptake phase, equal surface-specific uptake in both samplers was observed for HOCs with a molecular volume less than 300 Å. For those HOCs, transport in the WBL controls the uptake as mass transfer in the polymer is over 20-times faster. In such a case, sampled HOC mass can be converted into aqueous concentrations using available models derived for WBL-controlled sampling using performance reference compounds. In contrast, for larger molecules, surface-specific uptake to PE was lower than to SSP. Diffusion in PE is slower than in SSP, and it is likely that for large molecules, diffusion in PE limits the transport from water to the sampler, complicating the interpretation. Although both samplers provided mostly well comparable results, we recommend, based on simpler practical handling, simpler data interpretation, and better availability of reliable polymer-water partition coefficients, silicone-based samplers for future operation in the worldwide monitoring programme.
疏水性有机化合物（HOCs）如持久性有机污染物的污染对全球水质产生负面影响。为了更好地了解 HOCs 的分布和环境归宿，需要准确且具有全球可比性的监测数据。我们介绍了一项概念验证性全球监测活动——水生全球被动采样倡议（AQUA-GAPS）的首批结果，该活动于 2016 年至 2020 年期间进行，旨在评估全球地表水自由溶解 HOC 浓度的趋势。试点活动的目的之一是比较在相同条件下（即在同一地点、使用相同的部署设计和相同的时间）平行部署的硅树脂（SSP）和低密度聚乙烯（PE）片的性能特征。单次暴露时间在 36 至 400 天之间，从 22 个淡水和 40 个海洋地点采集了样本。采样器的可比较性基于共同基本原理的合理性，即 HOC 通过水边界层（WBL）扩散和聚合物吸收。在综合吸收阶段，对于分子体积小于 300 Å 的 HOC，两种采样器的表面比吸收相等。对于这些 HOC，WBL 中的传质控制着吸收，因为聚合物中的传质速度快 20 倍以上。在这种情况下，可以使用针对 WBL 控制采样的现有模型将采样的 HOC 质量转换为水溶液浓度。相比之下，对于较大的分子，PE 的表面比吸收低于 SSP。PE 中的扩散速度比 SSP 慢，对于大分子，PE 中的扩散可能会限制从水到采样器的传输，从而使解释变得复杂。尽管两种采样器都提供了大多可比较的结果，但我们建议基于更简单的实际处理、更简单的数据解释和更可靠的聚合物-水分配系数的可用性，在未来的全球监测计划中使用基于硅树脂的采样器。
