School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK.
Environ Sci Pollut Res Int. 2010 May;17(4):898-907. doi: 10.1007/s11356-009-0279-1. Epub 2009 Dec 19.
BACKGROUND, AIM, AND SCOPE: The occurrence and fate of pharmaceuticals in the aquatic environment is recognized as one of the emerging issues in environmental chemistry and as a matter of public concern. Existing data tend to focus on the concentrations of pharmaceuticals in the aqueous phase, with limited studies on their concentrations in particulate phase such as sediments. Furthermore, current water quality monitoring does not differentiate between soluble and colloidal phases in water samples, hindering our understanding of the bioavailability and bioaccumulation of pharmaceuticals in aquatic organisms. In this study, an investigation was conducted into the concentrations and phase association (soluble, colloidal, suspended particulate matter or SPM) of selected pharmaceuticals (propranolol, sulfamethoxazole, meberverine, thioridazine, carbamazepine, tamoxifen, indomethacine, diclofenac, and meclofenamic acid) in river water, effluents from sewage treatment works (STW), and groundwater in the UK.
The occurrence and phase association of selected pharmaceuticals propranolol, sulfamethoxazole, meberverine, thioridazine, carbamazepine, tamoxifen, indomethacine, diclofenac, and meclofenamic acid in contrasting aquatic environments (river, sewage effluent, and groundwater) were studied. Colloids were isolated by cross-flow ultrafiltration (CFUF). Water samples were extracted by solid-phase extraction (SPE), while SPM was extracted by microwave. All sample extracts were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the multiple reaction monitoring.
Five compounds propranolol, sulfamethoxazole, carbamazepine, indomethacine, and diclofenac were detected in all samples, with carbamazepine showing the highest concentrations in all phases. The highest concentrations of these compounds were detected in STW effluents, confirming STW as a key source of these compounds in the aquatic environments. The calculation of partition coefficients of pharmaceuticals between SPM and filtrate (observed partition coefficients, Kobsp, Kobsoc), between SPM and soluble phase (intrinsic partition coefficients, Kintp, Kintoc), and between colloids and soluble phase (Kcoc) showed that intrinsic partition coefficients (Kintp, Kintoc) are between 25% and 96%, and between 18% and 82% higher than relevant observed partition coefficients values, and are much less variable. Secondly, Kcoc values are 3-4 orders of magnitude greater than Kintoc values, indicating that aquatic colloids are substantially more powerful sorbents for accumulating pharmaceuticals than sediments. Furthermore, mass balance calculations of pharmaceutical concentrations demonstrate that between 23% and 70% of propranolol, 17-62% of sulfamethoxazole, 7-58% of carbamazepine, 19-84% of indomethacine, and 9-74% of diclofenac are present in the colloidal phase.
The results provide direct evidence that sorption to colloids provides an important sink for the pharmaceuticals in the aquatic environment. Such strong pharmaceutical/colloid interactions may provide a long-term storage of pharmaceuticals, hence, increasing their persistence while reducing their bioavailability in the environment.
Pharmaceutical compounds have been detected not only in the aqueous phase but also in suspended particles; it is important, therefore, to have a holistic approach in future environmental fate investigation of pharmaceuticals. For example, more research is needed to assess the storage and long-term record of pharmaceutical residues in aquatic sediments by which benthic organisms will be most affected. Aquatic colloids have been shown to account for the accumulation of major fractions of total pharmaceutical concentrations in the aquatic environment, demonstrating unequivocally the importance of aquatic colloids as a sink for such residues in the aquatic systems. As aquatic colloids are abundant, ubiquitous, and highly powerful sorbents, they are expected to influence the bioavailability and bioaccumulation of such chemicals by aquatic organisms. It is therefore critical for colloids to be incorporated into water quality models for prediction and risk assessment purposes.
背景、目的和范围：药品在水环境中的出现和命运被认为是环境化学中的一个新兴问题，也是公众关注的问题。现有数据往往侧重于水相中药物的浓度，而对沉积物等颗粒相中的浓度研究有限。此外，目前的水质监测没有区分水样中的可溶相和胶体相，这阻碍了我们对水生生物中药物的生物利用度和生物积累的理解。在这项研究中，调查了选定药物（普萘洛尔、磺胺甲恶唑、美贝维林、硫利达嗪、卡马西平、他莫昔芬、吲哚美辛、双氯芬酸和甲氯芬酸）在英国河水、污水处理厂（STW）废水和地下水的浓度和相态关联（可溶相、胶体相、悬浮颗粒物或 SPM）。
研究了在不同的水生环境（河流、污水和地下水）中选择的药物（普萘洛尔、磺胺甲恶唑、美贝维林、硫利达嗪、卡马西平、他莫昔芬、吲哚美辛、双氯芬酸和甲氯芬酸）的存在和相态关联。通过错流超滤（CFUF）分离胶体。水样通过固相萃取（SPE）提取，而 SPM 通过微波提取。所有样品提取物均通过液相色谱-串联质谱（LC-MS/MS）在多反应监测中进行分析。
在所研究的所有水样中均检测到五种化合物（普萘洛尔、磺胺甲恶唑、卡马西平、吲哚美辛和双氯芬酸），其中卡马西平在所有相中浓度最高。这些化合物的最高浓度出现在 STW 废水中，证实 STW 是这些化合物在水生环境中的关键来源。在 SPM 和滤液（观察到的分配系数，Kobsp，Kobsoc）、SPM 和可溶相（内在分配系数，Kintp，Kintoc）以及胶体和可溶相（Kcoc）之间分配系数的计算表明，内在分配系数（Kintp，Kintoc）在 25%到 96%之间，比相关的观察到的分配系数值高 18%到 82%，而且变化较小。其次，Kcoc 值比 Kintoc 值大 3-4 个数量级，表明水生胶体是比沉积物更强大的吸附剂，可积累药物。此外，药物浓度的质量平衡计算表明，普萘洛尔的 23%-70%、磺胺甲恶唑的 17%-62%、卡马西平的 7%-58%、吲哚美辛的 19%-84%和双氯芬酸的 9%-74%存在于胶体相中。
结果提供了直接证据，表明胶体的吸附为水中的药物提供了一个重要的汇。这种药物/胶体的强烈相互作用可能为药物提供了长期的储存，从而增加了它们在环境中的持久性，降低了它们的生物利用度。
不仅在水相中而且在悬浮颗粒中都检测到了药物化合物；因此，在未来的药物环境归宿研究中，需要采取整体方法。例如，需要更多的研究来评估药物残留在水生沉积物中的储存和长期记录，因为这将对底栖生物产生最大影响。已经表明，水生胶体占水中总药物浓度的主要部分，这明确表明了胶体作为水生系统中此类残留的汇的重要性。由于水生胶体丰富、普遍且具有强大的吸附能力，预计它们会影响水生生物对这些化学物质的生物利用度和生物积累。因此，将胶体纳入水质模型对于预测和风险评估目的至关重要。
