Department Material Physics and Analytics, BASF SE, Ludwigshafen, Germany.
Department of Aerosol Technology, BASF SE, Ludwigshafen, Germany.
Part Fibre Toxicol. 2017 Aug 7;14(1):29. doi: 10.1186/s12989-017-0210-8.
Man-made vitreous fibres (MMVF) are produced on a large scale for thermal insulation purposes. After extensive studies of fibre effects in the 1980ies and 1990ies, the composition of MMVF was modified to reduce the fibrotic and cancerogenic potential via reduced biopersistence. However, occupational risks by handling, applying, disposing modern MMVF may be underestimated as the conventional regulatory classification -combining composition, in-vivo clearance and effects- seems to be based entirely on MMVF after removal of the binder.
Here we report the oxide composition of 23 modern MMVF from Germany, Finland, UK, Denmark, Russia, China (five different producers) and one pre-1995 MMVF. We find that most of the investigated modern MMVF can be classified as "High-alumina, low-silica wool", but several were on or beyond the borderline to "pre-1995 Rock (Stone) wool". We then used well-established flow-through dissolution testing at pH 4.5 and pH 7.4, with and without binder, at various flow rates, to screen the biosolubility of 14 MMVF over 32 days. At the flow rate and acidic pH of reports that found 47 ng/cm/h dissolution rate for reference biopersistent MMVF21 (without binder), we find rates from 17 to 90 ng/cm/h for modern MMVF as customary in trade (with binder). Removing the binder accelerates the dissolution significantly, but not to the level of reference biosoluble MMVF34. We finally simulated handling or disposing of MMVF and measured size fractions in the aerosol. The respirable fraction of modern MMVF is low, but not less than pre-1995 MMVF.
The average composition of modern stone wool MMVF is different from historic biopersistent MMVF, but to a lesser extent than expected. The dissolution rates measured by abiotic methods indicate that the binder has a significant influence on dissolution via gel formation. Considering the content of respirable fibres, these findings imply that the risk assessment of modern stone wool may need to be revisited based on in-vivo studies of MMFV as marketed (with binder).
人造玻璃体纤维（MMVF）是大规模生产的隔热材料。在 20 世纪 80 年代和 90 年代对纤维效应进行了广泛研究之后，通过降低生物持久性来降低纤维化和致癌潜力，对 MMVF 的成分进行了修改。然而，由于对现代 MMVF 的处理、应用和处置的职业风险可能被低估，因为传统的监管分类——结合成分、体内清除率和效应——似乎完全基于去除粘合剂后的 MMVF。
在这里，我们报告了来自德国、芬兰、英国、丹麦、俄罗斯、中国（五个不同的生产商）和一个 1995 年前的 MMVF 的 23 种现代 MMVF 的氧化物组成。我们发现，大多数研究的现代 MMVF 可归类为“高铝、低硅羊毛”，但有几种接近或超过“1995 年前的岩石（石）羊毛”的边界。然后，我们使用在 pH4.5 和 pH7.4 下、有和没有粘合剂、在不同流速下的成熟的流动溶解测试，在 32 天内筛选了 14 种 MMVF 的生物溶解度。在报道参考生物持久性 MMVF21（无粘合剂）溶解率为 47ng/cm/h 的流速和酸性 pH 下，我们发现现代 MMVF 的溶解率为 17 至 90ng/cm/h，这是贸易中常见的（有粘合剂）。去除粘合剂会显著加速溶解，但不能达到参考生物可溶性 MMVF34 的水平。最后，我们模拟了 MMVF 的处理或处置，并测量了气溶胶中的粒径。现代 MMVF 的可呼吸部分较低，但不低于 1995 年前的 MMVF。
现代石绵 MMVF 的平均组成与历史上的生物持久性 MMVF 不同，但程度低于预期。非生物方法测量的溶解速率表明，粘合剂通过凝胶形成对溶解有显著影响。考虑到可呼吸纤维的含量，这些发现表明，需要根据市场上销售的 MMFV（有粘合剂）的体内研究来重新评估现代石绵的风险评估。
