Small and brief exceedances of chemicals above their guideline values in drinking water are unlikely to cause an appreciable increased risk to human health. As a result, short-term exposure values (STEV) can be derived to help decide whether drinking water can still be supplied to consumers without adverse health risks. In this study, three approaches were applied to calculate and compare STEV for pesticides. The three approaches included basing a STEV on the acute reference dose (ARfD) (Approach 1), removing conventional attribution rates and uncertainty factors from current guideline values (Approach 2) and extrapolating 1 d and 7 d no observed adverse effect levels (NOAEL) from existing toxicity data using a log-linear regression (Approach 3). Despite being very different methods, the three approaches produced comparable STEV generally within an order of magnitude, which often overlapped with other existing short-term exposure values such as short-term no adverse response levels (SNARL) and health advisories (HA). The results show that adjusting the current guideline value using standard extrapolation factors (Approach 2) often produced the most conservative values. Approach 2 was then applied to two other chemical classes, disinfection by-products (DBPs) and cyanotoxins, demonstrating the wider applicability of the approach.

中文翻译：

---

得出饮用水的安全短期化学暴露值（STEV）。

饮用水中少量和短暂地超过其指导值的化学品不太可能对人类健康造成明显的增加的风险。结果，可以得出短期接触值（STEV），以帮助确定是否仍可以向消费者提供饮用水而没有不利的健康风险。在这项研究中，采用了三种方法来计算和比较农药的STEV。这三种方法包括：在急性参考剂量（ARfD）的基础上建立STEV（方法1），从当前准则值中删除常规归因率和不确定性因素（方法2）以及推断1 d和7 d未观察到不良反应水平（NOAEL）使用对数线性回归从现有毒性数据中提取（方法3）。尽管方法截然不同，这三种方法产生的可比STEV通常在一个数量级内，通常与其他现有的短期暴露值（如短期无不良反应水平（SNARL）和健康建议（HA））重叠。结果表明，使用标准外推因子（方法2）调整当前准则值通常会产生最保守的值。然后将方法2应用于其他两个化学类别，即消毒副产物（DBP）和氰毒素，这表明该方法具有更广泛的适用性。结果表明，使用标准外推因子（方法2）调整当前准则值通常会产生最保守的值。然后将方法2应用于其他两个化学类别，即消毒副产物（DBP）和氰毒素，这表明该方法具有更广泛的适用性。结果表明，使用标准外推因子（方法2）调整当前准则值通常会产生最保守的值。然后将方法2应用于其他两个化学类别，即消毒副产物（DBP）和氰毒素，这表明该方法具有更广泛的适用性。