Variability of Escherichia coli Concentrations in Rivers during Base-Flow Conditions in New Zealand.
Variability of Escherichia coli Concentrations in Rivers during Base-Flow Conditions in New Zealand.
复制标题
新西兰基流条件下河流中大肠杆菌浓度的变化。
DOI：
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发表时间：
2018
影响因子：
2.4
通讯作者：
E. Meenken
中科院分区：
文献类型：
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作者：
R. Muirhead;E. Meenken
已知河流中的浓度差别很大。许多研究都集中在风暴事件和粪便微生物浓度和流量之间的关系。然而，在基流条件下，微生物浓度仍然存在相当大的变化，并且很少有研究来了解河流中的这种短期变化。我们调查了基流中浓度的变化，在时间尺度的分钟，小时和天，并比较这从实验室复制的测量方法的变化。这是在夏季和冬季在三个不同大小的河流。使用变异系数（CV）分析变异性估计值。分钟时间尺度的变异性为17%，而实验室重复变异性为15%。然后，在每小时和每日时间尺度下，CV分别增加至约32%和60%。有强有力的证据表明，时间尺度（< 0.001）和河流（< 0.001）对浓度变化都有显著影响。夏季的浓度高于冬季，在最小的溪流中效果显著，在一个地点，所有夏季样品中的浓度>2000最可能数（mpn）100 mL。在解释用于与水质标准进行比较或用于校准模型的一次性取样结果时，应考虑到浓度的这种可变性。
concentrations in rivers are known to vary considerably. Much research has focused on storm events and the relationships between fecal microbe concentrations and flows. However, there is still considerable variability in microbial concentrations during base-flow conditions, and little research has been conducted to understand this short-term variability in rivers. We investigated the variability of concentrations in base flows at the time scales of minutes, hours, and days and compared this to variability from laboratory replication of the measurement methods. This was conducted in three different-sized rivers in both summer and winter seasons. Estimates of variability were analyzed using the coefficient of variation (CV). The variability at the minute time scale was 17%, compared with the laboratory replication variability of 15%. The CV then increased to approximately 32 and 60% at the hourly and daily time scales, respectively. There is strong evidence that both time scale ( < 0.001) and river ( < 0.001) significantly affect the variation in concentrations. The concentrations were higher in summer than winter, with a marked effect in the smallest stream, where at one site the concentrations were >2000 most probable number (mpn) 100 mL in all summer samples. This variability of concentrations should be considered when interpreting the results from a one-off grab sample used to compare against water quality standards or for calibrating models.