Highly populated coastal environments receive large quantities of treated and untreated wastewater from human and industrial sources. Bivalve molluscs accumulate and retain contaminants, and their analysis provides evidence of past contamination. Rivers and precipitation are major routes of bacteriological pollution from surface or sub-surface runoff flowing into coastal areas. However, relationships between runoff, precipitation, and bacterial contamination are site-specific and dependent on the physiographical characteristics of each catchment. In this work, we evaluated the influence of precipitation and river discharge on molluscs' Escherichia coli concentrations at three sites in Central Italy, aiming at quantifying how hydrometeorological conditions affect bacteriological contamination of selected bivalve production areas. Rank-order correlation analysis indicated a stronger association between E. coli concentrations and the modelled Pescara River discharge maxima (r = 0.69) than between E. coli concentration and rainfall maxima (r = 0.35). Discharge peaks from the Pescara River caused an increase in E. coli concentration in bivalves in 87% of cases, provided that the runoff peak occurred 1–6 days prior to the sampling date. Precipitation in coastal area was linked to almost 60% of cases of E. coli high concentrations and may enhance bacterial transportation offshore, when associated with a larger-scale weather system, which causes overflow occurrence.

人口稠密的沿海环境接收大量来自人类和工业来源的经过处理和未经处理的废水。双壳类软体动物会积聚并保留污染物，它们的分析提供了过去污染的证据。河流和降水是地表或地下径流流入沿海地区的主要细菌污染途径。然而，径流、降水和细菌污染之间的关系因地点而异，并取决于每个集水区的自然地理特征。在这项工作中，我们评估了降水和河流流量对软体动物大肠杆菌的影响意大利中部三个地点的浓度，旨在量化水文气象条件如何影响选定双壳类产区的细菌污染。等级相关分析表明，大肠杆菌浓度与模拟的佩斯卡拉河流量最大值 ( r = 0.69) 之间的关联性强于大肠杆菌浓度与降雨最大值 ( r = 0.35)之间的关联。如果径流高峰发生在采样日期前 1-6 天，那么在 87% 的情况下，佩斯卡拉河的排放高峰会导致双壳类动物中大肠杆菌浓度的增加。近 60% 的大肠杆菌病例与沿海地区的降水有关 当与更大规模的天气系统相关时，高浓度并可能增强细菌在海上的运输，从而导致溢出发生。