As it is known temperature, protection from sunlight, presence of organic compounds, association with particulates and least attenuated microbial activity37-39 influence survivability of virus in groundwater, speciation (virus) and soil composition do so as well. Clay particles are particularly effective at protecting virus from natural decay.40,41 Some types of organic matter (i.e., proteins) are also reported to better protect viruses from inactivation.42
Of particular interest is the manner which virus accumulate within geologic strata by adsorption. Over time, virus in such areas become highly concentrated. Then subsequently desorbed unilaterally into the flowage of an aquifer, inherently creating highly concentrated plumbs of virus.39,42 Since virus-soil interactions are very sensitive to surface charge, any water quality change that is enough to cause a charge reversal will result in the desorption of virus.43,44 Water quality changes that can result in desorption include an increase in pH, a decrease in ionic strength, and the presence of organic matter.40,45-47 For example, when alkaline septic effluent mixes with groundwater, the increased pH allows rapid desorption and transport of virus, especially under saturated flow conditions.48 Rainfall recharge after a storm may decrease ionic strength and cause virus to desorb and transported. As such, viruses may continue to contaminate an aquifer at high concentrations on a periodic basis long after their initial entry.40,49
Due to the seasonality of porcine epidemic diarrhea (PEDV) and porcine reproductive and respiratory syndrome (PRRSV) outbreaks, it is apparent water temperature may serve as a critical factor regarding their survivability.
在对南非饮用水中腺病毒的一项为期一年的调查中，发现腺病毒的检测率在7月达到高峰(南非冬季)，经处理和未经处理的水样的腺病毒呈阳率分别为30%和60%。只有当水温低于23°C时，才能在南非豪登省的Florida西南部的一个河口处检测到肠病毒。在一项体外研究中，在22°C的海水中与在30°C的海水中相比，脊髓灰质炎病毒的存活率和检出率都有所提高。在人工海水中，用逆转录聚合酶链反应(RT - PCR)在22°C的水中至少可检测到病毒长达60天，而30°C的水中只能检测到30天。同样地，在海水中，4°C时需要671天才能灭活海水中90%的脊髓灰质炎病毒和甲肝病毒，而在25°C时只需要25天。在一项用聚合酶链反应(PCR)评估一个多功能河口中人和牛的肠道病毒的研究中，发现，所有病毒类型均与冷水温度相关，如图4.23所示23。
In a year-long survey of the occurrence of adenoviruses in drinking water in South Africa, adenovirus detection peaked in July (winter in South Africa), when up to 30% and 60% of treated and raw water samples were positive for adenoviruses, respectively. Enteroviruses were detected from an estuary in southwest Florida only when the water temperature was below 23° C. In an in vitro study, enhanced poliovirus survival and detection were observed at 22° Celsius (C) compared to 30° C in seawater. In artificial seawater, viruses were detected by reverse transcription polymerase chain reaction (RT-PCR) for at least 60 days at 22° C but for only 30 days at 30° C. Similarly, in seawater, it took 671 days to inactivate 90% of poliovirus and hepatitis A virus at 4° C and only 25 days at 25° C. In a study evaluating both human and bovine enteric viruses by polymerase chain reaction (PCR) in a mixed-use estuary, it was found that all virus types were correlated with cool water temperatures as shown in Figure 4.23
Human and bovine enteric viruses by PCR in a mixed-use estuary, correlated with cool water
注：2002年7月至12月，格鲁吉亚阿尔塔马哈河下游的月平均水温(°C)与人肠病毒、人腺病毒(同时检测到)以及牛肠病毒的样本阳性率(n = 5)4。文献：水生环境中人类和动物的肠道病毒：健康风险、检测和潜在的水质评估工具。作者：Theng-Theng Fong, Erin K. Lipp Microbiol Mol Biol Rev. 2005 Jun; 69(2): 357–371.
Note: Percentage of samples positive for human enteroviruses and human adenoviruses (detected simultaneously), as well as bovine enteroviruses, by month versus the mean monthly water temperature (°C) along the lower Altamaha River, Georgia, between July and December 2002 (n = 5)4.Enteric Viruses of Humans and Animals in Aquatic Environments: Health Risks, Detection, and Potential Water Quality Assessment Tools. Theng-Theng Fong, Erin K. Lipp Microbiol Mol Biol Rev. 2005 Jun; 69(2): 357–371.