Due to their size (Table 1) relative to the interstitial (void) space(s) within soils and unconsolidated sedimentary layers they pass through (Table 2 & Figure 2) virus are easily transported through soils and throughout aquifers. Several researchers have reported viruses primarily travel through preferential pathways. To help emphasize how efficiently pathogens within surface water sources may be transported into aquifers, it is estimated that up to 96% of water is transported through only 0.32% of the soil volume via preferential pathways.52 Pathways of preferential low can develop due to structures present in surface and subsurface soils and geologic structure(s)23 and serve to carry water and contaminants to depths very rapidly, resulting in greater impact on water quality than previously expected.23
Table 1: Size of virus
Table 2: Size of hydraulic pathways within soils and aquafers
Source: US Bureau of Soils
Figure 2: Comparative size of pathogens and hydraulic pathways
这些水通道可减少微粒(病毒)与土壤之间发生的潜在相互作用，这些相互作用与下列机制有关：A.) 吸附、B.) 布朗运动、C.) 离子交换、D.) 沉积、E.) 尺寸排阻、F.) 表面电荷(+/-)、E.) 范德瓦尔斯力。
Such hydraulic pathways serve to reduce potential interactions from occurring between particulates (virus) and soils related to the following mechanisms: A.) Adsorption, B.) Brownian motion, C.) Ion exchange, D.) Sedimentation, E.) Size exclusion, F.) Surface charge (+/-), and E.) Van Der Waals (forces).
由于流体力学的原因，优先路径也会阻止颗粒(病毒)从液体流动的通道中流出，而其他力则会导致水的析出。这些力量包括：A.) 渗透压(低→高浓溶液)；作用——析水量取决于地下水离子浓度与被输送的水(通常是地表水)之间的差异。当水被析出时，微粒和病毒并没有析出，导致它们在这些途径中剩余的水内的浓度增加。由于地下水的导电性(离子强度)通常与高浓度的钙、镁、硫酸盐和氯化物有关，所以对这种现象的敏感性通常与这些离子的高浓度有关。B.) 毛细力；作用——地下土壤颗粒间(和颗粒内部)的间隙越小，在颗粒内部吸引和保留液体的力就越大。这将影响水迁移到微粒和病毒不能到达的地方。反过来，这也有助于优先途径脱水和病毒集中。此外，诸如微生物(病毒)之类的微粒是以胶质的形态转移的52。因此，它们不会沉淀，也不能通过上述机制从水中去除，这就促使它们能转移到蓄水层并在整个蓄水层内迁移。
Due to the mechanics of fluid dynamics, preferential pathways also prevent particles (virus) from exiting channels of liquid flowage while other forces cause the extraction of water. These forces include: A.) Osmotic pressure (Low → High concentrate solutions); Effect –the amount of water extracted is dictated upon the difference in ionic concentration of groundwater verses the water being transported (typically surface water). As water is extracted, particulates and virus are not, causing their concentration within the remaining volume of water within such pathways to increase. Because ground water conductivity (ionic strength) is typically associated with higher concentrations of calcium, magnesium, sulfates and chlorides, susceptibility to this phenomenon is typically associated with higher concentrations of these ions. B.) Capillary Force; Effect – the smaller the interstitial spaces between (and within) granules of subsurface soils, the greater the force becomes to attract and retain fluids within them. his will affect water to migrate into areas where particulates and virus cannot. In turn, this also serves to dewater preferential pathways and concentrate virus. In addition, particulates such as microorganisms (virus) are transported as colloids.52 Accordingly, they will not settle and cannot be removed from water by the mechanisms described above and facilitates their transport to (and throughout) drinking water aquafers.
这些现象将在下面的参考文献中进一步描述10、24-29。有研究报告证明病毒可能在几周内从污染源转移到220 ~ 300米深的市政井21，而在裂隙基岩中的转移仅需几个小时30。
These phenomena are further described within the following references. 10、24-29 Studies report virus may be transported from a contaminant source to municipal wells that were 220 to 300 meters deep within a matter of weeks21 and on the order of hours in fractured bedrock.30
Penetration of pathogenic viruses through soils and geological strata into aquifers seems much more likely than for pathogenic bacteria and protozoa31 and survive for extended periods of time9,32 and transported over long distances.33 In addition to what is described above, Table 3 provides a selection of factors that influence virus entry and travel within groundwater aquifers.
Table 3: Factors that influence virus entry and travel throughout an aquifer
An additional note of interest is due to their unique genetic signatures, coupled with our current ability of detecting them in trace quantities, epidemiologists are now considering the use of clinical data as a means of tracing plumes of viral pathogens in aquifers over time (≤ 3 years). Such data sets produce virus “snapshots” of infected populations. Wherein, when correlated with the presence of viral pathogens, as measured within localized groundwater sources, serve as a marker for tracking virus and groundwater movement.34
The presence of viral genomes in groundwater demonstrate travel times in aquifers of two to three years.35 A conservative estimate for virus survival in groundwater is three years, whereas32 a reasonable estimate is one to two years.9 Figure 3 provides an overview of factors influencing virus survival.
Figure 3: An overview of factors influencing virus survival