adding exceptions in site representativeness

guidance_docs/SurveillanceStrategies-GuidanceDoc.md

@@ -27,7 +27,7 @@ The sampling site is where wastewater samples are collected as part of the waste
 
 2. **Representativeness of site**
 
-When determining which site is most appropriate, the target population within the selected location should be the primary consideration. For example, with a target population of an entire neighborhood, if sampling untreated wastewater, influent would be most appropriate as it would capture all waste coming into the plant. It is also possible to calculate the number of individuals represented by a particular wastewater treatment plant to assist with evaluating representativeness of a population ([Stikkers, 2022](https://repository.tudelft.nl/record/uuid:99b638a5-c0ff-4dd9-aa9b-2752cc6cc88d)). However, there are also wastewater surveillance programs with a more targeted population, such as travelers during the height of the Covid-19 pandemic. For example, the CDC Ginkgo Bioworks monitoring program sampled aircraft wastewater following international flights across the Atlantic in 2022 ([Morfino et al, 2023](https://www.cdc.gov/mmwr/volumes/72/wr/mm7208a3.htm?fbclid=IwAR1eldb9op1eu9rDkK8JsVKaskkkooBwDiKUw0qff5VqVMvZxH5mBpMO2eM)). In many contexts where wastewater transport networks are not available, it may be necessary to leverage information about local environmental flows and surface waters to identify good sampling sites (e.g., [McQuade & Blake et al. 2023](https://www.sciencedirect.com/science/article/pii/S2666524723000101?via%3Dihub)). The use of tools including [es.world](https://es.world/) allow for local topography, bodies of water, and population density to be used to ensure sampling sites are broadly representative. 
+When determining which site is most appropriate, the target population within the selected location should be the primary consideration. For example, with a target population of an entire neighborhood, if sampling untreated wastewater, influent would be most appropriate as it would capture all waste coming into the plant. It is also possible to calculate the number of individuals represented by a particular wastewater treatment plant to assist with evaluating representativeness of a population ([Stikkers, 2022](https://repository.tudelft.nl/record/uuid:99b638a5-c0ff-4dd9-aa9b-2752cc6cc88d)). However, there are also wastewater surveillance programs with a more targeted population, such as travelers during the height of the Covid-19 pandemic. For example, the CDC Ginkgo Bioworks monitoring program sampled aircraft wastewater following international flights across the Atlantic in 2022 ([Morfino et al, 2023](https://www.cdc.gov/mmwr/volumes/72/wr/mm7208a3.htm?fbclid=IwAR1eldb9op1eu9rDkK8JsVKaskkkooBwDiKUw0qff5VqVMvZxH5mBpMO2eM)). In many contexts where wastewater transport networks are not available, it may be necessary to leverage information about local environmental flows and surface waters to identify good sampling sites (e.g., [McQuade & Blake et al. 2023](https://www.sciencedirect.com/science/article/pii/S2666524723000101?via%3Dihub)). It is important to note that practitioners may need to develop sampling strategies for situations such as “flying toilets” in Kenyan slums or open defecation in fields (e.g., in Lao PDR), which are unlikely to be adequately represented in samples collected from main streams. The use of tools including [es.world](https://es.world/) allow for local topography, bodies of water, and population density to be used to ensure sampling sites are broadly representative. 
 
 3. **Uniformity across sites**