Is purification valid using water that is mixed with a source's location, unavoidable natural growth, or non-contaminating adjacent substances?

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Purification is valid in four distinct circumstances related to the Mudaaf category. First, when the addition is to the substance's natural location (like river or well water), where no separation is possible; this is agreed upon by all scholars. Second, water contaminated by things that cannot be avoided, such as algae, tree leaves falling in, or sediment at the bottom; this contamination is excused because avoidance is difficult, but if intentionally added, it follows the ruling of avoidable contaminants. Third, substances sharing water's properties of purity and purifying capability, such as soil (unless it thickens the water beyond flow) or sea salt, as their origin is water. Fourth, water changed by mere adjacency without actual mixture, such as being near oil, camphor, or amber, without dissolution, as this is a change of proximity.