The part of the sentence 'can only be collected' is correct and is commonly used in written English.
You can use it to describe an action or an item that is not immediately available and must be obtained in some way. For example: The books in this library are rare and can only be collected upon special request.
Under Nobel rules, the award can only be collected by the laureate or close family.
Original magazines with covers still attached come sealed in plastic packaging with a 'Category 1 Restriction' warning and can only be collected from a student office by providing proof of age.
We assume that observations can only be collected from this system once every n0 discrete time steps.
Sadly the prize can only be collected in San Francisco, which is a real bummer if you're totally into inflatable kangaroos.
However, because of the complexity and harshness of leaching process, data can only be collected sparsely, which results in data deficiency in the modeling process.
However, there are some orchid taxa which can only be collected opportunistically and in small numbers which need an alternative approach.
The watermark can only be extracted by collecting all these descriptions.
Different cultures and different countries with different economic levels can only be described by collecting appropriate additional data.
In practice, the exact value of t ij is unknown and can only be estimated by collecting measures on the network, which can be affected by measurement errors.
The second issue – testing the placement of these taxa – can only be addressed by collecting more data: filling in the gaps or sequencing new genes.
Carrier animals can only be identified by collecting esophageal-pharyngeal fluids for virus isolation and/or the detection of nucleic acids.
