The phrase "as it contained" is correct and usable in written English.
You can use it to refer to something that is included or encompassed within another thing, often in a descriptive or explanatory context.
Example: "The report was comprehensive, as it contained all the necessary data and analysis for the project."
Alternatives: "since it included" or "because it encompassed".
Web of Science was chosen as our primary citation index as it contained over 90 million records through its 7 online databases, which would have made searches into smaller citation indexes largely redundant (e.g., EMBASE contains over 28 million records).
A more problematic site is area 25 as it contained many labeled fibers, especially at its caudal levels.
This version was even more special as it contained sweet grape molasses and sometimes tahini.
But diplomats who had seen the proposal said it left out as much as it contained.
As it contained 2% THC – banned in the UK in concentrations above 0.3% – customs officials had to confiscate it.
Sunil happened to know this part of Mumbai, as it contained the cat-infested t.b. sanatorium where his mother and neighbors had been treated before they died.
"In this case, the file was kept closed and retained as it contained information from the security services and advice from the law officers.
Tokyo's governor recommended that babies be kept away from the city's tap water as it contained higher levels of radioactive iodine.
It allowed the Chamber Orchestra of Europe to blossom in Brahms as deftly as it contained the magnificent sonority of the Bavarian forces in Tchaikovsky.
The original pivot raised concerns in China, especially as it contained a new defence agreement with Australia, including the original announcement of the rotation of marines through a military base in Darwin.
Balotelli was charged by the FA after posting a picture of Super Mario on his Instagram page which contained racist and antisemitic language as it contained the phrases "jump like a black man and grab coins like a Jew".
