Sentence parsing?

Question

県民集会では、日米両政府や関係省庁などへ県民の健康調査や基地周辺の土壌・河川の調査などの実施、また県には、水の安全確保に取り組むことなどを求めた決議案を採択しました。

https://www.qab.co.jp/news/20220411149782.html

How should I parse this sentence? What is the main clause? 日米両政府や関係省庁 doesn’t seem to be the subject because of the use of へ, which seems to mean "to".

This is my understanding. During the assembly, a 決議案 was adopted. According to the 決議案, the citizens asked 日米両政府や関係省庁 to implement two things (県民の健康調査 and 基地周辺の土壌・河川の調査). They also asked the prefecture to ensure the water safety.

Answer 1

Your understanding seems just fine. The main clause is this:

県民集会では、決議案を採択しました。
At the 県民集会, (the participants) adopted a resolution.

Everything else is a long relative clause that ends with 求めた and modifies 決議案.

求める takes a pair of a direct object and an indirect object like so:

A(に/へ)Bを求める
to request B from A
to ask A for B

に and へ are interchangeable. And this 求める has two such pairs joined by また:

	Aに/Aへ	Bを
1	日米両政府や関係省庁などへ	県民の健康調査や基地周辺の土壌・河川の調査などの実施(を)
2	県に[は]	水の安全確保に取り組むことなどを

は in 県には is a contrastive-wa. It may have been easier to parse this sentence if there had been を also after 実施, but it's optional.

Put together,

At the 県民集会, (participants) adopted a resolution that requests 1) Japanese and U.S. governments and related ministries to conduct health surveys of prefectural residents and soil and river surveys around the base, and 2) the prefecture to work on the water safety.

This sentence is a little convoluted but there is no newspaper-specific grammar.