I have 5 sentences I want to combine.I want to know if there are any problems with the way that I combine them.1. Another hazard is...

In reviewing your posting, I would agree that your
sentence is "correct." However, remember also that when you are
writing, you want not only to include information, but you also want your work to be of
interest if it is to be read by others. This can be done without altering the content of
the information you are sharing or the tone that your writing
requires to be considered formal writing.

You have achieved
the sound of formal writing: there are no cliches, colloquialisms or slang used.
However, to make it more interesting, you can easily alter the word order in your
sentence(s). While simple writing uses a "subject-verb" word order, it can be switched
around, where a dependent clause or a prepositional phrase can be added to the beginning
of the sentence, followed by a more traditional word order for the remainder of the
writing. There are almost endless possibilities. When you really want to grab your
audience, use a variety of sentence structures.

readability="6">

Repetitious sentence patterns [are] monotonous.
...most common patterns [are]...simple subject+verb
sentences.

I would also make
sure that the context of your information is very
clear.

As an example, you might
write:

Though
it is often desirable, groundwater can be a hazard if it finds its
way into a burial site, thereby causing canisters to leak and radiation to be carried
into aquifers that hold fresh untainted
water.

Phrases like, "Though
it is often desirable" and "thereby" are not required, but they make the sentence more
interesting and more sophisticated, even though you have not
altered the content of the sentence as much as its "tone." ("Tone" is the author's
feeling toward his subject: here it is serious.) I also added a
reference to what aquifers are, which simply provides a context for
the sentence and points to the danger of the things you mention, such as "hazard,"
"leak" and "radiation."

It is not necessary to write this
way: your sentence covers the basics, but with few additions and changing the sentence's
"syntax" (word order), or structure, your writing can be more interesting and
engaging.