You should be able to read all the actual environment variables, for example.
:!echo $PATH
Your problem is with personal environment variables.
gvim? , -.
, bash .bash_profile.
, .bashrc, .
.bashrc, , , .
gvim , .bashrc , .
info bourne, . 9.1.2
, :
MYENVIRONMENTVARIABLE=new value of environment variable
export MYENVIRONMENTVARIABLE
.bash_profile, , - , , ( , , .bash_profile).
, , , , .