-Semester abroad in The University Of Leicester, UK
-Research experience: 20 days (total) at the Berkeley National Laboratory, ALS, doing EXAFS measurements.
-Applying to:
Chemistry graduate:
1.UC Berkeley
2. University of Maryland
3.University of Michigan
4.Arizona State University
5. Georgia Tech
Environmental Engineering:
1.University of Texas at Austin
2. University of Wisconsin Madison
I am afraid that the GRE scores will hurt your chances significantly at the highly selective of the programs you are applying to. I think you will have the highest chances at ASU of any others. You need to apply to some programs which are not as highly selective as these so that the GRE is not a filter that needs to be high before your full application is evaluated.
Find a program that does the kind of chemistry or environmental engineering that you are interested in and is not as highly ranked as the ones you list. Make sure that you are willing to go there and use it as your safety.
As @xraymancs says your GRE scores will hurt your chances, but so will your lack of research experience - if you only have 20 days total, that’s not much. Most PhD programs want you to have some experience doing research - at least a few months; commonly 1-2 academic years - before they will admit you.