I suggest looking at some intermediate general science texts. Often there will be some simple computational problems involving very minor* algebra.  You might be able to find some that appeal to you although you will have to see what part of the algebra sequence they correspond to.  Green stuff has been of interest going back at least to the seventies.  And often 7th-8th grade general science (sort of like pre chemistry and pre physics, the way pre algebra is pre algebra) have either part or most of the curriculum around environmental topics.

I would just caution you to keep it rather simple.  Word problems can be hard, in general.  And you don't want to pick ones that segue too much into needing to teach (or even explain) general science.  But you can still find examples.  But please make them extra easy. 

Also, you may be able to repurpose an example or exercise to use the physical example but repurpose it to your chapter of algebra.  For example they talk about biocentration (DDT getting worse as you go up the food chain) and in the context of ratios, but you can think how to steal the basic science concept and make up an example with an inequality or the like.

*Things like ratios, percents, unit conversions, etc.  And while these may be rather minor in math land, having facility with this sort of simple calculation is very important as a scientist, office worker, etc.