Why not significant, even though their compositions were different between before and after treatment?

This is our example.
difference between before and after treatment (After-before)
element1(family) -0.002631625
element2 -0.001704079
element3 -0.000329896
element4 -1.50E-05
element5 -0.000700726
element6 -0.000615348
element7 0.004196757
element8 -1.59E-05
Might because their compositions were too small, a significant P-value is hard to detect. However their trend is same, their abundances always rich at before intervention. Which way you recommend to quantify this trend?
Thank for your help.