  Space-time variation of fundamental physical constants in expanding Universe
is predicted by a number of popular models. The masses of second generation
quarks are larger than first generation quark masses by several orders of
magnitude, therefore space-time variation in quark masses may significantly
vary between each generation. We evaluate limits on variation in the s and c
quark masses from Big Bang nucleosynthesis, Oklo natural nuclear reactor, Yb+,
Cs and Rb clock data. The construction of 229Th nuclear clock is expected to
enhance these limits by several orders of magnitude. Furthermore, constraints
are obtained on an oscillating scalar or pseudoscalar cold dark matter field,
as interactions of the field with quarks produce variations in quark masses.
