Response of size-dependent chemical composition of dissolved organic and inorganic species to land use types in tropical coastal headstreams

•Agricultural streams enriched terrestrial DOM bound to Mg and aluminosilicate.•Forested streams contained more Zn-associated DOM in the 1 kDa-0.2 μm range.•Wetland streams enriched NaCl, KCl and microbially-transformed LMW-DOM.•FDOM and CDOM played an important role in the interaction of DOM and DIM.•Elements with large colloidal fractions (Ca, Mg, P, Fe, Mn) tend to bind with FDOM.