There are more information with this report" https://pubs.usgs.gov/tei/0159/report.pdf"

I attached it.

mostly all these metals/ ions are independent in nature. water - rock interaction play a important role for their dissolution processes. However in some particular place some correlation can not be overruled.

You need to understand and look up Eh-pH diagrams for uranium, iron, and arsenate as their speciation and aqueous solubility are dependent on the redox state and the pH of the water. For example, iron as a mineral in the aquifer matrix is present as Fe(III), which is insoluble. Under low redox conditions, Fe(III) reduces to Fe(II) cation, thereby becoming far more soluble in water. Uranium and Arsenic typically form oxyanions and should have some correlation....but you will still need to look at the differences in their Eh-pH diagrams to understand which species are present under different solution conditions.

Below attached file more informative.

Regards,

Mobility of U is very low in reducing conditions, as it remains bonded to organic matter (Wu et al., 2014). High U groundwater is mainly a phenomenon observed in oxidized aquifers, moreover, alkaline pH promoted by the abundance of HCO3 has also been found to improve the dissolution of U in water (Wu et al., 2014). Iron (hydr)oxides, especially amorphous ones have been found to be good sinks of U, as they can easily adsorb dissolved species of U like UO2OH. and (UO2)3(OH)5 at pH exceeding 5e6 (Hsi and Langmuir, 1985; Wu et al., 2014). Dissolution of such Fe (hydr)oxides under reducing conditions could potentially increase the levels of U in groundwater, however, under those conditions, the released U tend to re-precipitate (Wu et al., 2014). Therefore, it is unlikely that U and As would correlate under reducing conditions, as arsenic levels have been found to enhance under reducing conditions almost universally. Also, other studies like Nicolli et al. (1989) present a contrasting relation of U with Fe. Fluoride and U could potentially

show stronger correlation based on the similarities of their preferred environments, viz. rock-water interaction in drier oxidizing aquifers. For more detail refer to Das et al., 2018 published in Chemosphere.

We measured concentrations of co-occurring trace elements (Sb, Mo, V, U and Se) in groundwater from Holocene (high arsenic) and Pleistocene (low arsenic) aquifers in Bengal basin. The concentrations of U ranged from 0.02 to 14.3 μg/L in Holocene aquifer groundwater, and from 0.02 to 4.3 μg/L in Pleistocene aquifer groundwater. There was no statistical difference between U concentrations in these two aquifers. Results also showed that there was moderate linear correlation between U and Fe in Holocene aquifer, whereas weak-moderate linear correlation between U and Ca+Mg in Pleistocene aquifer. This suggests that at study sites in Holocene aquifer, U mobility was associated with Fe-reductive dissolution processes, whereas in Pleistocene aquifer, U mobility was associated with carbonate mineral dissolution processes.

Please see below the link to this paper. Hope this will be helpful.

Vega et al. (2020) Mobilization of co-occurring trace elements (CTEs) in arsenic contaminated aquifers in the Bengal basin. Applied Geochemistry.

Article Mobilization of co-occurring trace elements (CTEs) in arseni...

Yes. Generally one of natural source of uranium in ground water is phosphate rock. This rock also contain arsenic and arsenite ion(AsO3)3- cab replace phosphate. Not only that the clay-sand material contain As, uranium also absorbed by this materials. Fe also one of ingredient of rock. Except that sorption of uranium in Ferric hydrite is experimantally established. So in nature correlation in between Fe &U is a most probable phenomenon.