Nevertheless,
the facilities which acted as sources for certain other heavy
metals (e.g., Ga and As) could not be readily identified, although
both As and Ga in water and sediments were high. This is because
the effluents comprise of mixed wastewater from all facilities
located within the entire science park. Relevant fundamental
information on the specific heavy metal pollutants is lacking.
The second group of elements may have partly originated from
the same effluents because their dissolved concentrations followed
a pattern similar to that of the first-group elements. In addition,
a portion of the particulate forms of these elements may have
accumulated from the dissolved metals in the water via adsorption
onto the newly formed and originally existing Fe and Mn
oxides/hydroxides as pH increased from nearly neutral to slightly
basic and redox conditions changed from slightly reduced to oxidized
in surface water downstream of the intertidal estuary and
coastal ocean [27]. This suggestion can be supported by the result