Mercury

The concentration and distribution of selected heavy metals (Pb, Cd, Cu and Zn) in soils collected from the rice fields of MADA in Kedah, Malaysia

“…This finding is in agreement with the general findings, that Pb is highly immobile in soils and has high affinity for soil organic matter [19][20][21]. According to Adriano [18] , organic matter and clay are the dominant constituents contributing to Pb adsorption. This metal also has a tendency to be bound with Oxides of Fe and Mn in soils.…”

“…Geochemical fractions of Zn in the paddy soils of MADA, Kedah are tabulated in TABLE (2). The total Zn concentration ranged from 6.95 to 9.90 mg/kg, which was lower than the average total Zn found in paddy soils of West Malaysia (40 ppm) [18] and Pearl River Delta (50.4 ppm) [16]. The speciation results showed that Zn was distributed in the soil fractions following the decreasing order of station 1: RR > AR > ELFE > OO, stations 2 and 3: RR > ELFE > AR> OO, and stations 4 and 5: RR > ELFE > OO > AR.…”

“…This result could signify low availability of this metal to plants since this form is often regarded as bioavailable. [18]. Except for stations 4 and 5 the amount of Pb present in the soils was in the following decreasing order: OO > RR > AR > ELFE fractions, stations 4 and 5 were in the following decreasing order: OO > RR > ELFE > AR.…”

“…According to Adriano [18] , the input of anthropogenic Cu in soils might be contributed by copper fertilizers, fungicides and livestock manure. Although Cu is most available below pH6 [18], the bioavailability of Cu in these stations was very low. Thus, the results indicate that the low Cu concentrations in the study area were obtained naturally from the soil parent material.…”