Molybdenum is reported to be very toxic to ruminants and shows evidence of spermatogenesis
toxicity in animals and insects. Hence, its removal is important. In this study, we report on the
first isolation of molybdenum-reducing bacterium from agricultural soil. The bacterium reduces
hexavalent molybdenum (sodium molybdate) to molybdenum blue (Mo-blue); a colloidal
product, which can be trapped and removed from solution. Phylogenetic analysis resulted in a
tentative identification of the bacterium as Serratia sp. strain MIE2. The optimum conditions for
Mo-blue production using the normal one-variable-at-a-time (OVAT) approach were 10 mM of
sodium molybdate, pH 6.0, a temperature of 35°C, ammonium sulphate at 10 g/L as the nitrogen
source and sucrose concentrations of between 30-50 g/L as the carbon source and electron donor
for molybdate. Studies on the effects of pesticides and solvents on Mo-blue production showed
that Mo-blue production from whole cells was relatively more affected by these xenobiotics
compared to the crude enzyme. Nevertheless, the strain was resistant to most of the xenobiotics
tested. Based on the strain MIE characteristics, the bacterium will be a suitable candidate for the
remediation of aquatic bodies and agricultural soils contaminated with molybdenum.
Bioremediation is a new green economic approach in providing solutions for cleaning up
contaminated sites. Phytoremediation uses plants as a tool for remediation purposes. The usage
of plant species offers higher potential solution to remediate heavy metal contaminated sites.
This study aimed on screening potential plant species for phytoremediation of heavy metal
contaminated water. The potential of three aquatic macrophytes species (Eichorrnia crassipes,
Pistia stratiotes and Ipomoea aquatica) for chromium and nickel phytoremediations was tested.
The plants were exposed for 10 days under hydroponic conditions in heavy metal contaminated
water. E. crassipes showed the highest chromium and nickel concentrations in its biomass, 1.60
and 2.40 μg/L respectively. Meanwhile, P. stratiotes had chromium and nickel concentrations
detected at 0.89 and 0.081 μg/L, respectively; chromium and nickel concentrations of I.
aquatica detected were, 0.49 and 0.08 μg/L, respectively. The ability of these plants to
accumulate heavy metals and survived throughout the experiment demonstrates the potential of
these plants to remediate metal-enriched water. Among the three tested aquatic plants, E.
crassipes was proven to be the most suitable plant species that can phytoremediate heavy metal
contaminated water followed by P. stratiotes and I. aquatica.
Water contamination by herbicides and chelating agents is increasing mainly due to the
increasing agricultural activities. Water contamination by these compounds has become a
concern due to their adverse effects to the environment and humans. Seven sampling sites of
water sources in Selangor and Johor were chosen for the study. Contamination level of
Mecoprop (MCCP), Nitrilotriacetic acid (NTA) and Ethylenediaminetetraacetic acid (EDTA) in
these water body areas was determined by using Gas Chromatography-Electron Capture
Detector (GC-ECD). Our results indicated that water samples of Sungai Melot in Selangor
showed the highest presence of EDTA. MCCP was detected at a high level at Sungai Sarang
Buaya, Johor while NTA showed similar level of concentration at three different sites, Ladang
10, Ladang Sayur and Mardi, Selangor.