48 research outputs found
Highway increases concentrations of toxic metals in giant panda habitat
The Qinling panda subspecies (Ailuropoda melanoleuca qinlingensis) is highly endangered with fewer than 350 individuals inhabiting the Qinling Mountains. Previous studies have indicated that giant pandas are exposed to heavy metals, and a possible source is vehicle emission. The concentrations of Cu, Zn, Mn, Pb, Cr, Ni, Cd, Hg, and As in soil samples collected from sites along a major highway bisecting the panda's habitat were analyzed to investigate whether the highway was an important source of metal contamination. There were 11 sites along a 30-km stretch of the 108th National Highway, and at each site, soil samples were taken at four distances from the highway (0, 50, 100, and 300Â m) and at three soil depths (0, 5, 10Â cm). Concentrations of all metals except As exceeded background levels, and concentrations of Cu, Zn, Mn, Pb, and Cd decreased significantly with increasing distance from the highway. Geo-accumulation index indicated that topsoil next to the highway was moderately contaminated with Pb and Zn, whereas topsoil up to 300Â m away from the highway was extremely contaminated with Cd. The potential ecological risk index demonstrated that this area was in a high degree of ecological hazards, which were also due to serious Cd contamination. And, the hazard quotient indicated that Cd, Pb, and Mn especially Cd could pose the health risk to giant pandas. Multivariate analyses demonstrated that the highway was the main source of Cd, Pb, and Zn and also put some influence on Mn. The study has confirmed that traffic does contaminate roadside soils and poses a potential threat to the health of pandas. This should not be ignored when the conservation and management of pandas is considered
Assessment of Zn, Cu, Pb and Ni contamination in wetland soils and plants in the Lake Victoria basin
The impact of waste disposal on trace metal contamination was
investigated in eleven wetlands in the Lake Victoria Basin. Samples of
soil, water and plants were analysed for total Zn, Cu, Pb and Ni
concentrations using flame atomic absorption spectrophotometry. The
trace metal concentrations in soil were the highest in Katanga wetland
with the highest mean concentrations of 387.5±86.5 mg/kg Zn,
171.5±36.2 mg/kg Pb, 51.20±6.69 mg/kg Cu and 21.33±2.23
mg/kg Ni compared to the lowest levels observed at Butabika
(30.7±3.2 mg/kg Zn, 15.3±1.7 mg/kg Pb, 12.77±1.35 mg/kg
Cu and 6.97±1.49 mg/kg Ni). Katanga receives waste from multiple
industrial sources including a major referral city hospital while
Butabika is a former solid waste dumpsite. Wetland soil near a copper
smelter had a Cu concentration of 5936.3±56.2 mg/kg. Trace metal
concentrations in industrial effluents were above international limits
for irrigation water with the highest concentrations of 357,000
ÎŒg/L Cu and 1480 ÎŒg/L Zn at a Cu smelter and 5600 ÎŒg/L
Pb at a battery assembling facility compared to the lowest of 50
ÎŒg/L Cu and 50 ÎŒg/L Zn in water discharged from Wakaliga
dumpsite. Uptake of trace metals from soil differed from plant to plant
and site to site. Higher levels of trace metals accumulated in the root
rather than in the rhizome and the least amount was in the leaf. The
study identifies industry as a potential source of trace metal
contamination of water and the environment pent-up need for policy
intervention in industrial waste management