|
| Analysis of interannual variation of Cu，Zn contents andcomprehensive ecological risk level in polycuture fish ponds |
| |
| DOI： |
|
| Hits: 1679 |
| Download times: 627 |
| Abstract: |
| The contents of two heavy metals（Cu and Zn）in water and surface sediments（0-5 cm）in
polyculture fish ponds were measured by Flame Atomic Absorption Spectrophotometry for four consecutive years，in
order to investigate the content change trend and their potential ecological risks，by three different methods. The results
showed that the spatial distribution differences of Cu and Zn in fish pond water and surface sediments were not
significant，but the time distribution differences were significantly different，the heavy metal contents increased with
culture time increasing. In water，the contents of Cu and
Zn were relatively lower than the national water standards
o f c l a s s Ⅱ （ G B 3 8 3 8 - 2 0 0 2 ） ，t h e a v e r a g e
concentrations of Cu and Zn were 0.0691 mg/L and
0.1535 mg/L，the highest concentrations were 0.1605
mg/L and 0.4850 mg/L，the exceeded standard rates of
Cu and Zn were 96.9% and 37.5%，respectively. In
surface sediments，the average contents of Cu and Zn
were 64.8722 mg/kg and 295.1020 mg/kg. The average Igeo of Cu and Zn for four years were 0.996（slight to partial
moderate pollution）and 1.864（slight to moderate pollution）. The potential ecological risk indexes（Ei
r ）of Cu and
Zn were lower than 40，the comprehensive potential ecological risk indexes（RIs）were 13.769 to 26.201，and the
average was 21.596，indicating that the potential ecological risks were slight. The RIs of Cu and Zn had gradual upward
trend within four years，as follows：2012 > 2013 > 2014 > 2011. The results of dimensionless analysis displayed that the
Cu，Zn contents in water were higher than those in surface sediments in 2011 and 2012，and was lower than those in
surface sediments in 2013 and 2014. Correlation analysis showed that in freshwater ponds，the sources of Cu and Zn
were the same，the migration direction of Cu and Zn was consistent but the migration ways were different between water
and surface sediments，the total phosphorus content would be the main factor affecting the migration of Cu and Zn. |
|
View Full Text
View/Add Comment Download reader |
