| It’s necessary to study the distribution and ecological influence of mercury in different species in wetland ecosystems, moreover, which is helpful for the proper evaluation of ecological risk of mercury pollution, and the protection of endangered species. Wetlands were called as "mercury active database", and wetland birds is one important part of the wetland ecosystem, which located at the top of the food chain. Wetland birds exposured to mercury is mainly due to the consumption of fish enriched mercury, therefore, which had highest degree of enrichment of mercury in wetland ecosystems. Sanjiang Plain located at eastern Heilongjiang Province, Chinese largest swamp distribution area, which had abundant water resources and species in this region. The signification of studying of the effect of mercury pollution on wetland food chain is not only to help to monitor wetlands pollution and provide an effective basis for the protection of wetlands and wetland birds, moreover, but also to protect the biodiversity of wetlands.2013 June 10 to 30, feathers and tissue sample of Grey heron and great egret, and the sample of fish and insects were collected and analysized, then we studied the mercury bioaccumulation effect of fish and heron so as to explore the transfer and accumulation of mercury in the food chain of wetlands, results as following:(1)The total mercury content of Grey heron chicks, Grey heron adults and egg shell at the Qixing River Nature Reserve was 47.14±26.43μg/kg,825.97±418.00μg/kg and 21.91±4.88μg/kg respectively. The order of the total mercury content contribution was:Grey heron adults> Grey heron chicks>egg shell. The total mercury content of feathers of great egret was 35.19±14.2 μg/kg, compared with Grey heron chicks, which is lower, but it was no difference in statistics.(2)The total mercury content in various tissues of Grey heron chicks at Sanjiang Nature Reserve was respectively:liver 590.16±36.72 μg/kg, kidney 409.28±30.68μg/kg, muscle 350.90±70.24μg/kg, brain 182.63±11.23μg/kg. However, the total mercury content in various tissues of great egret chicks was respectively:liver 322.84±66.05μg/kg, kidney 230.15±18.01 μg/kg, muscle 197.00±12.08μg/kg, brain 111.23±23.50μg/kg. Mercury distribution in four kind of tissues of two herons was same:liver>kidney>muscle>brain; Mercury content within the same organization:Grey heron>Great egret.(3)The feeding habits similar rate of two herons at Qixing River Nature Reserve is 61%. The order of mercury content in eating fish of two herons was:Perccottus glenii>Phoxinus lagowskii Dybowski>Carassius auratus>Misgurnus anguillicaudatus. Divided the four kind of fish into two groups accounding to the diet:carnivorous(Perccottus glenii) and omnivorous(Phoxinus lagowskii Dybowski, Carassius auratus and Misgurnus anguillicaudatus). And the total mercury content of carnivorous fish is higher than omnivorous fish. The total mercury content is correlated positively with fish body length, with fish body length increasing, so the total mercury content could increase.(4)The order of mercury content in eating fish of two herons was:Saurogobio dabry> Carassius auratus>Grass carp. The distribution of mercury content in fish was:omnivorous fish(Saurogobio dabry)> herbivorous fish(Carassius auratus and Grass carp).(5)The total mercury content increases significantly in the food chain(insect-fish-heron) at two reserve with the trophic level improving, and the phenomenon of the transfer and bioaccumulation of mercury is obvious. |
PDF Full Text Request