Accumulation of mercury in the terrestrial food chain of the Liaohe estuary wetlands, China

Mercury is a global pollutant that can be enriched in organisms and eventually endanger human health. In this paper, we studied the soil, plants, and animals in the sandy beach, winged alkali pong wetland, reed wetland, and rice field in Liaohe estuary in 2018 and 2019, measured the plant and animal carbon and stable nitrogen isotopes, and carried out the food chain construction by animal carbon and nitrogen stable isotopes, and studied and analyzed the accumulation of mercury from the producer to the consumer of the food chain. The results showed that the food chain construction at the sampling sites was as follows: S-1: plants < flesh worms, ants < spiders; S-4: plants < moths, leaf beetles, mosquitoes, ants < spiders; S-6: plants < mosquitoes < spiders; S-7: plants < flattened hooks, mosquitoes, ants < spiders; S-9: plants < ants < spiders. The range of Hg in soil: S-1: 0.087-0.175 mg/kg; S-2: 0.035-0.197 mg/kg; S-3: 0.089-0.249 mg/kg; S-4: 0.050-0.167 mg/kg; S-5: 0.024-0.150 mg/kg; S-6: 0.066-0.152 mg/kg. S-7: 0.035-0.165 mg/kg; S-8: 0.026-0.083 mg/kg; S-9: 0.035-0.191 mg/kg. The range of Hg in plant samples: S-1: 0.019-0.242 mg/kg; S-2: 0.019-0.161 mg/kg; S-3: 0.025-0.142 mg/ kg; S4: 0.010-0.120 mg/kg; S-5: 0.015-0.269 mg/kg; S-6: 0.040-0.079 mg/kg; S-7: 0.014-0.300 mg/kg; S-8: 0.020-0.100 mg/kg; S-9: 0.022-0.208 mg/kg. Constructing the food chain of In animal samples, the accumulation of Hg: S-1: 0.061-0.355 mg/kg; S-3: 0.082-0.198 mg/kg; S-4: 0.051-0.230 mg/kg; S-6: 0.032-0.449 mg/kg; S-7: 0.078-0.195 mg/kg; S-9: 0.086-0.189 mg/kg By comparing the data, the annual accumulation of heavy metals in soil and plant samples showed an increasing trend and combined with the trophic level relationship of the food chain, it was found that the accumulation trend of heavy metals increased step by step with the trophic level of consumers.

Automated summary

In this study, the accumulation of mercury in various ecological systems in the Liaohe estuary was investigated, and food chain construction and heavy metal accumulation analysis were conducted. The results showed that the accumulation of heavy metals increased step by step with the trophic level of consumers.