Acute Toxic Effects of Reclamed Silt and Suspended Solids on Marine Organism Resources in Tianjin

Abstract:

The growing reclamation projects in Tianjin have exerted impacts on the marine ecosystem. From 2003 to 2012 the fishery production in Tianjin underwent a continuous decline. The situation was the most severe in 2008, which coincided with the large-scale reclamation in 2007. In this study we performed indoor simulation experiment, and explored the impacts of reclamations on marine organism resources. The results were shown as below: (1) Scapharca subcrenata and Mactra veneriformis displayed a vertical migration after being buried. The larger body length, the stronger biological migration ability. The mortality increased along with the burial depth. (2) As for the acute toxicity of the suspended solution on Artemia nauplii, the 96 h LC50 was 271 mg/L and the safe concentration was 27.1 mg/L. Biohazards of suspension increased over the time. (3) Test on the acute toxicity of the suspension on two economic fish species suggested that susceptibility of the larvae was raised over the time. Water temperature also affected the tolerance of larvae to the toxic suspension. With water temperature rose the tolerance was gradually reduced. The tolerance to toxic suspension varied greatly between different species.