Effects Of Petroleum Hydrocarbons In Bohai Bay Sediments On Macrobenthos Communities And Their Toxicity

Marine oil spills have occurred frequently and caused petroleum hydrocarbon pollution to become increasingly serious in the Bohai Bay of China,and it lead to a sharp decline in the number and species of marine macrobenthos.It has also increased a risk of the marine environment.It is unclear that the toxicological mechanism on petroleum hydrocarbons in the sediments of the Bohai Bay on macrobenthos is unclear,resulting in a lack of theoretical and technical basis for the restoration of the marine environment in the Bohai Bay.Therefore,in this paper,the data analysis of the monitoring results of the sediment and the macrobenthos community of the Bohai Bay was conducted by this research team,and a simulation experiment on the toxicity of petroleum hydrocarbons to the dominant species,Maoctra Veneriformis Reeve,was conducted to study the effects of petroleum hydrocarbons in sediments on the macrobenthos.The effects of macrobenthos on petroleum hydrocarbon pollution in sediments were studied from three levels: community level,individual level and cell level,respectively.Through this study,we clarify the toxicological process of petroleum hydrocarbons in sediments on macrobenthos pollution,and obtain the response mechanism of Maoctra Veneriformis Reeve to petroleum hydrocarbons,which provided theoretical and technical basis for the marine environment management and ecological restoration in the Bohai Bay.The main research conclusions are as follows:(1)According to the monitoring survey data of the sediments oil content and macrobenthos in Bohai Bay from 2004 to 2017,it is analyzed that changes in time and space of petroleum hydrocarbon content in sediments and the species composition,dominant species,abundance,biodiversity and community structure of large benthic animal communities.The results show that the overall trend of petroleum hydrocarbon content in sediments has gradually increased over the past 14 years.The lowest annual average appeared in 2004 was 15.4 ?g/g,and the highest annual average appeared in 2017 was 299.71 ?g/g.The total amount of petroleum hydrocarbons in the bay from south to north gradually increased,and gradually decreased from the near shore to the far shore.The total number of macrobenthos species was 228,the dominant species were Molluscs,and the proportion of arthropods and link animals increased significantly over time.The annual average abundance increased significantly from 2012 to 2014,and there was a phenomenon of miniaturization,showing a significant downward trend from south to north;the biodiversity index uses SPSS software for a single factor at a 99% confidence interval The analysis of variance showed that Shannon's Wiener diversity index H 'and species richness index d were extremely significantly different in 14 years(P?0.01).In general,changes in the content of petroleum hydrocarbons in the Bohai Bay sediments have a certain effect on the structure of macrobenthos communities.(2)In the 96-hour petroleum hydrocarbon poisoning experiment of Maoctra Veneriformis Reeve,the weight change trend was a decrease in the weight of the treatment group with the extension of the duration of the poisoning.The 96-hour mortality rate increased gradually with increasing concentration,with the largest mortality rate at 1600 mg / kg.In general,the 96-hour petroleum hydrocarbon toxicity test has certain effects on the growth and development of the clam.(3)In the 96-hour petroleum hydrocarbon toxicity experiment,the physiological and biochemical indexes POD,SOD,CAT,and GST of the Maoctra Veneriformis Reeve have four time-effects and dose-effects.In terms of time-effect,POD and GST show a trend of first decline and then increase with the increase of exposure time,SOD shows a trend of first decline and then increase and then decrease,and CAT shows a trend of first rise and then decrease;the time period is slightly different.In general,POD and CAT show a trend of rising,then falling,and then rising,and SOD and GST show a rising,then falling,and then rising and then falling.A one-way analysis of variance was performed at 95% and 99% confidence intervals,and it was concluded that the activities of the four enzymes in different concentration groups were significantly different and extremely significant.