Ecological Risk Assessment Of The Rare Fish Reserve In The Upper Reaches Of The Yangtze River

This research is based on the latest "Freshwater Aquatic Biological Water Quality Standards-Ammonia Nitrogen" and "Freshwater Aquatic Biological Water Quality Standards-Cadmium" promulgated by the Ministry of Ecology and Environment and previous studies on other pollutants,combined with the risk quotient model,to identify rare and unique fish in the upper reaches of the Yangtze River.The distribution characteristics and ecological risks of ammonia nitrogen and heavy metal elements cadmium,copper,mercury,hexavalent chromium,lead and metal-like elements arsenic were explored in national nature reserves.The ecological risks of ammonia nitrogen and heavy metals in the national nature reserve of rare and endemic fish in the upper reaches of the Yangtze River have been preliminarily explored.Seasonal and regional changes in the ecological risks of ammonia nitrogen and heavy metals have been conducted.The research results are expected to provide relevant departments with experience and data support for further development of protection measures for aquatic organisms in the region.This research mainly draws the following conclusions.Among the rare and endemic fish nature reserves in the upper reaches of the Yangtze River,the Jinsha River New Town Station is the station with the highest ecological risk of ammonia nitrogen in the rare and endemic fish reserves in the upper reaches of the Yangtze River.The mean values of short-term risk quotient(SRQ)and long-term risk quotient(LRQ)are 0.18 and 0.93,both of which are in medium risk levels.Xiluodu Station and Xiangjiaba Station are the stations with the lowest SRQ in the rare and endemic fish reserve in the upper reaches of the Yangtze River.The average SRQ is 0.01,which is in low risk level.Xiluodu Station is the lowest LRQ station in the rare and endemic fish reserve in the upper reaches of the Yangtze River.The average SRQ is 0.01,which is in low risk level.The main factors affecting the ecological risk of ammonia nitrogen are water temperature,pH and ammonia nitrogen concentration.In particular,it should be pointed out that in most of the measurement stations in the Rare and Endemic Fish Reserves in the upper reaches of the Yangtze River,there are problems of increased ammonia nitrogen toxicity due to the increase of water temperature or pH,and the decline of SWQC and LWQC,which in turn leads to increased ecological risks.Therefore,strengthening the pH value,especially in summer pH value detection and early warning should be the focus of future water resources management in the protected area.In the Rare Fish Reserve on the upper reaches of the Yangtze River,Gaochang Station is the station with the highest cadmium risk among all stations.Its SRQ is0.37,which belongs to the "medium" risk level,and the LRQ is 7.99,which belongs to the high risk level.The station with the lowest cadmium risk is Luzhou,which has an SRQ of 0.05,which is in low risk level,and an LRQ of 1.06,which is in high risk level;Xiangjiaba station is the station with the highest copper risk among all the stations.The SRQ is 0.24,which belongs to the medium risk level,and the LRQ is1.8,which belongs to the “high” risk level;Tuojiang Fushun Station is the station with the highest risk of arsenic,and its SRQ is 10.15,which belongs to the high risk level,and the LRQ is 17.8,Belongs to the high level;the Minjiang Gaochang Station is the station with the highest mercury risk,its SRQ is 21.358,and the LRQ is 79.715,both of which belong to the high risk level;the Tuojiang Fushun station has the highest lead risk level among all the stations The station has an SRQ of 0.19,which belongs to the “medium” risk level,and the LRQ is 9.85,which belongs to the high risk level;ecological risks of cadmium,copper,mercury,hexavalent chromium,lead and metal-like element arsenic are common in all stations Higher question.And there are general laws that vary with seasons and geographic locations.Therefore,strengthening the governance of the mining and smelting industries in southwest and south Sichuan should be one of the key tasks of environmental protection departments at all levels in the upper and middle reaches of the Jinsha River,Minjiang River,and Tuojiang River.At the same time,strengthening the monitoring and early warning of the content of important pollutants and their influencing factors in the rare fish reserve in the upper reaches of the Yangtze River should be one of the priorities of future water resources management in the reserve.