The use of technical HCH （1, 2, 3, 4, 5, 6-hexachlorocyclohexane）, DDT （dichlorodiphenyltrichloroethane） and lindane in Heilongjiang River Basin （HRB） of China was studied. Between 1952 and 1984 the total usage ...The use of technical HCH （1, 2, 3, 4, 5, 6-hexachlorocyclohexane）, DDT （dichlorodiphenyltrichloroethane） and lindane in Heilongjiang River Basin （HRB） of China was studied. Between 1952 and 1984 the total usage in the HRB was 108900 t for technical HCH, and 4900 t for DDT, respectively, and the use of DDT due to dicofol application in the HRB was 220 t from 1984 to 2003. The usage of lindane in HRB was 109 t from 1991 to 2000. The results show that the highest technical HCH use （41800 t） in HRB was on maize, accounting for 38.3% of the total usage on all crops, followed by the use on wheat （28000 t, 25.7%） and on soybean （26600 t, 24.4%）. The highest DDT use （2300 t） was on soybean, accounting for 46.8% of the total usage on all crops, followed by the use on maize （1500 t, 31.3%） and on sorghum （600 t, 13.2%）. The major use of lindane was mainly on wheat. Gridded usage inventories of these three OCPs （organochlorine pesticides）, in HRB with a 1/6° latitude by 1/4° longitude resolution have been created by using different gridded cropland as surrogates. Some soil samples have also been collected in HRB. Data of usage and soil concentrations of 5： HCH in HRB match quite well to those in Shanghai region, and much higher soil concentration of 5： DDT in Shanghai region could be due to much heavier dicofol use in this region.展开更多
Mid and high latitude wetlands are becoming fragmented and losing ecosystem functions at a much faster rate than many other ecosystems.This is due in part to increasing human activities and climate change.In this stud...Mid and high latitude wetlands are becoming fragmented and losing ecosystem functions at a much faster rate than many other ecosystems.This is due in part to increasing human activities and climate change.In this study,we analyzed wetland distribution and spatial pattern changes for the Heilongjiang River Basin over the past 100 yr.We identified the driving factors and quantified the relative importance of each factor based on landscape pattern metrics and machine learning algorithms.Our results show that wetlands have been fragmented into smaller and regular patches with dominant factors that varied at different periods.Geographic features play the most important role in patterns of wetland change for the entire basin(with 50%-60%of relative importance).Human activities are more important than climate change at the century scale,but less important when magnified at the decadal scale.In the early 1900s,human activities were relatively low and localized and remained that way in the subsequent decades.Thus,the effect of human activities on wetland area of the entire basin is weaker when examined at the magnified decadal scale.The results also show that human activities are more important on the Chinese side of the Heilongjiang River Basin,in the ZeyaBureya Plain on the Russian side,and at lower altitudes(0-100 m).Revealing the spatial and temporal processes and driving factors over the past 100 yr helps researchers and policymakers understand and anticipate wetland change and design effective conservation and restoration policies.展开更多
文摘The use of technical HCH （1, 2, 3, 4, 5, 6-hexachlorocyclohexane）, DDT （dichlorodiphenyltrichloroethane） and lindane in Heilongjiang River Basin （HRB） of China was studied. Between 1952 and 1984 the total usage in the HRB was 108900 t for technical HCH, and 4900 t for DDT, respectively, and the use of DDT due to dicofol application in the HRB was 220 t from 1984 to 2003. The usage of lindane in HRB was 109 t from 1991 to 2000. The results show that the highest technical HCH use （41800 t） in HRB was on maize, accounting for 38.3% of the total usage on all crops, followed by the use on wheat （28000 t, 25.7%） and on soybean （26600 t, 24.4%）. The highest DDT use （2300 t） was on soybean, accounting for 46.8% of the total usage on all crops, followed by the use on maize （1500 t, 31.3%） and on sorghum （600 t, 13.2%）. The major use of lindane was mainly on wheat. Gridded usage inventories of these three OCPs （organochlorine pesticides）, in HRB with a 1/6° latitude by 1/4° longitude resolution have been created by using different gridded cropland as surrogates. Some soil samples have also been collected in HRB. Data of usage and soil concentrations of 5： HCH in HRB match quite well to those in Shanghai region, and much higher soil concentration of 5： DDT in Shanghai region could be due to much heavier dicofol use in this region.
基金supported by the Joint Fund of National Natural Science Foundation of China(Nos.42101107 and 42271100).
文摘Mid and high latitude wetlands are becoming fragmented and losing ecosystem functions at a much faster rate than many other ecosystems.This is due in part to increasing human activities and climate change.In this study,we analyzed wetland distribution and spatial pattern changes for the Heilongjiang River Basin over the past 100 yr.We identified the driving factors and quantified the relative importance of each factor based on landscape pattern metrics and machine learning algorithms.Our results show that wetlands have been fragmented into smaller and regular patches with dominant factors that varied at different periods.Geographic features play the most important role in patterns of wetland change for the entire basin(with 50%-60%of relative importance).Human activities are more important than climate change at the century scale,but less important when magnified at the decadal scale.In the early 1900s,human activities were relatively low and localized and remained that way in the subsequent decades.Thus,the effect of human activities on wetland area of the entire basin is weaker when examined at the magnified decadal scale.The results also show that human activities are more important on the Chinese side of the Heilongjiang River Basin,in the ZeyaBureya Plain on the Russian side,and at lower altitudes(0-100 m).Revealing the spatial and temporal processes and driving factors over the past 100 yr helps researchers and policymakers understand and anticipate wetland change and design effective conservation and restoration policies.
