Heavy metals in Changjiang estuarine and offshore sediments: responding to human activities

Detection and calibration of anthropogenic lead emission in coastal sediments of China during the past 250 years

“…Lin et al (2002) found a profound Pb increase since 1972 AD in a mud area near the Yangtze River estuary by analyzing the Pb/Al ratio. Dong et al (2012) studied the Pb/Al ratio in muddy sediments near the Yangtze River estuary and suggested that Pb pollution began after 1990 AD. Several other researches focused on distinguishing anthropogenic and natural sources of Pb in offshore sediments by using Pb isotopes.…”

“…The impact of Pb emission is expected to occur right after the Industrial Revolution, but the noticeable increase of the Pb level in coastal sediments of China only occurred at about 100 years ago (Choi et al 2007), roughly the start time of modern industry of China. Furthermore, the reported earliest times of obvious impact of anthropogenic Pb emission in offshore sediments differ considerably even in the same area, and the links between human activities and Pb levels in coastal sediments seem elusive (Huh and Chen 1999;Lin et al 2002;Choi et al 2007;Hao et al 2008;Dong et al 2012;Sun et al 2012b). One of the main causes of the discrepancy might be the differences in the anthropogenic Pb emission detection methods.…”

“…In order to identify and detect anthropogenic Pb emissions, the concentrations of major elements, such as Si, Al, Fe, etc., have generally been used to normalize Pb concentration (e.g., Lin et al 2002;Dong et al 2012;Sun et al 2012a, b;Bing et al 2013). However, such normalization is based upon the assumption that these elements are of natural origin.…”

Spatial Analysis of Metal Profiles in Sediments in a Tropical Estuary: A Geostatistical Approach

“…Human activities, such as fishing and aquaculture, as well as urbanization and industrialization of the coastal zone, have been described as those causing the greatest impact to estuaries worldwide (Villanueva and Botello 1998;Kennish 2002;McLusky and Elliot 2004;Dong et al 2012). However, other activities, such as animal husbandry and agriculture, may also have negative effects on coastal ecosystems because of the excessive use of fertilizers and pesticides, some of which contain heavy metals (Nriagu and Pacyna 1988;GreenRuiz and Páez-Osuna 2003;Bjerregaard and Andersen 2007).…”

“…Whelan et al 2005;Dong et al 2012;Mohammed et al 2012;Mohan Raj et al 2013). Thus, the spatial distribution of heavy metals along an estuarine ecosystem has barely been examined at a finer spatial scale by means of a spatially explicit approach using geostatistical methods.…”