Sources and transports of organochlorine pesticides in the Nanshan underground river, China

Abstract

Karst areas have much higher ecological vulnerability and are prone to be contaminated. Organochlorine pesticides (OCPs) were detected in waters and sediment from the two sites of the karst Nanshan underground river system, China, to understand the sources and transport of OCPs in the underground river systems. Obviously, seasonal variations were found both in the waters and the sediments. Detected OCPs ranged from 61 to 936 ng L -1 in the groundwaters and 51-3,842.0 ng g -1 in the underground sediments, respectively. OCPs in groundwaters were mixture of younger and older residues from commercial sources. The maximum OCPs in the sediments of the underground river were historically older residues from commercial sources. The sources of OCPs in the waters and sediments of the underground river indicated that the surface systems play an important role in OCPs transport and pollution in the underground river. Karst features were liable for the transport behavior.

Occurrence of persistent organic pollutants and polycyclic aromatic hydrocarbons in sediments of the inner bay of Lake Titicaca, Puno-Perú

“…Spatial distribution of DDT indicates that pollution is closely related to human activities, discharge of untreated effluents from industrial and municipal activities, urban runoff, outflow from agricultural areas and atmospheric deposition, (Aksu et al, 2011). Likewise, its presence could be linked to the use of antifouling paints, (Alam et al, 2014). This compound was widely used in Peru as an insecticide due to its low cost and broad spectrum on many agricultural crops.…”

Ecological risk assessment of persistent organic pollutants (POPs) in surface sediments from aquaculture system

“…MS was run in the electron concentrations between 3 and 7 (Mitra et al, 2019) or between 4 and 7 (Tang et al, 2020) indicated the possible source of technical HCHs, while the ratio <4 indicates the use of lindane. Cischlordane/trans-chlordane ratio is evaluated based on (Alam et al, 2014). The value of cis-chlordane to trans-chlordane ratios <0.79 indicates the recent uses of commercial chlordane, while the value > 0.79 suggests historical use of commercial chlordane.…”

“…Chlordane is a ubiquitous and persistent pesticide, which was widely used for both agricultural and residential applications since its introduction in the 1940s (Ouyang et al, 2005). Although the use of chlordane was banned in the 1980s, it is still commonly detected in the aquatic system (Alam et al, 2014;Hirano et al, 2007).…”

“…Heptachlor, typically originates from technical chlordane, is also used as an insecticide (Baek et al, 2011). In order to evaluate the source of chlordane, we calculated the cis-chlordane/trans-chlordane ratios, based on work done by (Alam et al, 2014). The ratio was higher than 0.79, suggesting that detected chlordane was historical and weathered…”

Thematic Issue: Water of the Taihu Lake

“…The experimental results showed an exposed eutrophication trend in the northern area of Lake Taihu. Alam et al (2014) studied the transport of pesticides in the underground rivers connected to urban lakes. To better understand the eutrophication and pollution processes of lakes it is important to recognize their link to subsurface aquatic systems and reactive transport processes therein (Beinhorn et al 2005;Beyer et al 2006).…”