4 research outputs found
Selected Organochlorine Pesticides and Polychlorinated Biphenyls in Urban Atmosphere of Pakistan: Concentration, Spatial Variation and Sources
Robust
knowledge on the occurrence and distribution of persistent
organic pollutants (POPs) in the atmosphere of low-latitude regions
is inevitable to forecast their transportation to pristine ecosystem
and assess toxicological impacts upon local biota. Despite the earlier
revelation of organochlorine pesticides (OCPs) and polychlorinated
biphenyls (PCBs) in soils/sediments and water bodies in Pakistan,
knowledge about atmospheric levels and sources of these POPs remains
limited. For the first time, a network of XAD resin-based passive
air samplers (PAS) was established across megacities of Pakistan,
i.e., Karachi, the coastal city, and Lahore, lying in an agricultural
region. Typical geographical locations of the two cities allowed assessing
the influence of source regions on the occurrence and distribution
patterns of selected POPs. Average concentrations (ng/PAS) in both
cities ranged as endosulfan 39–101, DDTs 63–92, HCHs
33–65, heptachlor 10–26, and PCBs 48–61. High
concentrations of endosulfan and lindane as observed throughout Lahore
were certainly due to their ongoing applications in surrounding agricultural
fields. Lower proportions of parental DDTs as compared to their metabolites
were observed in both cities, suggesting inputs of DDTs from older
or secondary sources. Owing to ultimate discharge of country’s
agricultural/industrial waste through river streams in to Arabian
Sea, the coastal region of Karachi was found potential source of weathered
POPs that could be dissipated at regional/global scales by maritime
advections. The study contributes to the pool of information on fate
and geographical distribution of POPs in subtropical developing countries