Feasibility of using low density polyethylene sheets to detect atmospheric organochlorine pesticides in Alexandria, Egypt

Abstract

Egypt is a major agricultural country in Africa with a known past of organochlorine pesticides (OCPs) application, yet data on atmospheric levels of OCPs in Egypt is sparse. Low density polyethylene (LDPE) passive samplers were therefore deployed for 3 weeks each at 11 locations in July, 2010 and January, 2011 in Alexandria to screen for gas-phase OCPs. Performance reference compounds were used to investigate the uptake kinetics. Field-derived sampler-air partitioning coefficients (K PEA s) for OCPs were significantly correlated against the compounds' subcooled liquid vapour pressure (log P L): [log K PEA =-0.77+0.07 * log P L + 6.35+0.13 (R 2 = 0.90; n = 17; SE = 0.19; p < 0.001)]. Estimated and measured OCP concentrations in Alexandria agreed well (factor difference ≤ 2) indicating the feasibility of monitoring OCPs using LDPEs. OCP concentrations ranged from <LOD to 168 pg/m 3. Calculated isomeric ratios indicated recent usage of chlordanes and endosulfans.

Field calibration of low density polyethylene passive samplers for gaseous POPs

“…In recent years, low density polyethylene sheets (LDPE) have been used for monitoring of atmospheric PAHs 5,7,21,22 and OCPs. 6 LDPE sheets are essentially SPMD samplers without triolein lling. As compared to other matrices for passive sampling, LDPE is the simplest (in its chemical makeup), cheapest polymer available 23 and easy to deploy.…”

“…LDPE has been previously validated as passive air samplers for PAHs 5,22 and OCPs. 6 However, there is as of yet, no generalizable correlation that would allow the use of LDPEs across a wide range of organic contaminants. Being able to predict partitioning constants to LDPE for most POPs would enable the increased utilization of LDPE as a passive air sampler.…”

“…Initially, a random R s value was chosen and % equilibrium was calculated for all the investigated analytes using equation 6. These values were compared to the % equilibrium values calculated as shown in section 2.6.1 using a nonlinear least square model.…”

“…They are also relatively expensive, which limits their applicability in large scale sampling campaigns where concurrent samples are collected 1,4 . Accordingly, atmospheric monitoring of POPs was either not performed in many developing countries worldwide 5,6 or tend to be restricted to a small number of sites even in the large atmospheric monitoring campaigns such as the Integrated Atmospheric Deposition Network (IADN) around the Great Lakes 1 .…”

AIR-WATER EXCHANGE AND TRENDS OF PERSISTENT BIOACCUMULATIVE TOXICS (PBTs) ACROSS LAKE SUPERIOR

“…This independence means there are no limitations on spatial distribution, permitting higher resolution monitoring of large geographic areas. Comparisons between PEs and active sampling find an agreement generally within a factor of 2 (Khairy and Lohmann 2012;Khairy and Lohmann 2013).…”