TY - JOUR
T1 - Influence of dissolved organic matter on the photodegradation and volatilization kinetics of chlorpyrifos in coastal waters
AU - Pinto, Maria Isabel Araújo
AU - Salgado, R.
AU - Cottrell, Barbara A.
AU - Cooper, William J.
AU - Burrows, Hugh D.
AU - Vale, Carlos
AU - Sontag, Gerhard
AU - Noronha, João Paulo da Costa de
N1 - Sem PDF
PY - 2015/9/1
Y1 - 2015/9/1
N2 - Irradiation by a medium-pressure mercury (Hg) lamp was used to study the photodegradation of chlorpyrifos (O,O-diethyl-O-3,5,6-trichloropyridin-2-yl phosphorothioate) in salt, deionized water (unbuffered), and a natural saline water. The UV irradiation produces 3,5,6-trichloro-2-pyridinol (TCP) with accelerated photodegradation kinetics of the parent compound. The results show that chlorpyrifos photolysis followed pseudo-first-order kinetics in the presence and absence of salt with no significant difference between the photodegradation rates in saline waters and unbuffered deionized water. Addition of Suwannee River natural organic matter (SRNOM) to mimic the mixing of freshwaters with seawaters significantly changed the photodegradation rate constant of chlorpyrifos in saline waters. The influence of hydrolysis and volatilization was also evaluated. While photolysis was found to be the main transformation process in unbuffered deionized water, both volatilization and photolysis can be important pathways of chlorpyrifos loss in natural saline waters and under aerated conditions.
AB - Irradiation by a medium-pressure mercury (Hg) lamp was used to study the photodegradation of chlorpyrifos (O,O-diethyl-O-3,5,6-trichloropyridin-2-yl phosphorothioate) in salt, deionized water (unbuffered), and a natural saline water. The UV irradiation produces 3,5,6-trichloro-2-pyridinol (TCP) with accelerated photodegradation kinetics of the parent compound. The results show that chlorpyrifos photolysis followed pseudo-first-order kinetics in the presence and absence of salt with no significant difference between the photodegradation rates in saline waters and unbuffered deionized water. Addition of Suwannee River natural organic matter (SRNOM) to mimic the mixing of freshwaters with seawaters significantly changed the photodegradation rate constant of chlorpyrifos in saline waters. The influence of hydrolysis and volatilization was also evaluated. While photolysis was found to be the main transformation process in unbuffered deionized water, both volatilization and photolysis can be important pathways of chlorpyrifos loss in natural saline waters and under aerated conditions.
KW - Chlorpyrifos
KW - Dissolved organic matter
KW - Pesticides
KW - Photolysis
KW - Salinity
KW - UV irradiation
U2 - 10.1016/j.jphotochem.2015.05.024
DO - 10.1016/j.jphotochem.2015.05.024
M3 - Article
SN - 1010-6030
VL - 310
SP - 189
EP - 196
JO - Journal of Photochemistry and Photobiology A: Chemistry
JF - Journal of Photochemistry and Photobiology A: Chemistry
ER -