HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Raupach, M.R. Articles by Edge, V.E. Search for Related Content PubMed PubMed Citation Articles by Raupach, M.R. Articles by Edge, V.E. Agricola Articles by Raupach, M.R. Articles by Edge, V.E. Related Collections Water Quality Cotton Agricultural Pesticides Water Pollution

Endosulfan Transport

I. Integrative Assessment of Airborne and Waterborne Pathways

^a CSIRO Land and Water, GPO Box 1666, Canberra, ACT 2601, Australia
^b Dep. of Land and Water Conservation, P.O. Box 3720, Parramatta, NSW 2150, Australia
^c NSW Agriculture, Locked Bag 21, Orange, NSW 2800, Australia

View larger version (22K): [in a new window]   Fig. 1. Location of the focus area, showing the cotton-growing areas and major waterways in the mid and lower reaches of the Namoi River catchment, northern New South Wales, Australia. Cotton areas and catchment boundary from Peasley (1996) provided by Department of Land and Water Conservation, Gunnedah, NSW.

View larger version (27K): [in a new window]   Fig. 2. Schematic diagram of the physical and chemical interactions included in the endosulfan chemistry model, with reaction rates expressed as time scales (order of magnitude only). Ca, Cw, and Cp are respectively the endosulfan concentrations in air, in aqueous solution, and adsorbed on particles in the river (all in kg m-3).

View larger version (24K): [in a new window]   Fig. 3. Temperature dependence of the (a) water–air partition coefficient and (b) saturation vapor pressure of endosulfan , endosulfan ß, and endosulfan sulfate.

View larger version (27K): [in a new window]   Fig. 4. Estimated local surface runoff at Myall Vale for a sample period (1988 to 1991) using a simple water-balance model (Appendix C), observed precipitation and evaporation data, and predicted irrigation scheduling based on modeled root-zone soil moisture storage. Model parameters are for the central case (Appendix C).

View larger version (31K): [in a new window]   Fig. 5. Source and receptor geometry for integrated modeling of each 10 km stretch of river (of a total of 100 km). On either side of the river is a 500-m buffer zone, beyond which are 50 cotton fields of area 1 km2 (25 on each side of the river) alternating with unsprayed fields.

View larger version (28K): [in a new window]   Fig. 6. Modeled variation over time of + ß fraction and total riverine endosulfan concentration, integrating all transport pathways (spray + vapor + dust + runoff), for the (a) Namoi River and (b) Pian Creek, using model parameters in Table 3. Time traces are given for X = 10, 40, and 100 km downstream. A major runoff input occurs on Days 8 and 9 at X = 35 km.

View larger version (26K): [in a new window]   Fig. 7. Modeled variation with downstream distance of + ß fraction and total riverine endosulfan concentration, integrating all transport pathways (spray + vapor + dust + runoff), for the (a) Namoi River and (b) Pian Creek, using model parameters in Table 3. Plots with distance are given for times t = 2, 10, and 40 d after the start of spraying. A major runoff input occurs on Days 8 and 9 at X = 35 km. In (a) the 2-d line is beneath the 40-d line.

View larger version (35K): [in a new window]   Fig. 8. Modeled contributions to the total riverine endosulfan concentration at X = 50 km by each contributing transport pathway for the Namoi River and Pian Creek at t = 10 d and t = 40 d.

View larger version (15K): [in a new window]   Fig. 9. Measurements of total ( + ß + sulfate) waterborne endosulfan concentration for the Namoi River at Bugilbone and Pian Creek at Rossmore, September 1991 to March 1997, by the New South Wales Department of Land and Water Conservation (Muschal, 1998).