No abstract

A simple procedure is described for simultaneous extraction from soil of 2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine (atrazine), 2‐methylthio‐4‐ethylamino‐6‐isopropylamino‐s‐triazine (ametryne) and their common hydrolysate (hydroxyatrazine = HA). The procedure involves extraction by shaking in acidified methanol, centrifugation, and subsequent quantitative separation of HA from the parent triazines by liquid‐liquid partitioning. The pH of methanol was adjusted with 4N HCl to obtain a final pH of 2.5 in the soil extract, using a 1:10 soil/solvent ratio. HA recovery with one extraction was 94% for both Molokai (Typic Torrox) and Hilo (Hydrandept) soils having soil extract pH values of 2.4 and 3.4, respectively. In all cases atrazine and ametryne were quantitatively recovered in soil extracts. After protonation HA was quantitatively separated from the mixture of HA and atrazine or ametryne by partitioning in an aqueous methanolic soil‐extract/chloroform system when the water/methanol extract ratio was 1.25. HA extraction from soil was extremely pH dependent. Dissolution of calcium chloride in acidified methanol decreased recovery of added HA from 94% to 76% for Hilo soil but had no effect on % HA recovery from Molokai soil; the electrolyte was found to increase the pH of Hilo soil extract, a result of the net positive charge of this soil at low pH. The recovery of added HA from Ca‐montmorillonite was 33%, suggesting that the procedure may be less suitable for soils with high permanent negative charge.

No abstract

Analysis of sediments and soils associated with two estuaries on Oahu was conducted to determine if herbicides used in plantation crops reach coastal waters. Analytical procedures were developed for simultaneous extraction of atrazine (2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine), ametryn (2‐(ethylamino)‐4‐(isopropylamino)‐6‐(methylthio)‐s‐triazine), diuron (3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea), and DCA (3,4‐dichloroaniline). Field soil and runoff samples from two small monitored watersheds provided additional information on the dissipation of diuron in sugarcane (Saccharum officinarum) and pineapple (Ananas comosus) fields, and on diuron removal in runoff waters. Atrazine and ametryn dissipated rapidly in field soils, and neither was found normally in stream and estuarine sediments. Diuron, on the other hand, was sufficiently persistent in soils and sediments to be found in nearly all sediment samples obtained at 6‐month intervals at several sites for each estuary and its associated streams. Diuron in sediments was generally < 500 ppb (oven‐dry basis), but occasionally much higher concentrations were encountered at sites which were subject to localized contamination from spray equipment loading areas. Diuron appears to be transported in runoff waters principally in the solution phase rather than adsorbed on suspended solids. Estuarine waters (West Loch) contained 0.1 to 1 ppb diuron, while concentrations in runoff waters were several times higher. It is not known if these chronic low levels adversely affect the ecological balance of the estuary.

No abstract