Slags sourced from a derelict zinc–lead–copper–silver–tungsten mine were examined for their bulk elemental composition and mineralogy. pH, oxidation–reduction potential, and the leachability of selected elements (sulphur, calcium, iron, copper, zinc, and lead) were assessed during a 130-day deionised water extraction conducted under oxic conditions. Slags were rich in silicon, iron, copper, zinc, and lead, hosted within minerals including quartz (SiO2), goethite [FeO(OH)], augite [Ca(Mg,AI,Fe)Si2O6], and lead (Pb0). Leachates from the slags increased in analyte concentration throughout the 130-day experiment, with iron, copper, zinc, and lead attaining >5 mg l−1 in some samples. These findings indicate that this pyrometallurgical waste should not be considered environmentally inert, as leachates emanating from them in the field might pose a significant risk to the environment.

Metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] has considerable potential for yellow nutsedge (Cyperus esculentus L.) control in crops commonly produced in the Texas High Plains. Little information is available, however, concerning adsorption characteristics of metolachlor in soils of this region. Adsorption and movement of metolachlor were determined in three commonly occurring soils of the Texas High Plains. Organic carbon contents of the soils by weight varied from 0.3 to 0.5%, and the clay fraction ranged from 16 to 33%. Freundlich adsorption isotherms exhibited two linear regions for each soil, suggesting the possibility of multilayer adsorption. K′oc values and coefficients of determination for organic carbon and clay content vs. Freundlich K values indicated that organic matter was the predominant adsorbent for metolachlor in the soils studied. Desorption, soil column leaching, and thin-layer plate studies demonstrated metolachlor to be sufficiently mobile in scils low in organic matter to cause possible crop injury or loss of efficacy.

The influence of soil moisture on wild oat control from soil-incorporated methyl ester of diclofop {2-[4-(2,4-dichlorophenoxy)-phenoxy] propanoic} was determined in the greenhouse. Wild oat control with soil-incorporated diclofop at 1.5 or 3 ppmw increased linearly when soil moisture in a Tiffany sandy loam increased from 18.5 to 23.5% (75% to 125% of field capacity). The efficacy of soil-incorporated diclofop was not reduced when soil moisture was allowed to decrease from 21 (field capacity) to 18.5, 16, 13.5, or 11% (wilting point) before rewatering to 21%. The soil moisture level at the time of herbicide application determined the degree of wild oat control with soil-incorporated diclofop. Wild oat control with diclofop increased when a Tiffany sandy loam with 16% moisture (50% of field capacity) at the time of herbicide application, was watered to field capacity after 8 or 12 days delay, and control did not change with watering to field capacity at the time of herbicide application or when delayed 4 or 16 days. The movement of 14C-diclofop in soil columns was greater within coarse than fine textured soils and increased with water volumes applied, regardless of soil type. Further, the leachability of 14C-diclofop was two and a half times greater than that of 14C-trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine).