Interlaboratory validation of the Mehlich 3 method as a universal extractant for plant nutrients.

The Mehlich 3 (M3) method is widely used to extract plant-available phosphorus from soil over a wide range of pH values. The method is also used by many laboratories to determine multiple plant-available nutrients simultaneously. However, except for P, this method has not been statistically validated within and among laboratories.

Interlaboratory validation of the Mehlich 3 method for extraction of plant-available phosphorus.

The Mehlich 3 (M3) method is widely used for extraction of plant-available phosphorus (P) from soil over a wide range of pH values. The method is also used by many laboratories to determine multiple plant-available nutrients simultaneously. However, this method has not been statistically validated within and among laboratories.

Assessing availability, phytotoxicity and bioaccumulation of lead to ryegrass and millet based on 0.1 mol/L ca(NO3)2 extraction.

This study was conducted to assess availability, phytotoxicity and bioaccumulation of lead (Pb) to ryegrass (Lolium perenne L.) and millet (Echinochloa crusgalli) based on the 0.1 mol/L Ca(NO3), extraction.

Effect of soil properties on lead bioavailability and toxicity to earthworms.

Soil properties are important factors modifying metal bioavailability to ecological receptors. Twenty-one soils with a wide range of soil properties (USA; http://soils.usda.

Evaluating the contribution of soil properties to modifying lead phytoavailability and phytotoxicity.

Soil properties affect Pb bioavailability to human and ecological receptors and should be considered during ecological risk assessment of contaminated soil. We used path analysis (PA) to determine the relative contribution of soil properties (pH, organic C [OC], amorphous Fe and Al oxides [FEAL], and cation-exchange capacity [CEC]) in modifying Pb bioavailability. The response of biological endpoints (bioaccumulation and dry matter growth [DMG]) of lettuce (Lactuca sativa) grown on 21 Pb-spiked (2,000 mg/kg) soils were determined.

Soil characteristics and phosphorus level effect on phosphorus loss in runoff.

The loss of phosphorus (P) in runoff from agricultural soils may accelerate eutrophication in lakes and streams as well as degrade surface water quality. Limited soil specific data exist on the relationship between runoff P and soil P. This study investigated the relationship between runoff dissolved reactive phosphorus (DRP) and soil P for three Oklahoma benchmark soils: Richfield (fine, smectitic, mesic Aridic Argiustoll), Dennis (fine, mixed, active, thermic Aquic Argiudoll), and Kirkland (fine, mixed, superactive, thermic Udertic Paleustoll) series.

Ecotoxicological risks associated with land treatment of petrochemical wastes. III. Immune function and hematology of cotton rats.

Landfarming is a widely used method of treating petrochemical waste through microbial bio-degradation. The effects of residual petrochemical contamination on wildlife, especially terrestrial mammals, are poorly understood. The effects of contaminants on the immune system and hematology of cotton rats (Sigmodon hispidus) living on five abandoned petrochemical landfarms (units 1-5) in Oklahoma were studied.

Ecotoxicological risks associated with land treatment of petrochemical wastes. II. Effects on hepatic phase I and phase II detoxification enzymes in cotton rats.

The purpose of this study was to evaluate possible exposure and resultant hepatic effects of petrochemical waste on cotton rats (Sigmodon hispidus) living on landfarmed sites. Male and female cotton rats were collected in summer, fall, and winter from four landfarm sites and four ecologically similar reference sites. Hepatic methoxyresorufin O-deethylase (MROD) activity was significantly induced in male and female rats collected from landfarms compared to rats collected from reference sites.

Ecotoxicological risks associated with land treatment of petrochemical wastes. I. Residual soil contamination and bioaccumulation by cotton rats (Sigmodon hispidus).

Petrochemical waste contains both organic and inorganic contaminants that can pollute soil and may pose significant ecological risks to wildlife. Petrochemical waste typically is disposed of in land treatment units, which are widespread throughout Oklahoma and the United States. Few studies have been conducted evaluating possible toxicity risks to terrestrial organisms residing on these units.