Floral hemp (Cannabis sativa L.) responses to nitrogen fertilization under field conditions in the high desert.

While most studies on floral hemp (Cannabis sativa L.) concur that additions of nitrogen (N) increase plant growth, the performance of floral hemp is heavily influenced by environmental conditions, management and cultivar selection. In regions with a short growing season, the availability of soil N may determine plant developmental rates, final inflorescence biomass and cannabinoid concentrations, but no studies have addressed this for field-grown hemp under high-desert conditions.

Laboratory Measured Emission Losses of Methyl Isothiocyanate at Pacific Northwest Soil Surface Fumigation Temperatures.

Temperature is a major environmental factor influencing land surface volatilization at the time of agricultural field fumigation. Cooler fumigation soil temperatures relevant to Pacific Northwest (PNW) application practices with metam sodium/potassium should result in appreciably reduced methyl isothiocyanate (MITC) emission rates, thus minimizing off target movement and bystander inhalation exposure. Herein, a series of laboratory controlled flow-through soil column assessments were performed evaluating MITC emissions over the range of cooler temperatures (2-13°C).

Determination of methyl isocyanate in outdoor residential air near metam-sodium soil fumigations.

The soil fumigant metam-sodium (CH3NHCS2Na) produces the bioactive respiratory irritant methyl isothiocyanate (MITC). Recent laboratory gas-phase oxidative studies indicate that MITC rapidly transforms to the more toxic methyl isocyanate (MIC) in the lower atmosphere. Inhalation exposure risks from MITC plus MIC may therefore be an occupational worker and/or bystander health concern.

Gas-phase reaction of methyl isothiocyanate and methyl isocyanate with hydroxyl radicals under static relative rate conditions.

Gaseous methyl isothiocyanate (MITC), the principal breakdown product of the soil fumigant metam sodium (sodium N-methyldithiocarbamate), is an inhalation exposure concern to persons living near treated areas. Inhalation exposure also involves gaseous methyl isocyanate (MIC), a highly reactive and toxic transformation product of MITC. In this work, gas-phase hydroxyl (OH) radical reaction rate constants of MITC and MIC have been determined using a static relative rate technique under controlled laboratory conditions.

Correlation to estimate emission rates for soil-applied fumigants.

The emission rates [ER (μg m⁻² s⁻¹)] for subsurface injections and surface chemigations for 15 fumigant applications were combined with the physicochemical properties of the fumigants [vapor pressure, VP (Pa); water solubility, S(w) (mg L⁻¹); soil adsorption coefficient, K(oc) (mL g⁻¹)] and with application conditions [application rate, AR (kg ha⁻¹); depth of application, d (cm)]. This resulted in the regression Ln ER = 3.598 + 0.

Acrylamide release resulting from sunlight irradiation of aqueous polyacrylamide/iron mixtures.

Linear anionic polyacrylamide (PAM) has been used in irrigation practices as a flocculating agent to minimize water losses through seepage in earthen canals. The stability of PAM is of concern because of the possibility of acrylamide (AMD) monomer release during environmental weathering. Aqueous solutions of commercial PAM mixed with ferric sulfate, subjected to simulated and natural sunlight irradiation, showed polymer chain scission and release of the AMD monomer.

Removal of natural steroid hormones from wastewater using membrane contactor processes.

Growing demands for potable water have strained water resources and increased interest in wastewater reclamation for potable reuse. This interest has brought increased attention to endocrine-disrupting chemicals (EDCs) as emerging water contaminants. The effect of EDCs, and in particular natural steroid hormones, on humans is of heightened interest in the study of wastewater reuse in advanced life support systems (e.