4 research outputs found
Correction to An Improved Screening Tool for Predicting Volatilization of Pesticides Applied to Soils
Correction
to An Improved Screening Tool for Predicting
Volatilization of Pesticides Applied to Soil
Influence of Temperature, Relative Humidity, and Soil Properties on the Soil–Air Partitioning of Semivolatile Pesticides: Laboratory Measurements and Predictive Models
Soil–air partition
coefficient (<i>K</i><sub>soil‑air</sub>) values
are often employed to investigate the fate of organic contaminants
in soils; however, these values have not been measured for many compounds
of interest, including semivolatile current-use pesticides. Moreover,
predictive equations for estimating <i>K</i><sub>soil‑air</sub> values for pesticides (other than the organochlorine pesticides)
have not been robustly developed, due to a lack of measured data.
In this work, a solid-phase fugacity meter was used to measure the <i>K</i><sub>soil‑air</sub> values of 22 semivolatile current-
and historic-use pesticides and their degradation products. <i>K</i><sub>soil‑air</sub> values were determined for two
soils (semiarid and volcanic) under a range of environmentally relevant
temperature (10–30 °C) and relative humidity (30–100%)
conditions, such that 943 <i>K</i><sub>soil‑air</sub> measurements were made. Measured values were used to derive a predictive
equation for pesticide <i>K</i><sub>soil‑air</sub> values based on temperature, relative humidity, soil organic carbon
content, and pesticide-specific octanol–air partition coefficients.
Pesticide volatilization losses from soil, calculated with the newly
derived <i>K</i><sub>soil‑air</sub> predictive equation
and a previously described pesticide volatilization model, were compared
to previous results and showed that the choice of <i>K</i><sub>soil‑air</sub> predictive equation mainly affected the
more-volatile pesticides and that the way in which relative humidity
was accounted for was the most critical difference
Implications of Bioremediation of Polycyclic Aromatic Hydrocarbon-Contaminated Soils for Human Health and Cancer Risk
Bioremediation
uses soil microorganisms to degrade polycyclic aromatic
hydrocarbons (PAHs) into less toxic compounds and can be performed
in situ, without the need for expensive infrastructure or amendments.
This review provides insights into the cancer risks associated with
PAH-contaminated soils and places bioremediation outcomes in a context
relevant to human health. We evaluated which bioremediation strategies
were most effective for degrading PAHs and estimated the cancer risks
associated with PAH-contaminated soils. Cancer risk was statistically
reduced in 89% of treated soils following bioremediation, with a mean
degradation of 44% across the B2 group PAHs. However, all 180 treated
soils had postbioremediation cancer risk values that exceeded the
U.S. Environmental Protection Agency (USEPA) health-based acceptable
risk level (by at least a factor of 2), with 32% of treated soils
exceeding recommended levels by greater than 2 orders of magnitude.
Composting treatments were most effective at biodegrading PAHs in
soils (70% average reduction compared with 28–53% for the other
treatment types), which was likely due to the combined influence of
the rich source of nutrients and microflora introduced with organic
compost amendments. Ultimately, bioremediation strategies, in the
studies reviewed, were unable to successfully remove carcinogenic
PAHs from contaminated soils to concentrations below the target cancer
risk levels recommended by the USEPA
Understanding and Predicting the Fate of Semivolatile Organic Pesticides in a Glacier-Fed Lake Using a Multimedia Chemical Fate Model
Melting
glaciers release previously ice-entrapped chemicals to
the surrounding environment. As glacier melting accelerates under
future climate warming, chemical release may also increase. This study
investigated the behavior of semivolatile pesticides over the course
of one year and predicted their behavior under two future climate
change scenarios. Pesticides were quantified in air, lake water, glacial
meltwater, and streamwater in the catchment of Lake Brewster, an alpine
glacier-fed lake located in the Southern Alps of New Zealand. Two
historic-use pesticides (endosulfan I and hexachlorobenzene) and three
current-use pesticides (dacthal, triallate, and chlorpyrifos) were
frequently found in both air and water samples from the catchment.
Regression analysis indicated that the pesticide concentrations in
glacial meltwater and lake water were strongly correlated. A multimedia
environmental fate model was developed for these five chemicals in
Brewster Lake. Modeling results indicated that seasonal lake ice cover
melt, and varying contributions of input from glacial melt and streamwater,
created pulses in pesticide concentrations in lake water. Under future
climate scenarios, the concentration pulse was altered and glacial
melt made a greater contribution (as mass flux) to pesticide input
in the lake water