Mariana Gonzalez | Universidad Nacional de Mar del Plata (original) (raw)
Papers by Mariana Gonzalez
Chemosphere, 2021
We study a current shot noise in a macroscopic insulator based on a two-dimensional electron syst... more We study a current shot noise in a macroscopic insulator based on a two-dimensional electron system in GaAs in a variable range hopping (VRH) regime. At low temperature and in a sufficiently depleted sample a shot noise close to a full Poissonian value is measured. This suggests an observation of a finite-size effect in shot noise in the VRH conduction and demonstrates a possibility of accurate quasiparticle charge measurements in the insulating regime.
Journal of Soils and Sediments, 2018
PurposeIrrigation or flooding events with riverine waters containing compounds such as surfactant... more PurposeIrrigation or flooding events with riverine waters containing compounds such as surfactants, colloids, and dissolved organic carbon and plant growth will modify pesticide availability and leaching. This work studies the effect of a non-ionic surfactant (Tween 80: polyethylene glycol sorbitan monooleate, Tw-80), carboxylic acids (CA), and the role of dissolved organic matter on the lixiviation, availability, and degradation of aged DDT (p,p′-DDT, p,p′-DDE and p,p′-DDD) residues in soil.Materials and methodsUndisturbed soil columns were collected in a known polluted area and irrigated under saturation conditions with 4 L of riverine water (control), Tween 80 at 0.5 times the critical micellar concentration (Tw-80), and a 0.05 M solution of oxalic and citric acids (CA). After elution, columns were air-dried (24 h), opened, and divided into 5-cm sections for pesticide residue analysis in soil by GC-ECD. Batch desorption studies were conducted to assess pesticide availability before treatments. Metabolite ratios were analyzed in relation with the soil microbial activity measured by the dehydrogenase activity (DHA) assay. Soil organic matter and dissolved organic matter were analyzed, and humic substances were characterized in terms of humic and fulvic acid content by spectrophotometric ratios.Results and discussionThe p,p′-DDE>p,p′-DDT>p,p′-DDD pattern was found in all soil sections and treatments with decreased levels with depth. Levels of p,p′-DDE ranged between 8 and 280, between 8 and 80, and between 13 and 250 ng g−1 dry weight in control, Tw-80, and CA, respectively. Lixiviation of p,p′-DDE was enhanced in Tw-80 or CA. Compared to control, elution with Tw-80 diminished effectively soil DDT levels, while with CA results showed an enhancement of the transference to water. Higher (p,p′-DDE + p,p′-DDD)/p,p′-DDT ratio in Tw-80 or CA soils, with respect to control, were related with higher p,p′-DDD and DHA levels in CA and with lower p,p′-DDE and p,p′-DDT levels in Tw-80. Control and CA showed a positive correlation between p,p′-DDE and p,p′-DDT soil levels and desorption (r > 0.8, p < 0.02). Losses of fulvic acid content in soil after Tw-80 agree with the enrichment in fulvic acids in the desorption solution.ConclusionsThe influence of Tw-80 and CA on the availability of DDTs was related with the mobilization of organic matter fractions. Results highlight the role of the non-ionic surfactant Tw-80 in the mobilization of fulvic acids as well as on DDT desorption from soil. Both solutions might interact differentially with pesticides and with the soil microbial population controlling the fate of DDT residues in the soil matrix.
Ecotoxicology and Environmental Safety
Bulletin of Environmental Contamination and Toxicology
The Science of the total environment, Jan 3, 2016
The occurrence of persistent organic pollutants (POPs) in the environment can affect organisms in... more The occurrence of persistent organic pollutants (POPs) in the environment can affect organisms inhabiting aquatic systems, in particular shallow lakes that are vulnerable to environmental stressors. This study aimed to assess POPs accumulation and changes at histological and physiological levels in tissues of three fish species with different trophic habits. Gills, brain, muscle, liver and gonads of Odontesthes bonariensis, Oligosarcus jenynsii and Cyphocharax voga were collected from the shallow lake La Peregrina, located in an agricultural area from Argentina. In addition, contaminant levels in surface water (SW), suspended particulate matter (SPM) and bottom sediments (BS) were assessed. Histological lesions were evaluated in fish tissues and levels of vitellogenin (VTG) were assessed in plasma of male fish in order to correlate these alterations with the presence of POPs in the environment. Organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated dip...
Pesticide Biochemistry and Physiology, 2015
Revista de la Facultad de Ciencias Agrarias
La cuenca del Río Quequén Grande constituye una región representativa de los sistemas agrícolas p... more La cuenca del Río Quequén Grande constituye una región representativa de los sistemas agrícolas pampeanos. El acuífero en esta región es la principal fuente de abastecimiento de agua para todos los usos, lo que pone de manifiesto la importancia de desarrollar los elementos necesarios para el estudio de la movilidad de los contaminantes a través de los suelos hacia la zona saturada. El objetivo del presente trabajo fue obtener parámetros hidráulicos bajo condiciones de saturación en columnas intactas de distintos tipos de suelos de la región, contemplando suelos de uso agrícola y natural. Se estudiaron dos series de suelo: Serie Azul y Serie Semillero Buck, con muestras tomadas en dos sectores próximos a las localidades de Lobería y La Dulce, respectivamente. Las columnas fueron eluidas con una solución acuosa de iones cloruro y se midió el incremento progresivo de conductividad. A partir de las curvas de arribo obtenidas, se ajustó la ecuación de transporte, obteniendo los valores d...
The Science of the total environment, Jan 23, 2015
Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were assessed in blubber fr... more Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were assessed in blubber from 35 dead Southern Right Whales (SRW - Eubalaena australis) stranded at Península Valdés, Argentina. The life cycle includes a feeding period in high productivity areas of the South West Atlantic and a reproductive period in coastal template waters of Argentina. Organochlorine pesticides showed higher concentrations (22.6±13.8ng·g(-1)ww) than PCBs (7.5±10ng·g(-1)ww). Among pesticides, HCHs, DDTs, endosulfans, dieldrin, chlordans, heptachlor epoxide, and trans-nonachlor were detected. p,p'-DDE and p,p'-DDT were present in 69% and 26% of samples, respectively. p,p'-DDT/p,p'-DDE ratio showed low values (<0.33) as a result of aged DDT inputs. However, the occurrence of only p,p'-DDT in some samples suggests a recent pesticide input. α-HCH/γ-HCH ratio (<DL-0.37) indicated no recent contribution of technical HCH mixture and/or current use of lindane. Dieldrin was pre...
The Science of the total environment, 2013
This work reports the occurrence and distribution of organochlorine pesticides (OCPs), polychlori... more This work reports the occurrence and distribution of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in soil, sediment, suspended particle matter (SPM), streamwater and macrophytes, along the Río Negro basin, Argentinean Patagonia. The clear predominance of OCPs among all matrices indicates the impact of agriculture on the watershed. The highest levels were found for pp'-DDE which represented up to 95% in agricultural soils (42.0-1.27x10(3) ng/g d.w) from the Upper Valley (upstream), where long and historical intensive fruit cultures have been settled and represent a hot spot of legacy pesticides for the environment. The insecticide endosulfan, currently in use, was also found in all matrices. Levels ranged between 0.3 and 708.0 ng/g d.w, being the highest concentrations those of SPM from the Middle Valley, just before the delta area, where pesticides would be retained leading to lower concentrations as was observed d...
Environmental Earth Sciences, 2011
ACS Symposium Series, 2013
Science of The Total Environment, 2014
Science of The Total Environment, 2012
Pesticide Biochemistry and Physiology, 2014
Journal of Hazardous Materials, 2012
… of agricultural and …, Jan 1, 2003
Fifty-five surface sediment samples covering virtually the entire Bohai Sea (Bohai) were analyzed... more Fifty-five surface sediment samples covering virtually the entire Bohai Sea (Bohai) were analyzed for organochlorine pesticides (OCPs), in order to provide the extensive information of recent occurrence levels, distribution, possible sources and potential biological risk of these compounds in this area. Concentrations of total dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) in Bohai ranged widely from 0.24 to 5.67 ng g À1 (mean 1.36 ± 0.93 ng g À1 ) and 0.16 to 3.17 ng g À1 (mean 0.83 ± 0.57 ng g À1 ), respectively. High concentrations of DDTs were observed in the coastal areas especially at the isolated sites neighboring the harbor or port regions. The recent DDT inputs could be mainly attributed to the agricultural activity (e.g. dicofol), wastewater of chemical plants and the usage of antifouling paint. The distribution pattern of HCHs was different from that of DDTs due to their different physical-chemical properties and amounts of production and usage in the past. (DDE + DDD)/DDT ratios indicated that the degradation of the parent DDT occurred significantly. The contributions of previous and current inputs of pesticides in the coastal areas were distinguished by means of principal component analysis, suggesting that the recent usage of DDT and technical chlordane could serve as important fresh input sources for OCPs. DDTs and chlordanes are the two-main species of OCPs with more ecotoxicological concern in Bohai.
… of agricultural and …, Jan 1, 2003
Leek (Allium porrum) plants from organic farming were harvested at 15, 59, and 210 days after see... more Leek (Allium porrum) plants from organic farming were harvested at 15, 59, and 210 days after seed germination. Organochlorine pesticide (OCP) levels were quantified by GC-ECD in vegetative tissues (roots and aerial), bulk soil and rhizosphere. Leek plant bioaccumulate OCPs efficiently in their aerial and root tissues and alter the concentration of the soil where they are grown. OCPs distribution pattern of bulk soil was endosulfans &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; DDTs &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; dieldrin, while it was endosulfans &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; HCHs &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; DDTs in leek tissues. There were statistically significant declines in DDTs, chlordane, dieldrin, and heptachlor in the rhizosphere, indicating that recalcitrant residues of OCPs may be removed from contaminated soil using leek crops under normal growing conditions. The DDE/DDT and alpha-/gamma-HCH ratios of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 1 would indicate recent inputs of DDT and lindane in the environment. The occurrence of OCPs in this farm could be the result of atmospheric deposition and/or surface runoff of these pesticides.
Chemosphere, 2021
We study a current shot noise in a macroscopic insulator based on a two-dimensional electron syst... more We study a current shot noise in a macroscopic insulator based on a two-dimensional electron system in GaAs in a variable range hopping (VRH) regime. At low temperature and in a sufficiently depleted sample a shot noise close to a full Poissonian value is measured. This suggests an observation of a finite-size effect in shot noise in the VRH conduction and demonstrates a possibility of accurate quasiparticle charge measurements in the insulating regime.
Journal of Soils and Sediments, 2018
PurposeIrrigation or flooding events with riverine waters containing compounds such as surfactant... more PurposeIrrigation or flooding events with riverine waters containing compounds such as surfactants, colloids, and dissolved organic carbon and plant growth will modify pesticide availability and leaching. This work studies the effect of a non-ionic surfactant (Tween 80: polyethylene glycol sorbitan monooleate, Tw-80), carboxylic acids (CA), and the role of dissolved organic matter on the lixiviation, availability, and degradation of aged DDT (p,p′-DDT, p,p′-DDE and p,p′-DDD) residues in soil.Materials and methodsUndisturbed soil columns were collected in a known polluted area and irrigated under saturation conditions with 4 L of riverine water (control), Tween 80 at 0.5 times the critical micellar concentration (Tw-80), and a 0.05 M solution of oxalic and citric acids (CA). After elution, columns were air-dried (24 h), opened, and divided into 5-cm sections for pesticide residue analysis in soil by GC-ECD. Batch desorption studies were conducted to assess pesticide availability before treatments. Metabolite ratios were analyzed in relation with the soil microbial activity measured by the dehydrogenase activity (DHA) assay. Soil organic matter and dissolved organic matter were analyzed, and humic substances were characterized in terms of humic and fulvic acid content by spectrophotometric ratios.Results and discussionThe p,p′-DDE>p,p′-DDT>p,p′-DDD pattern was found in all soil sections and treatments with decreased levels with depth. Levels of p,p′-DDE ranged between 8 and 280, between 8 and 80, and between 13 and 250 ng g−1 dry weight in control, Tw-80, and CA, respectively. Lixiviation of p,p′-DDE was enhanced in Tw-80 or CA. Compared to control, elution with Tw-80 diminished effectively soil DDT levels, while with CA results showed an enhancement of the transference to water. Higher (p,p′-DDE + p,p′-DDD)/p,p′-DDT ratio in Tw-80 or CA soils, with respect to control, were related with higher p,p′-DDD and DHA levels in CA and with lower p,p′-DDE and p,p′-DDT levels in Tw-80. Control and CA showed a positive correlation between p,p′-DDE and p,p′-DDT soil levels and desorption (r > 0.8, p < 0.02). Losses of fulvic acid content in soil after Tw-80 agree with the enrichment in fulvic acids in the desorption solution.ConclusionsThe influence of Tw-80 and CA on the availability of DDTs was related with the mobilization of organic matter fractions. Results highlight the role of the non-ionic surfactant Tw-80 in the mobilization of fulvic acids as well as on DDT desorption from soil. Both solutions might interact differentially with pesticides and with the soil microbial population controlling the fate of DDT residues in the soil matrix.
Ecotoxicology and Environmental Safety
Bulletin of Environmental Contamination and Toxicology
The Science of the total environment, Jan 3, 2016
The occurrence of persistent organic pollutants (POPs) in the environment can affect organisms in... more The occurrence of persistent organic pollutants (POPs) in the environment can affect organisms inhabiting aquatic systems, in particular shallow lakes that are vulnerable to environmental stressors. This study aimed to assess POPs accumulation and changes at histological and physiological levels in tissues of three fish species with different trophic habits. Gills, brain, muscle, liver and gonads of Odontesthes bonariensis, Oligosarcus jenynsii and Cyphocharax voga were collected from the shallow lake La Peregrina, located in an agricultural area from Argentina. In addition, contaminant levels in surface water (SW), suspended particulate matter (SPM) and bottom sediments (BS) were assessed. Histological lesions were evaluated in fish tissues and levels of vitellogenin (VTG) were assessed in plasma of male fish in order to correlate these alterations with the presence of POPs in the environment. Organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated dip...
Pesticide Biochemistry and Physiology, 2015
Revista de la Facultad de Ciencias Agrarias
La cuenca del Río Quequén Grande constituye una región representativa de los sistemas agrícolas p... more La cuenca del Río Quequén Grande constituye una región representativa de los sistemas agrícolas pampeanos. El acuífero en esta región es la principal fuente de abastecimiento de agua para todos los usos, lo que pone de manifiesto la importancia de desarrollar los elementos necesarios para el estudio de la movilidad de los contaminantes a través de los suelos hacia la zona saturada. El objetivo del presente trabajo fue obtener parámetros hidráulicos bajo condiciones de saturación en columnas intactas de distintos tipos de suelos de la región, contemplando suelos de uso agrícola y natural. Se estudiaron dos series de suelo: Serie Azul y Serie Semillero Buck, con muestras tomadas en dos sectores próximos a las localidades de Lobería y La Dulce, respectivamente. Las columnas fueron eluidas con una solución acuosa de iones cloruro y se midió el incremento progresivo de conductividad. A partir de las curvas de arribo obtenidas, se ajustó la ecuación de transporte, obteniendo los valores d...
The Science of the total environment, Jan 23, 2015
Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were assessed in blubber fr... more Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were assessed in blubber from 35 dead Southern Right Whales (SRW - Eubalaena australis) stranded at Península Valdés, Argentina. The life cycle includes a feeding period in high productivity areas of the South West Atlantic and a reproductive period in coastal template waters of Argentina. Organochlorine pesticides showed higher concentrations (22.6±13.8ng·g(-1)ww) than PCBs (7.5±10ng·g(-1)ww). Among pesticides, HCHs, DDTs, endosulfans, dieldrin, chlordans, heptachlor epoxide, and trans-nonachlor were detected. p,p'-DDE and p,p'-DDT were present in 69% and 26% of samples, respectively. p,p'-DDT/p,p'-DDE ratio showed low values (<0.33) as a result of aged DDT inputs. However, the occurrence of only p,p'-DDT in some samples suggests a recent pesticide input. α-HCH/γ-HCH ratio (<DL-0.37) indicated no recent contribution of technical HCH mixture and/or current use of lindane. Dieldrin was pre...
The Science of the total environment, 2013
This work reports the occurrence and distribution of organochlorine pesticides (OCPs), polychlori... more This work reports the occurrence and distribution of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in soil, sediment, suspended particle matter (SPM), streamwater and macrophytes, along the Río Negro basin, Argentinean Patagonia. The clear predominance of OCPs among all matrices indicates the impact of agriculture on the watershed. The highest levels were found for pp'-DDE which represented up to 95% in agricultural soils (42.0-1.27x10(3) ng/g d.w) from the Upper Valley (upstream), where long and historical intensive fruit cultures have been settled and represent a hot spot of legacy pesticides for the environment. The insecticide endosulfan, currently in use, was also found in all matrices. Levels ranged between 0.3 and 708.0 ng/g d.w, being the highest concentrations those of SPM from the Middle Valley, just before the delta area, where pesticides would be retained leading to lower concentrations as was observed d...
Environmental Earth Sciences, 2011
ACS Symposium Series, 2013
Science of The Total Environment, 2014
Science of The Total Environment, 2012
Pesticide Biochemistry and Physiology, 2014
Journal of Hazardous Materials, 2012
… of agricultural and …, Jan 1, 2003
Fifty-five surface sediment samples covering virtually the entire Bohai Sea (Bohai) were analyzed... more Fifty-five surface sediment samples covering virtually the entire Bohai Sea (Bohai) were analyzed for organochlorine pesticides (OCPs), in order to provide the extensive information of recent occurrence levels, distribution, possible sources and potential biological risk of these compounds in this area. Concentrations of total dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) in Bohai ranged widely from 0.24 to 5.67 ng g À1 (mean 1.36 ± 0.93 ng g À1 ) and 0.16 to 3.17 ng g À1 (mean 0.83 ± 0.57 ng g À1 ), respectively. High concentrations of DDTs were observed in the coastal areas especially at the isolated sites neighboring the harbor or port regions. The recent DDT inputs could be mainly attributed to the agricultural activity (e.g. dicofol), wastewater of chemical plants and the usage of antifouling paint. The distribution pattern of HCHs was different from that of DDTs due to their different physical-chemical properties and amounts of production and usage in the past. (DDE + DDD)/DDT ratios indicated that the degradation of the parent DDT occurred significantly. The contributions of previous and current inputs of pesticides in the coastal areas were distinguished by means of principal component analysis, suggesting that the recent usage of DDT and technical chlordane could serve as important fresh input sources for OCPs. DDTs and chlordanes are the two-main species of OCPs with more ecotoxicological concern in Bohai.
… of agricultural and …, Jan 1, 2003
Leek (Allium porrum) plants from organic farming were harvested at 15, 59, and 210 days after see... more Leek (Allium porrum) plants from organic farming were harvested at 15, 59, and 210 days after seed germination. Organochlorine pesticide (OCP) levels were quantified by GC-ECD in vegetative tissues (roots and aerial), bulk soil and rhizosphere. Leek plant bioaccumulate OCPs efficiently in their aerial and root tissues and alter the concentration of the soil where they are grown. OCPs distribution pattern of bulk soil was endosulfans &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; DDTs &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; dieldrin, while it was endosulfans &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; HCHs &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; DDTs in leek tissues. There were statistically significant declines in DDTs, chlordane, dieldrin, and heptachlor in the rhizosphere, indicating that recalcitrant residues of OCPs may be removed from contaminated soil using leek crops under normal growing conditions. The DDE/DDT and alpha-/gamma-HCH ratios of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 1 would indicate recent inputs of DDT and lindane in the environment. The occurrence of OCPs in this farm could be the result of atmospheric deposition and/or surface runoff of these pesticides.