Transport Of Organochlorine Pesticides Research Articles

Atmospheric organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in the Antarctic marginal seas: Distribution, sources and transportation

From November 2013 to March 2014, air samples were collected in the Antarctic marginal seas during the 30th Chinese Antarctic research expedition. Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were analyzed in these samples. The mean concentrations were observed for hexachlorobenzene (HCB) >ΣPCBs >Σhexachlorocyclohexanes(HCHs) >Σdichlorodiphenyltrichloroethane(DDTs)>Σchlordanes. High levels of HCB were found near east Antarctica and in the Ross Sea, reflecting the re-emission of HCB from environmental reservoirs of these regions. Parent DDTs (p,p’- and o,p’-DDT) were rarely detected, suggesting that atmospheric DDT was predominantly influencedby weathered DDT from some secondarysources. However, fresh inputs of DDTs could not be excluded because there were still some samples with high proportions of parent DDTs. HCHs only were detected in the South Indian Ocean (near Australia), andthis result might be related to the intense emissions of HCHs from southern Australia. Ratios of trans-chlordane/cis-chlordanein most samples were lower than that in technical chlordane, reflecting the main influence of weathered chlordane. High levels of ΣPCBs were found in the Ross Sea, suggesting an intense re-emission of PCBs. Furthermore, atmospheric PCBs near the Antarctic Peninsula were also relatively high, this finding might be attributed to the emissions of PCBs from nearby Antarctic research stations. Comparing with the Arctic, transport of OCPs and PCBs towards Antarctica is more difficult. The Antarctic marginal seas would act as both barriers and “buffer zones”during the transportation processes.

The spatial distribution of organochlorine pesticides and halogenated flame retardants in the surface sediments of an Arctic fjord: The influence of ocean currents vs. glacial runoff

Selected organochlorine pesticides (OCs) and halogenated flame retardants (HFRs) were analyzed in surficial fjord sediments collected down the length of Kongsfjorden, Svalbard in the Norwegian high Arctic. Hexachlorocyclohexane (α-HCHs) was found to be the most abundant OC in the sediment, followed by BDE-209>chlordane>α-endosulfan>Dechlorane Plus (anti-DP)>trifluralin concentration ranges were high over the relatively small study area of the fjord (e.g. ∑HCH: 7.2–100pgg−1 dry weight (dw)), with concentrations broadly similar to, or lower than, measurements conducted in other parts of the Arctic. Concentrations of legacy OCs, including both HCH isomers and chlordane showed a decreasing trend from the outer, seaward end of the fjord to the inner, glacier end of the fjord. Conversely, sediment concentrations of α- and β-endosulfan (0.1–12.5pgg−1 dw) increased from the outer fjord to the inner fjord. This contrasting pattern may be attributed to the influence of historical vs. contemporary sources of these chemicals to the fjord area, whereby the North Atlantic/West Spitzbergen oceanic current dominates the transport and input of the legacy OCs, whereas atmospheric deposition and meltwater runoff from the glaciers influence the inner fjord sediments for endosulfan. Interestingly, BDE-209 and Dechlorane Plus did not reveal any clear spatial trend. It is plausible that both glacial runoff and oceanic current end members are playing a role in introducing these chemicals to the fjord sediments. The relatively low fractional abundance of the syn-DP isomer (fsyn), however, indicates the long-range transport of this chemical to this Arctic site.

Sources and transports of organochlorine pesticides in the Nanshan underground river, China

Karst areas have much higher ecological vulnerability and are prone to be contaminated. Organochlorine pesticides (OCPs) were detected in waters and sediment from the two sites of the karst Nanshan underground river system, China, to understand the sources and transport of OCPs in the underground river systems. Obviously, seasonal variations were found both in the waters and the sediments. Detected OCPs ranged from 61 to 936 ng L−1 in the groundwaters and 51–3,842.0 ng g−1 in the underground sediments, respectively. OCPs in groundwaters were mixture of younger and older residues from commercial sources. The maximum OCPs in the sediments of the underground river were historically older residues from commercial sources. The sources of OCPs in the waters and sediments of the underground river indicated that the surface systems play an important role in OCPs transport and pollution in the underground river. Karst features were liable for the transport behavior.

Organic pollutant levels in an agricultural watershed: the importance of analyzing multiple matrices for assessing streamwater pollution

This study is aimed at analyzing the occurrence and transport of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the Quequén Grande river basin, as representative of a catchment under diffuse pollution sources. Pollutant levels in soils, river bottom sediments (RBS), streamwater (Sw), suspended particle materials (SPMs), macrophytes and muscle of silverside were determined by GC-ECD. Soil K(d) values for the current-used insecticides, endosulfans and cypermethrin, were established. Total levels (ng g(-1) dry weight) in soil ranged between 0.07–0.9 for OCPs, 0.03–0.37 for PCBs and 0.01–0.05 for PBDEs. Endosulfan insecticide (α- + b- + sulfate metabolite) represented up to 72.5% of OCPs. The low soil retention for α-endosulfan (K(d): 77) and endosulfan sulfate (K(d): 100) allows their transport to Sw, SPM and RBS. Levels of endosulfan in Sw in some cases exceeded the value postulated by international guidelines for aquatic biota protection (3 ng L(-1)). PCB and PBDE pollution was related to harbour, dumping sites and pile tire burning. Tri and hexa PCB congeners predominated in all matrices and exceeded the quality guideline value of 0.04 ng L(-1) in Sw. Considering levels in silverside muscle, none of the oral reference doses were exceeded, however, PCBs accounted for 18.6% of the total daily allowed ingest for a 70 kg individual. Although the levels of PCBs and OCPs in soil and RBS were low and did not go beyond quality guidelines, these compounds could still represent a risk to aquatic biota and humanbeings, and thus actions towards preventing this situation should be undertaken.

Distribution and air–sea exchange of organochlorine pesticides in the North Pacific and the Arctic

Surface seawater and boundary layer air samples were collected on the icebreaker Xuelong (Snow Dragon) during the Fourth Chinese Arctic Research Expedition (CHINARE2010) cruise in the North Pacific and Arctic Oceans during 2010. Samples were analyzed for organochlorine pesticides (OCPs), including three isomers of hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), and two isomers of heptachlor epoxide. The gaseous total HCH (ΣHCHs) concentrations were approximately four times lower (average 12.0 pg m−3) than those measured during CHINARE2008 (average 51.4 pg m−3), but were comparable to those measured during CHINARE2003 (average 13.4 pg m−3) in the same study area. These changes are consistent with the evident retreat of sea ice coverage from 2003 to 2008 and increase of sea ice coverage from 2008 to 2009 and 2010. Gaseous β‐HCH concentrations in the atmosphere were typically below the method detection limit, consistent with the expectation that ocean currents provide the main transport pathway for β‐HCH into the Arctic. The concentrations of all dissolved HCH isomers in seawater increase with increasing latitude, and levels of dissolved HCB also increase (from 5.7 to 7.1 pg L−1) at high latitudes (above 73°N). These results illustrate the role of cold condensation processes in the transport of OCPs. The observed air–sea gas exchange gradients in the Arctic Ocean mainly favored net deposition of OCPs, with the exception of those for β‐HCH, which favored volatilization.

Characteristics and transport of organochlorine pesticides in urban environment: air, dust, rain, canopy throughfall, and runoff

Characteristics and transport of organochlorine pesticides (OCPs) in urban multiple environments, including air, dust, rain, canopy throughfall, and runoff water, are explored in this study. Hexachlorocyclohexanes (HCHs) dominated in both air and rain water, and dichlorodiphenyltrichloroethane (DDT) related substances showed a higher affinity to dust. Relatively high concentrations of DDT and dichlorodiphenyldichloroethylene (DDE) in air, rain and dust imply that technical DDT in the environment has been degrading, and there may be unknown local or regional emission sources that contain DDTs in the study area. Source identification showed that DDTs in Beijing urban environments with a fresh signature may originate from the atmospheric transport from remote areas. The ratio of α-/γ-HCH in dust, rain, canopy throughfall and runoff were close to 1, indicating the possible use of lindane. OCPs in runoff were transported from various sources including rain, dust, and canopy throughfall. In runoff, DDTs and hexachlorobenzene (HCB) were mainly transported from dust, and HCHs were mainly from rain and canopy throughfall.

Compilation, Evaluation, and Selection of Physical−Chemical Property Data for Organochlorine Pesticides

Accurate physical−chemical properties (aqueous solubility SW, octanol−water partition coefficient KOW, vapor pressure P, Henry's law constant H, octanol−air partition coefficient KOA, octanol solubility SO) and their temperature dependence are of fundamental importance for interpreting and simulating the environmental fate and transport of organochlorine pesticides (OCPs). A complete set of property data for 14 organochlorine chemicals is derived by evaluating, averaging, and regressing all measured values reported in the literature. The 14 chemicals are hexachlorobenzene (HCB), pentachlorobenzene (PeCB), cis-chlordane, trans-chlordane, 1,1,1-trichloro-2,2-bis-4-chlorophenyl-ethane (p,p‘-DDT) and its metabolites 1,1-dichloro-2,2-bis-4-chlorophenyl-ethene (p,p‘-DDE) and 1,1-dichloro-2,2-bis-4-chlorophenyl-ethylene (p,p‘-DDD), heptachlor and its metabolite heptachlor epoxide, aldrin, dieldrin, endrin, α-endosulfan, and β-endosulfan. Properties for each individual chemical are adjusted to ensure thermodynamic consistency. That adjustment is sized according to, and is usually smaller than, the measurement uncertainty. Internal energies of phase transfer ΔU could be derived only for HCB and PeCB. The lack of property measurements as a function of temperature for the other chemicals prevents their ΔU values from being derived.

Transport of organochlorine pesticides in soil columns enhanced by dissolved organic carbon

The objective of this study is to quantify the effects of humic acid solution infiltration on the transport of organochlorine pesticides (OCPs) in soil columns using a three-phase transport model. From experimental results, it is found that the dissolved organic carbon enhances the transport of OCPs in the soil columns. In the OCPs-only column, the concentration profiles of OCPs can be simulated well using a two-phase transport model with numerical method or analytical solution. In the OCPs-DOC column, the migrations of aldrin, DDT and its daughter compounds are faster than those in the OCPs-only column. The simulation with the three-phase model is more accurate than that with the two-phase model. In addition, significant decrease of the fluid pore velocities of the OCPs-DOC column was found. When DOC leachate is applied for remediation of soil or groundwater pollution, the decrease of mean pore velocities will be a crucial affecting factor.

Transport of organochlorine pesticides in soil columns enhanced by dissolved organic carbon

The objective of this study is to quantify the effects of humic acid solution infiltration on the transport of organochlorine pesticides (OCPs) in soil columns using a three-phase transport model. From experimental results, it is found that the dissolved organic carbon enhances the transport of OCPs in the soil columns. In the OCPs-only column, the concentration profiles of OCPs can be simulated well using a two-phase transport model with numerical method or analytical solution. In the OCPs-DOC column, the migrations of aldrin, DDT and its daughter compounds are faster than those in the OCPs-only column. The simulation with the three-phase model is more accurate than that with the two-phase model. In addition, significant decrease of the fluid pore velocities of the OCPs-DOC column was found. When DOC leachate is applied for remediation of soil or groundwater pollution, the decrease of mean pore velocities will be a crucial affecting factor.

Transport of organochlorine pesticides across the air/sea interface during the aerosol process

A modified Gershey apparatus was used to study the transfer to the atmosphere of selected organochlorine; pesticides from salt solutions with and without the addition of ionic and non-ionic surfactants at different concentrations and from untreated and filtered Tyrrhenian sea water. Pesticides were transported into the atmosphere both in the gas phase land in the liquid aerosol depending on their chemical structure and their physical characteristics (surface properties, volatility, water solubility, hydrophobicity). The results obtained gave useful information about the behaviour of the tested organocthlorinated compounds in long-range transport from temperate environments to frigid polar regions.