首页> 外文期刊>Journal of Environmental Management >Determination of octanol-air partition coefficients of organochlorine pesticides (OCPs) as a function of temperature: Application to air-soil exchange
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Determination of octanol-air partition coefficients of organochlorine pesticides (OCPs) as a function of temperature: Application to air-soil exchange

机译:测定有机氯农药辛醇-空气分配系数随温度的变化:在空气-土壤交换中的应用

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Octanol-air partition coefficients (K_(oa)) for 7 organochlorine pesticides (OCPs) were determined as a function of temperature using the GC retention time method. Log K_(Oa) values at 25 ℃ ranged over two orders of magnitude, between 8.32 (chlorpyrifos) and 10.48 (methoxychlor). The determined K_(Oa) values were within a factor of 0.5 (endosulfan sulfate) to 7.9 (endrin aldehyde) for values calculated as the ratio of octanol-water partition coefficient to dimensionless Henry's law constant. The internal energies of phase transfer between octanol and air (ΔU_(oa)) ranged between 71.8 and 95.4 kj mol~(-1) and they were within the reported range for OCPs (55.8-105 kJ mol~(-1)). Atmospheric and soil OCP concentrations were also measured in Izmir, Turkey, and data used to investigate the soil-air gas exchange. Net soil-air gas exchange fluxes of OCPs ranged from -0.01 (volatilization, cis-nonachlor) to 56.4 ng m~(-2) day~(-1) (deposition, chlorpyrifos) in winter, while in summer they ranged from -0.03 (trans-nonachlor) to 329 ng m~(-2) day~(-1) (endosulfan I). In both sampling periods, endosulfan I and II, trans-nonachlor, p,p'-DDD and p,p'-DDT were generally deposited to the soil while y-HCH and heptachlor epoxide mostly volatilized. Fluxes of other OCPs were variable (volatilization or absorption) due to their largely fluctuating ambient air concentrations. Calculated dry deposition and recently measured wet deposition fluxes were used to estimate the relative importance of different mechanisms (i.e., dry deposition, wet deposition, gas absorption, and volatilization) to the local soil pollutant inventory. Generally, all mechanisms contributed significantly to the soil OCP inventory. Volatilization fluxes were generally much lower than the sum of input fluxes (dry deposition, wet deposition and gas absorption) for most of the OCPs indicating a net deposition to the soil.
机译:使用GC保留时间方法确定了7种有机氯农药(OCP)的辛醇-空气分配系数(K_(oa))作为温度的函数。 25℃下的Log K_(Oa)值在两个数量级之间变化,介于8.32(毒死rif)和10.48(甲氧基氯)之间。对于以辛醇-水分配系数与无量纲亨利定律常数之比计算的值,所确定的K_(Oa)值在0.5(硫酸硫丹)至7.9(内酯醛)的范围内。辛醇与空气之间的相转移内能(ΔU_(oa))在71.8至95.4 kj mol〜(-1)之间,并且在报道的OCPs范围内(55.8-105 kJ mol〜(-1))。还在土耳其伊兹密尔测量了大气和土壤OCP的浓度,并使用数据来研究土壤与空气之间的气体交换。冬季,OCPs的土壤-空气净交换通量范围为-0.01(挥发,顺式-无氯)至56.4 ng m〜(-2)天〜(-1)(沉积,毒死rif),而夏季的范围为- 0.03(反式六氯)至329 ng m〜(-2)天〜(-1)(硫丹I)。在这两个采样期中,硫丹I和II,反式六氯尿,p,p'-DDD和p,p'-DDT通常沉积在土壤中,而y-HCH和七氯环氧化物大多挥发。由于其他OCP的通量变化很大,因此它们的环境空气浓度波动很大(挥发或吸收)。计算出的干沉降和最近测得的湿沉降通量被用于估计不同机制(即干沉降,湿沉降,气体吸收和挥发)对当地土壤污染物清单的相对重要性。一般而言,所有机制都对土壤OCP清单有重大贡献。对于大多数OCP,挥发通量通常远低于输入通量的总和(干沉降,湿沉降和气体吸收),表明土壤有净沉降。

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