Practical treatment system for polluted sea water and soil by tributyltin

为了恢复被三丁基锡（TBT）污染的海洋环境，“三丁基锡污染海水和土壤的实用处理系统”课题组于2004年和2005年在野外和实验室开展了综合研究。小组成员的角色如下：Kenji Jinno和Yoshinari Hiroshiro策划了从疏浚的海洋沉积物中分离TBT污染海水的整个方案和实际工厂设置。采用PSI-100混凝剂进行絮凝分离，然后采用纤维板、砂和活性炭串联渗滤。为了将处理后的水排放回工厂附近的大海，对三丁基锡化合物的浓度进行了仔细检查。经证实，拟议的系列处理厂能够将浊水中1，200 -1，450 ng/L的溶解TBT降低到允许释放水平的3 ng/L。除了建立拟议的制度外，还提出了评价方法， ...更多信息 成本性能进行了调查。到目前为止，研究表明，所提出的去除TBT的处理系统的最佳设计方案适用于现有的处理系统，并确定了纤维板、砂和活性炭的最佳组合。大岛雄二和本庄恒夫在海洋硬足类桡足类的无节幼体、桡足幼体和成体阶段进行了TBT的毒性生物测定，对不同化学品敏感性的虎柄虎耳草进行了生物测定，并在实际应用中进行了评价。在生物测定中，通过观察三丁基锡化合物的孵化率、各阶段的存活率、繁殖力和性比来检测毒性。SAEKI和敏研究了不同条件下沉积物中丁基锡化合物（BTs）、二丁基锡（DBT）和一丁基锡（MBT）的时间变化（光（紫外线、阳光和光排斥），水分（风干和水饱和）并在40℃下加热干燥12小时，每7天一次）为了评估BTs化合物的行为以及在该过程中发生的沉积条件的各种变化。因此，对沉积物进行脱水和日光干燥处理可能会促进沉积物中TBT的轻微降解。然而，需要注意的是，污染的扩展到周围环境中，因为这些处理可以加速沉积物颗粒的风散射。Kouki Zen研究了水泥搅拌和脱水方法（CMD）对污染的海底沉积物中重金属三丁基锡（TBT）和三苯基锡（TPT）的electrical控制的效果。TBT和TPT的溶出量受孔隙水pH值的影响，当pH值接近中性时，溶出量降低。因此，在CMD中使用低pH值水泥有利于从处理过的沉积物中有效控制TBT和TPT。Akihide Tada及其来自商业公司的同事应用了为海洋沉积物挖掘而开发的条形疏浚机。该装置能够将被三丁基锡化合物或其他有毒化学品污染的表层沉积物吸走，这些化学品通常吸附在表层有机土壤上。长崎和博多湾的挖掘面积约为700 ~ 800平方米。本田胜久在现场调查中研究了从疏浚的海洋沉积物中分离的沉淀物和上清液中的二恶英和有机锡化合物的解毒，并提出了添加化学试剂如氧化铁（Fe_3O_4）对解毒污染物是有用的。添加约5%的氧化铁沉淀物降解约20%的二恶英负荷在沉积物中。每重量沉淀物或上清液加入约5%的氧化铁，发生有机锡化合物的吸附和/或降解：TBT和TPT负荷分别下降了约30%和40%，这导致污染物的解毒率高于化学添加剂的量。进行了题为“三丁基锡污染海水和土壤的实用处理系统”的研究经证实，该方法适用于受TBT等有毒化学品污染的海水和沉积物。传统的工厂集成，通过混凝，渗透，胶结，降解和生物测定监测方案分离海水和沉积物。到目前为止，除了昂贵且规模庞大的系统外，对受污染的海洋沉积物的实用研究还很少。该小组成员相信，目前的研究可以突出沉默但受污染的海洋沉积物。少

In order to restore the deteriorated marine environment by Tributyltin (TBT), the integrated research was initiated by the group of "Practical treatment system for polluted sea water and soil by tributyltin" at the field and laboratory in 2004 and 2005. The roles of the group members were as follows : Kenji Jinno and Yoshinari Hiroshiro planed the entire scheme and the practical plant setup to separate the TBT contaminated sea water from the dredged marine sediment. The separation was successfully done by applying the coagulant named PSI-100,and then the series infiltration consisted of fiber sheet, sand and activated carbon. To release the treated water back to the sea nearby the plant, TBT concentration was carefully checked. It was confirmed that the proposed series of treatment plant was able to reduce the dissolved TBT with 1,200-1,450ng/L in the turbid water to 3ng/L which is admissible release level. Beside such establishment of the proposed system, the evaluation method for the … More cost performance was investigated. So far, it was shown that the optimal designing scheme for the proposed treatment system to remove TBT was applicable for the present treatment system and the optimal combination of the fiber sheet, sand and activated carbon for infiltration was determined considering the cost of materials.Yuji Oshima and Tsuneo Honjo carried out toxicity bioassay of TBT in nauplii, copepodite and adult stages of marine harpacticoid copepod, Tigriopus japonicus which shows different sensitivities to chemicals, and evaluated on practical use of this bioassay. In the bioassay, the toxicity of TBT was examined by observations of hatching ratio, survival in the each stage, fecundity, and sex ratio. The results suggested that the bioassay test has a potential to evaluate risk of chemicals in various life stages of this copepod less than 16 days.Kazutoshi SAEKI investigated the time-changes in butyltin compounds (BTs), dibutyltin (DBT) and monobutyltin (MBT) in the sediment treated with various conditions (light (UV, sunlight and light exclusion), moisture (air-drying and water saturation) and heated-drying at 40℃ for 12 hrs at every 7day) in order to evaluate the behavior of BTs compounds together with various changes of the sediment condition occurred in the process. Consequently, the dehydrating and sunlight drying treatments for the sediment were expected possibly to enhance the slight degradation of TBT in the sediment. However an attention is required for the expansion of the contamination to an ambient environment because these treatments could accelerate wind scattering of the sediment particles.Kouki Zen investigated the effect of cement-mixing and dehydration method (CMD) on the elusion control of heavy metals, tri-butyl tin (TBT) and tri-phenyl tin (TPT) in a contaminated marine bottom sediment. The elusions of both TBT and TPT are affected by the pH of pore water and they decrease as the pH comes to the neutrality. The use of low pH cement in the CMD has, therefore, an advantage to the elusion control of TBT and TPT from treated sediment.Akihide Tada and his colleagues from the commercial companies applied the strip dredging machine developed for the marine sediment digging. This device is able to vacuum up the surface sediment polluted by TBT or other toxic chemicals which are usually adsorbed on the surface organic soil. The excavated area in Nagasaki and Hakata bays extended approximately 700〜800m^2. It was demonstrated in these bays that only fine silty clay was dredged effectively resulting in the low remediation cost.Honda Katsuhisa investigated, in field examination, the detoxification of dioxins and organotin compounds in the precipitate and supernatant separated from the dredged marine sediment, and proposed that an addition of chemical agent such as iron oxide (Fe_3O_4) is useful for the detoxificating contaminants. About 5% addition of iron oxide per weight of precipitate degradated about 20% of dioxins burden in the sediment. About 5% addition of iron oxide per weight of precipitate or supernatant occurred adsorption and/or degradation of organotin compounds : TBT and TPT burdens declined, respectively, about 30% and 40%, which resulted in higher detoxification ratios of the contaminants than amounts of chemical additives.In conclusion, the conducted research entitled on "Practical treatment system for polluted sea water and soil by tributyltin" confirmed to be applicable for the polluted sea water and sediment by TBT and other toxic chemicals. The conventional plants are integrated to separate sea water and sediment through coagulations, infiltrations, cementing, degrading and the bio-assay monitoring schemes. Until now, there is little practical research on the polluted marine sediment except for the expensive and huge scale systems. The group members are confident that present research can highlight the silent but polluted marine sediment. Less