92 resultados para HCH


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调查了红枫湖周边水稻土的7种多氯联苯(PCBs)和13种有机氯农药(OCPs)的含量分布.结果显示,DDTs及其代谢产物、HCHs的异构体、异狄氏剂、七氯等有机氯农药及PCB 28和PCB 52在所有样品中均被检出.与国内外污染区相比,PCBs含量较低.研究区土壤中污染物的组成结果类似,PCBs以3~5氯取代的同属物为主,农药以DDTs为主.剖面土壤中∑PCBs含量范围为8.9~55.9 ng/g,主要以3~5氯取代的PCBs为主,平均占PCBs总量的89%.∑DDTs含量为4.7~42.6 ng/g,以p,p′-DDE,p,p′-DDT为主.DDT/(DDD+DDE)的比率表明红枫湖地区水稻田中DDTs的降解速率不同,暗示其环境条件的差异.α-HCH/γ-HCH为0.28~0.90,表明红枫湖地区水稻田中HCHs在环境中残留时间很长,经历了光解和生物作用等变化.PCBs对TEQ的贡献较低,为0.06~0.51 pg/g.

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本研究分别于2006、2007年5月在东海沿岸海域22个站位采集牡蛎、贻贝、四角蛤蜊、文蛤、花蛤5种贝类样品,采用荧光分光光度法和气相色谱法检测贝类体内的石油烃(TPHs)和有机氯农药(HCHs和DDTs) 含量,分析东海沿岸海域贝类体内的TPHs、HCHs和DDTs的时空分布特征和HCHs、DDTs的组分特征,比较不同贝类体内污染物含量的差异,探讨HCHs和DDTs的来源,并对贝类进行初步海洋生物质量评价和人体健康风险评价。研究结果表明: (1)东海沿岸海域贝类体内TPHs含量范围为0.40 74.40 mg kg-1,平均含量为9.42 mg kg-1;HCHs含量为ND~5.42×10-3mg kg-1,平均含量为1.47×10-3 mg kg-1;DDTs含量为2.09×10-3~197.66×10-3mg kg-1,平均含量为38.05×10-3 mg kg-1。其中,TPHs含量在长江口及邻近海域较高, HCHs和DDTs含量在江苏省的如东、海门和浙江省的各海域含量较高。与2006年相比,2007年贝类体内TPHs含量与2006年基本持平,HCHs含量有稍微降低,但是DDTs含量有明显升高趋势。 (2)HCHs和DDTs组分分析表明,α-HCH和β-HCHHCHs总量的绝大多数,γ-HCH和δ-HCH仅有极少量检出,大多数区域的α-HCH/γ-HCH比值在4-7之间,说明研究区域内有新的HCHs污染源; DDTs 中O,P’-DDT/P,P'-DDT的比值远高于工业DDTs中O,P’-DDT/P,P'-DDT的比值,分析认为其与周围区域使用三氯杀螨醇密切有关。 (3)贝类体内的TPHs、HCHs和DDTs与水体、沉积物中的相应有机物存在正相关性。相对于TPHs和HCHs,DDTs更容易在贝类体内富集;牡蛎对TPHs和HCHs、DDTs的累积能力明显高于四角蛤蜊和贻贝。 (4)质量评价显示TPHs在局部海域超标,HCHs未超标,DDTs含量超标严重。人体健康风险评估结果显示,东海沿岸海域贝类体内HCHs和DDTs的致癌风险和暴露风险均在可接受的范围之内,消费者因食用监测海域的贝类而受到HCHs和DDTs危害的可能性不大。 (5)与世界其他海域比较表明,东海海域贝类TPHs和HCHs含量处于中等水平, DDTs含量处于比较高的水平。

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Organochlorine contaminants including 12 polychlorinated biphenyl (PCB) congeners and 18 insecticides were determined in water, pore water and sediments of the Jiulong River Estuary and Western Xiamen Sea, China. The results showed that the levels of the total PCBs ranged from non-detectable to 1500 ngl(-1) in water, from 209 to 3870 ngl(-1) in pore water, and from 2.78 to 14.8 ng g(-1) dry weight in sediments. Total organochlorine insecticide concentrations were from below the limit of detection to 2480 ngl(-1) in water, from 267 to 33400 ngl(-1) in pore water, and from 4.22 to 46.3 ng g(-1) dry weight in sediments. Concentrations of PCBs and insecticides in pore water were significantly higher than those in surface water, due to the high affinity of these hydrophobic compounds for sediment phase. The PCB congeners with the highest concentrations were CB153, CB180 and CB194, which together accounted for 68-87% of total PCBs in water, pore water and sediment. Among the hexachlorocyclohexane (HCH) compounds, beta-HCH was found to be a major isomer. Analysis of 1,1,1-trichloro-2,2-bis-chlorophenyl-ethane (DDT) and its metabolites showed that 1, 1-dichloro-2[o-chlorophenyl]-2[p-chlorophenyl]-ethylene (DDE) was dominant in the group. In comparison to a 1998 study in the Western Xiamen Sea, levels of organochlorines were enhanced due probably to recent inputs and changes in sediments. (c) 2004 Elsevier Ltd. All rights reserved.

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To analyze and evaluate the status of organochlorine pollutants in the Changjiang (Yangtze River) estuary and adjacent waters, the concentrations of hexachlorocyclohexane (HCHs) and dichlorodiphenyltrichloroethane (DDTs) in shellfish collected in study area from 2006 to 2007 were determined with gas chromatography (GC). The concentration range of HCHs was (ND-12.13)x10(-3) mg/kg wet weight and averaged at 0.54x10(-3) mg/kg while the concentration of DDTs was in the range of (4.06-281.73) x10(-3) mg/kg with a mean of 57.52x10(-3) mg/kg in the survey areas. The concentrations of DDTs in the shellfish were higher than HCHs', so that DDTs could be considered as typical organochlorine pollutants in the areas. The concentrations of DDTs in the shellfish were higher than HCHs', so that DDTs could be considered as typical organochlorines pollutants. The HCHs in all the shellfish conformed to the first level of criterion (0.02 mg/kg) of the Marion Biology Quality (GB 18421-2001), and that of DDTs in most samples were beyond the first level (0.01 mg/kg) but conformed to the second level (0.10 mg/kg). On average, alpha-HCH and delta-HCH occupied the most part of HCHs, while O,P'-DDT and P,P'-DDT occupied the most part of DDTs. The concentrations of organocholorine pesticides in shellfish samples varied in site and in species. The highest level occurred at the Shengsi (SS), followed by Yangkougang (YKG), Lvsi (LS), Dongyuan (DY) and Beibayao (BBY), low concentrations were observed at Changsha (CS), Beidaodi (BDD), and Gouqi (GQ). The concentration of HCHs and DDTs in most sites decreased clearly from 2006 to 2007 except for YKG, DY, BDD, LYS, and SS. All of above results suggested that the study area was slightly affected by organochlorine pesticide, special by DDTs.

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本研究以红枫湖为主要研究对象,对环境各介质中PCBs和OCPs进行了研究,讨论了理化因素TOC、粒度、SPM、微生物等对于PCBs和OCPs的影响,对各介质中PCBs和OCPs的组成进行了分析,讨论了红枫湖地区PCBs和OCPs的来源,并对其污染水平进行了评价,得到以下几点认识: 1、对红枫湖水体和沉积物的理化性质进行了分析,和洱海进行了对比。湖泊沉积物有机质含量和C/N比值表明红枫湖沉积物有机质主要来源于河流输入和湖泊内部,洱海主要以湖泊内源为主,与后面PCBs和OCPs分析结果相符。湖泊沉积物有机质及DNA呈现同一规律,表层是有机质和DNA的含量较高的区域,表层至底层整体呈逐渐降低的趋势,表明表层是微生物量和活性最高的层段,有机质的降解主要发生在此区域。湖泊沉积物粒度与有机质和DNA变化趋势一致,暗示了有机质的降解过程主要发生在表层,SRI和SRB的分析表明微生物在有机质降解过程中起着至关重要的作用。 2、红枫湖沉积物中7种PCBs的含量范围在3.2~31.6ng/g之间,主要以PCB28和PCB52为主。其中PCB28的含量范围在0.5~4.6ng/g,平均为1.8ng/g, PCB52含量在0.4~28.1ng/g。PCB28和PCB52低氯取代的PCBs占PCBs总量的60%以上。各点沉积物中PCBs的组成基本一致,其含量的变化主要与其输入来源和环境条件相关。沉积物中PCBs随深度整体呈现降低的趋势,但表层含量比次表层低,表明近年PCBs的输入降低。PCBs与TOC和粒径呈现较显著的正相关关系,与其自身的理化性质相关,PCBs具有较高的憎水性,倾向于在颗粒态中分布,也暗示了其来源。 3、红枫湖沉积物中13种OCPs的组成主要以HCHs和DDTs为主。其中HCHs的含量范围1.6~8.9ng/g,平均值为3.2ng/g,沉积物柱均值表现为HW>DB>HE>JJD;DDTs的含量范围在0.9~25.7ng/g,平均值为7.8ng/g,沉积物柱均值表现为HW>HE>DB>JJD。HCHs按其组成来看,以β-HCH和γ-HCH为主,DDTs以p,p’-DDE和p,p’-DDT为主。α-HCH/γ-HCH的比值在范围在0.1~3.0之间,表明HCH在环境中发生了改变,而且林丹的用量高于混合HCHs。DDT/DDE+DDD的比值基本都小于1,暗示DDTs在环境中发生了较长期的变化,β-HCH和p,p’-DDE的高含量也暗示了大气来源可能也是红枫湖地区OCPs的主要来源之一。 4、红枫湖湖水、汇入汇出河流及其周边土壤中PCBs和OCPs的分析,显示PCBs和OCPS在过滤后水中含量较低,主要分配在悬浮颗粒物中,悬浮颗粒物中的PCBs和OCPs组成与周边土壤中的组成基本一致。HCHs和DDTs的组成和α-HCH/γ-HCH、DDT/DDE+DDD的比值暗示水中悬浮颗粒物及其PCBs和OCPs主要来源于周边土壤和大气沉降。 5、 红枫湖后五鱼体内PCBs主要以4~6氯取代的PCBs的同系物为主,OCPs以HCHs和DDTs为主。鱼体内PCBs和OCPs对于水体的富集系数达到102~105。PCBs富集系数随氯取代数目的增加而增加,表明其生物有效性随氯取代数目的增加而增加,高氯取代的PCBs更容易通过食物链在高营养级生物体内富集,对人体造成危害。 6、 大气总悬浮颗粒物TSP中及背景区土壤中PCBs和OCPs的分析,与其它环境介质中结果基本一致。红枫湖地区大气、水、沉积物、生物和土壤各环境介质中PCBs和OCPs的组成基本一致,表明其来源具有一致性。α-HCH/γ-HCH和 DDT/DDE+DDD的值,及β-HCH、p,p’-DDE的高的比例,暗示红枫湖地区OCPs在环境中经历了较长时间的变化,而且大气长距离传输对于该区OCPs和PCBs的来源具有一定的贡献。从各因子的分析可以得出,红枫湖为该地区PCBs和OCPs的汇。 7、我国PCBs和DDTs、HCHs的含量除了典型区外,在国内外都处于较低和中等污染水平,红枫湖地区整体处于较低污染水平。根据Long和Chapman等对沉积物中POPs的评价方法,红枫湖沉积物中PCBs只有一个样品处于ERL和ERM之间,其它都低于ERL值,表明PCBs对生物造成不利影响的可能性较低;DDTs的值大部分处于ERL和ERM值之间,对生物造成不利影响的可能性较大;γ-HCH的值都低于TEC值,对生物的潜在影响较小。

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Para la mentalidad colonialista del siglo XIX la raza negra estaba provista de una extraordinaria sexualidad y lujuria. En la metrópolis el equivalente era la mujer sexuada, la prostituta. En los primeros años del siglo XX este tándem, prostituta-colonizado, sirve a los artistas vanguardistas como elemento de confrontación con la moral imperante. Son las artistas mujeres, con una intención feminista, quienes principalmente utilizan el primitivismo asociado a la mujer en su crítica a los estereotipos. Figura pionera en ello es Hannah Höch, especialmente en su serie De un Museo Etnográfico, en el que asocia figuras femeninas y objetos de arte primitivo. En los años 70 del siglo XX, algunas artistas de la performance, como Carolee Schneemann o Ana Mendieta reivindican el cuerpo femenino con el significado de Origen y Fertilidad que tiene en las culturas primitivas. En este mismo contexto puede inscribirse la escultura Maman de Louise Bourgeois. El elemento de crítica social, que está vigente aún en nuestros días, puede verse en las obras de las Guerrilla Girls.

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The fate and cycling of two selected POPs is investigated for the North Sea system with an improved version of a fate and transport ocean model (FANTOM). The model uses atmospheric data from the EMEP MSC East POP model (Gusev et al., 2009), giving reasonable concentrations and seasonal distributions for the entire region, as opposed to the three observation stations that Ilyina et al. (2006) were limited to. Other model improvements include changes in the calculation of POP exchange between the water column and sediment.

We chose to simulate the fate of two POPs with very different properties, ?-HCH and PCB 153. Since the fate and cycling of POPs are strongly affected by hydrodynamic processes, a high resolution version of the Hamburg Shelf Ocean Model (HAMSOM) was developed and utilised. Simulations were made for the period 1996–2005. Both models were validated by comparing results with available data, which showed that the simulations were of very satisfactory quality.

Model results show that the North Sea is a net sink for ?-HCH and a net source to the atmosphere of PCB 153. Total masses of ?-HCH and PCB 153 in 2005 are reduced to 30% and 50%, respectively, of 1996 values.

Storms resuspending bottom sediments into the water column mobilise POPs into the atmosphere and have the potential to deliver substantial loads of these POPs into Europe.

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The fate and cycling of two selected legacy persistent organic pollutants (POPs), PCB 153 and gamma-HCH, in the North Sea in the 21st century have been modelled with combined hydrodynamic and fate and transport ocean models
(HAMSOM and FANTOM, respectively). To investigate the impact of climate variability on POPs in the North Sea in the 21st century, future scenario model runs for three 10-year periods to the year 2100 using plausible levels of both in
situ concentrations and atmospheric, river and open boundary inputs are performed. This slice mode under a moderate scenario (A1B) is sufficient to provide a basis for further analysis. For the HAMSOM and atmospheric forcing, results of the IPCC A1B (SRES) 21st century scenario are utilized, where surface forcing is provided by the REMO downscaling of the ECHAM5 global atmospheric model, and open boundary conditions are provided by the MPIOM global ocean model.
Dry gas deposition and volatilization of gamma-HCH increase in the future relative to the present by up to 20% (in the spring and summer months for deposition and in summer for volatilization). In the water column, total mass of
gamma-HCH and PCB 153 remain fairly steady in all three runs. In sediment,
gamma-HCH increases in the future runs, relative to the present, while PCB 153 in sediment decreases exponentially in all three runs, but even faster in the future, due to the increased number of storms, increased duration of gale wind conditions and increased water and air temperatures, all of which are the result of climate change. Annual net sinks exceed sources at the ends of all periods.
Overall, the model results indicate that the climate change scenarios considered here generally have a negligible influence on the simulated fate and transport of the two POPs in the North Sea, although the increased number and magnitude of storms in the 21st century will result in POP resuspension and ensuing revolatilization events. Trends in emissions from primary and secondary sources will remain the key driver of levels of these contaminants over time.

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The air-sea exchange of two legacy persistent organic pollutants (POPs), γ-HCH and PCB 153, in the North Sea, is presented and discussed using results of regional fate and transport and shelf-sea hydrodynamic ocean models for the period 1996–2005. Air-sea exchange occurs through gas exchange (deposition and volatilization), wet deposition and dry deposition. Atmospheric concentrations are interpolated into the model domain from results of the EMEP MSC-East multi-compartmental model (Gusev et al, 2009). The North Sea is net depositional for γ-HCH, and is dominated by gas deposition with notable seasonal variability and a downward trend over the 10 year period. Volatilization rates of γ-HCH are generally a factor of 2–3 less than gas deposition in winter, spring and summer but greater in autumn when the North Sea is net volatilizational. A downward trend in fugacity ratios is found, since gas deposition is decreasing faster than volatilization. The North Sea is net volatilizational for PCB 153, with highest rates of volatilization to deposition found in the areas surrounding polluted British and continental river sources. Large quantities of PCB 153 entering through rivers lead to very high local rates of volatilization.

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The environmental fate of selected persistent organic pollutants (POPs) in the North Sea system is modelled with a high resolution Fate and Transport Ocean Model (FANTOM) that uses hydrodynamic model output from the Hamburg Shelf Ocean Model (HAMSOM). Large amounts of POPs enter the North Sea from the surrounding highly populated, industrialised and agricultural countries. Major pathways to the North Sea are atmospheric deposition and river inputs, with additional contributions coming from bottom sediments and adjacent seas. The model domain covers the entire North Sea region, extending northward as far as the Shetland Islands, and includes adjacent basins such as the Skagerrak, Kattegat, and the westernmost part of the Baltic Sea. Model resolution (for both models) is 1.5’ latitude x 2.5’ longitude (approximately 3 km horizontal resolution) with 30 vertical levels. The POP model also has 20 sediment layers. Important model processes controlling the fate of POPs in the North Sea system are discussed. Results focus on Lindane gamma- HCH or gamma-hexachlorocyclohexane) and PCB 153.

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Fluxes of HCH isomers α- and γ-HCH dynamics were determined in four industrial U.K. rivers feeding the North Sea. Sampling was conducted weekly basis over a 2-year period. This was complemented by discrete studies of events where two hourly sampling periods were used to investigate the fine time scale dynamics of fluxes. Two intensively industrialized rivers had average isomer concentrations of ~20 ng L-1 for both isomers, while average concentrations in the two less industrialized rivers ranged between 1.5 and 5.0 ng L-1. α-HCH concentrations showed no strong temporal patterns on any river, which contrasts with γ-HCH levels that increased considerably during late summer/early autumn following sustained periods of low river flow. Sampling during high river flow events on rivers with differing HCH pollution histories both showed the same dynamics in HCH isomer concentrations. γ-HCH concentrations decreased 4-fold during events while α-HCH-concentrations stayed constant. The increases in γ-HCH concentrations under low flow conditions and the rapid dilution of this isomer during events indicate that γ-HCH has current inputs to these river systems. It was calculated that these four rivers export 30.8 kg yr-1 of γ-HCH and 14.8 kg yr-1 of α-HCH to the North Sea.

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The southern industrial rivers (Aire, Calder, Don and Trent) feeding the Humber estuary were routinely monitored for a range of chlorinated micro- organic contaminants at least once a week over a 1.5-year period. Environmental Quality Standards (EQSs) for inland waters were set under the European Economic Community for a limited number of problematic contaminants (18). The results of the monitoring program for seven classes of chlorinated pollutants on the EQS list are presented in this study. All compounds were detected frequently with the exception of hexachlorobutadiene (where only one detectable measurement out of 280 individual samples occurred). In general, the rivers fell into two classes with respect to their contamination patterns. The Aire and Calder carried higher concentrations of micro- pollutants than the Don and Trent, with the exception of hexachlorobenzene (HCB). For Σ hexachlorocyclohexane (HCH) isomers (α + γ) and for dieldrin, a number of samples (~ 5%) exceeded their EQS for both the Aire and Calder. Often, ΣHCH concentrations were just below the EQS level. Levels of p,p'- DDT on occasions approached the EQS for these two rivers, but only one sample (out of 140) exceeded the EQS. No compounds exceeded their EQS levels on the Don and Trent. Analysis of the ratio of γ HCHHCH indicated that the source of HCH for the Don and Trent catchments was primarily lindane (γHCH) and, to a lesser extent, technical HCH (mixture of HCH isomers, dominated by α HCH), while the source(s) for the Aire and Calder had a much higher contribution from technical HCH.

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Introduction : La présente étude explore pour la première fois en Afrique, l'association entre l'exposition aux pesticides organochlorés (POC) et le risque de diabète de type 2. L’étude se déroule dans la région du Borgou, au nord du Bénin, où l’utilisation intense de pesticides pour la culture du coton coïncide avec une prévalence élevée du diabète par rapport aux autres régions du pays. Objectifs: 1) Décrire le niveau d’exposition de la population des diabétiques et non diabétiques du Borgou par le taux sérique de certains pesticides organochlorés ; 2) Explorer la relation entre le risque de diabète de type 2 et les concentrations sériques des POC; 3) Examiner l’association entre l’obésité globale, le pourcentage de masse grasse et l’obésité abdominale avec les concentrations sériques des POC; 4) Explorer la contribution de certaines sources d’exposition alimentaire et non-alimentaire aux concentrations sériques des POC. Méthodes : Il s'agit d'une étude cas-témoin qui concerne 258 adultes de 18 à 65 ans identifiés par deux valeurs glycémiques capillaire et veineuse au seuil de 7 mmol/l pour les diabétiques et 5,6mmol/l pour les témoins non diabétiques. Les 129 témoins ont été appariés aux 129 cas selon les critères suivants : l’ethnie, l’âge ± 5ans, le sexe et la localité de résidence. Les informations personnelles et celles portant sur les modes d’exposition ont été recueillies par questionnaire. Les concentrations sériques des POC ont été obtenues par chromatographie gazeuse couplée d’une spectrométrie de masse. L’obésité globale est déterminée par l’IMC ≥ 30 kg/m2. L’obésité abdominale est obtenue par le tour de taille selon les critères consensuels d’Alberti et al. pour la définition du syndrome métabolique. Le pourcentage de masse corporelle a été mesuré par bio-impédance électrique et été considéré comme élevé au seuil de 33% chez les femmes et 25% chez les hommes. Résultats: En comparant les 3ème et premier terciles des concentrations de p,p’-DDE et p,p’-DDT, les sujets du 3e tercile étaient deux à trois fois plus susceptibles de présenter du diabète que ceux du 1er tercile. La probabilité d’obésité abdominale ou de l’obésité générale (en contrôlant pour le statut diabétique) était accrue de trois à cinq fois dans le dernier tercile pour trois des quatre POC qui étaient détectables soit p,p’-DDT, β-HCH et trans-Nonachlore. Les facteurs socioéconomiques associés aux POC sériques sont le niveau d’éducation élevé, un meilleur revenu et la résidence en milieu urbain. Les sources d’exposition non alimentaire significativement associées aux concentrations sériques de POC étaient l’exposition professionnelle mixte (primaire et secondaire) aux pesticides et la consommation de tabac local. L’achat en opposition à l’autoproduction de plusieurs groupes de denrées alimentaire était associé à de plus fortes teneurs de POC. La fréquence de consommation hebdomadaire du poisson, des légumes, du fromage, de l’igname séchée ainsi que du mil, de l’huile de palme et de certaines légumineuses comme le soya, le néré, le niébé et le voandzou était significativement associées aux POC sériques. Conclusion : L’étude a mis en évidence la relation entre le niveau sérique de pesticides organochlorés d’une part, du diabète ou de l’obésité d’autre part. Les concentrations de POC observées au Borgou sont assez élevées et méritent d’être suivies et comparées à celles d’autres régions du pays. Les facteurs contribuant à ces teneurs élevées sont le niveau d’éducation élevé, un meilleur revenu, la résidence en milieu urbain, l’achat et la fréquence de consommation de plusieurs aliments. La contribution du mélange des polluants auxquels les habitants de cette région sont exposés à la prévalence croissante du diabète mérite d’être examinée, notamment les pesticides utilisés actuellement dans la région pour les productions de rente et autres polluants persistants. Ces résultats contribuent à accroître les connaissances sur les facteurs de risque émergents pour le diabète que sont des polluants environnementaux comme les pesticides. Les implications pour la santé publique sont importantes tant pour la prévention des maladies chroniques que pour la sensibilisation des autorités politiques du pays pour une politique agricole et sanitaire adéquate visant la réduction de l’exposition aux pesticides.

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Industrial pollutants, consisting of heavy metals, petroleum residues, petrochemicals, and a wide spectrum of pesticides, enter the marine environment on a massive scale and pose a very serious threat to all forms of aquatic life. Although, earlier, efforts were directed towards the identification of pollutants and their major sources, because of a growing apprehension about the potential harm that pesticides can inflict upon various aquatic fauna and flora, research on fundamental and applied aspects of pesticides in the aquatic environment has mushroomed to a point where it has become difficult to even keep track of the current advances and developments. The Cochin Estuarine System (CES), adjoining the Greater Cochin area, receives considerable amounts of domestic sewage, urban wastes, agricultural runoff as well as effluent from the industrial units spread all along its shores. Since preliminary investigations revealed that the most prominent of organic pollutants discharged to these estuarine waters were the pesticides, the present study was designed to analyse the temporal and spatial distribution profile of some of the more toxic, persistent pesticides ——— organochlorines such as DDT and their metabolites; HCH-isomers; a cyclodiene compound," Endosulfan and a widely distributed, easily degradable, organophosphorus compound, Malathion, besides investigating their sorptional and toxicological characteristics. Although, there were indications of widespread contamination of various regions of the CBS with DDT, HCH-isomers etc., due to inadequacies of the monitoring programmes and due to a glaring void of baseline data the causative factors could not identified authentically. Therefore, seasonal and spatial distributions of some of the more commonly used pesticides in the CES were monitored systematically, (employing Gas Chromatographic techniques) and the results are analysed.