Spatial distribution and compositional profiles of organochlorine pesticides in the surface soil from the agricultural, coastal and backwater transects along the south-west coast of India.

South-west coast of India has a history of using pesticidal persistent organic pollutants (POPs) particularly endosulfan until aerial spraying was banned during early 2000. Since soil acts as a repository for such pesticidal persistent organic contaminants, we have monitored residues of seventeen organochlorine pesticides (OCPs) in the surface soil samples from the agricultural, coastal, and backwater transects along the south-west coast of India. OCPs concentration in soil were in the order agricultural > coastal > backwaters transects. Endrins, hexachlorocyclohexane (HCH) and heptachlors were among the dominant OCPs quantified in this study. Dominance of metabolites such as dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyldichloroethane (DDD) and endosulfan sulfate indicates past usage. All the OCPs were dominant in the agricultural transect where plantations/agricultural activities are prevalent. In some specific sites, traces of HCH isomers showed ongoing usage of technical HCH in those sites contradicting the ban in agricultural sector. Backwater sites which are background locations showed positive correlation between soil organic carbon and soil borne OCPs thereby indicating an aged source possibly due to the short/long atmospheric transport from the site of application. Based on the policies regarding control, prevention and other measures for the management of pesticides in Kerala, it was concluded that the implementation on the ground level and the legal framework should be strengthened to prevent further illegal use of the banned pesticides.

Organochlorine Pesticides in Gonad, Brain, and Blood of Mice in Two Agricultural Areas of Sinaloa.

The adverse effect of pesticides on non-target wildlife and human health is a primary concern in the world, but in Mexico, we do not know which wildlife species are at the greatest risk. The aim of this study was to determine organochlorine pesticides in mice of two agricultural fields in Sinaloa, Culiacan and Guasave. Procedures of extraction, analysis, and quantification were followed according to the modified EPA 8081b method. In three mouse tissues (gonad, brain, and blood), γBHC and decachlorobiphenyl with a frequency higher than 50% and endosulfan sulfate with 43% were observed. The wildlife fauna living in agricultural areas are at great risk due to: (1) diversity of the chemicals used for pest control, like mice, and (2) variety of organochlorine pesticides in direct or indirect contact with non-target organisms, affecting the health of animals and humans (toxic effects and accumulation).

Human Elimination of Organochlorine Pesticides: Blood, Urine, and Sweat Study.

Background. Many individuals have been exposed to organochlorinated pesticides (OCPs) through food, water, air, dermal exposure, and/or vertical transmission. Due to enterohepatic reabsorption and affinity to adipose tissue, OCPs are not efficiently eliminated from the human body and may accrue in tissues. Many epidemiological studies demonstrate significant exposure-disease relationships suggesting OCPs can alter metabolic function and potentially lead to illness. There is limited study of interventions to facilitate OCP elimination from the human body. This study explored the efficacy of induced perspiration as a means to eliminate OCPs. Methods. Blood, urine, and sweat (BUS) were collected from 20 individuals. Analysis of 23 OCPs was performed using dual-column gas chromatography with electron-capture detectors. Results. Various OCPs and metabolites, including DDT, DDE, methoxychlor, endrin, and endosulfan sulfate, were excreted into perspiration. Generally, sweat samples showed more frequent OCP detection than serum or urine analysis. Many OCPs were not readily detected in blood testing while still being excreted and identified in sweat. No direct correlation was found among OCP concentrations in the blood, urine, or sweat compartments. Conclusions. Sweat analysis may be useful in detecting some accrued OCPs not found in regular serum testing. Induced perspiration may be a viable clinical tool for eliminating some OCPs.

Organochlorine Pesticides (OCPs) in Sediment and Fish of Two Tropical Water Bodies Under Different Land Use.

In this study we quantified and compared bioaccumulated OCPs in target fish species Cichlasoma urophthalmus (Mayan cichlid) and Oreochromis niloticus (Nile tilapia) and sediment in two lentic systems neighboring areas with different land use (Xnoha = agricultural/Mocu = nature reserve). Fish at both sites showed the same number of pesticide compounds (17) while in sediment were 17 and 20, respectively. ∑chlordane concentrations were significantly higher in Xnoha in both fish and sediment (1.0 and 0.17 µg/g, respectively). Here higher concentrations of o,p'DDT were found in fish than in sediments, this was similarly demonstrated in Mocu but to a lesser extent. The proportion of endosulfan sulfate was lower in Xnoha (<20 %) than in Mocu (<50 %) compared to the original product. Detected concentrations of ∑DDT and chlordane exceed international permissible limits. Results indicate that OCPs were present in both aquatic systems regardless of the differences in land use.

Gamma radiolytic decomposition of endosulfan in aerated solution: the role of carbonate radical.

The present study elaborates the removal of endosulfan, an emerging water pollutant and potential carcinogenic, in aerated solution. The influence of Cl(-), NO3 (-), NO2 (-), CO3 (2-), HCO3 (-), SO3 (2-), and humic acid was assessed on the radiolytic degradation of endosulfan. A strong inhibition on the radiolytic degradation of endosulfan was observed in the presence of NO3 (-), NO2 (-), and SO3 (2-). Instead, a slight increase in the removal efficiency of endosulfan was observed at high concentrations of CO3 (2-) and HCO3 (-). The formation of CO3 (•-) in radiolytic degradation of endosulfan in the presence of CO3 (2-) and HCO3 (-) was demonstrated by adding SO3 (2-) that rapidly react with CO3 (•-). The results indicate that CO3 (•-) formed from the reactions of CO3 (2-) and HCO3 (-) and commonly found in natural water can play an important role in the degradation of endosulfan and other sulfur containing electron-rich compounds. The study showed faster degradation of endosulfan at lower concentration compared to high concentration and removal was found to follow pseudo-first-order kinetic. Endosulfan ether was found as the main degradation product and degradation pathway was found to be initiated at the S=O bond of endosulfan. The efficiency of gamma irradiation in the removal of endosulfan was examined in terms of formation of short chain organic acids and chloride ion accumulation.

Isomers and their metabolites of endosulfan induced cytotoxicity and oxidative damage in SH-SY5Y cells.

As an organochlorine insecticide, endosulfan has been widely banned or restricted, but it is still largely used in many developing countries. Previous studies have shown multiple adverse health effects of endosulfan. However, the neurotoxicity of endosulfan has not been fully elucidated. In this study, endosulfan isomers (α-/ß-endosulfan) and their major metabolites (endosulfan sulfate, endosulfan diol, and endosulfan lactone) were, respectively, exposed to human neuroblastoma SH-SY5Y cells. Results showed that both α-endosulfan and ß-endosulfan caused decrease of cell viability and morphological damages in a dose-dependent manner. Their median effective concentrations (EC50s) were respectively 79.6 µM (α-endosulfan) and 50.37 µM (ß-endosulfan) for 72 h exposure. EC50s of α/ß-endosulfan mixture were lower than that of the single isomer. However, EC50s of its metabolites were higher than that of technical endosulfan. Endosulfan and its metabolites caused increases of reactive oxygen species and the lipid peroxidation, but decrease of superoxide dismutase in a dose-dependent manner. These results indicate that α-endosulfan exhibits higher neurotoxicity than ß-endosulfan. Mixture of endosulfan isomers shows stronger cytotoxicity than the single isomer. After endosulfan is degraded, cytotoxicity of its metabolites decreases gradually. The neurotoxicity of endosulfan and its metabolites is closely related to oxidative damage and antioxidative deficit.

20 Years of Air-Water Gas Exchange Observations for Pesticides in the Western Arctic Ocean.

The Arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report the time trends and air-water exchange of OCPs and CUPs from research expeditions conducted between 1993 and 2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL), chlorobornanes (ΣCHBs and toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, and ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF), and trifluralin (TFN). Pentachloronitrobenzene (PCNB and quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT, and TFN) or showed no significant change (CPF and DAC), and most compounds declined in air. Chlordane compound fractions TC/(TC + CC) and TC/(TC + CC + TN) decreased in water and air, while CC/(TC + CC + TN) increased. TN/(TC + CC + TN) also increased in air and slightly, but not significantly, in water. These changes suggest selective removal of more labile TC and/or a shift in chlordane sources. Water-air fugacity ratios indicated net volatilization (FR > 1.0) or near equilibrium (FR not significantly different from 1.0) for most OCPs but net deposition (FR < 1.0) for ΣCHBs. Net deposition was shown for ENDO-I on all expeditions, while the net exchange direction of other CUPs varied. Understanding the processes and current state of air-surface exchange helps to interpret environmental exposure and evaluate the effectiveness of international protocols and provides insights for the environmental fate of new and emerging chemicals.

Human health risk assessment of pesticide residues in snappers (Lutjanus) fish from the Navachiste Lagoon complex, Mexico.

Organochlorine pesticides (OCPs) residues were determined in fillets of Lutjanus colorado, L. argentiventris, and L. novemfasciatus. Fillet samples were collected bimonthly from February 2012 to February 2013. OCPs average concentrations do not differ significantly according to size, weight, or season, nor do they relate with the physico-chemical parameters of the sea water. The highest concentration and most frequently encountered OCPs were endosulfan sulfate, δ-HCH, and heptachlor epoxide, which indicates their use in the recent past and confirms their persistence. Average concentrations of ∑HCHs, ∑chlordane, and ∑heptachlor in samples were above cancer MRLs according to data from monthly consumed portions. HCHs and heptachlor are listed in Appendix III of the Rotterdam Convention of chemicals placed on a prior informed consent procedure for import and export purposes; they are considered illegal in Mexico. The OCPs concentrations above cancer MRLs in Lutjanus spp. turn its frequent consumption into a human health risk.

[Pollution characteristics and distribution of polycyclic aromatic hydrocarbons and organochlorine pesticides in groundwater at Xiaodian Sewage Irrigation Area, Taiyuan City].

Sewage irrigation has been widely used in areas of water shortage in northern China, and it may introduce organic contaminants into groundwater. To characterize the organic contaminants in groundwater in sewage irrigation area, the Xiaodian sewage irrigation area in Shanxi Province was chosen as the case study area. A total of 16 groundwater samples (13 from shallow aquifer, 3 from deep aquifer) were collected. Polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography-mass spectrometry (GC-MS) and organochlorine pesticides (OCPs) were ainalyzed by gas chromatography-electron capture detection (GC-ECD). The results showed that the concentrations of PAHs ranged from 13.98 to 505.89 ng x L(-1) with an average concentration of 115.67 ng x (L)(-1). The 2 and 3 ring-PAHs were the main components, while naphthalene and phenanthrene were most frequently detected. The concentrations of OCPs were in the range of 13.91-103.23 ng x L(-1) with an average concentration of 40.99 ng x L(-1), while alpha-HCH, delta-HCH, o,p'-DDD, Aldrin, Endosulfan-sulfate and HCB were most frequently detected. Overall, shallow aquifers appeared more contaminated with these pollutants than deep aquifers. In the area, the order of the organic contaminants concentration in groundwater was: East Main Channel < Beizhang Drainage < Taiyu Drainage, which indicated the quality of groundwater was influenced by the sewage irrigation.

Organochlorine pesticides and PCBs in Southern Right Whales (Eubalaena australis) breeding at Península Valdés, Argentina.

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±13.8 ng·g(-1)ww) than PCBs (7.5±10 ng·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 (

Spatial distributions and seasonal variations of organochlorine pesticides in water and soil samples in Bolu, Turkey.

In this study, a total of 75 water samples (38 groundwater and 37 surface water samples) and 54 surface soil samples were collected from the five districts of Bolu, which is located in the Western Black Sea Region of Turkey in the summer season of 2009. In the autumn season, 17 water samples (surface water and groundwater samples) and 17 soil samples were collected within the city center to observe the seasonal changes of organochlorine pesticides (OCPs). Groundwater and surface water samples were extracted using solid phase extraction. Soil samples were extracted ultrasonically. Sixteen OCP compounds in the standard solution were detected by a gas chromatography-electron capture detector (GC-ECD). Therefore, the method validation was performed for those 16 OCP compounds. However, 13 OCP compounds could be observed in the samples. The concentrations of most OCPs were higher in samples collected in the summer than those in the autumn. The most frequently observed pesticides were endosulfan sulfate and 4,4'-dichlorodiphenyltrichloroethane (DDT) in groundwater samples, α-HCH in surface water samples, and endosulfan sulfate in soil samples. The average concentration of endosulfan sulfate was the highest in water and soil samples. Compared to the literature values, the average concentrations in this study were lower values. Spatial distribution of OCPs was evaluated with the aid of contour maps for the five districts of Bolu. Generally, agricultural processes affected the water and soil quality in the region. However, non-agricultural areas were also affected by pesticides. The concentrations of pesticides were below the legal limits of European directives for each pesticide.

Endosulfan isomers and sulfate metabolite induced reproductive toxicity in Caenorhabditis elegans involves genotoxic response genes.

Endosulfan is enlisted as one of the persistent organic pollutants (POPs) and exists in the form of its α and ß isomers in the environment as well as in the form of endosulfan sulfate, a toxic metabolite. General endosulfan toxicity has been investigated in various organisms, but the effect of the isomers and sulfate metabolites on reproductive function is unclear. This study was aimed at studying the reproductive dysfunction induced by endosulfan isomers and its sulfate metabolite in Caenorhabditis elegans (C. elegans). We also determined a role for the DNA-damage-checkpoint gene hus-1. Compared to ß-endosulfan and its sulfate metabolite, α-endosulfan caused a dramatically higher level of germ cell apoptosis, which was regulated by DNA damage signal pathway. Both endosulfan isomers and the sulfate metabolite induced germ cell cycle arrest. Loss-of-function studies using hus-1, egl-1, and cep-1 mutants revealed that hus-1 specifically influenced the fecundity, hatchability, and sexual ratio after endosulfan exposure. Our data provide clear evidence that the DNA-checkpoint gene hus-1 has an essential role in endosulfan-induced reproductive dysfunction and that α-endosulfan exhibited the highest reproductive toxicity among the different forms of endosulfan.

S1 certification of alpha-endosulfan, beta-endosulfan, and endosulfan sulfate in a candidate certified reference material (organochlorine pesticides in tea) by isotope dilution gas chromatography-mass spectrometry.

This paper presents the certification of alpha-endosulfan, beta-endosulfan, and endosulfan sulfate in a candidate tea certified reference material (code: GLHK-11-03) according to the requirements of the ISO Guide 30 series. Certification of GLHK-11-03 was based on an analytical method purposely developed for the accurate measurement of the mass fraction of the target analytes in the material. An isotope dilution mass spectrometry (IDMS) method involving determination by (i) gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS) and (ii) gas chromatography-electron ionization-high-resolution mass spectrometry (GC-EI-HRMS) techniques was employed. The performance of the described method was demonstrated through participation in the key comparison CCQM-K95 "Mid-Polarity Analytes in Food Matrix: Mid-Polarity Pesticides in Tea" organized by the Consultative Committee for Amount of Substance-Metrology in Chemistry in 2012, where the study material was the same as the certified reference material (CRM). The values reported by using the developed method were in good agreement with the key comparison reference value (KCRV) assigned for beta-endosulfan (727 ± 14 µg kg(-1)) and endosulfan sulfate (505 ± 11 µg kg(-1)), where the degree of equivalence (DoE) values were 0.41 and 0.40, respectively. The certified values of alpha-endosulfan, beta-endosulfan, and endosulfan sulfate in dry mass fraction in GLHK-11-03 were 350, 730, and 502 µg kg(-1), respectively, and the respective expanded uncertainties, due to sample inhomogeneity, long-term and short-term stability, and variability in the characterization procedure, were 27 µg kg(-1) (7.8 %), 48 µg kg(-1) (6.6 %), and 33 µg kg(-1) (6.6 %).

Trophodynamics of current use pesticides and ecological relationships in the Bathurst region vegetation-caribou-wolf food chain of the Canadian Arctic.

The bioaccumulation of current use pesticides (CUPs) and stable isotopes of carbon and nitrogen were investigated in vegetation-caribou-wolf food chain in the Bathurst region (Nunavut, Canada). Volumetric bioconcentration factors (BCF(v)) in vegetation were generally greatest for dacthal (10-12) ≥ endosulfan sulfate (10-11) > ß-endosulfan (>9.0-9.7) ≥ pentachloronitrobenzene (PCNB; 8.4-9.6) > α-endosulfan (8.3-9.3) > chlorpyrifos (8.0-8.7) >chlorothalonil (7.6-8.3). The BCF(v) values in vegetation were significantly correlated with the logarithm of the octanol-air partition coefficients (log K(OA)) of CUPs (r(2) = 0.90, p = 0.0040), although dacthal was an outlier and not included in this relationship. Most biomagnification factors (BMFs) for CUPs in caribou:diet comparisons were significantly less than 1. Similarly, the majority of wolf:caribou BMFs were either significantly less than 1 or were not statistically greater than 1. Significant trophic magnification factors (TMFs) were all less than 1, indicating that these CUPs exhibit trophic dilution through this terrestrial food chain. The log K(OA) reasonably predicted bioconcentration in vegetation for most CUPs but was not correlated with BMFs or TMFs in mammals. Our results, along with those of metabolic studies, suggest that mammals actively metabolize these CUPs, limiting their biomagnification potential despite entry into the food chain through effective bioconcentration in vegetation.

Assessment of organochlorine pesticide residues in Indian flue-cured tobacco with gas chromatography-single quadrupole mass spectrometer.

Presence of pesticide residues in tobacco increases health risk of both active and passive smokers, apart from the imminent potential health problems associated with it. Thus, monitoring of pesticide residue is an important issue in terms of formulating stringent policies, enabling global trade and safeguarding the consumer's safety. In this study, a gas chromatography-single quadrupole mass spectrometry (GC-MS) method based upon quantifier-qualifier ions (m/z) ratio was employed for detecting and assessing ten organochlorine pesticide residues (α-HCH, ß-HCH, γ-HCH, δ-HCH, 2,4-DDT, 4,4-DDT, endrin, α-endosulfan, ß-endosulfan and endosulfan sulphate) in 152 flue-cured (FC) tobacco leave samples from two major tobacco growing states, Karnataka and Andhra Pradesh, of India. In the majority of samples, pesticide residue levels were below the limit of quantification (LOQ). In few samples, pesticide residues were detected and they found to comply with the guidance residue levels (GRL) specifications of the Cooperation Center for Scientific Research Relative to Tobacco (CORESTA). Detection of the phase out pesticides like DDT/HCH might be due to transfer of persistent residues from the environmental components to the plant. This is the first report on these ten organochlorine pesticide residues in Indian FC tobacco.

[Distribution characteristics of organochlorine pesticides in soil from Daiyun Mountain Range in Fujian, China].

Totally 101 typical surface soil samples were collected from Daiyun Mountain Range, and 20 compounds of OCPs were analyzed by a Ni electron capture detector (GC-ECD) to investigate the horizontal distribution and composition of organochlorine pesticides (OCPs) in the surface soil of Daiyun Mountain Range. The results showed that all OCPs were detected in the soil samples. The detection ratios of OCPs were all over 90%, except for Endrin and beta-HCH. The sum concentration of HCHs, DDTs, Endosulfan and Endosulfan sulfate, accounted for 79.51% of the total OCPs, which were considered to be the dominant OCPs in the Daiyun Mountain Range. The OCPs concentrations in the surface soils ranged from 2.56 to 465.99 ng x g(-1) with a mean value of 38.00 ng x g)(-1). Compared with other regions, the concentrations of HCHs and DDTs in this study stayed in a low pollution level. Endosulfan and Endosulfan sulfate showed a certain degree of risk in the surface soil of the study area. Source analysis showed that new input of lindane and dicofol might occur in the survey region. The historical application was the prime source of Endosulfan. The residue level of OCPs in different lands was in the following order: paddy land > vegetable land > orchard. The OCPs pollution of orchard soil was primarily due to the new input of lindane and dicofol, while the pollution of paddy land was mainly from the usage of Endosulfan.

Analytical methodology for the study of endosulfan bioremediation under controlled conditions with white rot fungi.

A general procedure to study the biodegradation of endosulfan under laboratory conditions by white rot fungi isolated from native sources growing in YNB (yeast nitrogen base) media with 1% of glucose is presented. The evaluation of endosulfan biodegradation as well as endosulfan sulfate, endosulfan ether and endosulfan alcohol production throughout the whole bioremedation process was performed using an original and straightforward validated analytical procedure with recoveries between 78 and 112% at all concentration levels studied except for endosulfan sulfate at 50 mg L(-1) that yielded 128% and RSDs<20%. Under the developed conditions, the basidiomycete Bjerkandera adusta was able to degrade 83% of (alpha+beta) endosulfan after 27 days, 6 mg kg(-1) of endosulfan diol were determined; endosulfan ether and endosulfan sulfate were produced below 1 mg kg(-1) (LOQ, limit of quantitation).

Organochlorine pesticides and polychlorinated biphenyls in sediments and fish from freshwater cultured fish ponds in different agricultural contexts in north-eastern France.

Organochlorine pesticides (HCB, HCH with α-, ß-, and γ isomers, heptachlor, cis-heptachlor epoxyde, trans-heptachlor epoxyde, endosulfan with α- and ß isomers, sulfate endosulfan, o,p'-DDT, p,p'-DDT, o,p'-DDE, p,p'-DDE, o,p'-DDD, p,p'-DDD, chlorothalonil, alachlor, aldrin, dieldrin, methoxychlor, oxychlordane, chlordane with α- and γ isomers, p,p'-dicofol and o,p'-dicofol) and indicators PCBs (IUPAC nos. 28, 52, 101, 118, 138, 153, and 180) were studied both in sediments and muscles of farmed fish species (Cyprinus carpio and Perca fluviatilis). Samples were collected from fish ponds located in the hydrographic basin of the Moselle River (Lorraine Region, France). OCPs and PCBs were present at low concentrations both in sediments and fish muscles. Concerning sediments, ∑DDTs revealed concentrations ranging from 0.2 to 2.30 ng g(-1) dw and ∑PCBs ranged from 0.3 to 3.5 ng g(-1) dw. Concerning fish muscles, the highest concentrations in OCPs were those of p,p'-DDE, with average concentrations of 0.57±0.44 ng g(-1) ww for carp and 0.58±0.29 ng g(-1) ww for perch. The contamination profiles proved to be different depending on the fish species. Indeed, HCH-isomers, HCB, and dieldrin were detected only for the carp and always at low concentrations. For example, the highest concentration of HCHs was observed for ß-HCH with a mean value of 0.64±0.15 ng g(-1) ww for carp. As for PCBs, the levels of ∑PCBs ranged from 0.3 to 6.4 ng g(-1) ww in carp muscles and from 0.90 to 5.60 ng g(-1) ww in perch muscles.

Organochlorine pesticides in soils from south-western Uganda.

Organochlorine (OC) residues were analysed in soil samples collected from Kihiihi sub-county, Kanungu District, which is located in south-western Uganda. Mabira Central Forest Reserve which is located in central Uganda was used as a reference site in this study. The samples were collected at 15-20 cm depths below the soil surface and extracted with organic solvents. The extracts were cleaned using florisil, and were analysed using a gas chromatograph (GC) equipped with an electron capture detector (ECD). The results were confirmed using a GC equipped with a mass spectrometer (MS). The levels of the OC residues in soil from Kihiihi sub-county varied from non-detectable (ND) to 59 microg kg(-1) dry weight. The frequencies of detection for p,p'-DDT, p,p'-DDE and p,p'-DDD in the total soil samples were 47%, 24% and 11%, respectively. The o,p'compounds were detected in the following frequencies: o,p'-DDT (23%), o,p'-DDE (19%) and o,p'-DDD (8%). The low p,p'-DDE/p,p'-DDT residue ratios (0.2-0.9) in Kihiihi samples suggest recent inputs of DDT in Kihiihi sub-county. The detection frequencies for dieldrin, endosulfan-alpha, -beta and -sulphate in the soil samples were 21%, 26%, 31% and 19%, respectively. Mabira Forest Reserve soils showed detection frequencies of p,p'-DDT (5%) and p,p'-DDE (9% of the soil samples), varying from ND to 9 microg kg(-1). Although the use of OCPs has been banned, our results show that they can still be detected in the environment. Their presence may be attributed to adulteration of pesticides which are not banned and also atmospheric deposition.

Determination of pesticides in postmortem blood and bone marrow of pesticide treated rabbits.

Forensic toxicological analyses have traditionally focused on the use of blood, body fluids, and certain organs in examinations of deaths due to intoxication. However, in some situations, putrefaction and contamination make proper sampling from tissues impossible, such as in exhumation cases. In these cases, bone marrow might be useful as an alternative specimen since it is a potential depot for drugs. This study aims to determine pesticides in postmortem and putrefied bone marrow of pesticide treated rabbits, so as to reveal the diagnostic value of toxicological analysis of bone marrow in exhumation cases. Out of thirteen rabbits, a 110 mg/kg dose of endosulfan was orally given to six through a gavage tool, and a 2500 mg/kg dose of diazinon was given to six using the same method. One rabbit was not treated with anything and served as a control sample. Venous blood, liver, lung, kidney, brain, and bone marrow samples were collected just after spontaneous death or cervical dislocation. After this, the rabbits were buried in soil. All of them were exhumed 1 month later, and putrefied viscera and bone marrow were sampled. Blood and tissue samples underwent solvent extraction and solid phase extraction, and then the samples were analyzed by GC-MS. Mean residue levels of diazinon in early postmortem samples were 85 mg/kg, 71 mg/kg, 23 mg/kg, 21 mg/kg, 19 mg/kg, and 0.4 mg/l in the liver, bone marrow, kidney, lung, brain, and blood, respectively. Mean residue levels of diazinon in the putrefied body were 3327 mg/kg in putrefied viscera and 1783 mg/kg in the bone marrow. Mean residue levels of endosulfan isomers and metabolites in early postmortem samples (blood, liver, lung, kidney, brain, and bone marrow) were 0.46 mg/kg (endosulfan sulfate), 0.32 mg/kg (alpha and beta isomers of endosulfan), and 0.14 mg/kg (endosulfan ether) while the same levels were 0.26 mg/kg (endosulfan sulfate), 0.24 mg/kg (alpha and beta isomers of endosulfan), and 0.1 mg/kg (endosulfan ether) in putrefied samples (putrefied bone marrow and putrefied viscera). Based on these experimental results, it can be concluded that cause of death can be determined as acute pesticide poisoning by toxicological analysis of samples from bone marrow and putrefied viscera in exhumation cases.