Environmental exposure to residues after aerial spraying of endosulfan: residues in cow milk, fish, water, soil and cashew leaf in Kasargode, Kerala, India

Geospatial assessment of variations in the heavy metals and pesticides concentration in the agricultural environment of Kasaragod District, Kerala, India

The impact of heavy metals and pesticides in our environment largely varies based on their chemical composition and the geographical conditions where they are present. This study assesses the variation in the concentration of heavy metals and pesticides in Kasaragod District, Kerala, Southern India. For the assessment, soil samples were collected from eight different locations of agricultural land during the three different seasons of 2017 and 2018. All the samples were tested for physicochemical characteristics, levels of heavy metals, and pesticides. The spatial distribution of trace metals and pesticides in the study area was performed by using the software Arc GIS, version 10.6. Significant variation in the physicochemical properties was observed during the different seasons. Similarly, the variation in the concentration of heavy metals in the soil ranged from 0.01 to 1018 [Formula: see text]g/kg. Among various heavy metals detected, aluminum (Al) was the most abundantly detected metal in the region of Malakallu, and cobalt (Co) was the scarcely detected metal in the region of Panathady. The average levels of organochlorine pesticides (OCPs) and organophosphorus pesticides (OPs) in the soil samples were from below detectable level (bdl) to 610 [Formula: see text]g/kg and bdl to 441 [Formula: see text]g/kg respectively. Thus, our study indicates the continuous occurrence and persistent nature of contaminants in the agricultural soil of Kasaragod. Therefore, periodic monitoring of soil contaminants is recommended in Kasaragod to assess its effect on the ecosystem and to develop an effective remediation strategy.

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.

Contamination from organochlorine pesticides (OCPs) in agricultural soils of Kuttanad agroecosystem in India and related potential health risk

The presence and distribution of a few organochlorine pesticides (OCPs) in the paddy fields of the Kuttanad agroecosystem (KAE) was examined in the present study. Kuttanad forms a part of the Vembanad wetland system which is a Ramsar site of international importance in the state of Kerala. This study, to the best of our knowledge, is the first report on the occurrence of OCP residues in KAE. Pesticide residue analysis was done with gas chromatograph (GC-ECD). Twenty-one soil samples were collected for the multiresidual analysis of OCPs. Sixteen OCP residues with a notable concentration were observed from the study area. α-BHC; β-BHC; γ-BHC; δ-BHC; α-chlordane; γ-chlordane; heptachlor; 4,4-DDT; 4,4-DDE; 4,4-DDD; α-endosulfan; β-endosulfan; aldrin; dieldrin; endrin aldehyde; and endrin ketone were the residues observed. The percentage-wise occurrence of OCP residues in the soil samples analysed (total of 63 samples from 21 sites, three samples per site) exhibits the following order: Σ BHC˃ Σ chlordane ˃ Σ dieldrin ˃ Σ aldrin ˃ Σ endrin˃ Σ heptachlor = endosulfan˃ Σ DDT. All pesticides detected from KAE are in the list of priority pollutants of US Environmental Protection Agency (USEPA). The distribution pattern of OCPs in the KAE soils revealed their origin as both historical and recent application of pesticides. Health risk assessment of OCP residues on human population was also conducted. The findings indicated that the concentrations of OCPs were within the permissible limits of USEPA, thus, the human population in the study area was safe.

Exposure to Endosulfan can result in male infertility due to testicular atrophy and reduced sperm count

Endosulfan (ES) is a widely used organochlorine pesticide and is speculated to be detrimental to human health. However, very little is known about mechanism of its genotoxicity. Using mouse model system, we show that exposure to ES affected physiology and cellular architecture of organs and tissues. Among all organs, damage to testes was extensive and it resulted in death of different testicular-cell populations. We find that the damage in testes resulted in qualitative and quantitative defects during spermatogenesis in a time-dependent manner, increasing epididymal reactive oxygen species levels, affecting sperm chromatin integrity. This further culminated in reduced number of epididymal sperms and actively motile sperms. Finally, we show that ES exposure affected fertility in male but not in female mice. Therefore, we demonstrate that ES exerts pathophysiological changes in mice, induces testicular atrophy, affects spermatogenesis, reduces quantity and vigour of epididymal sperm and leads to infertility in males.

Occurrence and sources of selected organochlorine pesticides in the soil of seven major Indian cities: Assessment of air-soil exchange

India is an agricultural country and organochlorine pesticides (OCPs) accounts for nearly three fourth of the annual pesticide consumption. Selected OCPs were therefore quantified in 81 soil samples along urban-suburban-rural transect from New Delhi and Agra in the north, Kolkata in the east, Mumbai and Goa in the west and Chennai and Bangalore in the southern part of India. ΣOCPs ranges from 2 to 410 ng/g dry weight (Mean, 35) with dominance of endosulfan sulfate in the rural sites. Urban centers and suburbs reflects OCP usage for vector control. Lower winter temperature in New Delhi favored site-specific deposition of most OCPs in soil. Volatilization of OCPs from soil occurred in the Indian cities having higher ambient temperature. Due to the compounded impact of past and ongoing usage of selected OCPs like DDT, a sporadic cycle of emission and re-emission from Indian soil is expected to continue for many more years to come.

Determination of organochlorine pesticide residue in sediment and water from the Densu river basin, Ghana

The distribution of organochlorine pesticides in the aquatic ecosystem from the Densu river revealed varying levels of concentration in water and the sediment samples. Three locations were sampled along the river to evaluate the levels of organochlorine pesticide residue in the river. Sediment and surface water samples were extracted by soxhlet and liquid-liquid extraction respectively and analyzed using Gas Chromatograph coupled with electron capture detector. The detectable organochlorine pesticides were gamma-hexachlorocyclohexane (HCH), delta-hexachlorocyclohexane, heptachlor, aldrin and dieldrin. The other pesticides that were investigated are gamma-chlordane, alpha endosulfan, endosulfan sulfate, p,p'-DDT and its metabolite p,p'-DDE, methoxychlor, endrin and its metabolite endrin aldehyde and endrin ketone. The order of increasing frequency of detection of samples was higher in sediment than water. In sediment, the mean concentration ranged from 0.030 μg kg(-1) dry weight (endrin) to 10.98 μg kg(-1) dry weight (aldrin). The highest detected concentration of organochlorine in water was endosulfan sulfate with mean concentration of 0.185 μg L(-1). Analysis of variance indicated significant differences for most organochlorine pesticide residue in the sediment sampled from the various locations. Some of the levels of organochlorine pesticides detected in water were relatively high compared to guideline values set by World Health Organization and Australia and thus could be harmful if the trend is not checked.

The environmental pollutant endosulfan disrupts cerebral cortical function at low doses

Endosulfan can induce convulsions that could lead to brain damage. The variability and lack of specificity of neurological signs and symptoms in the pre-convulsive stages makes early diagnosis difficult. We sought to determine if electrophysiological exploration of the cerebral cortex could yield objective signs of endosulfan intoxication at levels that do not elicit convulsions. Endosulfan was administered intravenously to Sprague-Dawley adult rats under urethane anesthesia at doses from 0.5 to 4mg/kg. EEG power and the evoked potentials (EP) to forepaw electrical stimulation were studied over the contralateral (S1CL) and homolateral (S1HL) cortical somatosensory areas and the contralateral visual area (V1CL). At each area, five EP waves were measured. Arterial blood pressure, heart rate and body temperature were also recorded. Endosulfan induced a dose-related increase in EPs at all sites. At S1CL, EP peak amplitude was greater than baseline at 1, 2 and 4mg/kg for the first negative, second positive and third negative waves, and at 2 and 4mg/kg for the first and third positive waves. Similar but less marked trends were observed at S1HL and V1CL. A shift of EEG power to higher frequencies (alpha and beta EEG bands) was only present at 4mg/kg. In conclusion, endosulfan induced a large increase of cortical evoked potentials amplitudes at doses that did not elicit convulsions. These responses could be used as a non-invasive diagnostic tool to detect low-level endosulfan intoxication in humans and to help establish the NOAEL and LOAEL levels of this pollutant.

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.

Organochlorine pesticides residues in bottled drinking water from Mexico City

This work describes concentrations of organochlorine pesticides in bottled drinking water (BDW) in Mexico City. The results of 36 samples (1.5 and 19 L presentations, 18 samples, respectively) showed the presence of seven pesticides (HCH isomers, heptachlor, aldrin, and p,p'-DDE) in bottled water compared with the drinking water standards set by NOM-127-SSA1-1994, EPA, and World Health Organization. The concentrations of the majority of organochlorine pesticides were within drinking water standards (0.01 ng/mL) except for beta-HCH of BW 3, 5, and 6 samples with values of 0.121, 0.136, and 0.192 ng/mL, respectively. It is important monitoring drinking bottled water for protecting human health.

The effects of endosulfan on the testes of bluegill fish, Lepomis macrochirus: a histopathological study

The effect of endosulfan, an Organochlorine pesticide, on bluegill testes was studied. Endosulfan is aqua-toxic and has an immediate effect on fish and other aquatic life. In this experiment, we exposed the fish for 24-, 48-, 72-, 96-h, and 1- and 2-week periods. A second group of fish without exposure to endosulfan served as the control. The control testis appeared structurally normal. The seminiferous tubules were of round or oval shape and contained primary spermatogonia, primary spermatocytes, secondary spermatocytes, spermatozoa, spermatids, Sertoli cells, and interstitial cells of Leydig. Within the connective tissue that connected the seminiferous tubules were Leydig cells. After 24 h of exposure, there was evidence of slight signs of connective tissue splintering. The 48-h exposure resulted in breakage of primary spermatocyte walls and separation from the seminiferous tubules. The 72-h testis showed further connective tissue damage and migration of primary spermatogonia into the lumen. After 96 h, there was significant damage to connective tissue and the seminiferous tubules were less pronounced. After 1 and 2 weeks, the seminiferous tubule walls were disrupted and missing in places and the structure of the testis was very disorganized compared to the control testis. Biometric analysis indicated that the diameter of the primary spermatogonia decreased from 24 h to two weeks. There also appeared to be fewer Leydig cells, responsible for testosterone production, over the exposure period and damaged Sertoli cells, which support, protect, and nourish the spermatogenic cells, synthesize ABP, and assist in maintaining the necessary concentration of testosterone in the seminiferous tubules so that spermatogenesis can progress. These kinds of damage could affect the spermatids and spermatozoa and possibly have a negative impact on spermatogenesis and male fertility, affecting bluegill fish population.

5-Aminosalicylic acid reverses endosulfan-induced testicular toxicity in male rats

Pre-treatment with 5-aminosalicylic acid (5-ASA) significantly reduced sperm-shape abnormalities in endosulfan-treated rats. The number of abnormal sperm in the epididymis was markedly increased by endosulfan treatment but pre-treatment with 5-ASA kept these values close to normal. Treatment with 5-ASA at a dose of 25 mg/kg bw was more effective in reducing sperm-shape abnormality and sperm count than at a dose of 50 mg/kg bw. Endosulfan significantly increased the level of lactate dehydrogenase (LDH) in rats but a marked decrease was observed upon pre-treatment with 25 mg/kg bw 5-ASA. Changes in plasma testosterone levels were not significantly correlated with 5-ASA pre-treatment but histopathological analysis of seminiferous tubules and Leydig cells showed significant protection from endosulfan-induced tissue damage such as necrosis. The population of Sertoli cells increased and the lumen of the seminiferous tubules contained a greater number of spermatids. There was a corresponding increase in the number of Leydig cells. A curative study with 5-ASA showed a similar protection from endosulfan-induced toxicity and cellular damage, but the extent of protection was significantly lower.

Rapid analytical method for the determination of pesticide residues in sunflower seeds based on focused microwave-assisted Soxhlet extraction prior to gas chromatography-tandem mass spectrometry

A rapid analytical method for determination of organochlorine pesticide residues in sunflower seeds based on focused microwave-assisted Soxhlet extraction has been developed. The main factors affecting the extraction efficiency--namely microwave power, irradiation time, volume of extractant and number of cycles--were optimized by a two-level factorial fractional design. After extraction, a liquid-liquid extraction and a clean-up step including the use of Florisil macrocolumns were required prior to injection of the extracts into the chromatograph in order to isolate the pesticide residues from the lipid fraction of the original extract. The MS-MS ion preparation mode was selected due to the high sensitivity and selectivity it provides. Seed samples were used collected near a crop subjected to aerial pesticide application. Residues of hexachlorocyclohexane isomers and endosulfan were found in the seeds although they were not subjected to pesticide application, thus showing the spray-drift contamination. The validation of the proposed approach was carried out by comparison with the ISO 659-1988 reference extraction method obtaining similar, or even better efficiencies by the proposed approach.

Determination of residues of endosulfan in human blood by a negative ion chemical ionization gas chromatographic/mass spectrometric method: impact of long-term aerial spray exposure

A new and sensitive analytical method using negative ion chemical ionization gas chromatography/mass spectrometry in selective ion monitoring (SIM) mode has been developed for the determination of residues of endosulfan in the human blood. The residues of endosulfan are extracted from whole blood samples without separating the serum by the addition of 60% sulfuric acid at 10 degrees C followed by partition with hexane + acetone (9 + 1 by volume). The total endosulfan is quantified as the sum of alpha-endosulfan, beta-endosulfan and endosulfan sulfate in SIM mode. The mass-fragment ions used for this purpose that are monitored for in SIM mode include endosulfan diol: 95, 169, 214, 313, alpha-endosulfan: 99, 242, 270, 406, beta-endosulfan: 99, 242, 270, 406, and endosulfan sulfate: 97, 353, 386. Recovery experiments were conducted at the concentration range 1.0-100 pg ml(-1). Results showed 112-98% recovery of total endosulfan from the whole blood samples. The relative standard deviation was 1.49-2.68%. The method was found to be highly sensitive in quantifying endosulfan residues down to the 0.1 pg ml(-1) level. Conversion of endosulfan to endosulfan diol was found to be less than 0.1% under the conditions used. The results were compared with published data. The applications of the analytical method for the determination of endosulfan residues in real samples was tested by analyzing 106 human blood samples collected from a population living in Padre village, Kasargode District, Kerala, India, where aerial spraying of endosulfan has been a common agricultural practice over the years. The results showed that none of the blood samples contained residues of endosulfan (alpha-endosulfan 4 beta-endosulfan + endosulfan sulfate) or endosulfan diol. The results were confirmed by the detection of the appropriate amounts in a number of these samples which had subsequently been spiked with endosulfan.