Organochlorine Concentrations Research Articles

Review on Organochlorine Pollution in Malaysia

Organochlorine is a type of persistent organic pollutants which can last long in environment due to the resistance towards the microbial degradation. Previously, the organochlorine pesticides are widely used to reduce the pests in the farm so, the crop yield could be increased, and the losses can be decreased. The organochlorine pesticides previously are used without having a proper study on the effect of organochlorine to the environment. Although the use of organochlorine pesticides has been banned, the residues of organochlorine from previous usage, still exist in the environment, causing negative impacts to the environment and human health. The distribution of the organochlorine pollution in Malaysia is required to be studied more to ensure that the organochlorine concentration will not be increasing according to time. Due to the ban of organochlorine pesticides, other pests control methods such as organophosphate pesticides, and integrated pest management are being used by the farmers. However, there are challenges raised such as financial problem of the farmers to afford the new chemicals or methods and the negative effect from the use of new chemicals, and these challenges should be solved to improve the pest control in Malaysia. Impacts of organochlorines on human health and environment are discussed in this review to show the hazard of organochlorines.

Impacts of a warming climate on concentrations of organochlorines in a fasting high arctic marine bird: Direct vs. indirect effects?

The present study examined how climate changes may impact the concentrations of lipophilic organochlorines (OCs) in the blood of fasting High Arctic common eiders (Somateria mollissima) during incubation. Polychlorinated biphenyls (PCBs), 1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p′-DDE), hexachlorobenzene (HCB) and four chlordane compounds (oxychlordane, trans-chlordane and trans- and cis-nonachlor) were measured in females at chick hatching (n = 223) over 11 years (2007–2017). Firstly, median HCB and p,p′-DDE concentrations increased ~75 % over the study period, whereas median chlordane concentrations doubled (except for oxychlordane). PCB concentrations, in contrast, remained stable over the study period. Secondly, both body mass and clutch size were negatively associated with OC levels, suggesting that females with high lipid metabolism redistributed more OCs from adipose tissue, and that egg production is an important elimination route for OCs. Thirdly, the direct climate effects were assessed using the mean effective temperature (ET: air temperature and wind speed) during incubation, and we hypothesized that a low ET would increase redistribution of OCs. Contrary to expectation, the ET was positively correlated to most OCs, suggesting that a warmer climate may lead to higher OCs levels, and that the impact of ET may not be direct. Finally, potential indirect impacts were examined using the Arctic Oscillation (AO) in the three preceding winters (AOwinter 1–3) as a proxy for potential long-range transport of OCs, and for local spring climate conditions. In addition, we used chlorophyll a (Chla) as a measure of spring primary production. There were negative associations between AOwinter 1 and HCB, trans-chlordane and trans-nonachlor, whereas oxychlordane and cis-chlordane were negatively associated with Chla. This suggests that potential indirect climate effects on eiders were manifested through the food chain and not through increased long-range transport, although these relationships were relatively weak.

ORGANOCHLORINE PESTICIDES POLLUTION OF THE BOTTOM SEDIMENTS OF NAKHODKA BAY AND PARTIZANSKAYA RIVER

Link for citation: Mazlova E.A., Blinovskaya Ya.Yu., Sokolova L.I., Tursunova G.Sh. Organochlorine pesticides pollution of the bottom sediments of Nakhodka bay and Partizanskaya river. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 25-35. In Rus. Relevance. The new data on the organochlorine pesticides pollution of the bottom sediments of Nakhodka bay and Partizanskaya river were obtained in 2020–2021. The objective of the article is to report the organochlorine pesticides pollution level of the bottom sediments and to define the possible sources of organochlorine pesticides in the marine environment. Techniques: sample collection of bottom sediments, Gas Chromatography Mass Spectrometry analysis of samples, Gas-liquid Chromatography method with electronic capture detector, statistical processing, assessment of the organochlorine pesticides contamination of sediments. Results. The new data were obtained on the organochlorine pesticides concentrations in Nakhodka bay in 2020–2021. The previous data on the studied area are described. The concentration of HCH pesticides (α- , β- and γ-HCH), DDT and its metabolites was analyzed. It was found that the concentration of α- , β- HCCH and DDT in bottom sediments increased in 2021.To determine the quality of bottom sediments, the average annual values of organochlorine pesticides concentrations in the bottom sediments gathered during the field works were compared with the quality guidelines. There are no approved quality guidelines for maximum permissible concentrations of pollutants in bottom sediments in the Russian Federation. For this reason, we used the quality guidelines applied in foreign countries («Dutch sheets» (Neue Niederlandische Liste. NNL) and Canadian quality standards for marine and estuarine bottom sediments (Canadian Sediment Quality Guidelines, CSQGs). Possible sources of organochlorine pesticides in the marine environment were analyzed. The results of this work showed that despite the ban on the use of these substances, these pesticides are included in the multiple compounds used in different industries and continue to enter and accumulate in the marine environment.

Organochlorines as contaminants in butter and other shortenings: occurrence and exposure assessment

In the present work, experimental measurements were carried out on dietary fats purchased in stores or bought online and produced in different countries of the world. Shortenings of animal origin (lard, butter) or vegetable-made (margarine, coconut oil, hydrogenated palm/soybean oil) were selected. The concentrations of organochlorines (OC pesticides and PCBs) were measured to ascertain whether the level of these contaminants in food has decreased since they were banned and to assess the today consumer exposure to such xenobiotics. Analyses were carried out by GC-ECD and GC-MS according to the United Nations Environment Program on persistent organic pollutants. Organochlorines were detected in 85% of the samples analysed. The observed levels were not high (maximum value 5.54 ± 2.33 ng g−1) and point out a slow decline over the last years. Butter from Europe was the most studied matrix showing HCB and 4,4′-DDE as the main organochlorines that were constantly detected above the limit of quantitation. This can be explained if the past use of the two pesticides is considered. Consumption data from the EFSA database were combined with the HCB and 4,4′-DDE concentrations measured in the present research to obtain the Estimated Daily Intakes (EDIs) of the two contaminants from butter. The comparison with the Tolerable Daily Intakes (TDIs) set by World Health Organization indicates that the observed EDIs are far below the TDIs, so allowing to conclude that the risk deriving from the intake of the investigated organochlorines through butter is acceptably low for European consumers. Results relating to some non-Aroclor PCBs detected in shortenings, such as PCB 47, which have recently been discovered to be released into the environment are also reported.

Organochlorine contaminants in sediments and factors influencing their distribution in the natural marine protected area in the gulf of Mexico

The aim of this study was to determine the concentration of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in marine sediments of a natural marine protected area (NMPA), Veracruz Reef System (VRS), in the Gulf of Mexico (GoM). This NMPA represents one of the first coastal sites with port activity in Mexico, which causes a range of human activities that require adequate planning so as not to impact and destroy this marine protected area; In this sense, this work represents the first effort aimed at diagnosing the presence of organochlorine contaminants in reef sediments from the mainland, both from the adjacent port area and from more distant regions with dominant agricultural activities that ultimately affect this NMPA. Content of organic matter (OM), carbonates and grain-size composition were determined to investigate their influence on compounds distribution in the sediment through multivariate analysis. The potential risk represented by organochlorines concentrations was evaluated taking as reference Sediment Quality Guidelines (SQGs). Levels of ∑PCBs, ∑DDTs, ∑HCHs and ∑Cyclodienes ranged from 11.59 to 29.79, < 0.01 to 34.11, 22.10 to 102.80, and 17.21–104.45 ng g−1 dry weight (DW), respectively. The statistical analysis revealed that the content of mud and organic matter were the parameters that might influence PCBs distribution in the sediment while OCPs could be influenced by sand and carbonate. The theoretical risk assessment estimated with the results obtained showed that concentrations of lindane, endrin, dieldrin and p,p’-DDT could have an adverse effect on the reef benthic community and continued monitoring is required. The data obtained on the organochlorine contaminants (OCs) considered in this work will contribute to support the strategies proposed by the Mexican federal government entity to continue with the conservation and surveillance of this NMPA and thereby guarantee the least impact derived mainly from port and related agricultural activities.

Persistent organic pollutants and trace elements detected in New Zealand fur seals (long-nosed fur seal; Arctocephalus forsteri) from New South Wales, Australia, between 1998 and 2019

Environmental pollution is a growing threat to wildlife health and biodiversity. The relationship between marine mammals and pollutants is, however, complex and as new chemicals are introduced to ecosystems alongside concomitant, interacting threats such as climate change and habitat degradation, the cumulative impact of these stressors to wildlife continues to expand. Understanding the health of wildlife populations requires a holistic approach to identify potential threatening processes. In the context of environmental pollution in little studied wildlife species, it is important to catalogue the current exposome to develop effective biomonitoring programs that can support diagnosis of health impacts and management and mitigation of pollution. In New South Wales, Australia, the New Zealand fur seal (Arctocephalus forsteri) is a resident species experiencing population growth following devastating historic hunting practices. This study presents a retrospective investigation into the exposure of New Zealand fur seals to a range of synthetic organic compounds and essential and non-essential trace elements. Liver tissue from 28 seals were broadly analyzed to assess concentrations of organochlorine and organophosphate pesticides, polychlorinated biphenyls, per- and polyfluoroalkyl substances, and essential and non-essential trace elements. In addition to contributing extensive pollution baseline data for the species, the work explores the influence of sex, age, and body condition on accumulation patterns. Further, based on these findings, it is recommended that a minimum of 11 juvenile male New Zealand fur seals are sampled and analyzed annually in order to maintain a holistic biomonitoring approach for this population.

Serum Concentrations of Organochlorines in Breast Cancer Women: A Pilot Hospital Based-case Control Study in Vietnam

Cancer, in general, and breast cancer in particular, is one of the noncommunicable diseases (NCDs) that is increasing rapidly in the world, especially in developing countries like Vietnam. Along with other etiological factors (e.g., genetics, family history, age, etc.), there is growing scientific evidence that exposure to environmental carcinogens, especially endocrine disrupting chemicals-EDCs (e.g., organochlorine pesticides (OCPs) and some other organic compounds), is potentially associated with increased incidence of several NCDs including breast cancer in animal and human studies. People are frequently exposed to various carcinogens, such as pesticides, in their lifetime. Organochlorine pesticides (OCPs) are frequently used worldwide as insecticides, fungicides, herbicides and termiticides, and people may be exposed to these substances at different levels due to direct and/or indirect ways. Therefore, the aim of this paper is to study the accumulation level of serum organochlorines in breast cancer in a case-control study in Vietnam. A random collection of blood samples was carried out from the cases (breast cancer patients, n=146) and controls (healthy women, n=146) with informed consent in a hospital-based case and control study. Serum was separated within 2h of blood collection and then subjected to further purification before analysis by Gas chromatography–mass spectrometry (GC-MS) method. The determination of 18 organochlorines (Aldrin, α-BHC, β-BHC, δ-BHC, γ-BHC, Heptaclor, Heptaclor epoxide, Diendrin, Endosulfan I, Endosulfan II, Endosulfan sulfat, Endrin, Endrin aldehyde, Endrin ketone, p,p’ DDD, p,p’ DDT, p,p’DDE, Methoxyclor) showed that only p,p′-DDE (as a main metabolite of p,p′-DDT) was detected in the blood samples of the cases (26.0%) and controls (10.3%). In addition, p,p′-DDT was the only pesticide detected in the disease group with low concentration (3.4%). The average concentration of p,p'-DDE in the case (3.51 ± 0.99 ppb) was higher than that in the control (1.89 ± 0.43 ppb) with a significant statistical difference (p &lt; 0.05).

Organochlorine contaminant concentrations and lipid profiles in eastern North Pacific gray whales (Eschrichtius robustus)

Organochlorine (OC) contaminant concentrations in tissues and lipid profiles in blubber are summarised for 101 gray whales (Eschrichtius robustus) from the eastern North Pacific stock. Samples were obtained from presumably healthy gray whales during a 1994 subsistence hunt in the Russian Arctic (n = 17) and also from biopsy sampling of live animals from the Washington coast (n = 38). In addition, tissues were collected from two groups of animals (1988-1991, n = 22; and 1999, n = 24) that stranded along the west coast of the USA. These whales represent a diverse group of animals with respect to lipid stores, age, gender, health and reproductive status. Information about these biological factors is necessary before contaminant concentration data can be properly interpreted. Differences in blubber lipid levels and profiles were examined among these groups of whales. Significantly higher lipid levels were found in the blubber of subsistence animals that were sampled following summer feeding in the Bering and Chukchi Seas, compared to lipid levels in the biopsied and stranded animals. Lipid class profiles from blubber of presumably healthy gray whales (i.e. from subsistence and biopsy sampling) contained primarily triglycerides and were very different from those of stranded animals that showed lipid decomposition (increased proportions of free fatty acids, cholesterol and phospholipids). Furthermore, lipid class profiles were found to be a means of estimating the quality of a blubber sample from stranded cetaceans. An examination of how biological factors (e.g. gender, reproductive status, age) contribute to interpreting the differences found in contaminant concentrations among the gray whales was also undertaken. Although not statistically significant, higher (OC) concentrations were found in males compared to females, thus suggesting the tendency of the mother to shift her contaminant burden to her calf during gestation and lactation. Results also indicated that there was no significant increase in concentrations of contaminants in the blubber with increase in length (surrogate for age). Higher concentrations of OC contaminants were found in stranded juvenile gray whales, compared to juvenile subsistence whales, and were thought to result from retention of OCs in blubber of the stranded animals as lipid stores are mobilised for energy and total lipid levels decrease, rather than from a difference in diet or feeding areas. OC concentrations in various tissues (blubber, liver, kidney, muscle, brain) were similar on a lipid weight basis, except for brain, which had lower lipid-adjusted OCs because the blood-brain barrier limits contaminant transfer.

Sea spray as a secondary source of chlorinated persistent organic pollutants? - Conclusions from a comparison of seven fresh snowfall events in 2019 and 2021

Secondary sources of persistent organic pollutants (POPs) gain in importance worldwide as primary sources decline. In this work, we aim to determine whether sea spray may be a secondary source of chlorinated POPs to the terrestrial Arctic, since a similar mechanism was proposed there only for the more water-soluble POPs. To this end, we have determined polychlorinated biphenyls and organochlorine pesticides concentrations in fresh snow and seawater collected in the vicinity of the Polish Polar Station in Hornsund in two sampling periods covering spring 2019 and 2021. To support our interpretations, we include also metal and metalloid, and stable hydrogen and oxygen isotopes analysis in those samples. A significant correlation was found between the concentrations of POPs and the distance from the sea at the sampling point, yet the confirmation of sea spray impact lies more in capturing an event with negligible long-range transport influence where the detected chlorinated POPs (Cl-POPs) matched in composition the compounds enriched in the sea surface microlayer, which is both a source of sea spray and a seawater microenvironment rich in hydrophobic substances.

Pesticide Exposure among Latinx Children in Rural Farmworker and Urban Non-Farmworker Communities: Associations with Locality and Season.

This study uses repeated measures to document the pesticide exposure of rural and urban Latinx children (age eight at baseline), and to compare these children in terms of the frequency and concentration of their exposure to a large set of pesticides, accounting for season. We used silicone wristbands worn for one week up to ten times at quarterly intervals from 2018 to 2022 to assess pesticide exposure in children from rural farmworker (n = 75) and urban non-farmworker (n = 61) families. We determined the detection and concentrations (ng/g) of 72 pesticides and pesticide degradation products in the wristbands using gas chromatography electron capture detection and gas chromatography mass spectrometry. The most frequently detected pesticide classes were organochlorines, pyrethroids, and organophosphates. Controlling for season, organochlorine or phenylpyrazole detections were less likely for rural children than for urban children. Detections of organochlorines, pyrethroids, or organophosphates were lower in spring and summer versus winter. Controlling for season, urban children had greater concentrations of organochlorines, while rural children had greater concentrations of pyrethroids and Chlorpyrifos. Pesticide concentrations were lower in winter and spring compared with summer and fall. These results further document that pesticides are ubiquitous in the living environment for children in vulnerable, immigrant communities.

Post-mortem stability of blubber retinoids in by-caught harbour porpoises (Phocoena phocoena): implications for the design of biomarker studies

The effect of post-mortem time (0-48 hours) on retinoid concentrations in the blubber and liver of harbour porpoises under natural conditions is investigated to assess the stability of samples collected from animals after death. Organochlorine compounds and lipid content were also determined to assess their potential effects on retinoid status. Organochlorine concentrations remained low throughout the postmortem period and were considered unlikely to influence retinoid body dynamics. Retinoid concentrations in liver were 5-6 times higher than those in blubber and both were highly correlated. In contrast with liver, blubber can be easily sampled from live individuals using nondestructive biopsy techniques and is therefore considered an alternative tissue to assess retinoid status in marine mammals. Neither significant differences nor trends were detected in the concentration of retinoids over the studied period, indicating that degradation agents (ultraviolet rays, oxygen exposure and heat) did not affect them. Blubber can thus be regarded as a reliable tissue for the assessment of the retinoid status of unpreserved specimens kept up to 48 hours in conditions similar to those of this study.

Strandings, mortality and morbidity of Indo-Pacific humpback dolphins in Hong Kong, with emphasis on the role of organochlorine contaminants

Factors related to mortality and disease in Indo-Pacific humpback dolphins (Sousa chinensis) from Hong Kong waters were investigated by detailed examination of dolphin specimens found stranded from 1995-2004. In total, 86 specimens were necropsied, but many of these were too badly decomposed to provide much information. Skin and blubber biopsies were also collected from six identified living individuals and concentrations of organochlorines (DDTs, PCBs and HCHs) were determined from blubber samples of stranded and biopsied dolphins. A large proportion of the strandings (53.2%) were young-of-the-year. The most commonly diagnosed causes of death were net entanglement and vessel collision. The pesticide DDT showed the highest concentrations and the ratio of DDT to its breakdown products (and other information) suggests that there may be a recent or nearby source of DDT into the dolphins’ ecosystem. Concentrations of both DDTs and PCBs showed a pattern of increasing with age in males. In females, they increased until sexual maturity, then decreased, and finally increased again in late life. This is consistent with a hypothesised transfer of pollutants from mother to offspring during gestation and lactation. Inter-laboratory differences and effects of decomposition of specimens are two potential biases that may significantly affect the quality of the present data. In order to resolve the potential problems associated with these issues, a long-term biopsy collection programme has recently been initiated.

Assessment of Aox Content in Bleaching Effluent of Eucalyptus Tereticornis Kraft Pulps

The research aim is to reduce the organochlorine content in bleach plant effluents by modifying conventional (CEHH) bleaching sequences. Majority of pulp and paper mills generally adopted CEHH or CEH bleaching sequences, using chlorine or chlorinated compounds to remove the color from pulps. Organochlorine compounds are mainly generated from chlorination and alkali extraction stages. The purpose of the study is to substitute elemental chlorine in bleaching with oxygen, chlorine dioxide, or peroxide. Investigations of AOX content of various traditional and innovative ECF bleaching sequences were conducted. In this study, kraft pulps of Eucalyptus tereticornis with kappa numbers of 44.91 and 26.46 and its oxygen-delignified pulps of kappa numbers 21.32 and 13.03 were used. In terms of AOX, various ECF bleaching sequences were compared to the reference sequence (CEHH). AOX value was 4.45, 3.42, 2.27 kg/tp for the pulp bleached adopting OCEH, ODEH, ODEP bleaching sequence and 9.24 kg/tp for the pulp bleached adopting CEHH bleaching sequence for the pulp corresponding to Kappa number 44.91. Similarly, the AOX value was 2.60 , 1.78 1.24 Kg/tp for the pulps bleached adopting the OCEH, ODEH, ODEP bleaching sequence and 5.56 Kg/tp for the pulp bleached adopting the CEHH sequence for the pulp corresponding kappa number 26.46. Due to partial-delignification of oxygen, AOX production was reduced up to 50%.

Sublethal Toxicity Insecticide Organochlorine Endosulfan on The Value of Blood Sugar Levels and The Level of Life in Tilapia (Oreochromis niloticus) Seeds

AbstrakThe use of pesticides in agriculture continues to increase. One of the classifications of pesticides is organochlorine endosulfan insecticide that can cause river pollution. One type of fish that is often cultivated in ponds is tilapia. River pollution can trigger stress and even fish death. The stress level of the fish can be seen from the value of its blood sugar levels. This research was conducted on March 20 - April 28, 2021, in Microbiology Laboratory and Anatomy-Aquaculture Laboratory, Faculty of Fisheries and Marine, Universitas Airlangga, to determine the toxicity effect of sublethal endosulfan organochlorine insecticide on blood sugar level value and tilapia seed life rate. This study used experimental methods with CRD through exposure to different organochlorine concentrations, namely P0 (0%), P1 (10%), P2 (30%), P3 (50%), P4 (70%) with four replays. Analysis of the data was processed using ANOVA and DMRT, which showed that sublethal toxicity of endosulfan organochlorine insecticides had an effect (p<0.05) on blood sugar levels and the level of tilapia seed resistance. Using only a concentration of 10% has increased blood sugar levels significantly on the 7th day and continues to increase until the 28th day (114.50 mg/dL). Also, the level of fish life insecurity indicates a value below the Indonesian National Standard (72.50 %).

Organochlorine Pesticide Characterisation of Emede Wetland Isoko South Delta for Pen Aquaculture in Secondary Schools as an Emerging Trend in Vocational and Technical Education in the 21st Century Nigeria

This study is an ex-post facto research that investigated the organochlorine pesticides content of Emede wetland for its suitability for pen aquaculture in secondary school. The study answered 3 research questions and tested a hypothesis. To achieve this, the research area Emede wetland was mapped out into research cells. From each of the research cells, water samples were collected from 10 sampling spots, bulked and a composite drawn and fixed with HNO3 and stored in ice cooled boxes for laboratory analysis. The analytical standards adopted for the study were USEPA, APHA and ASTM and the analytical instrument deployed for determination of the organochlorine pesticides was EPA 8081 ECD. The mean results obtained are as follows: adrin 0.76±1.4µg/l, diedrin 1.26±0.30 µg/l, DDT 2.13±0.42 µg/l, endrin 0.62±0.55 µg/l and heptachlor 2.13±0.42 µg/l. The results obtained were subjected to test of significance with ANOVA at 0.05 level of significance deploying SPSS model 21. The p-value is 0.31 thus rejecting Ho. The study recommends that pen aquaculture should not be implemented in Emede wetland, the pollutions source should be identified and blocked and remediation should be carried out in the wetland to resuscitate the wetland to its hitherto healthy status.

Toxic Effects of Organophosphorus and Organochlorine Pesticides on Testudineus (Bloch)

Now-a-day modern techniques employed in agriculture and newer chemicals used have contributed much to environmental pollution, particularly to water pollution. This can result in local effects on the environment. The killing of fish by pesticides is quite common. In the present paper, an attempt has been made to evaluate the impact of 48-h LC 50 concentration of Organphosphors (Cythion and Metacid) and Organochlorine (DDT and Lindane) on the coagulation time (CT) and the total Thrombocyte count (THC) of male and female Anabas testudineus used animal. The study reveals towards pathological disturbances involiving injury and haemorrhage in tissues of the test fish with significant lowered CT value and higher THC count at different levels of the ‘t’ value. Therefore, gradual phasing out of pesticides in fishery resources in fishery resources is suggestive. Further in order to check the use and accidental entry of pesticides in the water bodies, a number of alternative pest control methods have been developed but a complete success has not yet been achievd and thus more needed in this direction.

Organochlorine Pesticide Quantification of Otogor Wetland Ughelli Delta for Secondary Schools Cage Aquaculture for Hunger Eradication in Nigeria

United Nations Sustainable Development Goal 2 requires all member Nations to achieve zero hunger by 2030. Agriculture especially aquaculture adopting cage technique has been recognised as a very viable option in achieving this set goal. Aquaculture requires water devoid of pollutants and that underscores the study. This is an ex-post facto research that answered 3 research questions and tested a hypothesis and its focus is on the determination of the organochlorine pesticides content of Otogor wetland for cage aquaculture in secondary schools for zero hunger. To achieve this, Otogor wetland was mapped out into research cells A, B, C, D, E. From each of the cells, water was sampled with clean sampling bottle tied to a graduated string from 5 spots at 10 cm depth. The water samples from each cell were then bulked, a composite drawn, fixed with HNO3 and stored in ice cooled box for analysis. The analytical standards adopted were USEPA 3570, APHA, Steindwandter and Shufter 1978. The analytical instrument deployed for determination is Agilent 6100 series single quadrupole LC/MS. The mean results of the organochlorine pesticides investigated in Otogor wetland were DDT 1.27±0.21μg/l, heptachlor 3.01±0.45μg/l, a-lindane 0.33±0.09μg/l, adrin 3.52±1.00 μg/l and endrin 0.32±0.11μg/l. The results of the organochlorine pesticides investigated were subjected to test of significance with ANOVA with numerator 4 and denominator 20. The F ratio calculated value is 5.59 while F ratio critical value is 2.87, thus rejecting Ho and accepting Ha. The study thus recommend that cage aquaculture should not be deployed in Otogor wetland with the present pollution status. The pollutants source point should be identified and discontinued and remediation should be commissioned in Otogor wetland to return the wetland to its healthy state to allow for the deployment of cage aquaculture for youths empowerment for zero hunger in Nigeria.

Feasibility of Producing Sodium Hypochlorite for Disinfection Purposes using Desalination Brine

On the Fernando de Noronha archipelago of northeast Brazil, the water supply comes from the desalination of seawater. The main environmental problem related to desalination is the brine resulting from the process, comprised of highly concentrated salts. The present study aimed to produce oxidant solutions from brine for disinfection purposes. The experiment was carried out on a laboratory scale. The brine had a chloride concentration of 40000 mg/L. The electrolysis process lasted twenty-four hours, monitoring pH, electrical conductivity, temperature, and chlorine. The sodium hypochlorite production was 2.27% and 3.61% m/m. The oxidant solutions were tested on domestic effluents and achieved a 99.99% removal rate of thermotolerant coliforms while maintaining the concentration of organochlorines below the upper limit established by legislation for the disposal of effluents. Therefore, the use and more proper brine disposal are sustainable alternatives, enabling the on-site production of sodium hypochlorite on the archipelago in a safe, effective, reliable way and comparable to other oxidants.

Changes and distribution of gas-phase polycyclic aromatic hydrocarbons and organochlorine compounds in a high-mountain gradient over a three-year period (Pyrenees, 2017–2020)

The atmospheric gas-phase concentrations of several polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), hexachlorobenzene (HCB), and pentachlorobenzene (PeCB) were measured in six high-mountain sites in the Pyrenees (1619–2453 m). Polyurethane foam passive air samplers were used for this purpose, providing continuous records spanning over three years (2017–2020). The mean concentrations of ∑PCBs, HCB, and PeCB, 13 ± 4 pg m−3, 44 ± 18 pg m−3, and 23 ± 20 pg m−3, respectively, were of the order of those reported in other mountain sites and similar to those measured 20 years ago in the same area, evidencing the persistence of these compounds despite the international regulatory actions. The mean concentration of ∑PAHs was 631 ± 238 pg m−3, representing between two- and three-times lower values than 20 years ago in the same area, but still in the range of other mountain regions. Statistically significant increases in gas-phase concentrations at higher temperatures were observed for most compounds. The experimental phase-change pseudo-enthalpies calculated from the slopes of the regressions between the natural logarithm of the concentrations and the reciprocal of temperature were lower than the reference values for nearly all compounds. This difference suggested a main contribution of long-range atmospheric transport of the gas-phase PAH and organochlorine concentrations in this mountain area. However, the less volatile compounds such as benz[a]anthracene, PCB138, and PCB180 showed a closer similarity between experimental and laboratory enthalpies, indicating that a significant portion of the variations in concentration of these compounds originated from temperature-dependent diffusive exchange by re-volatilization from local surfaces. The concentrations found in these sentinel ecosystems demonstrate that long-range transport of organic pollutants remains a risk in remote continental environments.

Bioavailability of legacy and current-use pesticides in juvenile Chinook salmon habitat of the Sacramento River watershed: Importance of sediment characteristics and extraction techniques

The Sacramento River watershed, California, provides important rearing and migratory habitat for several species of conservation concern. Studies have suggested significant benefits for juvenile fish rearing in floodplain habitats of the watershed compared to the mainstem Sacramento River. However, the potential for contaminant exposure in each of these two habitats is poorly understood. Consequently, the present study aimed to determine the distribution and occurrence of bioavailable pesticides within two known salmon habitats using a suite of approaches including exhaustive chemical extraction, single-point Tenax extraction (SPTE) and ex situ passive sampling. Sediment samples were collected from sites within both habitats twice annually in 2019 and 2020, with inundation of the floodplain and high flows for both areas in 2019 and low flow conditions observed in 2020. Sediment characteristics including total organic carbon, black carbon and particle size distribution were determined to elucidate the influence of physical characteristics on pesticide distribution. Using exhaustive extractions, significantly greater sediment concentrations of organochlorines were observed in the floodplain compared to the Sacramento River in both years, with bioaccessible organochlorine concentrations also significantly greater in the floodplain (ANOVA, p < 0.05). Using both SPTEs and exhaustive extractions, significantly fewer pesticides were detected across both sites under low flow conditions as compared to high flow conditions (Poisson regression, p < 0.05). Sediment characteristics including percent fines and black carbon had significant positive relationships with total and bioaccessible pyrethroid and organochlorine concentrations. Fewer analytes were detected using low-density polyethylene (LDPE) passive samplers as compared to SPTEs, suggesting greater sensitivity of the Tenax technique for bioavailability assessments. These findings suggest that threatened juvenile fish populations rearing on the floodplain may have greater exposure to organochlorines than fish inhabiting adjacent riverine habitats, and that pesticide exposure of resident biota may be exacerbated during high-flow conditions.