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.

Persistent organic pollutants in air from Asia, Africa, Latin America, and the Pacific

In support of the United Nations Environment Programme (UNEP) global monitoring plan under the Stockholm Convention concentrations of persistent organic pollutants (POPs) were determined during two years in air from 42 countries in Asia, Africa, Latin America, and the Pacific by using polyurethane foams installed in passive samplers. The compounds included were polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenylethers (PBDEs), one polybrominated biphenyl and hexabromocyclododecane (HBCD) diastereomers. Total-DDT and PCBs were the highest in concentrations in about 50% of the samples, which shows their high persistency. Total DDT in air from the Solomon Islands ranged from 200 to 600 ng/polyurethane foam disk (PUF). However, at most locations, a decreasing trend is observed for PCBs, DDT and most other OCPs. Patterns varied per country with e.g. elevated dieldrin in air from Barbados and chlordane in air from the Philippines. A number of OCPs, such as heptachlor and its epoxides, some other chlordanes, mirex and toxaphene have decreased down to almost undetectable levels. PBB153 was hardly found and penta and octa--mix related PBDEs were also relatively low at most locations. HBCD and the decabromodiphenylether were more prominent at many locations and may even still increase. To draw more holistic conclusions more colder climate countries should be included in this program.

The impact of climate sensitive factors on the exposure to organohalogenated contaminants in an aquatic bird exploiting both marine and freshwater habitats

To assess how climate-sensitive factors may affect the exposure to organochlorines (OCs) and perfluoroalkyl substances (PFASs), we monitored concentrations in eggs of the common goldeneye (Bucephala clangula) over two decades (1999-2019) in central Norway. The goldeneye alternates between marine and freshwater habitats and is sensitive to climate variation, especially due to alterations in ice conditions which may affect feeding conditions. We assessed how biological factors such as diet (stable isotopes δ¹³C and δ¹⁵N), the onset of egg laying, and physical characteristics such as winter climate (North Atlantic Oscillation: NAO_w) influenced exposure. We predicted compounds to show different temporal trends depending on whether they were still in production (i.e. some PFASs) or have been banned (i.e. legacy OCs and some PFASs). Therefore, we controlled for potential temporal trends in all analyses. There were declining trends for α- and γ-hexachlorocyclohexane (HCH), oxychlordane, cis-chlordane, cis-nonachlor, p,p'-dichlorodiphenyltrichloroethane (p.p'-DDT) and less persistent polychlorinated biphenyl (PCB) congeners (e.g. PCB101). In contrast, the dominant compounds, such as p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and persistent PCB congeners, were stable, whereas hexachlorobenzene (HCB) increased over time. Most OCs were positively related to δ¹⁵N, suggesting higher exposure in birds feeding at upper trophic levels. Chlordanes and HCB were positively associated with δ¹³C, indicating traces of marine input for these compounds, whereas the relationships to most PCBs were negative. Among PFASs, perfluorooctanesulfonamide (PFOSA) and perfluorohexane sulfonic acid (PFHxS) declined. Most PFASs were positively associated with δ¹³C, whereas there were no associations with δ¹⁵N. Egg laying date was positively associated to perfluoroheptanesulfonic acid (PFHpS), perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), suggesting that some of the PFAS load originated from the wintering locations. Although NAOw had little impact on the exposure to organohalogenated contaminants, factors sensitive to climate change, especially diet, were associated with the exposure to OHCs in goldeneyes.

Teratogenic Effects of Organohalogen Contaminants Extracted from Whale Bacon in a Whole-Rat-Embryo Culture System

Marine foods can be contaminated with organochlorines and the risk to human beings who consume these foods needs to be evaluated. We examined the teratogenic effects of contaminants extracted from whale bacon on rat embryos using a whole-embryo culture system. Embryonic day 11.5 embryos were cultured for 48 h with organohalogens extracted from whale bacon at low (polychlorinated biphenyls (PCBs): 0.32 ppm, dichlorodiphenyltrichloroethanes (DDTs): 0.16 ppm, chlordanes (CHLs): 0.02 ppm) and high (PCBs: 2.15 ppm, DDTs: 1.99 ppm, CHLs: 0.20 ppm) doses. The levels of organohalogen compounds in cultured embryos were determined. The organochlorine contaminants extracted from whale products were readily transferred to the cultured rat embryos. The number of heartbeats, yolk sac circulation score, and embryonic body circulation score of embryos did not change during the culture period in either exposure group. Cultured embryos treated with the low-dose contaminated medium for 48 h showed abnormalities of the mandible, and craniofacial or forelimb hematomas with an incidence of 50%. All embryos treated with the high-dose medium showed craniofacial abnormalities and cleft lip, and limb abnormalities and hematomas. These results indicate that the organohalogen contaminants in whale bacon may be teratogenic in a dose-dependent manner. Further studies are necessary to determine the dose-effect relationship.

Spatio-temporal variations and ecological risks of organochlorine pesticides in surface waters of a plateau lake in China

Qilu Lake is one of the 9 plateau lakes in Yunnan, China, with a lake surface altitude of 1796.62 m above sea level. In spite of the importance and agriculturally-intensive phenomenon in Qilu Lake Basin, few studies have provided a modern evaluation of pesticide residues and potential effects to local aquatic organisms. The primary goal of this study was to determine the spatio-temporal variations of organochlorine pesticides (OCPs) in this area, and to further assess the related ecological risks. Of the 25 OCPs analyzed, 14 were detected, and the concentrations of ∑₂₅OCPs were highest in the upstream of rivers, followed by regions close to the lake shore, and the lowest concentrations were found in Qilu Lake in every season except winter. The concentrations of ∑₂₅OCPs were the highest in summer, and the lowest in winter. OCP concentrations in spring and in autumn were similar. 4,4'-DDD, γ-HCH, HCB, trans-chlordane, and cis-chlordane were 5 OCPs with relatively high risk in Qilu Lake Basin. Interestingly, higher OCP concentrations do not necessarily correspond to higher ecological risk levels. Low predicted no-effect concentration (PNEC) values and relatively high toxicity of these OCPs led to their high risk quotient (RQ) values. This work further illustrated that although OCPs have been banned for many years, they were still frequently detected in surface waters, and caused risks to aquatic animals.

Enantioselective characteristics, bioaccumulation and toxicological effects of chlordane-related compounds in laying hens

Chlordane-related compounds are ubiquitously detected in the environment and can transfer and accumulate to animals through food chain to cause adverse effects. In this study, the dynamic distribution and the enantiomeric profile of chlordane-related compounds in laying hens over time were investigated. The effect of these compounds on immune-associated cells in the intestinal tract and histopathology in some tissues were also evaluated after long-term exposure. The chlordane-related compounds preferentially accumulated in fat, followed by the intestines, ovum, and egg yolk during long-term exposure. The metabolites heptachlor epoxide and oxychlordane were mainly formed in the liver of hens by epoxidation or hydroxylation. The high accumulation ratios of trans-nonachlor and MC5 were found in ovum and egg yolk after long-term exposure, implying a greater risk to the hens' offspring. Chlordane-related compounds may cause abnormal lipometabolism and glycometabolism in liver of hens. Additionally, (-)-Cis-chlordane was dominant in all tissues of laying hens and its dominance increased over time. Conversely, (+)-isomer of metabolite oxychlordane was overwhelmingly dominant during the experiment. These findings about enantioselectivity, metabolic processes and toxicological effects are crucial in understanding the exposure risk of chlordane-related compounds.

Widespread pesticide contamination of drinking water and impact on cancer risk in Brazil

Pesticides, which are associated with endocrine dysfunction, immunological dysregulation, and cancer, are widespread sources of drinking water contamination. The state of Paraná has a population of 11 million, is the second largest grain producer in Brazil and is a leading consumer of pesticides. In this study, we analyzed the extent of drinking water contamination from 11 proven, probable, or potentially carcinogenic pesticides (alachlor, aldrin-dieldrin, atrazine, chlordane, DDT-DDD-DDE, diuron, glyphosate-AMPA, lindane-γ-HCH, mancozeb-ETU, molinate, and trifluralin) in 127 grain-producing municipalities in the state of Paraná. Extensive contamination of drinking water was found, including legacy pesticides such as aldrin-dieldrin (mean 0.047 ppb), DDT-DDD-DDE (mean: 0.07), chlordane (mean: 0.181), and lindane-HCH (mean: 2.17). Most of the municipalities were significantly above the maximum limits for each one of the currently allowed pesticides (67% for alachlor, 9.44% for atrazine, 96.85% for diuron, 100% for glyphosate-AMPA, 80.31% for mancozeb-ETU, 91.33% for molinate, and 12.6% for trifluralin). Ninety-seven percent of municipalities presented a sum of all pesticides at levels significantly above (189.84 ppb) the European Union preconized limits (<0.5 ppb). Using the mean pesticide concentration in water (ppb), the exposed population for each municipality, and the benchmark cancer risk for pesticides, we estimated the minimum number of cancer cases attributable to pesticide-contaminated drinking water during the period (total of 542 cases). More than 80% were attributed to mancozeb-ETU and diuron. Glyphosate-AMPA and diuron-attributable cases strongly correlated with the total cancer cases in the same period (R = 0.8117 and 0.8138, respectively) as well as with breast cancer cases (R = 0.7695 and 0.7551, respectively). Water contamination was significantly correlated with the sum of the estimated cancer cases for all 11 pesticides detected in each city (R = 0.58 and p < 0.0001). These findings reveal extensive contamination of drinking water in the state of Paraná and suggest that contamination may increase the risk of cancer in this region.

A comprehensive evaluation of organic micropollutants (OMPs) pollution and prioritization in equatorial lakes from mainland Tanzania, East Africa

A lack of understanding the fate of highly toxic organic micropollutants (OMPs) in the equatorial lakes of Tanzania hinders public awareness for protecting these unique aquatic ecosystems, which are precious water resources and stunning wildlife habitats. To address this knowledge gap, the occurrence of 70 anthropogenically-sourced OMPs, including phthalates (PAEs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), was investigated in the water and sediment of 18 lakes in Tanzania. Similar residue concentrations were found in both compartments, showing higher pollution of PAEs ranging from 835.0 to 13,153.1 ng/L in water and 244.6-8691.8 ng/g dw in sediment, followed by PAHs, while OCPs and PCBs were comparatively lower. According to the multi-criteria scoring method for prioritization, the final OMP priority list for the lake environment in Tanzania comprised 25 chemicals, specifically 5 PAEs (DEHP, DIBP, DBP, DCHP and DMPP), 6 PCBs (PCB153, PCB105, PCB28, PCB156, PCB157 and PCB167), 6 PAHs (BaP, BaA, BbF, Pyr, DahA and InP) and 8 OCPs (cis-chlordane, trans-chlordane, p,p'-DDD, p,p'-DDE, p,p'-DDT, endrin, methoxychlor and heptachlor epoxide), suggesting the key substances for conventional monitoring and pollution control in these equatorial lakes, with an emphasis on PAEs, especially DEHP, due to the top priority and endocrine disruptor properties.

Chlordane exposure causes developmental delay and metabolic disorders in Drosophila melanogaster

The incidence of metabolic diseases is increasing every year, and several studies have highlighted the activity of persistent organic pollutants (POPs) in causing hyperlipidemia and diabetes, and these compounds are considered to be endocrine disrupting chemicals (EDCs). Chlordane is classified as an endocrine disruptor, but the mechanism of how it functions is still unclear. This study investigates the effects of chlordane exposure on Drosophila larvae. Drosophila was cultured in diet containing 0.01 μM, 0.1 μM, 1 μM, 5 μM, and 10 μM chlordane, and the toxicity of chlordane, the growth and development of Drosophila, the homeostasis of glucose and lipid metabolism and insulin signaling pathway, lipid peroxidation-related indicators and Nrf2 signaling pathway were evaluated. We here found that exposure to high concentrations of chlordane decreased the survival rate of Drosophila and that exposure to low concentrations of chlordane caused disruption of glucose and lipid metabolism, increased insulin secretion and impairment of insulin signaling. Notably, it also led to massive ROS production and lipid peroxidation despite of the activation of Nrf2 signaling pathway, an important pathway for maintaining redox homeostasis. Collectively, chlordane causes lipid peroxidation and disrupts redox homeostasis, which may be a potential mechanism leading to impaired insulin signaling and the metabolism of glucose and lipid, ultimately affects Drosophila development.

Keystone taxa shared between earthworm gut and soil indigenous microbial communities collaboratively resist chlordane stress

Chlordane is an organochlorine pesticide that is applied extensively. Residual concentrations that remain in soils after application are highly toxic to soil organisms, particularly affecting the earthworm gut and indigenous soil microorganisms. However, response mechanisms of the earthworm gut and indigenous soil microorganism communities to chlordane exposure are not well known. In this study, earthworms (Metaphire guillelmi) were exposed to chlordane-contaminated soils to investigate their response mechanisms over a gradient of chlordane toxicity. Results from high-throughput sequencing and network analysis showed that the bacterial composition in the earthworm gut varied more significantly than that in indigenous soil microbial communities under different concentrations of chlordane stress (2.3-60.8 mg kg^-1; p < 0.05). However, keystone species of Flavobacterium, Candidatus Nitrososphaera, and Acinetobacter remained stable in both the earthworm gut and bacterial communities despite varying degrees of chlordane exposure, and their relative abundance was slightly higher in the low-concentration treatment group (T1, T2) than in the high-concentration treatment group (T3, T4). Additionally, network analysis demonstrated that the average value of the mean degree of centrality, closeness centrality, and eigenvector centrality of all keystone species screened by four methods (MetagenomeSeq, LEfSe, OPLS-DA, Random Forest) were 161.3, 0.5, and 0.63, respectively, and that these were significantly higher (p < 0.05) than values for non-keystone species (84.9, 0.4, and 0.2, respectively). Keystone species had greater network connectivity and a stronger capacity to degrade pesticides and transform carbon and nitrogen than non-keystone species. The keystone species, which were closely related to the microbial community in soil indigenous flora and earthworm intestinal flora, could resist chlordane stress and undertake pesticide degradation. These results have increased understanding of the role of the earthworm gut and indigenous soil bacteria in resisting chlordane stress and sustaining microbial equilibrium in soil.

Organochlorine pesticides contamination in agricultural soils of southern Iran

There is limited information about pesticide contamination in Iran's agricultural land, particularly in plains producing exportable fruits. The aim of this investigation was to evaluate the concentration of organochlorine pesticides (OCPs) including hexachlorocyclohexane (HCH), heptachlor, dichloro-diphenyl-trichloroethane (DDT), chlordane (CHL), and their isomers compounds in agricultural soils of southern Iran. A total of 28 topsoil samples were collected from agricultural lands of Dalaki and Shabankare areas, Bushehr, Iran. In Dalaki area, the mean value of ΣHCH (α, β, γ, δ), ΣDDT (o,p-DDE, o,p-DDD, o,p-DDT, p,p-DDE, p,p-DDD, p,p-DDT, and DDT), and ΣCHL (Trans-chlordane, Cis-chlordane, Heptachlor-exo-epoxide, and Heptachlor) was found to be 0.411 ng/g (dry weight, dw), 4.37 ng/g dw, and 2.04 ng/g dw, respectively. In Shabankare area the mean value of ΣHCH, ΣDDT, and ΣCHL was measured to be 1.38 ng/g dw, 11.99 ng/g dw, and 1.62 ng/g dw, respectively. The concentration trend of pesticides in both areas was as follows: DDT > CHL > HCH. Source identification indicated recent usage of HCH and DDT in the studied areas. Obtaining a cis-chlordane/trans-chlordane ratio greater than one in Shabankare farmlands showed that chlordane was not used recently. The health risk assessment showed that children and adults groups in both areas are exposed to negligible cancer risk. More serious attempts are necessary to reduce usage of OCPs during the agricultural process and the protection of soil and human health in the studied areas.

Annual changes in concentrations and health risks of PCDD/Fs, DL-PCBs and organochlorine pesticides in ambient air based on the Global Monitoring Plan in São Paulo

Ambient air contains a number of persistent organic pollutants (POPs), to which inhalation exposure has drawn worldwide concern. However, information regarding annual changes in the concentrations and health risks of POPs in the ambient air of São Paulo, Brazil, are limited. This study provides comprehensive information on annual changes in polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs), and 10 groups of organochlorine pesticides (OCPs) in the ambient air of São Paulo between 2010 and 2015 based on the Global Monitoring Plan. The mass concentrations of the studied POPs (PCDD/Fs, DL-PCBs, and OCPs) showed declining trends from 2010 to 2015 (from 2.65 × 10^-2 to 1.33 × 10^-2 pg m^-3, from 9.89 × 10^-2 to 3.12 × 10^-2 pg m^-3, and from 0.313 to 0.100 ng m^-3, respectively), which might be due to the decrease of non-intentional emissions. The carcinogenic risk (CR) and non-carcinogenic risk (Non-CR) of the studied POPs were 1.48 × 10^-11 to 6.08 × 10^-7 and 3.44 × 10^-8 to 3.34 × 10^-3, respectively, which are lower than the generally accepted threshold values (10^-6/10^-5 and 1 for CR and Non-CR, respectively), suggesting that the health risks posed by the studied POPs were acceptable. PCDD/Fs had the highest CR (6.08 × 10^-8-4.81 × 10^-7), whereas the 95th percentile CR of DL-PCBs and nine of the OCPs were lower than 10^-7, suggesting that among the studied POPs, PCDD/Fs in the ambient air warrant special attention. The 95th percentile CRs of dichlorodiphenyltrichloroethane (2.30 × 10^-8), dieldrin (1.30 × 10^-8), hexachlorocyclohexanes (1.05 × 10^-8), heptachlor (8.97 × 10^-9), hexachlorobenzene (6.47 × 10^-9), chlordane (5.89 × 10^-9), heptachlor epoxide (1.42 × 10^-9), aldrin (1.33 × 10^-9), and mirex (2.71 × 10^-10) in ambient air were relatively low, suggesting that their threats to human health were negligible. In general, PCDD/Fs, DL-PCBs, and OCPs in the ambient air of São Paulo did not pose serious threats to human health during 2010-2015.

Experimental Study on the Role of Sedimentation and Degradation Processes on Atmospheric Deposition of Persistent Organic Pollutants in a Subtropical Water Column

The goal of this study is to experimentally assess the role of vertical sinking and degradation processes of persistent organic pollutants (POPs) in a subtropical water column. This was done by measuring the concentrations of selected typical organochlorine pesticides, including hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), dichlorodiphenyltrichloroethanes (DDTs), trans-chlordane (TC), and cis-chlordane (CC), in atmosphere (gas phase), water (dissolved and particulate phases), and sedimentation samples simultaneously from October 2011 to April 2013 in a subtropical lake. The fugacity ratios suggested net deposition for α-HCH, γ-HCH, p,p'-DDT, p,p'-DDD, p,p'-DDE, o,p'-DDT, TC, and CC, indicating that the subtropical lake was acting as a "sink" for these chemicals. The enantiomer fractions of α-HCH, o,p'-DDT, TC, and CC in the dissolved phase samples were much more deviated from the racemic values than were those in the air samples, suggesting that these chemicals have suffered microbial degradation in the subtropical lake. In fact, 99% to 100% of atmospheric input of α-HCH and γ-HCH to the subtropical lake was estimated to be depleted via microbial degradation, while the role of hydrolysis and vertical sinking was very small. For more hydrophobic p,p'-DDT, o,p'-DDT, TC, and CC, the role of vertical sinking was 2 to 3 orders of magnitude larger than that for α-HCH and γ-HCH. Microbial degradation was also very important for removing p,p'-DDT, o,p'-DDT, TC, and CC from the water column.

Brominated flame retardants and organochlorine compounds in duplicate diet samples from a Portuguese academic community

Concentrations of persistent organic pollutants (POPs), including polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs), polychlorinated biphenyls (PCBs), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), chlordane compounds (CHLs) and dichlorodiphenyltrichloroethane and its metabolites (DDTs), were measured in duplicate diet samples from 21 volunteers at a Portuguese academic community (University of Aveiro). Overall, the levels of the target compounds were low, with detection frequencies varying widely depending on the compounds and with brominated flame retardants (BFRs) registering the lowest detection frequencies. Among PCB congeners, nondioxin-like PCBs were predominant and detected in the majority of the samples. Organochlorine pesticides were also detected in the majority of the samples, with 100% detection for DDTs and HCHs. Estimated daily intakes (EDIs) were calculated using lower and upper bound estimations, and in both cases values were far below the currently established tolerable daily intakes for PCBs and OCs and the reference doses for PBDEs and HBCDDs.

Organic and metal contamination in marine surface sediments of Guánica Bay, Puerto Rico

Land based sources of pollution have the potential to adversely impact valuable coral reef ecosystems. In Guánica Bay (Puerto Rico) sediment samples collected and analyzed in 2009 demonstrate unusually high concentrations of total chlordane, total PCBs, nickel and chromium. A variety of other contaminants (total DDT, total PAHs, As, Cu, Hg, and Zn) were also at levels which may indicate sediment toxicity. With the exception of chromium, all of these contaminants were detected in coral tissues (Porites astreoides), although it is unclear at what level these contaminants affect coral health. PCBs and chlordane are environmentally persistent and likely represent legacy pollution from historical uses in close geographic proximity to the Bay. We hypothesize that the high nickel and chromium levels are due to a combination of naturally high Ni and Cr in rock and soils in the watershed, and enhanced (human driven) erosional rates.

Altered bcl-2 family expression during non-genotoxic hepatocarcinogenesis in mice

Dysregulation of apoptosis is an important component of multistage hepatocarcinogenesis. Members of the bcl-2 protein family are important in the regulation of apoptosis and their expression is altered in several cancers. The objectives of the present study were to determine whether the expression of members of the bcl-2 protein family are altered in mouse liver during acute treatment with non-genotoxic carcinogens and throughout non-genotoxic hepatocarcinogenesis. Acute treatment of B6C3F1 mice with phenobarbital resulted in increased levels of bcl-2 and decreased levels of bax protein, while acute treatment with WY-14,643 resulted in increased bcl-2 and BAG-1 protein in the liver. Following chronic treatment, altered hepatic foci and adenomas were classified as: small-cell, heterogeneous basophilic lesions (spontaneous or tetrachlorodibenzo-p-dioxin-induced); large-cell, homogeneous basophilic lesions (WY-14,643-induced); acidophilic lesions (phenobarbital- or chlordane-induced). Of the small-cell heterogeneous basophilic lesions, 86% of foci (31/36) and 85% of adenomas (35/41) exhibited increased bcl-2 protein levels compared with surrounding normal hepatocytes, whereas only 12.5% of foci (4/36) and 12% of adenomas (5/41) exhibited increased bcl-X(L) levels. Of the large-cell, homogenous, basophilic lesions, 100% of foci (3/3) and 90% of adenomas (9/10) expressed bcl-2 protein, whereas 100% of foci (3/3) and 80% of adenomas (8/10) exhibited increased bcl-X(L) protein levels compared with surrounding normal hepatocytes. Of the acidophilic lesions, the majority of foci (28/32, 88%) and adenomas (47/50, 94%) expressed increased bcl-X(L), whereas increased bcl-2 was observed in only 12.5% of acidophilic preneoplastic foci (4/32) and 14% of acidophilic adenomas (7/50). Of the carcinomas analyzed, 81% expressed increased bcl-2 (54/67), 78% expressed increased bcl-X(L) (52/67) and 69% expressed increased levels of both bcl-2 and bcl-X(L) (46/67). Collectively, only 8% of preneoplastic foci, 3% of adenomas and 1.5% of carcinomas did not express either bcl-2 or bcl-X(L). These results suggest that regulation of apoptotic proteins is altered during non-genotoxic carcinogenesis in mouse liver. Furthermore, there were both chemical- and lesion-specific aspects of expression of apoptotic proteins during hepatocarcinogenesis in mice.

Most unwanted

Persistent organic pollutants (POPs) can travel thousands of miles, accumulate in the food chain, and persist in the environment, taking as long as centuries to degrade. POPs are known to play a role in birth defects, cancer, immune system dysfunction, and reproductive problems in wildlife. While the effects of POPs on human health are unclear, many researchers believe that long-term exposure contributes to increasing rates of birth defects, fertility problems, greater susceptibility to disease, diminished intelligence, and certain cancers. Twelve POPs have been identified by the United Nations Environment Programme as requiring urgent regulatory attention. They include the pesticides aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene, mirex, and toxaphene. Of the remaining three POPs, polychlorinated biphenyls are industrial products (used in electrical transformers), and dioxins and furans are unintentional by-products of industrial processes.

CHLORINATED INSECTICIDES: FATE IN AQUEOUS SUSPENSIONS CONTAINING MOSQUITO LARVAE

Aldrin, p,p'-DDT, dieldrin, gamma chlordane. heptachlor, heptachlor epoxide, J-hydroxychlordene, and lindane were bioassayed against larvae of Anopheles quadrimaculatus Say; the remnant amounts of insecticide and metabolites in larvae and medium were determined by electron-affinity gas chromatography. The insecticides were surprisingly nonpersistent at concentrations normally used.

Behavioral and physiological resistance to insecticides in the German cockroach (Dictyoptera: Blattellidae): an experimental reevaluation

Although physiological resistance to pesticides has been demonstrated in German cockroaches, Blattella germanica (L.), behavioral resistance has not been shown clearly. To test for the possible development of behavioral resistance, choice-test experiments were done to determine whether adult males and females from physiologically resistant and susceptible strains differed in avoidance of three emulsifiable formulations (chlorpyrifos, cypermethrin, and chlordane). Physiological resistance was verified by estimation of LC50s. Within 6 h, each cockroach chose between an untreated and a treated harborage. In the resistant strain, both sexes avoided harborages treated with cypermethrin and survived the choice tests, but more females than males avoided harborages treated with chlorpyrifos and survived. In the susceptible strain, neither sex avoided harborages treated with cypermethrin or chlorpyrifos, and most died. The physiologically resistant strain was more resistant to chlorpyrifos and cypermethrin than was the susceptible strain, with females generally having higher LC50s. However, in choice tests with chlordane in which physiological resistance levels were similar between the strains, the strains did not differ in avoidance of treated harborages or survivorship. Avoidance of treated harborages may be facilitated by high levels of physiological resistance, but we detected no behavioral resistance traits. High levels of physiological resistance permitted cockroaches to absorb an amount of pesticide that led to detection and subsequent avoidance of treated harborages. Results of our study suggest that previous research on insects has not demonstrated the evolution of stimulus-dependent behavioral resistance in field populations exposed to pesticides.

Mortality of workers employed in the manufacture of chlordane: an update

A prospective mortality study was conducted of the 800 employees who worked 3 months or more during the period January 1946 through June 1985, in the only plant in the US where the termiticide chlordane has been produced. The study covers the entire period of chlordane production to date and includes 7,347 person-years of employment at the chlordane plant and 21,585.5 person-years of follow-up since commencement of employment. All but three former employees considered to be alive at the end of the study period were either contacted directly or were identified as alive by a variety of reliable sources. Death certificates were obtained for 161 of the 181 decedents and reliable causes of death were reported for an additional 11 cases. Overall death rate was slightly less than expected but not to the level of statistical significance. Production workers with higher pesticide blood levels had lower standardized mortality ratios for cancer than nonproduction employees, and there appears to be an inverse relationship of cancer mortality to length of employment. An unexplained excess of cerebrovascular deaths was observed, offset by a lesser degree of cardiovascular deaths.

Morphological classification of mouse liver tumors based on biological characteristics

Examination of three strains of inbred mice suggested that specific morphological types of hepatic tumors are the result of genetic predisposition while other types of tumors are associated with exposure to chemical carcinogens. A simple classification system is proposed. Additional studies indicated that a putative promoting agent, such as phenobarbital, increased the incidence of those tumor types usually associated with spontaneous appearance and only in strains with a genetic predisposition to spontaneous tumorigenesis. Carcinogens induce an increase in all types of tumors.

alpha-Fetoprotein levels and hepatic alterations during chemical carcinogenesis in C57BL/6N mice

Hepatocellular carcinomas were induced by administration of acetylaminofluorene or chlordane to C57BL/6N mice. Lesions which closely resembled the neoplastic nodule described as a putative premalignant lesion in rats were evident. alpha-Fetoprotein elevations were noted only in the presence of the malignant lesions for both carcinogens. In this regard, the responses of these mice were similar to those seen during spontaneous hepatocarcinogenesis.

Susceptibility to insecticides of Lasioderma serricorne (F.) (Coleoptera anobiidae) grown on vitamin-deficient diets

Variations in the susceptibility to pyrethrum and chlordane (two contact insecticides) of Lasioderma serricorne grown on different vitamin-deficient diets were studied and reasons for such variation were proposed.

Reference Raman spectra of DDT and five structurally related pesticides and of five pesticides containing the norbornen group

The Raman spectra of DDT and 5 structurally related pesticides, TDE (DDD), Perthane, methoxychlor, dicofol, and tetradifon, and of 5 pesticides containing the norbornene group, heptachlor, chlordane, dieldrin, endrin, and endosulfan, have been recorded. These spectra are presented, along with tables giving values for the frequencies.

Averaged Brain Activity Following Saccadic Eye Movement

Since a change of stimulus is required to effect a visual response, and since saccadic eye movements change the locus of the retinal image, the hypothesis was developed that there should be a brain response following saccadic eye movement.- The hypothesis was tested experimentally by averaging the activities following successive saccadic eye movements. A response was found whose characteristics were dependent on illuminance of the stimulus.

HEMATOLOGICAL DISORDERS FOLLOWING EXPOSURE TO INSECTICIDES

The medical literature dealing with hematological disorders following exposure to insecticides (chiefly chlorinated hydrocarbons and organic phosphorus compounds) is briefly reviewed. The development of blood dyscrasias as a consequence of exposure to insecticides is considered unlikely. Reported cases are few in number and often involve persons with little contact with these materials. It is often impossible to prove (or to disprove) a cause-and-effect relation in the individual case. Pointers which may be of assistance in evaluating this relationship are described. Purpura as a result of allergic vascular changes after exposure to insecticides is also discussed.