Extent Of Environmental Contamination Research Articles

An investigation of an outbreak of Salmonella Typhimurium infections linked to cantaloupe – United States, 2022

In 2022, the Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC), and state health and regulatory partners investigated an outbreak of Salmonella enterica serovar Typhimurium infections linked to cantaloupes from southwest Indiana, resulting in 87 ill persons and 32 hospitalizations reported in 11 states. Epidemiologic and traceback evidence confirmed cantaloupe as the vehicle for these infections. Based on records collected by FDA, traceback of cantaloupe exposures for 14 ill people converged on a packing house in southwest Indiana, which supplied cantaloupe to eight of the 11 points of service where ill people purchased cantaloupe. Salmonella isolates were recovered from environmental samples collected by FDA from three growers and a packing house in southwest Indiana. Whole genome sequencing analyses of these isolates found that isolates collected from one grower matched the Salmonella Typhimurium outbreak strain, and samples collected from the other two growers and the packing house matched a 2020 Salmonella Newport outbreak strain. State and federal public health and agricultural partners identified potential conditions and practices that could have possibly resulted in the contamination of cantaloupe, including the presence of Salmonella spp. in on-farm, post-harvest, and off-farm environments. This is the third outbreak of salmonellosis confirmed to be linked to melons, sourced from southwest Indiana in the last decade. The 2012, 2020, and 2022 outbreaks of reoccurring and persisting strains of Salmonella illustrate the need for additional efforts to determine the source and extent of environmental contamination in the melon growing region of southwest Indiana and for outreach and education to help promote practices to reduce contamination of melons.

PFAS Contamination in Europe: Generating Knowledge and Mapping Known and Likely Contamination with "Expert-Reviewed" Journalism.

While the extent of environmental contamination by per- and polyfluoroalkyl substances (PFAS) has mobilized considerable efforts around the globe in recent years, publicly available data on PFAS in Europe were very limited. In an unprecedented experiment of "expert-reviewed journalism" involving 29 journalists and seven scientific advisers, a cross-border collaborative project, the "Forever Pollution Project" (FPP), drew on both scientific methods and investigative journalism techniques such as open-source intelligence (OSINT) and freedom of information (FOI) requests to map contamination across Europe, making public data that previously had existed as "unseen science". The FPP identified 22,934 known contamination sites, including 20 PFAS manufacturing facilities, and 21,426 "presumptive contamination sites", including 13,745 sites presumably contaminated with fluorinated aqueous film-forming foam (AFFF) discharge, 2911 industrial facilities, and 4752 sites related to PFAS-containing waste. Additionally, the FPP identified 231 "known PFAS users", a new category for sites with an intermediate level of evidence of PFAS use and considered likely to be contamination sources. However, the true extent of contamination in Europe remains significantly underestimated due to a lack of comprehensive geolocation, sampling, and publicly available data. This model of knowledge production and dissemination offers lessons for researchers, policymakers, and journalists about cross-field collaborations and data transparency.

An investigation of an outbreak of Salmonella Newport infections linked to melons – United States, 2020

The United States are one of the world's leading consumers of melons. In 2020, the Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC), and state health and regulatory partners investigated an outbreak of Salmonella Newport infections linked to melons from southwest Indiana, resulting in 80 ill persons and 18 hospitalizations reported across 15 states. Epidemiologic and traceback data indicated melons as the vehicle for these infections, but the collinearity of melon varieties purchased and consumed together in combination with the traceback investigation that could not rule out either melon type, did not allow investigators to delineate whether the vehicle was cantaloupe alone or, both cantaloupe and watermelons. Analysis of traceback records for cantaloupe and/or watermelon exposures for 12 ill people indicated convergence on a grower in southwest Indiana which supplied cantaloupe to the nine of eleven points of service where ill people purchased cantaloupe; similar convergence was not observed for watermelon. While Salmonella isolates were recovered from environmental samples collected by FDA throughout the growing operation, they were not highly genetically related to the outbreak strain by whole genome sequencing analyses, i.e. greater than a 10 high quality single nucleotide polymorphisms difference. This outbreak illustrates the need for additional efforts to determine the source and extent of environmental contamination in the melon growing region of southwest Indiana and emphasizes the need for outreach and education efforts to help promote farm practices to reduce pathogen contamination of melons.

Environmental detection of SARS-CoV-2 in hospital rooms in different wards of a university hospital

BackgroundTransmission of SARS-CoV-2 can occur through direct, indirect, or close contact with infected people. However, the extent of environmental contamination is unknown. The nature of the relation between patients’ symptoms and SARS-CoV-2 environmental shedding remains unclear. The aim of this study was to assess the relationship between patient covid-19 status and environmental contamination.MethodsBetween May to November 2020, environmental swabs were taken before and after room disinfection at day 7 after symptom onset in a cohort of patients clinically or biologically diagnosed positive for Covid-19. Twelve surfaces per room were collected in 13 rooms. Sample analysis was performed by RT-PCR for SARS-CoV-2 detection (SARS-CoV-2 R-Gene® (Biomérieux)). Clinical data (day of illness, symptoms, RT-PCR results) was collected from the clinical software.ResultsFive medical units were included in the study. Of 156 samples collected in 13 rooms, 5 rooms (38.5%) presented 11 SARS-CoV-2 positive samples. These positive samples were detected on 8 different surfaces. There was no association between detection of SARS-CoV-2 and patient’s age (p= 1) or patient’s symptoms (p= 0.3).ConclusionViral shedding during Covid-19 appears unrelated to the presence of symptoms, patient’s age, and low value cycle threshold of patient’s test. This study supports the evidence for the environmental shedding of SARS-CoV-2 until at least 7 days after patient’s symptoms onset. It emphasizes the need for strict compliance with contact precaution, hand hygiene, the correct use of personal protective equipment and a room disinfection for the routine care of Covid-19 patients.

Elements that make up the diet of the Cattle Egret (Bubulcus ibis) in Hidalgo, Mexico

The Cattle Egret (Bubulcus ibis) is an avian species native to Africa that has the ability to adapt to different habitats, environmental characteristics, and available food sources. We collected a total of 2,400 Cattle Egret excreta from four resting colonies during the months of January to March 2020, in the region of Tulancingo de Bravo, Hidalgo, Mexico; in order to identify the elements that make up the diet of the Cattle Egret. Samples were placed in 70% alcohol, and later analysed with a stereoscopic microscope. We identified a total of 1,677 items from 16 taxonomic entities that could be grouped in four categories. Arthropods were the main component in samples (51.8%), particularly insects of the order Orthoptera and Coleoptera. Other components in samples were plant material (26.6%), animal remains (13.9%), and plastic or other non-biological material (7.7%). We also report the first record of the Red-Spotted Toad (Anaxyrus punctatus) as a possible component in the diet of the Cattle Egret. The predominance of insects, particularly Orthoptera and Coleoptera, in the Cattle Egret diet in our study reflects the extent of agricultural activities in the region. Our study provides the first report on the diet of the Cattle Egret in an agricultural area or Hidalgo, Mexico, and corresponds with other studies, where variations in diet depend on the region, habitat, climate, and extent of environmental contamination.

SARS-CoV-2 RNA contamination on surfaces of a COVID-19 ward in a hospital of Northern Italy: what risk of transmission?

SARS-CoV-2 can reportedly exist on inanimate surfaces for a long duration, but there is limited data available from Italian COVID-19 hospital wards, especially for non-intensive care units hosting patients that do not require mechanical ventilation. Identification of the extent of environmental contamination can help in understanding possible virus transmission routes, limit hospital infections and protect healthcare workers. Thus, we investigated virus contamination on surfaces of the acute COVID-19 ward of an Italian hospital. Ward surfaces, including four points inside and six points outside the patients' rooms were sampled by swabs, seven hours after routine sanitation. To minimize the risk of underestimation of virus detection, two different sensitive molecular methods were used comparatively, and specific internal controls were added to enhance the efficiency of all the analysis steps. SARS-CoV-2 contamination was detected in only three out of all the collected samples, i.e., on two floors and one-bathroom sink, likely reflecting aerosol and saliva contamination, respectively. The overall level of contamination was low, and the floors exhibited a very low level of SARS-CoV-2 presence, evidenced by only one of the two methods used. The existence of SARS-CoV-2 on hospital surfaces may be limited, although it was reported to persist for a longer duration on surfaces under controlled laboratory conditions. Thus, effective transmission of SARS-CoV-2 by surfaces/fomites within the hospital ward may be a rare event. However, the results highlight the importance of assessing method sensitivity and including controls when investigating low-level virus contamination so as to avoid the risk of underestimation of virus presence.

Environmental contamination by SARS-CoV-2 in a designated hospital for coronavirus disease 2019

BackgroundCoronavirus disease 2019 (COVID-19) is characterized by risk of nosocomial transmission; however, the extent of environmental contamination and its potential contribution of environmental contamination to SARS-CoV-2 transmission are poorly understood. This study aimed to investigate whether environmental contamination may play a role in SARS-CoV-2 transmission.MethodsAir samples were collected by natural precipitation, and environmental surface samples were collected by conventional surface swabbing. SARS-CoV-2 RNA detection was performed using reverse transcription polymerase chain reaction.ResultsViral RNA was not detected in the 44 air samples. The positive rates in 200 environmental surface samples in medical areas (24.83%) was higher than that in living quarters (3.64%), with a significant difference (P < .05). The positive rates were 25.00% and 37.50% for the general isolation ward and intensive care unit, respectively, and no significant difference was observed between them (P = .238). The top 5 sampling sites with a positive rate in medical areas were beepers (50.00%), water machine buttons (50.00%), elevator buttons (42.86%), computer mouses (40.00%), and telephones (40.00%).ConclusionsMost of the touchable surfaces in the designated hospital for COVID-19 were heavily contaminated, suggesting that the environment is a potential medium of disease transmission. These results emphasize the need for strict environmental surface hygiene practices and enhanced hand hygiene to prevent the spread of the virus.

Who in the world is most exposed to polychlorinated biphenyls? Using models to identify highly exposed populations

Human subpopulations experience different exposure to persistent organic pollutants (POPs) because of differences in the structure of their food webs and the extent of environmental contamination. Here we quantify the time-variant exposure of different human populations around the world to one representative POP, namely the polychlorinated biphenyl (PCB) congener 153, based on a dynamic simulation of both global environmental fate (using the model BETR-Global) and human food chain bioaccumulation (using the model ACC-HUMAN). The approach identifies subpopulations whose diets include a carnivorous mammal as experiencing the world’s highest PCB-153 exposure, i.e. the very large biomagnification potential of their food web more than makes up for the remoteness of their living environment. However, for subpopulations that do not eat warm-blooded carnivores, the proximity to sources of PCBs is more important than food web structure and environmental conditions for differentiating their exposure to PCBs.

Economic and Environmental Criteria and Trade-Offs for Recovery Processes

Volatile organic component (VOC) and solvent recovery processes are two industrially important processes to limit the release of potentially harmful components into the environment. The extent of environmental contamination depends on the recovery system used for the harmful components, which indirectly contributes to the cost of process. Recently, VOC and solvent recovery systems have been optimized for multiple economic and environmental criteria such as profit before tax (PBT), net present worth (NPW), and potential environmental impact (PEI). Besides PEI, there are other aggregate environmental indicators such as IMPact Assessment of Chemical Toxics 2002+ (IMPACT), green degree (GD), and inherent environmental toxicity hazard (IETH). In this study, we consider the optimization of VOC and solvent recovery processes for PBT, NPW, PEI, IETH, GD, and IMPACT as well as their individual components as simultaneous objectives, to explore the trade-offs among them. The two processes are simulated using a commercial simulator, and then optimized using the elitist nondominated sorting genetic algorithm in a spreadsheet along with an interface to the simulator. From the results, it can be concluded that optimization of aggregated IMPACT indicator is similar to optimization of its individual end-point damage categories. In the case of other environmental indicators, optimization for individual categories may be necessary to explore trade-offs among them.

POPs in breast milk: women's breast cancer risk

PurposePersistent organic pollutants (POPs) have become widespread pollutants and now represent a global contamination problem. The presence of POPs in human serum and adipose tissues have raised public concern regarding their possible role as important etiologic agents in the development of human cancer. This paper aims to investigate the extent of environmental contamination with pesticides and their association with women's risk of breast cancer.Design/methodology/approachVarious stages of carcinogenesis (initiation, promotion, progression), causes and risk factors associated with breast cancer are delineated. A possible mechanism of xenoestrogen and its association with breast cancer incidences in women is included. Recommendations for reducing breast cancer risks in women are also given.FindingsEpidemiological studies have revealed that persistent pesticide residues in human serum and adipose tissues may increase women's risk of breast cancer. Women are at a greater risk than men of pesticide exposure. The association between organochlorine compounds and breast cancer is a controversial issue and there exists an exigency to execute extensive worldwide epidemiological studies under identical conditions of detected compounds, blood sampling procedures and analytical techniques to achieve conclusive results.Practical implicationsWomen's risk of breast cancer associated with pesticide residues could be subjugated by avoiding prolonged occupational exposures, adopting precautionary measures, and changing lifestyle and dietary habits.Originality/valueThe paper shows that restrictions on the application of POPs and the avoidance of prolonged occupational exposure would result in lower concentrations of POP in blood, serum and adipose tissue, thus minimising women's risk of breast cancer.

Bioaccumulation of Elements in Bryophytes from Serra da Estrela, Portugal and Veluwezoom, the Netherlands (9 pp)

Pollution by heavy metals over large areas and long periods of time may cause chronic damage to living organisms and must be carefully controlled. One way to determine the extent of environmental contamination is by measuring the levels of contaminants in plants. The use of mosses as biomonitors is a convenient method to determine levels of (atmospheric) deposition, as terrestrial mosses obtain most of their supply of mineral elements from precipitation and dry deposition of airborne particles. Mosses have therefore received increasing attention as a suitable tool for monitoring regional patterns of elemental deposition from the atmosphere in large-scale studies in various countries, in areas close to industrial installations as well as in areas not expected to be contaminated. Although this technique is widely known, ecological studies of this type have rarely been done in Portugal. The aim of this paper is to evaluate and compare the spatial distribution of heavy metals in Hypnum cupressiforme, Pleurozium schreberi, Dicranum scoparium and Polytrichum piliferum collected from the Serra da Estrela natural park in Portugal and in the Veluwezoom natural park in the Netherlands. The selected species are the most widely used bryophytes for biomonitoring in the boreal region. The popularity of these species for this purpose is due to their wide ecological amplitude and distribution. At 54 sampling sites in both nature parks, samples of Hypnum cupressiforme, Pleurozium schreberi, Dicranum scoparium and Polytrichum piliferum were collected. Plant digests were analysed for Al, Ba, Ca, Cr, Fe, K, Mg, Mn, Ni, Sr, V, Zn, Pb, Cu, Cd, N and P. Differentiations between sampling sites in terms of concentrations of elements in mosses were evaluated by ANOVA and the least significant difference was calculated. The normality of the analysed features was checked with the chi square test. After standardization, the matrix of 54 samples and 10 heavy metals was subjected to numerical classification to detect groups of samples with similar patterns of metal concentrations. The clustering algorithm was prepared with Ward's method, and the City Block Manhattan method was used for the similarity measure. Metals and samples were also subjected to ordination to reveal possible gradients of heavy metal levels, using PCA. Correlations were calculated between concentrations of metals and factors 1 and 2, allowing the dependence between the concentration of metals and factors (factor loading) to be estimated. All species examined in both areas contained elevated levels of Mn and Pb. For each particular species, concentrations of N, P and Pb were significantly higher at Serra da Estrela, while concentrations of Cu were significantly higher at the Veluwezoom. Mosses from Portugal and the Netherlands differed significantly mainly in the concentrations of Al, Ba, Cr, Fe, Mn, Ni, Pb and V. This differentiation did not exceed that within the mosses from Portugal. Mosses from Portugal and the Netherlands differ significantly mainly in the concentrations of Al, Ba, Cr, Fe, Mn, Ni, Pb and V. This differentiation does not exceed the differentiation within the mosses from Portugal. Further research is required into the origin and deposition of the polluting elements in other environmental compartments.

Chemical and ecotoxicological assessment of polycyclic aromatic hydrocarbon—contaminated sediments of the Niger Delta, Southern Nigeria

The extent of environmental contamination and sources of polycyclic aromatic hydrocarbons (PAHs) compounds to sediments of the Niger Delta, Nigeria were assessed using combined chemical analysis and toxicity bioassay techniques. Concentrations of two- to six-ring PAHs of molecular mass 128–278 and toxicity to Vibrio fischeri and Lemna minor are considered in this investigation. Levels of the sum of the 16 USEPA priority pollutant PAHs varied from 20.7 to 72.1 ng/g dry weight. Sediment PAH levels were highest in samples collected from Delta Steel located at the outskirts of Warri, and Quality control centre, Ughelli West; with total PAH concentrations of 72.1 and 67.5 ng/g dry weight, respectively. The overall levels of PAHs in this study are low compared to other regions and reveal moderate PAHs pollution in the sediments of the Niger Delta. Two- and three-ring aromatic hydrocarbons predominated in almost all the sediments, which indicate a petrogenic origin. The sediment total PAH (PAH tot) concentration, normalized to organic carbon content (OC), ranged from 120.2 to 1.99 ng PAH tot/mg OC; and showed distinctively that the sedimentary organic matter of the sample from Delta Steel is highly contaminated with PAHs, and had a value of 120.2 ng PAH tot/mg OC. The toxicity bioassays indicated that the sample collected from Warri Refinery Area (SDWRR) was the most toxic to V. fischeri, with an EC 50 value of 0.45 mg sediment equiv./mL test medium; and samples from Ogunu (SDOGN) and Warri Refinery area (SDWRR) showed high toxicity to L. minor, with percent inhibitions of 42.6% and 33.67%, respectively, after 7 days of exposure. The total PAH concentrations showed no correlation with toxicity bioassays, and thereby implied that chemical analysis of PAHs cannot be an indicator of sediment toxicity.

Aerosols produced by high-speed cutters in cervical spine surgery: extent of environmental contamination.

High-speed cutters are used in the surgery of the cervical spine. Such high-speed devices can produce an aerosol cloud. As a patient can be a reservoir for pathogens, with aerosol-borne paths of transmission, such an aerosol has to be seen as a potential risk of infection for health care professionals present during the surgery and for patients if micro-organisms are transferred through the medical personnel. The study was performed in order to measure the extension of environmental and body contamination through contaminated aerosols produced by a high-speed cutter. Three laminectomies (C4-C6) were performed on an intact human cadaver with a high-speed 0.6-mm ball cutter. A complete surgical setup was arranged, including surgical draping and a barrier drape to the anesthesiologist's workplace. Body and environmental contamination was detected by the use of surveillance cultures. The irrigation solution was artificially contaminated with Staphylococcus aureus ATCC 12600. Following the surgery, staphylococci were detected in the operating room at an extension of 5x7 m. Everybody showed extensive face and body contamination with Staphylococcus aureus. The study showed that the use of high-speed cutters in surgery of the cervical spine produces an aerosol cloud that is spread over the whole surgical room and contaminates the theater and all personnel present. Such aerosols can be contaminated with pathogens if the patient was infected or colonized. Therefore, sufficient protective measures have to be recommended for everyone present in the operating room during such surgeries. In addition, efficient disinfection of the room and all mobile equipment is necessary after each surgery involving high-speed cutting devices.

Polycyclic Aromatic Hydrocarbons (PAHs) in Sediments of the White Sea, Russia

The extent of environmental contamination and sources of polycyclic aromatic hydrocarbon (PAH) compounds to sediments of the White Sea are evaluated and compared with previously published results for adjacent Arctic Sea areas. Concentrations of two- to six-ring PAHs of molecular mass 128–278 including perylene and sediment characteristics are considered in this investigation. Mean ΣPAH concentration was 61±34 ng/g dw ( n=11) for all samples and 87±43 ng/g dw ( n=6) for pelite-rich samples (>83% pelite). These concentrations are 2–3 times lower than were previously reported for the SE Barents Sea. Concentrations of ΣPAH and ΣCPAH in the central White Sea have increased by a factor of 2-5 over pre-industrial background levels based on 210Pb age-dating of one sediment core. Using principal component analysis (PCA), two common factors explained 87.5% of the total variance for the White Sea data. Factor 1 is associated with high-temperature combustion processes and is related to emissions from a local aluminium smelter. Factor 2 is associated mainly with the introduction of petrogenic PAH compounds and perylene into Dvina Bay via the Severnaya Dvina River. A comparison of the White Sea and SE Barents Sea data indicates that similarities exist in the composition of parent PAH compounds. However, based on a comparative analysis of parent PAH ratios and relative contents of alkyl-substituted homologues, a common atmospheric source of anthropogenic pollutants can be ruled out. Further investigations are needed to determine whether sedimentary PAH signatures in areas of the Barents Sea that are in closer proximity to the White Sea are related to emissions from the aluminium smelter.

Analysis of urinary S-phenylmercapturic acid and trans, trans-muconic acid as exposure biomarkers of benzene in petrochemical and industrial areas of Korea.

Recently, S-phenylmercapturic acid (S-PMA) and trans,trans-muconic acid (t,t-MA) in urine have been proposed as reliable biomarkers for monitoring occupational exposure to benzene. The aim of this study was to test the applicability of S-PMA and t,t-MA as exposure biomarkers and to monitor the occupational exposure level and the extent of environmental contamination from benzene in Korea. The urinary excretion of S-PMA and t,t-MA in rats after the intraperitoneal administration of benzene (0.88-800 mg/kg body weight, 7 days) was examined. These biomarkers were also validated in human urine samples collected from elementary schoolchildren in several industrial areas including chemical manufacturing plants, oil refineries, and natural gas-producing installations in Korea. Urine was collected from elementary schoolchildren in a mountain village with no known occupational exposure to benzene and air pollution as the reference group. In rats, there was a significant relationship between the benzene concentration and the excretion of the urinary S-PMA and t,t-MA as a function of concentration, and the excretion of benzene metabolites peaked on the first day after intraperitoneal administration. In human urine, higher levels of S-PMA and t,t-MA were detected more frequently in petrochemical industrial areas than in areas with no known occupational exposure to benzene. These results show that the quantitative determination of S-PMA and t,t-MA in urine can be used as a reliable exposure biomarker for benzene, and they also suggest that extensive attention to benzene exposure is needed for maintaining the health of the population in Korea.

Soil interactions with petroleum hydrocarbons: Abiotic processes

Soil and groundwater resources in many parts of the world are threatened by spilled petroleum products. These products generally consist of complex mixtures of volatile hydrocarbons with different vapor pressures. The volatilization of light hydrocarbon fractions leads to changes in viscosity and density of the residual nonaqueous liquid. This may cause changes in the transport characteristics of the porous matrix and of the residual liquid. Differing volatilization and solubility characteristics result in differential distribution of released hydrocarbon components in air, soil, and water environmental compartments. Soil frequently serves as the site of petroleum spills and hence the capacity of the soil to filter, retain, or release hydrocarbons is fundamental in determining the type and extent of environmental contamination. Retention, volatilization, and transport of hydrocarbons as affected by soil physical and chemical properties is reviewed.

A conceptual cost estimate for remediation activities at a multisite federal facility

AbstractThe Sandia National Laboratories Environmental Restoration Project is in the process of determining the nature and extent of environmental contamination at numerous potential release sites. Sites found to be contaminated above certain action levels must be remediated. Sandia is responsible for preparing preliminary cost estimates for remediation activities in order to meet Department of Energy planning requirements for future funding. Sandia used the ENVEST parametric cost‐estimating model to prepare conceptual cost estimates for remediation prior to having definitive knowledge of the nature and extent of contamination. This article describes the estimating approach and the results achieved at Sandia.

Uptake and Excretion of Chemicals by Aquatic Fauna

Factors influencing the movement of chemicals across biological membranes are: solubility in lipids and in water, chemical stability, ionization, and molecular weight of the chemical. On the part of aquatic fauna, the transport of chemicals is affected by metabolic activity and by the physiological state of the animals. Additional factors include water temperature, hardness or salinity, and presence of other chemicals. The effects of these factors will be discussed and illustrated by examples. The uptake of highly lipid-soluble compounds by fish appears to be determined by their solubility in water, and compounds with extremely low solubility in water are not taken up in spite of their high solubility in lipids. Examples are hexabromo-benzene, highly brominated biphenyls, C24 chlorinated paraffins, and some flame retardants of the Dechlorane series. In addition to solubility in water, there may be a high molecular weight threshold, beyond which compounds are not taken up, and factors based on the chemical structure of the compounds may play a role as well. For example, Dechlorane 604, a tetrabromophenyl norbornene, is accumulated by fish to a much lesser degree than a tribromophenyl norbornene, present as a minor impurity in Dechlorane 604. Chemical and biochemical stability of compounds are additional factors determining the extent of environmental contamination. Examples are the widespread contamination of aquatic biota by two nonachlors, present originally as relatively minor components in technical chlordane, and the contamination by some components of toxaphene. The use of a one compartment model in studies of accumulation and excretion of chemicals by aquatic fauna, and its extension to the determination of lethality curves, will be mentioned.

Tissue Burdens of Toxic Pollutants

An article in this issue ofThe Journal(p 2112) presents new information on the tissue burden of polybrominated biphenyls (PBBs) of Michigan residents and relates this to the tissue burdens of polychlorinated biphenyls (PCBs) and 2,2′-<i>bis</i>-(<i>p</i>-chlorophenyl)-1,1-dichloroethylene (DDE), a metabolite of dichlorodiphenyl trichloroethane (DDT). The finding that 70% of a random sample of the population have detectable levels of PBB in serum and 9796 have PBB in adipose tissue is a dramatic one. It is another reminder of our vulnerability to the increasing number and volume of potentially toxic chemicals used in manufacturing, agriculture, pest control, and food processing. The concomitant tissue burdens of PCB, PBB, and DDE may have greater biologic significance than each considered separately. The nature and extent of environmental contamination by the three chemicals vary greatly. The oldest is PCB, which was introduced in the United States in 1930. Its use in manufacturing

Reactor-released radionuclides in Susquehanna River sediments

Three Mile Island (TMI) and Peach Bottom (PB) reactors have introduced 137Cs, 134Cs, 60Co, 58Co and several other anthropogenic radionuclides into the lower Susquehanna River. Here we present the release history for these nuclides (Table 1) and radionuclide concentration data (Table 2) for sediment samples collected in the river and upper portions of the Chesapeake Bay (Fig. 1) within a few months after the 28 March 1979 loss-of-coolant-water problem at TMI. Although we found no evidence for nuclides characteristic of a ruptured fuel element, we did find nuclides characteristic of routine operations. Despite the TMI incident, more than 95% of the total 134Cs input to the Susquehanna has been a result of controlled low-level releases from the PB site. 134Cs activity released into the river is effectively trapped by sediments with the major zones of reactor-nuclide accumulation behind Conowingo Dam and in the upper portions of Chesapeake Bay. The reported distributions document the fate of reactor-released radionuclides and their extent of environmental contamination in the Susquehanna–Upper Chesapeake Bay System.