Local Environmental Contamination Research Articles

Relative risks of childhood developmental vulnerabilities in three Australian communities with exposure to per- and polyfluoroalkyl substances: data linkage study.

Aqueous film forming foams (AFFF) containing per- and polyfluoroalkyl substances (PFAS) caused local environmental contamination in three Australian residential areas: Katherine in the Northern Territory (NT), Oakey in Queensland (Qld) and Williamtown in New South Wales (NSW). We examined whether children who lived in these areas had higher risks of developmental vulnerabilities than children who lived in comparison areas without known contamination. All children identified in the Medicare Enrolment File-a consumer directory for Australia's universal healthcare insurance scheme-who ever lived in exposure areas, and a sample of children who ever lived in selected comparison areas, were linked to the Australian Early Development Census (AEDC). The AEDC data were available from four cycles: 2009, 2012, 2015 and 2018. For each exposure area, we estimated relative risks (RRs) of developmental vulnerability on each of five AEDC domains and a summary measure, adjusting for sociodemographic characteristics and other potential confounders. We included 2,429 children from the NT, 2,592 from Qld and 510 from NSW. We observed lower risk of developmental vulnerability in the Communication skills and general knowledge domain in Katherine (RR = 0.74, 95% confidence interval (CI) 0.57 to 0.97), and higher risks of developmental vulnerability in the same domain (RR = 1.49, 95% CI 1.18 to 1.87) and in the Physical health and wellbeing domain in Oakey (RR = 1.31, 95% CI 1.06 to 1.61). Risks of developmental vulnerabilities on other domains were not different from those in the relevant comparison areas or were uncertain due to small numbers of events. There was inadequate evidence for increased risks of developmental vulnerabilities in children who ever lived in three PFAS-affected areas in Australia.

Relative rates of cancers and deaths in Australian communities with PFAS environmental contamination associated with firefighting foams: A cohort study using linked data

BackgroundPer- and polyfluoroalkyl substances (PFAS) are environmental contaminants that are potentially harmful to health. We examined if rates of selected cancers and causes of deaths were elevated in three Australian communities with local environmental contamination caused by firefighting foams containing PFAS. The affected Australian communities were Katherine in Northern Territory, Oakey in Queensland and Williamtown in New South Wales. MethodsAll residents identified in the Medicare Enrolment File (1983–2019)—a consumer directory for Australia’s universal healthcare—who ever lived in an exposure area (Katherine, Oakey and Williamtown), and a sample of those who ever lived in selected comparison areas, were linked to the Australian Cancer Database (1982–2017) and National Death Index (1980–2019). We estimated standardised incidence ratios (SIRs) for 23 cancer outcomes, four causes of death and three control outcomes, adjusting for sex, age and calendar time of diagnosis. FindingsWe observed higher rates of prostate cancer (SIR=1·76, 95 % confidence interval (CI) 1·36–2·24) in Katherine; laryngeal cancer (SIR=2·71, 95 % CI 1·30–4·98), kidney cancer (SIR=1·82, 95 % CI 1·04–2·96) and coronary heart disease (CHD) mortality (SIR=1·81, 95 % CI 1·46–2·33) in Oakey; and lung cancer (SIR=1·83, 95 % CI 1·39–2·38) and CHD mortality (SIR=1·22, 95 % CI 1·01–1·47) in Williamtown. We also saw elevated SIRs for control outcomes. SIRs for all other outcomes and overall cancer were similar across exposure and comparison areas. InterpretationThere was limited evidence to support an association between living in a PFAS exposure area and risks of cancers or cause-specific deaths.

Genetic characterization of Toxoplasma gondii in meat-producing animals in Iran

BackgroundThe consumption of uncooked or undercooked food from infected intermediate hosts can result in Toxoplasma gondii infection in humans. However, few studies have investigated the genetic diversity of this protozoan parasite in Iran. The aim of the present study was to genetically characterize isolates of T. gondii from intermediate host animals in Mazandaran Province, Iran.MethodsBlood and heart tissue samples were collected from 204 ruminants, and brain tissue was collected from 335 birds. The prevalence of T. gondii infection in these samples was determined serologically using the modified agglutination test and by conventional PCR assays. Those PCR samples positive for T. gondii DNA and 13 DNA samples extracted from aborted fetuses in a previous study were genotyped with 12 genetic markers using the multilocus-nested PCR-restriction fragment length polymorphism (Mn-PCR–RFLP) technique.ResultsAntibodies for parasites were found in 35.7% of the ruminant (39.1% of sheep and 26.4% of goats) samples and in 51.3% of the bird (100% of geese, 52.3% of free-range chickens and 46% of ducks) samples. Molecular detection by PCR of the repetitive 529-bp DNA fragment revealed contamination of 13.2% of ruminant (14.6% of sheep and 9.4% of goats) samples and of 9.6% of bird (11.1% of chickens, 5.7% of ducks and 0% of geese samples). The results from 30 DNA samples revealed five ToxoDB (genome database for the genus Toxoplasma) PCR–RFLP genotypes, including #1 (Type II), #2 (Type III), #10 (Type I), #27 and #48, with genotype #1 the most predominant.ConclusionsAs evidenced by the results of this study, ruminants and birds are infected with T. gondii in the region, suggesting that they are likely to be involved in the transmission of T. gondii to humans through meat consumption. The identification of different genotypes may suggest a higher genetic diversity of this parasite in Mazandaran, reflecting local environmental contamination. These results have important public health implications for the prevention and control strategies of infection.Graphical

Mercury concentrations in coastal Elasmobranchs (Hypanus guttatus and Rhizoprionodon porosus) and human exposure in Pernambuco, Northeastern Brazil.

Elasmobranchs are long-lived predatory fish that show high Hg concentrations generally reflecting environmental levels, notwithstanding they are widely consumed in Brazil increasing Hg exposure to humans. This study reports on Hg concentrations in largely consumed sharks (Rhizoprionodon porosus) and rays (Hypanus guttatus) from the Pernambuco coast, NE Brazil and the risk associated with their consumption. Muscle tissue concentrations of Hg in H. guttatus and R. porosus varied from 40 to 1,020 ng.g-1 w.w. (median = 125; mean = 124 ± 48 ng.g-1 w.w.) in sharks and from 129 to 2,130 ng.g-1 w.w. (median = 976; mean = 919 ± 139 ng.g-1 w.w.) in rays. Concentrations of Hg positively correlated with size in sharks, but not in rays. Concentrations reflect the local environmental contamination of a large urban center and industrial park concentrated in a short extension of mangrove-dominated coastline (50 km) and are higher compared to other Brazilian sites where Hg concentrations in these species have been reported. Sharks had a risk coefficient (HQ) range of 0.04 to 1.1, not surpassing the reference level of exposure. On the other hand, rays' HQ ranged from 0.14 to 2.3, and exceeds the reference level of exposure and suggests adverse effects to consumers.

Spatial variability and influence of biological parameters on microplastic ingestion by Boops boops (L.) along the Italian coasts (Western Mediterranean Sea)

Recently, many studies focus on the ingestion of microplastics by marine biota. Fish exploit almost every kind of marine environment, occupy many ecological niches and are an important food source for human populations worldwide. For these reasons, they seem to represent very appropriate biological indicators of microplastic ingestion. UNEP/MAP SPA/RAC (2018) identified the bogue, Boops boops (Linnaeus, 1758), as a possible target species for monitoring microplastic ingestion in fish populations. This study provides the first report of microplastic ingestion by B. boops from the Tyrrhenian and the Ligurian Seas (Western Mediterranean Sea). Generalized Linear Mixed Models were used to analyse the relationship among biological parameters and environmental factors. A total of 379 bogues were collected in three Italian regions, subject to different anthropogenic pressures (river input, human population, shipping lanes and distance from the coast). Microplastics were detected in the gastrointestinal tract of most individuals (56%) with a mean of 1.8 (±0.2) microplastics per individual. Our study further confirms that this species is able to highlight differences in the ingestion of microplastics according to local anthropization, resulting Latium region to be the most polluted. Fish with lower physical condition are more likely to ingest microplastics, suggesting a relationship with the level of local environmental contamination. Finally, the ingestion of microplastics might be influenced by behavioural differences between sexes. According to our results, males ingest significantly more microplastics than females (p < 0.05). Our research confirms that an extensive knowledge on the biology of a bioindicator species is a priority for developing a valid monitoring strategy, such as the Marine Strategy Framework Directive for European waters.

Cumulative exposure to organic pollutants of French children assessed by hair analysis

Children represent one of the most vulnerable parts of the population regarding the effects of pollutants exposure on health. In this study, hair samples were collected between October 2013 and August 2015 from 142 French children originating from different geographical areas (urban and rural) and analysed with a GC/MS-MS method, allowing for the detection of 55 biomarkers for pesticides and metabolites both persistent and non-persistent from different families, including: organochlorines, organophosphates, pyrethroids, azoles, dinitroanilines, oxadiazines, phenylpyrazoles and carboxamidas; 4 polychlorobiphenyls (PCBs) and 5 polybromodiphenylethers (PBDEs). The number of compounds detected in each sample ranged from 9 up to 37 (21 on average), which clearly highlighted the cumulative exposure of the children. The results also showed a wide range of concentration of the pollutants in hair (often more than 100 times higher in the most exposed child compared to the less exposed), suggesting significant disparities in the exposure level, even in children living in the same area. In addition to the detection of currently used chemicals, the presence of persistent organic pollutants (POPs) in children also suggests that the French population is still exposed to POPs nowadays. PCP, DEP, PNP, 3Me4NP, trans-Cl2CA, 3PBA, fipronil and fipronil sulfone, presented statistically significant higher concentration in the hair of boys compared to girls. PCP, PNP and 3Me4NP presented statistically significant higher concentration in younger children. Finally, this study also suggests that local environmental contamination would not be the main source of exposure, and that individual specificities (habits, diet…) would be the main contributors to the exposure to the pollutants analysed here. The present study strongly supports the relevance of hair for the biomonitoring of exposure and provides the first values of organic pollutant concentration in the hair of French children.

Epidemiology of Buruli Ulcer Infections, Victoria, Australia, 2011-2016.

Buruli ulcer (BU) is a destructive soft-tissue infection caused by the environmental pathogen Mycobacterium ulcerans. In response to rising BU notifications in the state of Victoria, Australia, we reviewed all cases that occurred during 2011–2016 to precisely map the time and likely place of M. ulcerans acquisition. We found that 600 cases of BU had been notified; just over half were in residents and the remainder in visitors to defined BU-endemic areas. During the study period, notifications increased almost 3-fold, from 66 in 2013 to 182 in 2016. We identified 4 BU-endemic areas: Bellarine Peninsula, Mornington Peninsula, Frankston region, and the southeastern Bayside suburbs of Melbourne. We observed a decline in cases on the Bellarine Peninsula but a progressive increase elsewhere. Acquisitions peaked in late summer. The appearance of new BU-endemic areas and the decline in established areas probably correlate with changes in the level of local environmental contamination with M. ulcerans.

Polybrominated Diphenyl Ether (PBDE) Accumulation in Farmed Salmon Evaluated Using a Dynamic Sea-Cage Production Model.

Food is an important source of human exposure to hazardous chemicals. Chemical concentration in a food item depends on local environmental contamination, production conditions, and, for animal-derived foods, on feed. Here, we investigate these influences on the accumulation of individual polybrominated diphenyl ether congeners (PBDEs) in farmed Atlantic salmon ( Salmo salar). We develop a dynamic model over a full sea-cage salmon production cycle. To assess the influence of metabolic debromination on PBDE congener profiles, in vitro measurements of debromination rates in fish liver cells were extrapolated to whole-body metabolic rate constants. Model results indicate that the dominant factors governing PBDE concentration in Atlantic salmon fillet are uptake via contaminated feed and fish growth, whereas the influence of metabolic debromination is minor. PBDE concentrations in fish feed depend on several factors, including the geographic origin of fish feed ingredients, which are produced and traded globally. Human exposure to PBDE via salmon consumption is less influenced by environmental concentrations at the location of salmon farming than by environmental concentrations influencing feed components. This dependence of PBDE concentrations in salmon on the origin and composition of feed reveals the complexity of predicting contaminant concentrations in globally traded food.

Exposure to polybrominated diphenyl ethers and perfluoroalkyl substances in a remote population of Alaska Natives

BackgroundMany Alaska Native communities rely on a traditional marine diet that contains persistent organic pollutants (POPs). The indoor environment is also a source of POPs. Polybrominated diphenyl ethers (PBDEs) and perfluoroalkyl substances (PFASs) are present both in the traditional diet and the home indoor environment. ObjectivesWe assessed exposure to PBDEs and PFASs among residents of two remote Alaska Native villages on St. Lawrence Island. Ninespine stickleback (Pungitious pungitious) and Alaska blackfish (Dallia pectoralis) were used to detect accumulation of these compounds in the local environment. MethodsConcentrations of PBDEs and PFASs were measured in dust collected from 49 households on St. Lawrence Island, as well as in blood serum from 85 island residents. Resident ninespine stickleback and Alaska blackfish were used as sentinels to detect accumulation of PBDEs and PFASs in the food web. ResultsSerum concentrations of perfluorononanoic acid (PFNA) and perfluoroundecanoic acid (PFUnDA) were elevated, despite low concentrations of PFASs in dust samples. Concentrations of PBDEs in dust and serum were similar to those from the contiguous United States. Statistical associations between dust and serum concentrations are apparent for a small number of PBDEs, suggesting a possible route of exposure. Predominant compounds were similar between human sera and stickleback; however, blackfish accumulated PFASs not found in either stickleback or human sera. ConclusionHousehold dust contributes to PBDE exposure, but not PFAS exposure. Elevated concentrations of long chain PFASs in serum are likely due to exposure from traditional foods. The presence of both PFASs and PBDEs in sentinel fish species suggests atmospheric deposition and bioaccumulation, as well as local environmental contamination.

Development, comparison and application of sorbent-assisted accelerated solvent extraction, microwave-assisted extraction and ultrasonic-assisted extraction for the determination of polybrominated diphenyl ethers in sediments

Fast and selective analytical methods were developed based on sorbent-assisted mechanism and microwave-assisted extraction (SA-MAE), accelerate solvent extraction (SA-ASE) and ultrasonic-assisted extraction (SA-UAE) for the determination of polybrominated diphenyl ethers (PBDEs) in sediments. The experimental parameters, such as extraction conditions and sorbent amounts, were optimized according to Taguchi Orthogonal Arrays. The accuracy of developed SA-methods was a satisfactory ranging from 71% to 118%. The inter/intra-day RSDs were <10% indicating a good method precision. The limits of quantification (LOQ) for target BDEs were ≤1.0ng/g dry weight (dw) with an exception of BDE 209 which was 10.0ng/g dw. The proposed methods were validated by the analysis of PBDEs in standard reference materials (SRM 1944) and the method performances were compared with each other. The results approved the feasibility of SA-methods for PBDEs analysis in sediments. Meanwhile, the optimization processes indicated the mixed sorbents mainly worked on matrix effects elimination. The compositions of sorbents deserved careful optimization because different characteristics of the matrix and extraction intensity may produce various matrix effects. In addition, the developed SA-ASE method was successfully applied on real environmental samples collected from a typical polluted area. The data and calculation suggested local environmental contamination pattern and potential pollution source.

Evidence for genetic diversity of Toxoplasma gondii in selected intermediate hosts in Serbia

To contribute to the insight into the worldwide population structure of Toxoplasma gondii, we genetically characterized a total of eight strains isolated from intermediate hosts including humans, sheep and pigeons in Serbia. Although parasite DNA was detected in 28.2% (60/213) of the human samples from 162 patients serologically suspected of active toxoplasmosis, as well as in 5/7 seropositive pigeons and in 2/12 seropositive sheep examined, multilocus PCR-RFLP genotyping, using SAG1, 5'SAG2, 3'SAG2, GRA6, 5'GRA7 and 3'GRA7 as markers, was successful in only four human isolates (of which one was isolated from both the bronchoalveolar lavage fluid and blood samples of a single patient), one sheep and three pigeons. Of the eight isolates, five were type II (62.5%), one was type III, one was atypical, and one had a type I allele at GRA6 as the single locus genotyped. Although type II, as elsewhere in Europe, predominated, these results may suggest a higher genetic diversity of T. gondii in Serbia, reflecting local environmental contamination and also the geographical position of the country in South-East Europe.

Assessment of the genotoxic impact of pesticides on farming communities in the countryside of Santa Catarina State, Brazil.

The aim of this study was to assess the use of pesticides on farms located in the Lambedor River watershed in Guatambu, State of Santa Catarina, as well as to determine, by micronucleus testing, the risk of genotoxic impact. Samples from locally collected Cyprinus carpio, Hypostomus punctatus, Rhamdia quelen and Oreochromis niloticus gave evidence of a mean increase in micronuclei frequency from 6.21 to 13.78 in 1,000 erythrocytes, a clear indication of the genotoxic potenciality of pesticide residues in regional dams, and their significant contribution to local environmental contamination.

COMPARISON OF THREE TREE‐RING SAMPLING METHODS FOR TRACE METAL ANALYSIS

Tree‐ring growth analysis can provide information about tree development for forest inventory, environmental assessment, atmospheric and soil monitoring. Metal concentrations in wood increment correlate with metal concentrations in the environment and can indicate local environmental contamination sources. One of the most important steps of tree analysis is tree‐ring sampling. To determine trace metal (TM) concentrations precisely in a separate ring, the possibility of random errors during wood sampling must be eliminated. This guides to choose a precise tree‐ring sampling method. This paper examines three tree‐ring sampling tools (common chisels, arched chisels and a plane) and compares TM concentrations (Mn, Zn, Ni, Cr, Cu, Pb,) in wood samples collected by each of the methods employed. Average values of metals in tree rings sampled with common chisels, arched chisels and plane were 17.0±0.16 mg/kg for Mn, 4.7±0.21 mg/kg for Zn, 0.49±0.20 mg/kg for Pb, 0.29±0.02 mg/kg for Cu, 0.21±0.02 mg/kg for Ni and 0.12±0.01 mg/kg for Cr and were in the range of typical concentrations in investigated region as well as for Pinus sylvestris L. The average values were calculated for the three methods used. Statistical analysis (Anderson–Darlin test, Kruskal–Wallis tests, median and percentage coefficient of variation) revealed no significant differences between metal concentrations determined in tree rings which were sampled using common chisels, arched chisels and planing. Various techniques – common chisels, arched chisels and plane – can be successfully used for tree‐ring sampling, however, an increment borer provides possibility of sampling a non‐felled tree. Santrauka Medienos metiniu rieviu analize suteikia informacijos apie medžio vystymasi, svarbios inventorizuojant miškus, vertinant aplinkos poveiki, atliekant aplinkos oro ir dirvožemio monitoringa. Sunkiuju metalu koncentracijos metinese rievese susijusios su metalu koncentracijomis aplinkoje ir gali nusakyti vietines aplinkos taršos lygi. Vienas iš svarbiu medienos analizes etapu yra metiniu rieviu eminiu emimas. Siekiant tiksliai nustatyti sunkiuju metalu koncentracija metineje rieveje svarbu išvengti atsitiktiniu paklaidu. Šiame darbe aptariami trys metiniu rieviu eminiu emimo metodai (iprastiniai kaltai, lenktieji kaltai ir obliavimas) ir lyginamos pagrindiniu sunkiuju metalu (Mn, Zn, Ni, Cu, Cr, Pb) koncentracijos eminiuose, paimtuose kiekvienu iš minetuju metodu. Vidutines sunkiuju metalu koncentracijos, nustatytos šiais metodais, sieke 17,0±0,16 mg/kg Mn, 4,7±0,21 mg/kg Zn, 0,49±0,20 mg/kg Pb, 0,29±0,02 mg/kg Cu, 0,21±0,02 mg/kg Ni ir 0,12±0,01 mg/kg Cr ir buvo panašios i koncentracijas, aptiktas Pinus sylvestris L. medienoje nagrinejamoje teritorijoje. Apskaičiuotos vidutines vertes. Atlikus statistine analize (Anderson ir Darlin testas, Kruskal ir Wallis testas, variacijos koeficientas) tebuvo tik nereikšmingas sunkiuju metalu koncentraciju metinese rievese skirtumas, eminius emus aptartais metodais. Ivairūs metodai – iprastiniai kaltai, lenktieji kaltai ir obliavimas – gali būti sekmingai taikomi metiniu rieviu eminiams imti, tačiau “amžiaus” gražtu eminius galima imti nenukertant medžio. Резюме Анализ годичных колец древесины предоставляет информацию о развитии дерева, что важно для инвентaризации леса, оценки воздействия на окружающую среду и мониторинга воздуха и почвы. Концентрации тяжелых металлов в годичных кольцах древесины зависят от их концентрации в окружающей среде и могут свидетельствовать об уровне загрязнения местности. Одним из важных этапов анализа древесины является взятие проб годичных колец. Для точного определения концентрации тяжелых металлов в годичных кольцах древесины важно избежать случайных погрешностей. В статье анализируются три метода взятия проб годичных колец древесины (дробление обычным долотом, круглым долотом и строгание) и сравниваются концентрации основных тяжелых металлов (Mn, Zn, Ni, Cu, Cr, Pb) в пробах, взятых каждым из названных методов. Средние концентрации тяжелых металлов при их измерении указанными методами достигали 1,695±0,161 мг/кг для Mn, 0,471±0,206 мг/кг для Zn, 0,487±0,202 мг/кг для Pb, 0,290±0,021 мг/кг для Cu, 0,210±0,023 мг/кг для Ni и 0,117±0,010 мг/кг для Cr. Эти концентрации тяжелых металлов аналогичны концентрациям в древесине сосны (Pinus sylvestris L) на данной исследуемой территории. При помощи статистического анализа [тест Андерсона–Дарлина (Anderson–Darlin), тест Крускаля–Валиса (Kruskal–Wallis), коэффициент вариации] выявлена лишь незначительная разница между концентрациями тяжелых металлов в годичных кольцах древесины, взятых уже названными методами. Методы дробления обычным долотом, круглым долотом и строгания могут успешно применяться для взятия проб годичных колец древесины, однако сверло „века“ предоставляет возможность взятия пробы без спиливания дерева.

Issue Framing and Citizen Apathy Toward Local Environmental Contamination

We adapt the frame-alignment perspective in order to demonstrate how institutional framing shapes media coverage of a toxic crisis. This framing activity is described as a new approach to managing public responses to contamination that differs from the approach characterizing contamination episodes at Love Canal and Woburn, MA. Our analysis focuses on the process by which actors responsible for managing toxic crises carefully construct and manage a coordinated risk frame. We refer to this as institutional framing and illustrate how it shapes media framing of a toxic event. We conclude by proposing further research to identify the causal relationship between institutional framing and the absence of mobilization. The discovery of dioxin contamination in 1999 in the Woonasquatucket River in North Providence, RI, did not lead to community mobilization or even loosely organized community opposition even though concern about the contamination was high. Forms of mobilization range from letter-writing campaigns, citizen protests at public meetings, and demands of public officials to the formation of grassroots neighborhood groups that, in addition to these activities, may organize sit-ins, perform their own scientific analyses of environmental health effects, and bring lawsuits against responsible parties. Each of these types of mobilization can be seen in the literature on

Airborne toxic emission hazards in Texas: Measuring the vulnerability of place

The Toxic Release Inventory (TRI) provides the public with a general idea of the potential for public health problems associated with exposure to industrial toxic chemicals. It is, essentially, a public risk communication tool. TRI data are usually presented to the public as gross quantity of toxic chemicals annually emitted into air, into water, onto land, or transferred to other sites by facilities in the United States that handle a selected set of hazardous materials. Simply reporting annual emissions, however, fails to communicate a realistic measure of the potential for adverse impacts stemming from exposure to these emissions and fails to accurately measure a region's vulnerability. Health problems caused by local environmental contamination are, after all, of great interest to the general public. Annual reports of toxic releases for the counties of the state of Texas are used to test whether inclusion of other spatial attributes improves the association between county-level hazard measures and patterns of selected airborne-exposure-related diseases. Spatial, demographic, and toxicity-related factors are combined with release quantities into an aggregated value. Simple linear regressions and analyses of variance show that the revised value is a better predictor of mortality from certain exposure-related illnesses. The strength and significance of association between disease patterns and patterns of place vulnerability is improved by the new measure, particularly in rural counties. © 1997 John Wiley & Sons, Inc.

081005 (M00, B20) The effects of community pluralism on press coverage health risks from local environmental contamination: Griffin R.J., Dunwoody S., Gehrmann C.,Risk Analysis Vol. 15, Number 4, 1995, pp. 449–458

081005 (M00, B20) The effects of community pluralism on press coverage health risks from local environmental contamination: Griffin R.J., Dunwoody S., Gehrmann C.,Risk Analysis Vol. 15, Number 4, 1995, pp. 449–458

The effects of community pluralism on press coverage of health risks from local environmental contamination.

Based on the conflict/consensus model of Tichenor, Donohue and Olien, we proposed that mass mediated information signalling that local agents are contaminating the local environment and posing health risks is conflict-generating information and, therefore, will be controlled in the interest of community stability. We expected such control to vary by community structure. A content analysis of nine months of coverage by 19 newspapers supported the hypothesis that papers in more pluralistic communities were more likely than papers in less pluralistic communities to link contamination from local agents to threats to human health in the community and to frame such stories as problems. Newspapers in less pluralistic communities were more likely to frame local contamination in the context of solutions to the problem and were more likely to link contamination to health risks if the contamination were in a distant community.

Mineral relationships and ecological distribution ofFissidens cristatusWils.

AbstractStudies carried out in the laboratory indicate that Fissidens cristatus Wils., a moss of chalk and limestone grassland, requires the following conditions for optimum growth: pH, 8.0; calcium, 10 mg/1; potassium, 10 mg/1; magnesium, 50–80 mg/1; iron, less than 0.1 mg/1; It has also been demonstrated that calcium inhibits the short-term uptake of potassium from the culture solution.Within the shoots of specimens collected from the natural habitat, the potassium content was always higher in the current growth segments, whereas that of calcium was always lower. Seasonal variations in the total content of calcium, potassium and magnesium were observed.The need to wash material collected in the field prior to chemical analysis has been established and the results are discussed in relation to the distribution and local environmental contamination of F. cristatus.