Effects of herbicides on streamAufwuchs productivity and nutrient uptake

The effects of atrazine and a combination of alachlor, atrazine, metolachlor, and metribuzin on the productivity and nutrient uptake rates of native streamAufwuchs communities were investigated in two separate artificial stream experiments. After an 8-day colonization period, the first experiment employed constant doses of atrazine at 0 g/L (control), 24 g/L and 134 g/L. The second experiment employed a pulsed dose having maximum concentrations of 35 g/L alachlor, 109 g/L atrazine, 90 g/L metolachlor, and 21 g/L metribuzin. Each 20-day experiment was run at both 10C and 25C. Constant exposure to 24 g/L atrazine yielded a significant reduction in both ash-free dry weight (AFDW) and chlorophylla at 25C but not at 10C. Constant exposure to 134 g/L atrazine yielded significantly less AFDW and chlorophylla at both temperatures. The pulsed exposure to four herbicides yielded significantly less AFDW at both temperatures, while chlorophylla was significantly less only at 10C. During continual exposure to 134 g/L atrazine, both NO₂ + NO₃ and silica uptake rates appeared to be reduced at both temperatures, although the differences were generally not statistically significant. At 10C uptake rates of soluble reactive phosphorus and NO₂ + NO₃ were depressed temporarily by exposure to the pulse of four herbicides, recovering to control rates within a few days, while no effect on uptake rates was discerned at 25C. The temperature difference between experimental runs had a greater effect on nutrient uptake rates than did the herbicide treatments during a run. The results indicate thatAufwuchs growth and nutrient uptake rates may be reduced temporarily by herbicide exposures in agricultural streams. However, greater effects on these processes may be exerted by other factors accompanying storm events, such as reduced temperatures.     

Reliability of Birth Certificate Data: A Multi-Hospital Comparison to Medical Records Information

Objective: To examine the reliability of birth certificate data and determine if reliability differs between teaching and nonteaching hospitals. Methods: We compared information from birth certificates and medical records in 33,616 women admitted for labor and delivery in 1993–95 to 20 hospitals in Northeast Ohio. Analyses determined the agreement for 36 common data elements, and the sensitivity, specificity, and positive and negative predictive values of birth certificate data, using medical record data as a gold standard. Results: Sensitivity and positive predictive value varied widely (9–100% and 2–100%, respectively), as did agreement, which was almost perfect for measures of prior obstetrical history, delivery type, and infant Apgar score ( = 0.854–0.969) and substantial for several other variables (e.g., tobacco use ( = 0.766), gestational age ( = 0.726), prenatal care ( = 0.671)). However, agreement was only slight to moderate for most maternal risk factors and comorbidities ( = 0.085–0.545) and for several complications of pregnancy and/or labor and delivery ( = 0.285–0.734). Overall agreement was similar in teaching (mean = 0.51) and nonteaching ( = 0.52) hospitals. Although agreement in teaching and nonteaching hospitals varied for some variables, no systematic differences were seen across types of variables. Conclusions: Our findings indicate that the reliability of birth certificate data vary for specific elements. Researchers and health policymakers need to be cognizant of the potential limitations of specific data elements.     

Polychlorobiphenyis (PCBs) in sediments of Tokyo Bay,Japan

Sediment cores were collected from five sites in Tokyo Bay. The sediment age was estimated by the²¹⁰Pb method and the polychlorobiphenyls (PCBs)(2,5,2,4,5 — pentachlorobiphenyl,3,4,2,4, 5-pentachlorobiphenyl, 3,4,2,3,4-pentachlorobiphenyl, 2,3,6,2,3,6-hexachlorobiphenyl, 2,4, 5,2,4,5-hexachlorobiphenyl, and 2,4,5,2,3,4, 5-heptachlorobiphenyl) profiles in the sediments were determined quantitatively by gas chromatography. With respect to the horizontal distribution of PCBs, the levels were highest off Tokyo and Kawasaki, the inner western part of the bay off the mouths of the Tama and Arakawa Rivers, and declined in the direction of the eastern and southern parts of the bay. It was assumed that most of the PCBs supplied to the bay from the adjacent rivers and the industrial zones along the western coast were coprecipitated with suspended particles near the river mouths and the western coast, while PCBs adsorbed by fine particles are carried throughout the bay by the current. The accumulation rate of PCBs in Tokyo Bay sediments gradually increased, starting about 1936, and reached a maximum value in 1972 and declined moderately thereafter. The time-dependent changes in the quantity released into the environment were estimated from the amount of PCBs manufactured and used. The accumulation rate of PCBs in Tokyo Bay sediments was then compared with the estimated rate of release into the environment.     

Pesticide residues in human colostrum: Seasonal variations,Yugoslavia

Levels of HCH, HCH, HCH,o,pDDE,p,pDDE andp,pDDT were measured in 59 samples of colostrum collected in the autumn 1982 and the spring 1983 from healthy nursing mothers on the third day after delivery. Pesticide residues were identified and quantitated on a gas chromatograph. Concentrations of HCH were significantly higher in the autumn (mean, 1.71g/L) than in the spring (0.67g/L), while concentrations of HCH were significantly lower in the autumn (0.49g/L) than in the spring (1.50g/L). The differences between the two seasons were not statistically significant for HCH (0.95 g/L vs 0.88g/L),o,pDDE (0.73g/L vs 1.34g/L),p,pDDE (68.63g/L vs 53.72g/L) andp,pDDT (20.00 (g/L vs 14.29 (g/L).Calculated average daily HCH (Lindane) intake of 0.04g/kg body wt (b.w.) and total DDT intake of 4.16 (/kg b.w. in a 3.5 kg newborn, ingesting 60 ml/kg b.w. of colostrum on the third day of life was below the upper limit of FAO/WHO Acceptable Daily Intake (ADI) (0.01 mg/kg b.w. for Lindane and 0.005 mg/kg b.w. for DDT) in the spring. In the autumn, Lindane intake of 1.10k/kg b.w. was below the FAO/WHO ADI and total DDT intake of 5.36 g/kg b.w. was slightly above the FAO/WHO ADI.     

The association of respiratory problems in a community sample with self-reported chemical intolerance

This epidemiological study evaluated respiratory histories in those individuals reporting chemical intolerance (CI) in a community population sample. The subsample of 181 completed standard Respiratory Health Questionnaires. CI was determined from self-ratings of feeling moderately to severly ill from exposure to at least three of five common chemicals (paint, pesticides, car exhaust, new carpet, and perfume); the prevalence rate was 22.7%. The comparison group (CN) (31.5% of the sample) were selected from their reports of never feeling ill from the same chemicals. The prevalence rate of CI in females was over twice that in males (28% vs 12.9%), a significant difference. There were no significant differences in smoking, age, or education between CI and CN. Prevalence rates for symptoms and Relative Risk Ratios (RR) indicated that the CI were significantly more likely to report chronic cough, phlegm, wheeze, chest tightness, exertional dyspnea, acute respiratory illnesses, hay fever, child respiratory trouble, and physician confirmed asthma. Several of these respiratory symptoms were significantly, though differentially, related to current asthma and hay fever reports. Results suggest a potential vulnerability to and greater interference from respiratory illness for the CI, which have implications for women's health and quality of life.     

Effects of Kepone® on the sheepshead minnow in an entire life-cycle toxicity test

A life-cycle toxicity test with the estuarine sheepshead minnow (Cyprinodon variegatus) and the insecticide Kepone^® (chlordecone) in seawater showed that the maximum acceptable toxicant concentration (MATC) lies between 0.074 and 0.12 g Kepone/L, based on reduced standard length of progeny at 0.12g/L and higher concentrations. The application factor range (MATC/96-hr LC50) for sheepshead minnows exposed continuously to Kepone is from 0.001 to 0.002. Other adverse effects of Kepone exposure were: External signs of poisoning in fish exposed to concentrations 0.074g/L, fatty degeneration of the liver and histological evidence of vertebral damage in some fish exposed to 0.78g/L, reduced growth of parental fish at 0.39 and 0.78g/L, reduced fecundity and fertility of eggs at 0.78g/L, and reduced survival of embryos produced by fish exposed to 0.78g/L. Average bioconcentration factors (concentration in tissue ÷ average measured concentration in water) ranged from 2,600 for 21-day-old juveniles to 7,600 for adult males. ^®Registered trademark, Allied Chemical Corp., 40 Rector St., New York, NY 10006. Mention of trade names or commercial products does not constitute endorsement by the Environmental Protection AgencyGulf Breeze Contribution No. 425     

Rethinking Our Understanding of the Resident Group in Group Care

The author of this article lived in two residential homes in order to understand, and create a model of, the residents' social group. By understanding the way in which the group grants power to its members and the beliefs and actions which it values, residential staff have the opportunity to identify and support positive individual and group behaviours. It is a model which starts from the group rather than imposing our adult notions of how young people should behave. The way in which the everyday activities of young people, for example their use of humour, serves to maintain group expectations, organisations and relationships, should not be overlooked but rather identified, understood and encouraged.     

Translation,cultural adaptation,and initial reliability and multitrait testing of the Kidney Disease Quality of Life instrument for use in Japan

Background: The Kidney Disease Quality of Life instrument (KDQOL) consists of 79 items: 36 asking about health-related quality of life (HRQOL) in general (the Medical Outcomes Study SF-36) and 43 asking about QOL as it is affected by kidney disease and by dialysis. Aim: Translation, cultural adaptation and initial reliability and multitrait testing of the KDQOL for use in Japan. Methods: Translation and cultural adaptation began with two translations into Japanese, two backtranslations into English, and discussions among the translators, the project coordinators in Japan, and the developers of the original (US-English) version. Focus-group discussions and field testing were followed by analyses of test–retest reliability, internal consistency, and convergent and discriminant construct validity. Results: All eight of the SF-36 scales met the criterion for internal consistency (Cronbach's ranged from 0.73 to 0.92) and were reproducible (intraclass correlations between test and retest scores ranged from 0.60 to 0.82). Of the 10 kidney-disease-targeted scales, only two had coefficients of less than 0.70: sleep (0.61) and quality of social interaction (0.35). One item on the quality of social interaction scale had a very weak correlation with the remainder of that scale (r = 0.10). Eliminating that item from scoring increased the coefficient of the scale from 0.35 to 0.64. All three items on the quality of social interaction scale had very strong correlations with other scales. Conclusions: First, in Japanese patients receiving dialysis the SF-36 scales are internally consistent and their scores are reproducible. Second, with the possible exception of the quality of social interaction scale, the Japanese version of the KDQOL,can provide psychometrically sound kidney-disease-targeted data on quality of life in such patients.     

Polychlorinated biphenyl congeners (PCBs),p,p′-DDE and hexachlorobenzene in human milk in three areas of upstate New York

Forty human milk samples from women in an urban and a rural vicinity on Lake Ontario (Rochester and Oswego) and a mixed urban and rural location on the Hudson River (Albany), New York, were analyzed for 74 PCB congeners,p,p-DDE, hexachlorobenzene, and mirex in order to determine the intake of breast-fed infants. All of the compounds were detected in the samples, but only eight PCB congeners andp,p-DDE accounted for 88% of the chlorinated hydrocarbons detected.p,p-DDE was the predominant pollutant (mean 78 ng/g wet weight), but the levels detected were low compared with the results from other parts of North America. Eight individual PCB congeners comprise 52% of the total PCB residue (mean 26.5 ng/g of whole milk); they ranged in mean concentration from 3.2 ng/g (2,4,5,2,4,5-hexachlorobiphenyl) to 1 ng/g (2,3,4,3,4-pentachlorobiphenyl). Statistical correlation analysis among PCB congeners indicates a possible higher exposure to less chlorinated congeners at Oswego than at Albany.     

Congener-specific data on polychlorinated biphenyls in tissues of common porpoise from Puck Bay,Baltic Sea

Individual congeners of polychlorinated biphenyls (PCBs), including the highly toxic non-ortho coplanar 3,3,4,4-tetrachlorobiphenyl (IUPAC No. 77), 3,3,4,4,5-pentachlorobiphenyl (IUPAC No. 126), and 3,3,4,4,5,5-hexachlorobiphenyl (IUPAC No. 169), and their mono- and di-ortho analogs, have been identified and quantified in the blubber, liver, and muscles of three female common porpoise Phocoena phocoena collected from the Puck Bay (inner Gulf of Gdask, Poland) in 1989–1990, to elucidate actual concentrations and toxic potential. The total 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalent for 13 coplanar PCBs in blubber was 1,500±470 pg/g wet wt. 2,3,4,4,5-Pentachlorobiphenyl (IUPAC No. 118) was the most contributing individual and occupied between 57 and 67% in total toxic equivalent of coplanar PCBs in blubber, while 2,2,4,4,5,5-hexachlorobiphenyl (IUPAC No. 153), 2,3,3,4,4-pentachlorobiphenyl (IUPAC No. 105) and 2,2,3,4,4,5-hexachlorobiphenyl (IUPAC No. 138) comprised between 9.5–14, 7.6–11.5, and 7.2–11.0%, respectively (totally 82–95%), and 2,3,3,4,4,5-hexachlorobiphenyl (IUPAC No. 156) was absent. A potentially most toxic non-ortho PCB members such as 3,3,4,4,5-pentachlorobiphenyl, 3,3,4,4,5,5-hexachlorobiphenyl and 3,3,4,4-tetrachlorobiphenyl were only minor contributors, altogether occupying between 1.0 and 14.5% in total TEQ of coplanar PCBs. Concentrations of total PCBs in lipids of the blubber ranged from 26 to 47 g/g and were comparable or lower than reported earlier for common porpoises from the Baltic Sea, North Sea, and North Atlantic by other authors.     

Applications of computerized adaptive testing (CAT) to the assessment of headache impact

Objective: To evaluate the feasibility of computerized adaptive testing (CAT) and the reliability and validity of CAT-based estimates of headache impact scores in comparison with static surveys. Methods: Responses to the 54-item Headache Impact Test (HIT) were re-analyzed for recent headache sufferers (n = 1016) who completed telephone interviews during the National Survey of Headache Impact (NSHI). Item response theory (IRT) calibrations and the computerized dynamic health assessment (DYNHA^®) software were used to simulate CAT assessments by selecting the most informative items for each person and estimating impact scores according to pre-set precision standards (CAT-HIT). Results were compared with IRT estimates based on all items (total-HIT), computerized 6-item dynamic estimates (CAT-HIT-6), and a developmental version of a static 6-item form (HIT-6-D). Analyses focused on: respondent burden (survey length and administration time), score distributions (ceiling and floor effects), reliability and standard errors, and clinical validity (diagnosis, level of severity). A random sample (n = 245) was re-assessed to test responsiveness. A second study (n = 1103) compared actual CAT surveys and an improved static HIT-6 among current headache sufferers sampled on the Internet. Respondents completed measures from the first study and the generic SF-8 Health Survey; some (n = 540) were re-tested on the Internet after 2 weeks. Results: In the first study, simulated CAT-HIT and total-HIT scores were highly correlated (r = 0.92) without ceiling or floor effects and with a substantial reduction (90.8%) in respondent burden. Six of the 54 items accounted for the great majority of item administrations (3603/5028, 77.6%). CAT-HIT reliability estimates were very high (0.975–0.992) in the range where 95% of respondents scored, and relative validity (RV) coefficients were high for diagnosis (RV = 0.87) and severity (RV = 0.89); patient-level classifications were accurate 91.3% for a diagnosis of migraine. For all three criteria of change, CAT-HIT scores were more responsive than all other measures. In the second study, estimates of respondent burden, item usage, reliability and clinical validity were replicated. The test–retest reliability of CAT-HIT was 0.79 and alternate forms coefficients ranged from 0.85 to 0.91. All correlations with the generic SF-8 were negative. Conclusions: CAT-based administrations of headache impact items achieved very large reductions in respondent burden without compromising validity for purposes of patient screening or monitoring changes in headache impact over time. IRT models and CAT-based dynamic health assessments warrant testing among patients with other conditions.     

Mutagenicity of 4,4′-methylene-bis-(2-chloroaniline) “MOCA” and its N-acetyl derivatives in S. typhimurium

Summary 4,4-methylene-bis-(2-chloroaniline) (MOCA) and two identified urinary N-acetyl and N,N-diacetyl derivatives were tested in a Salmonella/mammalian microsome assay. No mutagenic activity was observed without rat liver S9 mix activation. In the presence of rat liver S9 mix, the chemicals were mutagens, but the mutagenicity of N-acetyl derivatives to strain TA 100 was reduced when compared to that of MOCA, and a greater amount of S9 was required to exhibit the mutagenicity of the N,N-diacetyl-MOCA. These data suggest that N-acetylation does not account for the mutagenic effectiveness of MOCA.     

Socioeconomic status, overweight and obesity in prepuberal children: A study in an area of Northern Italy

The aim of this study was to determine whether socio-economical status (SES) is associated with overweight and obesity in prepuberal children. In an area of North-Western Italy a sample of 1420 children, aged 10–11 years, had his/her height and weight recorded, (overweight and obesity were defined, respectively, as relative body weight 120% and 140%), and parents were requested to compile a questionnaire exploring some demographic and social conditions. 23% of the sample resulted overweight or obese. Prevalence rate ratios (PRR) of overweight and obesity (together) were calculated, adjusting for parents' age, parents' area of birth, and school district. PRR for mother's lowest educational level compared to the highest was 1.59 (95% CI: 1.19–2.13), while for father's education was 1.21 (0.90–1.63). PRRs for unemployed or manual mother compared to upper non manual were respectively 1.83 (1.20–2.79) and 2.20 (1.31–3.68), while for unemployed or manual father were 2.63 (1.97–2.63), and 1.63 (1.27–2.09). The cultural resources of the mother, and the economical resources of the family seem to influence the prevalence of weight gain in prepuberal children. This should be taken into account when planning programs for the prevention or reduction of obesity in children.     

Levels of β-HCH,HCB, p,p′-DDE,p,p′-DDT and PCBs in human milk from a continental town in Croatia,Yugoslavia

Summary Concentrations of -HCH, HCB, p,p-DDE, p,p-DDT and PCBs were determined by gas chromatography in 50 human milk samples collected from the general population during 1981/1982 in a continental town in Croatia (Yugoslavia). The samples were collected between one and 22 weeks after delivery from mothers breast-feeding one child only. The mothers' age was 18 to 31 years, and they were nursing their first or second child. All 50 samples contained -HCH, HCB, p,p-DDE and PCBs, whereas p,p-DDT was present in 37 samples. The concentrations of -HCH, HCB, p,p-DDE, p,p-DDT and PCBs expressed on a whole milk basis were (median in g/kg): 11, 7.1, 67, 7.3 and 22 respectively, and expressed on a fat basis (median in mg/kg): 0.28, 0.21, 1.9, 0.18 and 0.62 respectively. The fat content was 3.7% (median). PCBs were present in a mixture containing penta-, hexa- and heptachlorobiphenyls.     

Concentrations and chromatographic profile of DDT metabolites and polychlorobiphenyl (PCB) residues in stranded beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary,Canada

The concentrations and high resolution gas Chromatographic profiles of DDT metabolites and polychlorobiphenyl (PCB) congeners were determined in blubber, liver, kidney and lung tissue and milk samples of stranded beluga whales (Delphinapterus leucas) collected at localities along the coasts of the Saint Lawrence Estuary, Canada from November 1983 through December 1984. The analyses indicate that the major PCB components of the tissues were 2,2,5,5-tétra-, 2,2,4,4,5-penta-, 2,2,3,4,4,5-hexa-, 2,2,4,4,5,5-hexa-, 2, 2,3,3,4,5-hexa-, 2,3,3,5,5,6-hexa-, 2,2,3,4, 5,5,6-hepta- and 2,2,3,4,4,5,5-heptachlorobiphenyls. Although the highest organochlorine chemical concentrations were found primarily in the blubber, concentrations of 1.72 g/g for PCB and 2.04 g/g for DDT were determined in one milk sample. No correlation was established between PCB,p,p-DDE and DDT concentrations and the fat content of the kidney liver and lung tissues. The Chromatographie patterns of the PCB congeners were similar from one tissue to another with the exception of the kidney; the profile indicates the retention of PCB congeners which are minor components in the other tissues. Relations of residue concentrations between tissue are described and the significance of congener-specific PCB analysis is discussed in terms of the structureactivity effects on PCB persistence and toxicity.Portions of this work were presented at the Sixth Biennial Conference on the Biology of Marine Mammals, Vancouver, British Columbia, November 22–26, 1985.     

Comparative toxicokinetics of 2,2′- and 4,4′-dichlorobiphenyls in the pond snailLymnaea stagnalis (L.)

Pond snails (Lymnaea stagnalis (L.)) were treated with 2,2-dichlorobiphenyl (DCB) or 4,4-DCB, to examine the toxicokinetic profile of these compounds. Snails were treated orally with 210 g 4,4-DCB (impregnated on food) for 14 hr, or snails were injected with 50 g of 2,2-DCB or 4,4-DCB in the foot. At different times after starting feeding or injection, tissues (albumen gland, digestive gland and digestive tube, central nervous system, remainder parts), hemolymph and faeces were analyzed for unchanged 2,2- or 4,4-DCB. The results showed that in case of oral administration of 4,4-DCB after 144 hr, 97.5% of the dose was excreted unchanged in the faeces. During the first 48 hr 4,4-DCB was found in all tissues. Thereafter, an exponential elimination was found (the rate constant of elimination (k_el) varied from 0.010–0.021 per hr, t_1/2 from 33–60 hr and the apparent clearance from 0.02–0.3 g/hr for the different tissues). After injection, the compounds were found in all the above mentioned tissues, especially in the digestive gland. There was a clear difference between snails injected with 2,2- and 4,4-DCB. Firstly, k_el for 2,2-DCB was higher (0.028 per hr vs 4,4-DCB: 0.001 per hr). Secondly, 2,2-DCB was lethal; 63% of the animals died after 72 hr.     

Lead in Feathers and δ-Aminolevulinic Acid Dehydratase Activity in Three Raptor Species from an Unpolluted Mediterranean Forest (Southeastern Spain)

This paper presents the levels of lead found in the feathers of adult and blood of nestlings of booted eagle (Hieraaetus pennatus), European buzzard (Buteo buteo), and goshawk (Accipiter gentilis) sampled in the 1999 and 2000 breeding seasons in a Mediterranean forest of the Province of Murcia (Southeastern Spain) located far from potential sources of metal contamination. Levels of -aminolevulinic acid dehydratase activity (-ALAD) in blood were also measured in the nestlings. Lead concentrations ranged from 1.1 to 11.21 g/dl in blood of nestlings and from 0.35 to 1.66 mg/kg d.w. in the feathers of their parents. A significant relationship was found between blood -ALAD and lead ( = –568), showing a negative correlation with blood lead levels even at lead concentrations below 5 g/dl. This fact suggests the usefulness of this enzymatic biomarker for low lead exposure in forest raptors. There were also positive relationships between the lead concentrations in blood of nestlings and those in feathers of their parents ( = 0.817), suggesting the usefulness of feathers for biomonitoring environmental exposure to lead.     

Determinants of household health expenditure on western institutional health care

We try to identify determinants of illness reporting, provider choice and resulting expenditure with different econometric models using data from a representative household panel survey of 800 households in Nouna health district, Burkina Faso, during 2000–2001. The factors being an adult, married, illness occurred in rainy season and severe illness significantly increased the magnitude of health expenditure. Compared to malaria, individuals spent more on other infectious diseases, injury and the other disease category. In contrast, people were less likely to spend on chronic illness. An individual who belonged to a household headed by a female, a literate household head and with a higher household expenditure had a significantly positive association with the magnitude of expenditure. Findings from this study can be used for policy implication to improve health system performance in Burkina Faso through enhancing health care utilization.     

Chronic toxicity and bioaccumulation of 2,5,2′,5′- and 3,4,3′,4′-tetrachlorobiphenyl and Aroclor® 1242 in the amphipodHyalella azteca

The addition of 100 (g/L of Aroclor^® 1242 (A1242) or 2,5,2,5-tetrachlorobiphenyl (TeCB) during 10 week chronic toxicity tests withHyalella azteca resulted in complete mortality. There were no effects on survival, growth, or reproduction after addition of 30 g/L. Toxic effects were observed at tissue levels of between 30 and 180 g/g on a wet weight basis, and tissue levels appear to be a better indicator of toxicity than levels in water. No toxic effects were observed after additions of up to 2,700 g/L of the coplanar congener 3,4,3,4-TeCB.H. azteca has the ability to avoid accumulating in excess of 140 g/g 3,4,3,4-TeCB. The amount taken up was proportional to the amount added in water up to 100 g/L, but was constant at higher additions, possibly accounting for its relatively low toxicity. The low toxicity of the coplanar congener, as compared to the non-coplanar 2,5,2,5-TeCB, is in direct contrast to the high toxicity of coplanar PCB congeners to mammals and may be associated with slower rates of aromatic hydrocarbon metabolism in amphipods. Polychlorinated biphenyl levels measured in amphipods from Lake Ontario are approximately 100-fold below levels associated with toxicity inH. azteca, but are above levels which, through biomagnification up the food chain, lead to salmonid residues in excess of 2 g/g, a tolerance limit for human consumption.     

Cyanide and thiocyanate levels in blood and urine of workers with low-grade exposure to cyanide

Summary The concentrations of free cyanide in the blood and in the urine, and the levels of free thiocyanate (oxidized to cyanide and distilled) as well as total thiocyanate (directly determined and quite unspecific) were determined in the urine of 140 volunteers.There were four main categories of volunteers: (i) non-smokers, not exposed to cyanide in the atmosphere, (ii) smokers, not exposed to cyanide, (iii) non-smokers, exposed to various levels of cyanide in their occupation, and (iv) smokers who were also exposed to cyanide.The cyanide concentration in the blood did not show a clear relationship to either smoking or moderate occupational exposure; the levels were found to lie between 2.0 and 15.0 g of free cyanide per 100 ml of blood, with an average of 5.4 g for all categories of volunteers.It was found that the individual concentrations of free CN and CNS in the urine varied considerably and could not be used for detecting undue chronic exposure to cyanide at the concentrations encountered in the atmosphere. The average values, on the other hand, varied in a regular pattern for each of the four categories listed above. The influence of smoking had a far greater effect on the values obtained than the influence of atmospheric cyanide.Because of the great variations caused by other factors, concentrations of CN and CNS in the urine are not appropriate tools for individual routine control of minor occupational exposure to cyanides. However, non-smokers exposed to moderate cyanide levels in the air, and any individual exposed to high cyanide levels show higher than average values of CN and CNS in their urine.The cyanide values reported in this paper may be useful for the evaluation of analytical results from individual cases where poisoning from cyanide in the atmosphere is suspected.