Phytoextraction of lead and its relationship with histidine in six plant species using ICP-MS and HPLC-MS

High-performance liquid chromatography-mass spectrometry and inductively coupled plasma mass spectrometer (ICP-MS) methods were used for determination of histidine and lead in leaves of six plant species taken from industrial areas, including Gaziantep and Bursa cities, Turkey. For extraction of histidine from plant samples, ultrapure water was used at 90°C for 30?min. Using optimum conditions of 0.2?mL?min^?1, 70?V, 15?µL and 20°C, concentrations of histidine (in mg?kg^?1) were found to be between 2 and 9 for Morus L., 6 and 13 for Robinia pseudoacacio L., 2 and 10 for Populous nigra L., 3 and 10 for Thuja, 1 and 11 for Cupressus arizonica and 4 for Cedrus libani. Concentrations of lead were in the ranges of 4–378?mg?kg^?1 for Morus L., 1–122?mg?kg^?1 for R. pseudoacacio L., 1–14?mg?kg^?1 for P. nigra L., 1.6–224?mg?kg^?1 for Thuja (Cupressaceae), 1.5–57?mg?kg^?1 for C. arizonica and 1.8?mg?kg^?1 for C. libani. Related with correlation coefficient, significant linear correlation for Thuja (Cupressaceae) (r?=?0.81) and insignificant linear correlation for P. nigra L. (r?=?0.50) were seen. Further, the leaves of Morus L., Thuja and R. pseudoacacio L. have a potential as biomonitor and/or hyperaccumulator for Pb because the rates of their maximum/minimum concentrations were found higher than 90.     

Levels of selected urinary metabolites of volatile organic compounds in a representative sample of US adolescents

Data from National Health and Nutrition Examination Survey for the years 2011–2012 were used to evaluate the variability in the observed levels of 20 urinary metabolites of 16 parent volatile organic compounds by age, gender, race/ethnicity, and smoking status for adolescents aged 12–19 years. Smokers were found to have statistically significantly higher adjusted levels than nonsmokers for selected urinary metabolites of acrylonitrile (p < 0.05) and 1,3-butadiene (p < 0.05). For example, for N-Acetyl-S-(2-cyanoethyl)-L-cysteine, the adjusted levels for smokers were 29.2 ng/mL and 2.0 ng/mL for nonsmokers (p < 0.05). Females were found to have higher adjusted levels of selected metabolites of crotonaldehyde (p < 0.05), cyanide (p < 0.05), and tetrachloroethylene (p < 0.05) than males. For example, the adjusted levels of 2-Aminothiazoline-4-carboxylic acid or ATCA were 218.9 and 108.6 ng/mL for females and males, respectively (p < 0.05). Non-Hispanic whites (NHW) had higher adjusted levels than non-Hispanic blacks (NHB) for selected metabolites of N,N-dimethylformamide (p < 0.05) and ethylbenzene, styrene (p < 0.05). For example, for N-Acetyl-S-(N-methylcarbamoyl)-L-cysteine or AMCC, the adjusted levels for NHW and NHB were 122.7 and 80.2 ng/mL, respectively (p < 0.05). The reverse was true for selected metabolites of carbon-disulfide and tetrachloroethylene. For example, for N-Acetyl-S-(benzyl)-L-cysteine or BMA, adjusted levels for NHW and NHB were 6.7 and 10.3 ng/mL, respectively (p < 0.05).     

Estimating soil carbon turnover using radiocarbon data: A case-study for European Russia

Turnover rates of soil carbon for 20 soil types typical for a 3.7 million km² area of European Russia were estimated based on ¹⁴C data. The rates are corrected for bomb radiocarbon which strongly affects the topsoil ¹⁴C balance. The approach is applied for carbon stored in the organic and mineral layers of the upper 1 m of the soil profile. The turnover rates of carbon in the upper 20 cm are relatively high for forest soils (0.16–0.78% year⁻¹), intermediate for tundra soils (0.25% year⁻¹), and low for grassland soils (0.02–0.08% year⁻¹) with the exception of southern Chernozems (0.32% year⁻¹). In the soil layer of 20–100 cm depth, the turnover rates were much lower for all soil types (0.01–0.06% year⁻¹) except for peat bog soils of the southern taiga (0.14% year⁻¹). Combined with a map of soil type distribution and a dataset of several hundred soil carbon profiles, the method provides annual fluxes for the slowest components of soil carbon assuming that the latter is in equilibrium with climate and vegetation cover. The estimated carbon flux from the soil is highest for forest soils (12–147 gC/(m² year)), intermediate for tundra soils (33 gC/(m² year)), and lowest for grassland soils (1–26 gC/(m² year)). The approach does not distinguish active and recalcitrant carbon fractions and this explains the low turnover rates in the top layer. Since changes in soil types will follow changes in climate and land cover, we suggest that pedogenesis is an important factor influencing the future dynamics of soil carbon fluxes. Up to now, both the effect of soil type changes and the clear evidence from ¹⁴C measurements that most soil organic carbon has a millennial time scale, are basically neglected in the global carbon cycle models used for projections of atmospheric CO₂ in 21st century and beyond.     

Removal of congo red and basic violet 1 by chir pine (Pinus roxburghii) sawdust,a saw mill waste: batch and column studies

The efficiency of chir pine sawdust (CPS) for adsorptive removal of the dyes, congo red (CR) and basic violet 1 (BV), from aqueous solution was evaluated using batch and column studies. The equilibrium was attained in 60 min for CR and 45 min for BV. The adsorption of BV obeyed the Langmuir isotherm model while the Freundlich isotherm fitted the equilibrium data of CR adsorption. The Langmuir monolayer adsorption capacities (Q_o) of CPS for BV and CR were 11.3 and 5.8 g kg^?1, respectively. The kinetic data for CR were best fitted to the Lagergren pseudo-first-order model and for BV to the pseudo-second-order model. The intra-particle diffusion was found to be the rate-controlling step for CR adsorption, while the adsorption kinetics of BV were controlled by both intra-particle and liquid-film diffusion. The thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic in nature. The adsorption activation energy (E_a) for CR (124 kJ mol^?1) implied chemical adsorption while that for BV (5.4 kJ mol^?1) indicated physical adsorption. An increase in the Thomas model constant (K_Th) with increasing flow indicated that for both dyes the mass transport resistance decreased during adsorption. Thus, CPS may be an efficient low-cost adsorbent for decolorization of dye-containing wastewaters.     

Energetics of Euphausia pacifica. I. Effects of body carbon and nitrogen and temperature on measured and predicted production

Laboratory production during the life span of Euphausia pacifica was measured directly (as the sum of growth, molting and reproduction) and indirectly (as assimilation minus metabolism and leakage) to test the hypothesis that weight-specific production is a constant for all sizes. Euphausiids were collected in Puget Sound, Washington State, USA, from September 1973 to March 1978. Equations were determined (in terms of carbon and nitrogen at 8° and 12° C) expressing the relationships between body weight and the daily rates of growth, molting, reproduction, ingestion and metabolism. The allometric equation (R=aW ^b ) best related body weight (W) to the rate (R) for growth, molting, ingestion, respiration and excretion for life stages from late larvae through adults. As predicted by the original above hypothesis, the weight-specific coefficient (b) was close to 1.0 for ingestion and excretion; in contrast, b was 0.62 for growth, and 0.77 to 0.85 for molting and respiration. The Q₁₀ s also varied: 3.5 for growth, 2.4 for molting, about 3.0 for ingestion, and 2.0 for respiration and excretion. Assimilation efficiencies, for all weights and at both temperatures, were 81.3% of carbon and 85.9% of nitrogen ingested. The relationships between rate and body weight of early larvae for growth and molting were linear, as was the relationship for reproduction in adults. Weight-specific production was higher by I to 2% at 12° than 8° C for all life stages, and was 2 to 4% for carbon and 2 to 6% for nitrogen in adults, but 13 to 17% for carbon and 14 to 15% for nitrogen in early furcilia larvae. The null hypothesis was rejected for production measured directly, but would have been accepted if only an indirect measurement of nitrogen production had been considered. Clearly, indirect measurement incorporates all errors of measurement and assumption and makes interpretation difficult.     

Liver Metallothionein Level and Metal Content in Fish of Chung-Kung Stream,Taiwan-Tilapia and Liza Macrolepsis

A survey of Chung-Kung sttream fish was undertaken on six occasions from March 1994 to August 1995. Tilapia (Oreochromis hybrid) and Liza macrolepsis were the major species found downstream and were chosen as the target species for metallothionein (MT) analysis of liver tissue. in total MT of 77 tilapia and 48 Liza macrolepsis liver samples were analyzed. Significantly higher values (p >0.05) were found for the August 1995 samples than for samples taken earlier at site B (6 km from the sea) for tilapia and at site A (estuary) for Liza macrolepsis. Liver zinc, copper and cadmium were analyzed for the 1995 samples. for tilapia, liver MT concentration was found to correlate well with zinc concentration (r = 0.84, p > 0.001). for Liza macrolepsis, good correlation was found for MT with both zinc (r = 0.89, p > 0.001) and copper (r = 0.90, p > 0.001). These results indicate that in the Chung-Kung stream, zinc and copper may be the major inducers of fish liver MT. Since these two species are ubiquitous in tropical areas, they would provide a good biomarker for evaluation of integrated metal exposure in the tropical aquatic environment.     

Calorific,ash, carbon and nitrogen content in relation to length and dry weight of Parathemisto gaudichaudi (Amphipoda: Hyperiidea) in the North East Atlantic Ocean

The calorific, ash, carbon and nitrogen content, length and dry weight were determined for the hyperiid Parathemisto gaudichaudi (Guerin). Regression equations for all these variables were determined so that they can be estimated by calculation from measurements of length of the hyperiid. Mean values for total nitrogen and carbon were 7.79±0.85% and 36.80±4.18% of the dry weight, respectively. The carbon to calorific equivalent for P. gaudichaudi was 10.37 kcal g^-1 carbon (9.13 kcal g^-1 when corrected for nitrogen). The calorific value for ash-free adult P. gaudichaudi was 5.138 kcal g^-1±1.309 (4.510 kcal g^-1 when corrected for nitrogen). This large variation in the calorific content (coefficient of variation of 25.84%) can be accounted for largely by variation in the ash content (coefficient of variation of 21.84%). The calorific value determined for P. gaudichaudi is similar to that measured for other carnivorous crustaceans and adds support to the hypothesis that animals with high calorific content have a low fecundity and an energy-rich store which can be used as a buffer during unfavourable periods in their life.     

Probabilistic movement model with emigration simulates movements of deer in Nebraska, 1990–2006

Movements of deer can affect population dynamics, spatial redistribution, and transmission and spread of diseases. Our goal was to model the movement of deer in Nebraska in an attempt to predict the potential for spread of chronic wasting disease (CWD) into eastern Nebraska. We collared and radio-tracked >600 white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) in Nebraska during 1990–2006. We observed large displacements (>10 km) for both species and sexes of deer, including migrations up to 100 km and dispersals up to 50 km. Average distance traveled between successive daily locations was 166 m for male and 173 for female deer in eastern Nebraska, and 427 m for male and 459 for female deer in western Nebraska. Average daily displacement from initial capture point was 10 m for male and 14 m for female deer in eastern Nebraska, and 27 m for male and 28 m for female deer in western Nebraska. We used these data on naturally occurring movements to create and test 6 individual-based models of movement for white-tailed deer and mule deer in Nebraska, including models that incorporated sampling from empirical distributions of movement lengths and turn angles (DIST), correlated random walks (CRW), home point fidelity (FOCUS), shifting home point (SHIFT), probabilistic movement acceptance (MOVE), and probabilistic movement with emigration (MOVEwEMI). We created models in sequence in an attempt to account for the shortcomings of the previous model(s). We used the Kolmogrov–Smirnov goodness-of-fit test to verify improvement of simulated annual displacement distributions to empirical displacement distributions. The best-fit model (D = 0.07 and 0.08 for eastern and western Nebraska, respectively) included a probabilistic movement chance with emigration (MOVEwEMI) and resulted in an optimal daily movement length of 350 m (maximum daily movement length of 2800 m for emigrators) for eastern Nebraska and 370 m (maximum of 2960 m) for western Nebraska. The proportion of deer that moved as emigrators was 0.10 and 0.13 for eastern and western Nebraska, respectively. We propose that the observed spread of CWD may be driven by large movements of a small proportion of deer that help to establish a low prevalence of the disease in areas east of the current endemic area. Our movement models will be used in a larger individual-based simulation of movement, survival, and transmission of CWD to help determine future surveillance and management actions.     

Assessment of heavy metals contamination in soils surrounding a gold mine: comparison of two digestion methods

This study investigated two digestion methods (USEPA 3051: microwave, HNO₃ or Hossner: hot plate, HF–H₂SO₄–HClO₄) for heavy metals analysis in contaminated soil surrounding Mahad AD'Dahab mine, Saudi Arabia. Moreover, contamination metal levels were estimated. The Hossner and USEPA 3051 methods showed, respectively, average total contents of 17.2 and 18.1 mg kg^?1 for Cd, 11.6 and 10.6 mg kg^?1 for Co, 45.7 and 34.7 mg kg^?1 for Cr, 1030 and 1100 mg kg^?1 for Cu, 33,300 and 27,400 mg kg^?1 for Fe, 963 and 872 mg kg^?1 for Mn, 33.2 and 22.8 mg kg^?1 for Ni, 791 and 782 mg kg^?1for Pb, and 6320 and 2870 mg kg^?1 for Zn. A lack of significant differences and a high correlation coefficient (>90%) for Cd, Pb and Cu between the two digestion methods suggest that the total-recoverable method (USEPA 3051) may be equivalent to the total-total digestion method (Hossner) for determining these metals in the studied soil. However, significantly higher concentrations of Cr, Fe, Ni and Zn were found by the Hossner method comapred with the USEPA 3051 method. The soil samples have very or extremely high levels of Zn, Cu, Cd and Pb contamination, indicating very high potential ecological risk.     

Resource utilization for decorating in three intertidal majid crabs (Brachyura: Majidae)

 For three spider crabs (Tiarinia cornigera, Micippaplatipes and Pugettia quadridens quadridens), patterns of algal utilization for decorating were compared with the dynamics of algae on an intertidal rocky shore reef where the crabs co-occurred. T. cornigera and P. quadridens quadridens were most abundant from autumn to spring when the dominant algae (Boodleacoacta, Sargassum hemiphyllum, S. thunbergii and Corallina pilulifera) occurred in high coverage, while M. platipes was most abundant from spring to autumn. Monthly change of algae used for decorating was not correlated with algae growing in the crab habitat for T. cornigera, but for M. platipes, it was positively correlated for two algal species, and for P. quadridens quadridens, negatively correlated for one algal species. Each species of the spider crabs used some algal species preferentially for decoration. Decorating preference experiments conducted in the laboratory showed that M. platipes and P. quadridens quadridens exhibited similar preference to their algal utilization in the field, whereas for T. cornigera, algal preference in the experiment differed from utilization in the field. Comparisons between materials used for decoration and gut contents revealed that T. cornigera and M. platipes used algal species differently for decorating and feeding, while P. quadridens quadridens used the same algal species for both decorating and feeding. Different tactics for camouflage are discussed in terms of algal utilizations by the three majid species. Received: 25 September 1999 / Accepted: 22 June 2000     

Risk assessment in Nile tilapia (Oreochromis niloticus) and African mud catfish (Clarias gariepinus) exposed to cassava effluent

Toxicity of cassava effluent in water on aquatic lives was examined via acute and chronic bioassay experiments on Clarias gariepinus (I) and Oreochromis niloticus (II) under laboratory conditions, using standard procedures. The effluent cyanide concentration exceeded the WHO limit for wastewater. Fish body weights and haematological parameters (HMP) significantly decreased with increasing effluent concentration at p≤0.05. Toxicity on HMP for the respective (I) and (II) varied from 5.4 to 52.8; 4.8 to 51.9% for packed cell volume, 4.1 to 43.9; 5.3 to 64.0% for red blood count, 0.0 to 15.7; 0.0 to 61.4% for white blood count, 3.6 to 45.9; 5.2 to 49.5% for haemoglobin, 11.6 to 71.9; 28.4 to 63.8% for total protein, 11.5 to 75.5; 15.0 to 58.2% for albumin and 11.8 to 75.0; 46 to 83.9% for globulin. Acute exposure yielded 96-h LC₅₀ values of 0.45% for (I) and 0.25% for (II) and chronic exposure caused reduced growth and poor blood quality.     

Settlement-competency periods of larvae of three species of scleractinian corals

The pattern of settlement over time of three broadcast spawning coral species (Cyphastrea serailia, Acanthastrea lordhowensis, and Goniastrea australensis) from the Solitary Islands (30°00′S; 153°20′E) was studied in 1995 and 1996 in order to determine the maximum length of time these larvae could remain in the water column and still retain the ability to settle and metamorphose. Larvae were maintained in aquaria and the number which had settled on biologically-conditioned tile pairs was monitored every 5 to 10 d. While the majority of larvae settled quickly after becoming competent, some larvae survived and settled for extended periods after spawning. Competency periods ranged from 26 d for C. serailia to 56 d for G. australensis and 78 d for A. lordhowensis. These data greatly extend the known competency periods for larvae of broadcast-spawning corals and indicate the potential for transport of broadcast-spawned coral larvae over large distances. Medium to long-distance larval dispersal of the species studied provides a mechanism for their widespread distribution in subtropical regions, on reefs which are often widely spaced and relatively isolated. Received: 27 May 1997 / Accepted: 27 November 1997     

Relationship between total concentration and dilute HCl extraction of heavy metals in sediments of harbors and coastal areas in Korea

Total concentrations of Cr, Ni, Cu, Zn, Cd and Pb in surface sediments were determined to investigate the regional trends of heavy metal contamination in 11 coastal areas in Korea. Enrichment factor (EF) of heavy metals was calculated by comparing the level of their regional background. The averages of EF values in study areas were 0.99 for Cr, 1.05 for Ni, 4.23 for Cu, 1.80 for Zn, 3.92 for Cd and 1.54 for Pb, respectively. Dilute HCl extractions were useful to deduce the anthropogenic sources of heavy metals and the 1 M HCl extractable fractions of each metal varied from 0.3 to 37.3% for Cr, 1.9 to 66.3% for Ni, 4.2 to 92.9% for Cu, 7.1 to 99.7% for Zn, 10.9 to 98.9% for Cd and 15.0 to 99.1% for Pb. Comparing 1 M HCl extractable fraction to total concentration, large portions of Cu, Zn, Cd and Pb were present as potentially bioavailable fractions from anthropogenic input and were significantly correlated with their EF values showing r > 0.68.     

Seasonal variation assessment of impact of industrial effluents on physicochemical parameters of surface water of River Challawa,Kano, Nigeria

The physicochemical characteristics of the River Challawa in the Kumbotso Local Government Area of Kano State were studied across four seasons (warm and dry, cold and dry, hot and dry, and warm and wet seasons) between October 2006 and August 2008. Physicochemical parameters like pH, electrical conductivity (EC), total dissolved solids (TDSs), total suspended solids (TSS), alkalinity, turbidity, hardness, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), ammonia, chloride, nitrate, sulfate, and phosphate were analyzed and compared with standard permissible limits. The mean range of parameters determined across the seasons revealed: 8.36–8.59 for pH; 209.57–335.27 µS cm^?1 for EC; 134.05–208.5 mg L^?1 for TDS; 182.4–273.45 mg L^?1 for TSS; 125.3–276.07 mg L^?1 for hardness; 16.11–40 mg L^?1 of CaCO₃ for alkalinity; 2.76–3.78 mg L^?1 for DO; 1.9–43.33 mg L^?1 for BOD; 231.67–310.06 mg L^?1 for COD; 221.67–441.67 mg L^?1 for turbidity; 17.98–35.89 mg L^?1 for chloride; 5.12–8.89 mg L^?1 for nitrate; 37–558.83 mg L^?1 for sulfate; and 0.47–0.81 mg L^?1 for phosphate. Data showed that all parameters determined were significantly different among the various sampled sites across seasons. With the exception of COD, EC, and phosphate, all other parameters determined were within the WHO and USPH standard limits.     

Comparative analysis of metal translocation in red maple (Acer rubrum) and trembling aspen (Populus tremuloides) populations from stressed ecosystems contaminated with metals

Uptake of contaminants by plants and their mechanisms have been the subjects of several studies, but reports on the analysis of metal translocation in hardwood trees are limited. The main objective of this study is to compare metal accumulation and translocation in red maple (Acer rubrum) and trembling aspen (Poplar tremuloides) growing in Northern Ontario. Results show that P. tremuloides leaf tissues accumulate more nickel (Ni) and zinc (Zn) than roots. The concentrations of these elements in A. rubrum were low in leaf, branch, and roots tissues compared to the bioavailable levels of these metals in soil. The translocation factors (TFs) of metals from roots to leaves were low for copper (Cu) and high for iron (Fe), magnesium (Mg), Ni, and Zn in P. tremuloides. They varied from 0.52 to 3.26 for Fe, 3.39 to 5.47 for Mg, 2.6 to 16.4 for Ni, and 1.41 to 4.1 for Zn. For A. rubrum the TF was low for all the elements except Mg. For this species, the TF values from roots to leaves varied from 0.08 to 0.17 for Fe, 2.62 to 4.13 for Mg, 0.26 to 0.81 for Ni, and 0.71 to 0.90 for Zn. Overall, Cu does not accumulate in P. tremuloides and A. rubrum tissues, and the two species have different mechanisms in dealing with the other main contaminants in the region, specifically Ni and Zn. P. tremuloides is an accumulator for Ni and Zn while A. rubrum is an excluder for Zn and it uses the avoidance strategy to deal with soil Ni contamination.     

Determination of lethal dissolved oxygen levels for selected marine and estuarine fishes, crustaceans, and a bivalve

The objective of this study was to provide a database of the incipient lethal concentrations for reduced dissolved oxygen (DO) for selected marine and estuarine species including 12 species of fish, 9 crustaceans, and 1 bivalve. All species occur in the Virginian Province, USA, which is a cold temperate region. The study period was August 1987 to September 1995. Standard bioassay procedures were employed, with most tests being of 4-day duration. Up to eight lethal concentrations (LCs) between LC₀₅ and LC₉₅ were estimated. The study provides four general conclusions about determining lethal thresholds of low DO for these organisms. First, the concentration response curve of most species did not change greatly beyond day 1 of the exposure with the exception of crustacean larvae, which were usually more sensitive on day 4, possibly due to molting. Second, acute LC₅₀ values (1- to 4-day) for low DO were influenced by life-stage and habitat, with pelagic larvae generally being the most sensitive and benthic juveniles the least. Species mean LC₅₀ values ranged from 1.4 to 3.3 mg l^-1 for larvae, 1.0 to 2.2 mg l^-1 for postlarvae, and 0.5 to 1.6 mg l^-1 for juveniles. No intraspecific differences in LC₅₀ were detected between larval stages in crustaceans or with age in larval fishes. The response range between LC₀₅ and LC₉₅ was narrowest for the least sensitive organisms (0.6 mg l^-1), and broadened with sensitivity. The mean LC₁₀:LC₅₀ ratio for all species was 1.32 for larvae and juveniles, and 1.36 for postlarvae. The ratio for postlarvae represents only four species, and hence is not considered different from the other life stages. Third, variability increased with increased species and life stage sensitivity to low DO, and with endpoints of LC₁₅ and below, which reduces the certainty of some of these results. Lastly, no influence of temperatures between 20°C and 30°C was detected in a small set of tests with thermally acclimated crustacean larvae. This data set has been used to describe protection limits for juvenile and adult survival, and for larval recruitment for the case of persistent (₄ h) low DO for estuarine and coastal waters of the Virginian Province, USA.     

Balanus amphitrite (Cirripedia: Thoracica) — A potential indicator of fluoride,copper, lead,chromium and mercury in North Adriatic lagoons

The capacity of the barnacle Balanus amphitrite Darwin to accumulate pollutants above ambient levels was examined in two North Adriatic lagoons with respect to fluoride, copper, lead, chromium and mercury. Levels in soft tissues ranged from 138 to 312 ppm (dry weight) for fluoride, 41 to 109 ppm for copper, 7.1 to 11.7 ppm for lead, 2.10 to 3.89 ppm for chromium, and from 0.96 to 1.35 ppm for mercury. The concentration factor was of the order of 10² for fluoride, 10³ for copper, and possibly higher than 10³ for lead, chromium and mercury. The differences of about 2:1 in the fluoride and copper concentrations in the waters of the two lagoons were clearly reflected by the levels in the barnacles. B. amphitrite that had set on experimental panels had levels similar to those found in specimens collected from long-term natural populations as early as 42 days after immersion of the panels. Compared with literature data, the accumulation levels found in B. amphitrite for fluoride were among the highest known for invertebrates; the values for copper and lead were considerable, but exceeded by others published for B. balanoides; the results for chromium and mercury were one order of magnitude lower than values reported for other suspension-feeders or indicator organisms. B. amphitrite appears to possess most of the properties considered essential for a biological indicator. Eventual determination of the response time of the barnacle to changes in environmental level could profitably be carried out utilizing experimental panels.     

Comparative sensitivities of the tropical cladoceran,Ceriodaphnia rigaudii and the temperate species Daphnia magna to seven toxicants

The toxicities of seven chemicals [cadmium (Cd) chloride, potassium dichromate, sodium dodecyl sulfate, potassium chloride (KCl), Triton X-100, zinc (Zn) chloride and copper (Cu) (II) sulfate] were determined using the tropical freshwater cladoceran, Ceriodaphnia rigaudii and the temperate species, Daphnia magna. Data generated was subsequently used to determine the relative sensitivities of both species, using interspecies correlation to compare the 48?h LC50 values for both species. The 48?h LC50 values for C. rigaudii ranged from 0.002?mg?L^?1 (potassium dichromate) to 21.1?mg?L^?1 (KCl), whereas those for D. magna ranged from 0.3?mg?L^?1 for Cu to 418.87?mg?L^?1 for KCl. The LC50 values for C. rigaudii were significantly less than that for D. magna for six of the compounds tested. The interspecies correlation also showed a low, positive correlation suggesting that the sensitivities of both species were not similar for the compounds tested. The sensitivity factors for C. rigaudii and D. magna ranged between 0.01 and 12.3. These values further suggested that for six of the compounds tested, C. rigaudii appeared to be more sensitive than D. magna. It is therefore possible that because of these differences in relative sensitivities, toxicity data generated with D. magna may not be appropriate for Trinidad.     

Total arsenic concentrations in Chinese children’s urine by different geographic locations,ages, and genders

Little is known about the variation of Chinese children’s exposure to arsenic by geography, age, gender, and other potential factors. The main objective of this study was to investigate the total arsenic concentration in Chinese children’s urine by geographic locations, ages, and genders. In total, 259 24-h urine samples were collected from 210 2- to 12-year-old children in China and analyzed for total arsenic and creatinine concentrations. The results showed that the upper limit (upper limit of the 90% confidence interval for the 97.5 fractile) was 27.51 µg/L or 55.88 µg/g creatinine for Chinese children. The total urinary arsenic levels were significantly different for children in Guangdong, Hubei, and Gansu provinces (P < 0.05), where the upper limits were 24.29, 58.70, and 44.29 µg/g creatinine, respectively. In addition, the total urinary arsenic levels were higher for 2- to 7-year-old children than for 7- to 12-year-old children (P < 0.05; the upper limits were 59.06 and 44.29 µg/g creatinine, respectively) and higher for rural children than for urban children (P < 0.05; the upper limits were 59.06 and 50.44 µg/g creatinine, respectively). The total urinary arsenic levels for boys were not significantly different from those for girls (P > 0.05), although the level for boys (the upper limit was 59.30 µg/g) was slightly higher than that for girls (the upper limit was 58.64 µg/g creatinine). Because the total urinary arsenic concentrations are significantly different for general populations of children in different locations and age groups, the reference level of total urinary arsenic might be dependent on the geographic site and the child’s age.     

Kinetics of acetyl CoA: Arylamine N‐acetyltransferase from rapid and slow acetylator fish tissues

N‐acetyltransferase (NAT) activity was determined in 100 fish (Oreochromis mossambicus) livers using 2‐aminofluorene and p‐aminobenzoic acid as substrates. Overall, the liver NAT activity of the 50 females was higher than the liver NAT activity of the 50 males. The activities (mean ± SD) of NAT from kidney, blood, intestine, and liver of males was 0.42 ± 0.11, 0.12 ± 0.03, 0.12 ± 0.08, and 1.56 ± 0.54 nmol/min/mg protein for the acetylation of 2‐aminofluorene and 0.36 ± 0.09, 0.09 ± 0.01, 0.11 ± 0.04, and 0.46 ± 0.15 nmol/min/mg protein for the acetylation of p‐aminobenzoic acid. In kidney, blood, intestine, and liver from female fish, the activities obtained were 1.60 ± 0.12, 0.35 ± 0.07, 0.15 ± 0.09, and 1.89 ± 0.50 nmol/min/mg protein for 2‐aminofluorene and 0.95 ± 0.11, 0.27 ± 0.03, 0.13 ± 0.09, and 0.57 ± 0.12nmol/min/mg protein for p‐aminobenzoic acid. Kinetic constants for arylamine N‐acetyltransferase activity in kidney, blood, intestine, and liver from fish with rapid, intermediate, and slow acetylator activity were determined. Apparent K _m and V _max values for 2‐aminofluorene were 5.5 and 7‐fold higher for liver than for the other tissues. Apparent K _m and V _max values for p‐aminobenzoic acid were 3.5 and 4.7‐fold higher for liver than for the other tissues. Based on the 2‐aminofluorene NAT activity of liver, there appears to be a polymorphism in NAT activity with 16 rapid, 28 intermediate, and 56 slow acetylators among the 100 fish assayed. This is the first demonstration of acetyl CoA: arylamine N‐acetyltransferase activity in fresh water fish and could lead to the development of a fish model for monitoring the effect of pollution of water environments on native species.