CADMIUM ACCUMULATION AND TOXICITY IN SUBMERGED PLANT HYDRILLA VERTICILLATA (l.f.) ROYLE

Cadmium accumulation and its toxicity in relation tochlorophyll, protein, cysteine contents and in vivo nitrate reductaseactivity were studied under controlled conditions in Hydrillaverticillata, a submerged commonly occurring macrophyte. Plants weresubjected to six different concentrations of Cd ranging from 1.0 to 25.0 µM for 24, 48, 72 and 168 h. Tissue Cd concentration was maximum (13.71 µmoles/g dw) at 25 µM background concentration. At this concentration, a decrease of approximately 79 and 72% was found in chlorophyll and protein content. In vivo nitrate reductase activity was stimulated at 1.0 µM; however, the activity gradually declined beyond this concentration. Exposure to various cadmium concentrations resulted in an increase in cysteine content of the plant.     

Environmental Contaminants in Blood, Hair, and Tissues of Ocelots from the Lower Rio Grande Valley, Texas, 1986–1997

The ocelot (Felis pardalis) isan endangered neotropical cat distributed within asmall range in the Lower Rio Grande Valley (LRGV), inTexas, U.S.A. Studies of the impacts of environmentalcontaminants in wild cats are few. Approximately onefourth of the estimated population (about 100) ofocelots in the LRGV was sampled to evaluate theimpacts of chlorinated pesticides, polychlorinatedbiphenyls, and trace elements on the population. Hairwas collected from 32 ocelots trapped between 1986–1992,and blood was collected from 20 ocelots trappedbetween 1993–1997. A few blood samples were obtainedfrom individuals recaptured two or three times. Tissue samples from 4 road-killed ocelots were alsoanalyzed. DDE, PCBs, and Hg were some of the mostcommon contaminants detected in hair and blood. MeanHg levels in hair ranged from 0.5 to 1.25 g g^-1 dw,Se from 1.5 to 3.48 g g^-1 dw, and Pb from 0.56 to26.8 g g^-1 dw. Mean DDE concentrations in plasma ranged from 0.005 g g^-1 ww to 0.153 g g^-1 ww, and PCBs ranged from 0.006 g g^-1 ww to 0.092 g g^-1 ww. Mean Hg levels in red blood cells rangedfrom 0.056 g g^-1 dw to 0.25 g g^-1 dw. Concentrations of DDE, PCBs, or Hg, did not increasesignificantly with age, although the highestconcentrations of DDE and Hg were found in olderanimals. Overall, concentrations of DDE, PCBs, and Hgwere low and at levels that currently do not pose anythreat to health or survival of the ocelot. This isfurther supported by good reproduction of the ocelotin the LRGV, where adult females averaged about 1.5kittens/litter. Thus, it seems that the current majorthreat to recovery of the ocelot in the LRGV may behabitat loss, although potential impacts of newgeneration pesticides, such as organophosphorus andcarbamate insecticides need further study.     

Research on the relationship between the fractional coverage of the submerged plant Vallisneria spiralis and observed spectral parameters

The present paper discusses the relationship between the coverage fraction of submerged plants and the observed spectral characteristics. The purpose of this paper is to validate a remote sensing technology to monitor the change in the plant composition of a water body. In the current study, the reflectance spectra of the submerged plant Vallisneria spiralis at different fraction coverages of the wetland in Hangzhou Bay were measured. The relationships between the fraction coverage of V. spiralis and simulated Quickbird normalized difference vegetation index (NDVI), red edge, and other spectral characteristic parameters were established. The results showed that the spectral reflectance characteristics of submerged plant V. spiralis were mainly in the visible light (490–650 nm) and near infrared (700–900 nm). The rate of change of the blue band curve and simulated Quickbird NDVI showed a higher correlation with the V. spiralis coverage, so estimation models of the fraction coverage were constructed using these parameters. The estimated fraction coverage of V. spiralis with different models were validated with ground data, and the accuracy of estimation models was assessed. The most suitable estimated fraction coverage of V. spiralis was obtained using the rate of change of the blue band curve and simulated Quickbird NDVI. The present work demonstrated a method to monitor the distribution and dynamical variation of submerged plants at the large scale.     

Bioremediation of tannery effluent by Cr- and salt-tolerant bacterial strains

Microorganisms have great potential to control environmental pollution, particularly industrial sources of water pollution. Currently, leather industry is regarded as the most polluting and suffering from negative impacts due to the pollution it adds to the environment. Chromium, one of the hazardous pollutants discharged from tanneries, is highly toxic and carcinogenic in nature. Effective treatment of tannery effluent is a dire need of the era as a part of environmental management. Among all the wastewater treatment technologies, bioremediation is the most effective and environment-friendly tool to manage the water pollution. The present study evaluated the potential of 11 previously isolated bacterial strains, tolerant to high concentrations of salts and Cr for the bioremediation of tannery effluent. Among all the tested strains, Enterobacter sp. HU38, Microbacterium arborescens HU33, and Pantoea stewartii ASI11 were found most effective in reducing biological oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS), and chromium (Cr) 70, 63, 57, 87, and 54%, respectively, of tannery effluent and proliferated well under highly toxic conditions, at 9 days of incubation. The pollutant removal efficacy of these bacterial strains can be improved by extending the incubation period or by increasing the amount of inoculum.     

Toxicity of a complex mixture of atmospherically transported pesticides to Ceriodaphnia dubia

The presence of several anthropogenic chemicals has been documented in the atmosphere of the Canadian prairies. The deposition of these chemicals as a mixture is of importancesince little is known of the combined effects of these chemicalson aquatic organisms. This study was designed to evaluate theacute and chronic toxicity of a complex mixture of nineatmospherically transported pesticides to Ceriodaphniadubia. The nine selected pesticides (bromoxynil, dicamba, 2,4-D,MCPA, triallate, trifluralin, pentachlorophenol, lindane, and4,4-DDT) were detected in appreciable quantities in dryatmospheric deposits. The concentration of each pesticide in themixture was based on maximum measured daily dry deposition ratesfor central Canada, except for pentachlorophenol, which wasestimated based on atmospheric concentrations. The 48-h LC50estimate for C. dubia exposed to the pesticide mixture was174.60 g L^-1 (340 times the measured total dry deposition concentration). The estimated NOEC and LOEC for bothsurvival and reproduction, as determined in the 7-d chronic toxicity test, were 51.3 (100 times) and 154 g L^-1 (300 times), respectively. A basic risk assessment, using the toxic unit approach, suggested that the toxicity of the pesticide mixture was mainly due to 4,4-DDT. Overall, this atmospherically transported complex mixture of pesticides appearsto pose a negligible toxicological risk to non-target aquatic invertebrates such as zooplankton.     

Mercury, Methylmercury, and Selenium Concentrations in Eggs of Common Loons (Gavia immer) from Canada

Concentrations of Hg and Se were determined for a total of 125Common Loon (Gavia immer) eggs collected from lakes in Alberta, Saskatchewan, Ontario, Quebec, New Brunswick and NovaScotia, Canada between 1972 and 1997. Resulting data were compared to Hg and/or Se concentrations known or suspected tocause reproductive impairment in birds. Organic (methyl) Hg analyses were also performed on a subset of 24 loon eggs. Thirty-nine of 125 eggs had total Hg levels exceeding those (0.6 g g^-1 ww, or 2.5 g g^-1 dw)previously reported to be associated with reproductive impairment in common loons (Barr, 1986), and 9 of 125 eggshad Hg concentrations higher than the level associated withreproductive impairment in birds generally 1 g g^-1 ww; (Thompson, 1996). Selenium concentrations in loon egg samples were less than levels known to cause reproductiveimpairment in birds. A weak but significant positive correlation was observed between egg-Hg and -Se concentrations(r = 0.511, p < 0.05). On average, methylmercury accounted for about 87% of total Hg in 24 eggs analysed for both total and organic Hg. In this subset of eggs, the relationship between organic (methyl) Hg and Se was significant (r = 0.538, p = 0.007) while that found between inorganic Hg and Se in the same eggs was not significant (r = 0.353, p = 0.091). This relationship was unexpected and was contrary to relationships established for organic and inorganic Hg vs. Se in adult loon liver and kidney tissue (Scheuhammer et al., 1998b).     

The prevalence of bacterial resistance in clinical, food, water and some environmental samples in Southwest Nigeria

The resistance pattern and mechanisms of bacterial isolates obtained from clinical origin, soil, industrial effluent, orange juice products and drinking water were studied using commonly used antibiotics. The microbial load of the water samples, industrial effluent and orange juice products were 1.0 × 10¹–2.25 × 10⁶, 2.15 × 10⁵, and 3.5 × 10⁴–2.15 × 10⁵ cfu mL^–1, respectively. The faecal coliform test revealed that only two out of twenty orange juice products had MPN of 2 and 20, the MPN of water ranged from 1–1800, while the effluent had MPN of 1800. The bacterial isolates that were isolated include E. coli, S. aureus, P. vulgaris, S. marcescens, S. pyogenes, B. cereus, B. subtilis, Micrococcus sp., Klebsiella sp., P. aeruginosa, and Enterobacter sp. Also, clinical and soil isolates of P. aeruginosa were used in the study. Among the eight antibiotics tested for resistance on five strains of each bacterium, seven different resistance patterns were observed among the bacterial isolates obtained from water, effluent and orange juice products. Among the clinical and soil isolates of P. aeruginosa, four multiple-drug resistance patterns were obtained. Thirty strains of E. coli and S. aureus were tested for -lactamase production and fourteen strains, seven each of E. coli and S. aureus that had high Minimum Inhibitory Concentration values (MIC) for both Amoxycillin and Cloxacillin were positive.     

Distribution of heavy metals in plants and fish of the Yamuna river (India)

The distribution of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in the plants and fish of Yamuna river from Delhi to Allahabad, a distance of about 840 km, at five sampling stations was determined in the year 1981. The results have shown wide variations in the heavy metal levels from one sampling station to the other. The concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn in the plants (Eicchornia crassipes) were found to be 0.02–0.12, 2.7–21.3, 4.6–64.8, 9.8–114.0, 193.0–1835.0, 380.0–1443.0, 4.4–83.0, 4.8–30.2, and 22.1–356.5 g g^-1 respectively whereas in the fish (Heteropnuestes fossilis) were found to be ND-0.40, 2.3–13.7, 3.7–26.9, 8.33–58.1, 278.3–1108.0, 81.3–213.8, 2.8–32.7, 1.4–12.8 and 101.8–364.8 gg^-1 respectively on dry weight basis.     

Distribution of selected carcinogenic hydrocarbon and heavy metals in an oil-polluted agriculture zone

Owing to the importance of clean and fertile agricultural soil for the continued existence of man, this study investigated the concentrations of total petroleum hydrocarbons (TPHs), polycyclic aromatic hydrocarbons (PAHs) and some heavy metals in soils and selected commonly consumed vegetables and tubers from oil-polluted active agricultural farmland in Gokana of Ogoniland, Rivers State, Nigeria. Samples from Umuchichi, Osisioma Local Government Area in Abia State, Nigeria, a non-oil-polluted area constituted the control. In test and control, up to 3,830?±?19.6 mgkg^?1 dw and 6,950?±?68.3 mgkg^?1 dw (exceeding DPR set limits) and 11.3?±?0.04 mgkg^?1 dw and 186?±?0.02 mgkg^?1 dw for TPH and PAHs, respectively, were recorded in test soil and plant samples, respectively. Among the metals studied (Pb, Cd, Cr, Mn, Fe and Zn), Pb and Cr uptake exceeded WHO set limits for crops in test samples. Combined sources of pollution were evident from our studies. Bitterleaf and Waterleaf could be tried as bioindicators owing to expressed contaminants uptake pattern.     

Biomagnification factors (fish to Osprey eggs from Willamette River,Oregon, U.S.A.) for PCDDs,PCDFs, PCBs and OC pesticides

A migratory population of 78 pairs of Osprey (Pandion haliaetus) nesting along the Willamette River in westernOregon was studied in 1993. The study was designed to determinecontaminant concentrations in eggs, contaminant concentrationsin fish species predominant in the Ospreys diet, andBiomagnification Factors (BMFs) of contaminants from fish specieseaten to Osprey eggs. Ten Osprey eggs and 25 composite samplesof fish (3 species) were used to evaluate organochlorine (OC)pesticides, polychlorinated biphenyls (PCBs), polychlorinateddibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans(PCDFs). Mercury was also analyzed in fish. Geometric meanresidues in Osprey eggs were judged low, e.g., DDE 2.3 g g^-1 wet weight (ww), PCBs 0.69 g g^-1, 2,3,7,8-TCDD 2.3 ng kg^-1, and generally well below known threshold values for adverse effects on productivity, and the population was increasing. Osprey egg residue data presentedby River Mile (RM) are discussed, e.g., higher PCDDs were generally found immediately downstream of paper mills and eggsfrom the Willamette River had significantly elevated PCBs and PCDDs compared to reference eggs collected nearby in the CascadeMountains. Prey remains at nest sites indicated that the Largescale Sucker (Catostomus macrocheilus) and NorthernPikeminnow (Ptychocheilus oregonensis) accounted for an estimated 90.1% of the biomass in the Osprey diet, and composite samples of these two species were collected from different sampling sites throughout the study area for contaminant analyses. With the large percentage of the fishbiomass in the Osprey diet sampled for contaminants (and fisheaten by Ospreys similar in size to those chemically analyzed),and fish contaminant concentrations weighted by biomass intake, a mean BMF was estimated from fish to Osprey eggs for the largeseries of contaminants. BMFs ranged from no biomagnification(0.42) for 2,3,7,8-TCDF to 174 for OCDD. Our findings for themigratory Osprey were compared to BMFs for the resident HerringGull (Larus argentatus), and differences are discussed. Webelieve a BMF approach provides some basic understanding ofrelationships between contaminant burdens in prey species offish-eating birds and contaminants incorporated into their eggs,and may prove useful in understanding sources of contaminants inmigratory species although additional studies are needed.     

Status of Heavy Metals in Water and Bed Sediments of River Gomti – A Tributary of the Ganga River, India

The concentrations of cadmium, chromium, copper, iron, lead, manganese, nickel, and zinc in water and bed sediments of river Gomti have been studied in a fairly long stretch of 500 km from Neemsar to Jaunpur. Grab samples of water (October 2002–March 2003) and bed sediments (December 2002 and March 2003) were collected from 10 different locations following the standard methods. The river water and sediment samples were processed and analyzed for heavy metals viz., Cd, Cr, Cu, Fe, Pb, Mn, Ni, and Zn, and using ICP-AES. The heavy metals found in the river water were in the range: Cd (0.0001–0.0005 mg/L); Cr (0.0015–0.0688 mg/L); Cu (0.0013–0.0.0043 mg/L); Fe (0.0791–0.3190 mg/L); Mn (0.0038–0.0.0973 mg/L); Ni (0.0066–0.011 mg/L); Pb (0.0158–0.0276 mg/L); and Zn (0.0144–0.0298 mg/L) respectively. In the sediments the same were found in the range: Cd (0.70–7.90 g/g); Cr (6.105–20.595 g/g); Cu (3.735–35.68 g/g); Fe (5051.485–8291.485 g/g); Mn (134.915–320.45 g/g); Ni (13.905–37.370 g/g); Pb (21.25–92.15 g/g); and Zn (15.72–99.35 g/g) of dry weight respectively. Some physico-chemical parameters viz., pH, total solids, total dissolved solids, total suspended solids, dissolved oxygen, biological oxygen demand, chemical oxygen demand, hardness etc. were estimated as these have direct or indirect influence on the incidence, transport and speciation of the heavy metals. Based on the geoaccumulation indices, the Gomti river sediments from Neemsar to Jaunpur are considered to be unpolluted with respect to Cr, Cu, Fe, Mn, and Zn. It is unpolluted to moderately polluted with Pb. In case of Cd it varies from moderately polluted to highly polluted. As far as Ni is concerned the sediment is very highly polluted at Barabanki and Jaunpur D/s. No correlation was found between enrichment factor and geoaccumulation index.     

A study on the phytoaccumulation of waste elements in wetland plants of a Ramsar site in India

Some wetland plant species are adapted to growing in the areas of higher metal concentrations. Use of such vegetation in remediation of soil and water contaminated with heavy metals is a promising cost-effective alternative to the more established treatment methods. Throughout the year, composite industrial effluents bringing various kinds of heavy metals contaminate our study site, the East Calcutta Wetlands, a Ramsar site at the eastern fringe of Kolkata city (formerly Calcutta), India. In the present study, possible measures for remediation of contaminated soil and water (with elements namely, Ca, Cr, Cu, Pb, Zn, Mn, and Fe) of the ecosystem had been investigated. Ten common regional wetland plant species were selected to study their efficiency and diversity in metal uptake and accumulation. Results showed that Bermuda grass (Cynodon dactylon) had the highest total Cr concentration (6,601 ± 33 mg kg^???1 dw). The extent of accumulation of various elements in ten common wetland plants of the study sites was: Pb (4.4?C57 mg kg^???1 dw), Cu (6.2?C39 mg kg^???1 dw), Zn (59?C364 mg kg^???1 dw), Mn (87?C376 mg kg^???1 dw), Fe (188?C8,625 mg kg^???1 dw), Ca (969?C3,756 mg kg^???1 dw), and Cr (27?C660 mg kg^???1 dw) indicating an uptake gradient of elements by plants as Ca>Fe>Mn>Cr>Zn>Cu>Pb. The present study indicates the importance of identification and efficiency of metal uptake and accumulation capabilities by plants in relation to their applications in remediation of a contaminated East Calcutta Wetland ecosystem.     

Spatial and Temporal Variations in Trace Metal Concentrations in the Cockle, Austrovenus Stutchburyi from Otago, New Zealand

This is the first comprehensive study of sources of variation in metal concentrations within the whole tissues of a shallow burrowing, filter-feeding intertidal clam, Austrovenus stutchburyi. Samples were collected from 12 sites in April, August, November and February in 1993–1994 in the vicinity of Otago Harbour and Peninsula, New Zealand. Total tissue trace metal concentrations (μg g⁻¹ dry weight) were measured in individual animals for the essential metals : Mn, Cu, Zn, Ni and the non-essential Cr using trace-metal clean acid-digestion and ICP-OAES techniques. Average metal concentrations were 3–60 μg g⁻¹ for Cu, 40–118 μg g⁻¹ for Zn, 2–12 μg g⁻¹ for Mn, 5–35 μg g⁻¹ for Ni and 1–44 μg g⁻¹ for Cr. These levels decreased with body weight and differed amongst sites except for Cr in February (mid-summer). Highest concentrations occurred at sites close to a city (Dunedin) and within the central harbour region although the Cu, Zn, Ni and Cr concentrations did not correlate with the environmental gradient or season. At one coastal site, samples of both the blue mussel Mytilus galloprovincialis and cockles gave similar trends in trace metal levels. These results suggest that the cockle could be a useful trace metal biomonitor within NZ estuaries.     

Nickel and Cadmium Concentrations in Plasma and Na+/K+ATPase Activities in Erythrocyte Membranes of the People Exposed to Cement Dust Emissions

The aim of this study was to determine the concentrations of nickel and cadmium in blood plasma of the people exposed to cement dust emissions and to investigate the effects of exposure period on the activities of Na⁺/K⁺ ATPase enzymes in their erythrocyte membranes. The study was carried out on people living in Eskiehir Çukurhisar rural area, located near a cement factory. Blood samples of the individuals residing in this area were taken from 80subjects (30 for control) following a physical examination. The analysis of plasma samples showed that nickel concentrations in subject group were found to be significantly higher than those of the control group (p < 0.001). Cadmium concentrations were found to be within the reference values for both group and no difference was found between the subjects and controls (p > 0.05). Furthermore, no correlation was observed between the levels of Na⁺/K⁺ ATPase activity in erythrocyte membranes of the subject group and the ages of people living in the region (p > 0.05, r = 0.133). It was also observed that nickel concentrations increased by age (p < 0.001, r = 0.646) while no effect was observed in means of cadmium. Na⁺/K⁺ ATPase activities in the erythrocyte membranes were not affected.In conclusion although there was no difference between the Na⁺/K⁺ ATPase activity in means of age, there was an environmental pollution and may be it was due to the industrial plant.     

Concentrations of Cadmium, Mercury and Selenium in Blood, Liver and Kidney of Common Eider Ducks from the Canadian Arctic

We determined concentrations of selected trace elements inlivers, kidneys and blood samples from common eiders (Somateria mollissima borealis) from the eastern Canadianarctic during 1997 and 1998. Concentrations of totalmercury and organic mercury were generally low in the liversof these birds (less than 6 and 4 g g^–1 dry wt,respectively). Selenium ranged between 11–47 g g^–1 inlivers. Renal cadmium concentrations were among the highestever published for this species (range: 47–281 g g^–1). The regressions of log-transformed concentrations ofthese trace elements in blood samples on those in liver orkidney were significant (all P-values < 0.05) andpositive. However, except for organic mercury (RM ² = 0.83), the co-efficients of determination were low tomoderate (range of R ²: 0.26–0.52), suggesting poorto moderate predictive capability. Furthermore, therelationships between total mercury in blood and liverchanged between 1997 and 1998, suggesting that it would notbe possible to predict consistently, concentrations ofmercury in blood from those in liver based on samples takenin one year. Blood samples can be used to determineconcentrations of these trace elements in common eiders (andprobably other sea duck species as well). The use of bloodsamples is especially warranted when it is undesirable tokill the animal such as when working with rare or endangeredsea duck species or when the objective is to relate traceelement exposure to annual survival rates. However, thepredictive equations developed here should not be used topredict expected concentrations in one type of tissue fromthose in the other.     

Assessment of heavy metal pollution in vegetables and relationships with soil heavy metal distribution in Zhejiang province,China

There are increasing concerns on heavy metal contaminant in soils and vegetables. In this study, we investigated heavy metal pollution in vegetables and the corresponding soils in the main vegetable production regions of Zhejiang province, China. A total of 97 vegetable samples and 202 agricultural soil samples were analyzed for the concentrations of Cd, Pb, As, Hg, and Cr. The average levels of Cd, Pb, and Cr in vegetable samples [Chinese cabbage (Brassica campestris spp. Pekinensis), pakchoi (Brassica chinensis L.), celery (Apium graveolens), tomato (Lycopersicon esculentum), cucumber (Colletotrichum lagenarium), cowpea (Vigna unguiculata), pumpkin (Cucurbita pepo L.), and eggplant (Solanum melongena)] were 0.020, 0.048, and 0.043 mg kg^?1, respectively. The Pb and Cr concentrations in all vegetable samples were below the threshold levels of the Food Quality Standard (0.3 and 0.5 mg kg^?1, respectively), except that two eggplant samples exceeded the threshold levels for Cd concentrations (0.05 mg kg^?1). As and Hg contents in vegetables were below the detection level (0.005 and 0.002 mg kg^?1, respectively). Soil pollution conditions were assessed in accordance with the Chinese Soil Quality Criterion (GB15618-1995, Grade II); 50 and 68 soil samples from the investigated area exceeded the maximum allowable contents for Cd and Hg, respectively. Simple correlation analysis revealed that there were significantly positive correlations between the metal concentrations in vegetables and the corresponding soils, especially for the leafy and stem vegetables such as pakchoi, cabbage, and celery. Bio-concentration factor values for Cd are higher than those for Pb and Cr, which indicates that Cd is more readily absorbed by vegetables than Pb and Cr. Therefore, more attention should be paid to the possible pollution of heavy metals in vegetables, especially Cd.     

Intake of Chromium by the Adult Population of Mumbai City

Electro Thermal Atomic Absorption Spectrophotometry (ET-AAS), is used for the determination of chromium (Cr) in a variety of environmental matrices. The detection limit for the estimation of Cr is 2 pg absolute for a volume injection of 20 l. The precision of the method is established by analysing Cr from a synthetic mixture containing various elements in different qualities (0.5–10 ppm) and is found to be within ± 8%. The reliability of estimation is further assessed through the analysis of Standard Reference Materials (SRMs) of soil, hay, milk powder and lake sediment obtained from IAEA.The total intake of Cr through air, water and food works out to be 54 g/day for the adult population of Mumbai city. The dietary intake through food is the major contributor to the total intake of Cr. The concentration of Cr in atmospheric air and drinking water collected from different suburbs showed geometric mean concentrations of 0.09 g/m³ and 0.3 g/l, respectively. The daily intake of Cr, though lower, is closer to the lower bound of the recommended value of 50–200 g/day.     

Characterisation of particulate matter emissions from the Zimbabwe Mining and Smelting Company (ZIMASCO) Kwekwe Division (Zimbabwe): a ferrochrome smelter

Particulate matter emissions from stack number 2 of a majorferrochrome smelter, Zimbabwe Mining and Smelting Company(ZIMASCO) were characterized and the rates at which the elementsCr, Fe, Cu and Zn and total ferrochrome dust are emitted into theatmosphere were determined. The extent of soil contamination bythe dust deposited around the smelter in the generally prevailingsoutheasterly wind direction around the smelter was carried out.The highest concentrations of Cr and Fe occurred in the fineparticulates of sizes less than 59 m whilst that of Cu and Znoccurred in the coarse particulates of size range 70-100 m.The emission rates from stack 2 were; total ferrochromeparticulates 62.17 kg h^-1, Cr 6.217 kg h^-1, Fe 2.423 kg h^-1, Zn42 mg h^-1 and 6 mg h^-1 for Cu. Particulate matter was emitted at arate of 289 mg m^-3 from stack number 2. This value exceeds thelegal limit of 200 mg m^-3. Chromium and iron are the metalsin the largest amounts. The particles that constitute the largestproportion of the dust were in the range of 58-107.5 m. Thisis a characteristic feature of the particulate matter emissionsfrom ZIMASCO. Soils in the downwind direction from the smelterwere polluted with Cr up to a distance of about 700 m outward fromthe perimeter of the boundary of the smelter.     

Optical Resilience of the Paraíba do Sul River (Brazil) during a Toxic Spill of a Wood-Pulping Factory: The Cataguazes Accident

This study investigates the inherent optical properties (IOP) of a Brazilian river during a non-natural, anthropogenically mediated, toxic spill of a wood-pulping factory (the ‘Cataguazes accident’). The results indicated an outstanding transformation in the river water chromophoric dissolved organic matter (CDOM) pools. For instance, increases in CDOM absorption coefficients, a _CDOM (λ), which were averaged at specific spectral intervals, , ranged from 58-fold at the UV-B and UV-A ranges to 95-fold at the PAR range. As a result, the water color expressed as CDOM absorption at 440 nm, a _CDOM (440), varied from 4.16 to 365.03 m^-1. For S-coefficient, the variations ranged from ∼1.1 to 5.6-fold, respectively, at the 300–650 nm and UV-B range. The variability of S as a proxy of dissolved chromophores was thus clearly influenced by the spectral range used. Optical proportions were also investigated through the use of and S ratios at the UV-B, UV-A, and PAR ranges and, in the case of , also at the NIR range. This approach also showed clear variations between the water samples, likely reflecting changes in the composition of optically active substances in the river system. As a whole, the findings obtained here indicated that both the quantity and quality of the chromophoric material dissolved in the river water were greatly altered by the toxic spill. The changes in the optical properties of the river water, although extreme and likely with no parallel in the literature, were quite rapid as indicated by the optical resilience of the system. Overall, this study indicates that IOP might be thought, and possibly used, as a metric tool for monitoring the state of waters and aquatic ecosystems.     

Atrazine and Alachlor Inputs to Surface and Ground Waters in Irrigated Corn Cultivation Areas of Castilla-Leon Region, Spain

The inputs of atrazine and alachlor herbicides to surface and ground waters from irrigated areas dedicated to corn cultivation in the Castilla-León (C-L) region (Spain) as related to the application of both herbicides were studied. Enzyme-linked immunosorbent assays (ELISA) were used for monitoring the atrazine and alachlor concentrations in 98 water samples taken from these areas. Seventy-nine of the samples were of ground waters and 19 were of surface waters. The concentration ranges of the herbicides detected in the study period (October 1997–October 1998) were 0.04–25.3 g L^–1 in the surface waters and 0.04–3.45 g L^–1 in the ground waters for atrazine, and 0.06–31.9 g L^–1 in the surface waters and 0.05–4.85 g L^–1 in the ground waters in the case of alachlor. The highly significant correlation observed between the concentrations of both herbicides in the surface waters (r = 0.89, p < 0.001) pointed to a parallel transport of atrazine and alachlor to these waters. A study was made of the temporal evolution of the concentrations of both herbicides, and it was found a maximum recharge of atrazine in the ground waters for April 1998 and of alachlor in October 1997 and October 1998. The temporal evolution of the concentrations of both herbicides in surface waters was parallel. The highly significant correlations observed between atrazine concentrations determined by ELISA and by HPLC (r = 0.92, p < 0.001) and between alachlor concentrations also determined by both methods (r = 0.96, p < 0.001) confirmed the usefulness of ELISA for monitoring both herbicides in an elevated number of samples. Using HPLC, the presence in some waters of the alachlor ethanesulfonate (ESA) metabolite was found at a concentration range of 0.52–4.01 g L^–1. However the interference of ESA in the determination of alachlor by ELISA was negligible. The inputs of atrazine and alachlor to waters found in this study, especially the inputs to ground waters, could pose a risk for human health considering that some waters, though sporadically, are even used for human consumption.