Mercury pollution of effluent,air, and soil near a battery factory in Tanzania

Effluent, air, and soil samples near a battery factory in Dar es Salaam, Tanzania, where HgCl₂ is used to prevent mold growth, were collected to explore the potential for pollution of the environment from industrial discharge of Hg. Flameless atomic absorption spectrophotometry was used for Hg determinations. The concentration of Hg in the effluent ranged from <0.2 to 5.2 mg L^?1 and the Hg concentration varied greatly within and among sampling days, showing different peaks. Air contained a mean of 4.0 μg m^?3 with little variation within and between sampling days. Soils near the factory contained high Hg levels, from 6.7 to 472 mg kg^?1 in the immediate vicinity, the highest level being associated with disposal of solid waste (defective batteries). Downwind the concentration of Hg decreased with increasing distance from the factory resulting in a soil concentration of 1.0 mg Hg kg^?1 about 2 km away. Upwind the Hg concentration decreased drastically within a distance of 100 to 200 m.     

Chronic effects of low ph and elevated aluminum on survival,maturation, spawning and embryo-larval development of the fathead minnow in soft water

Fathead minnows (Pimephales promelas) were exposed to a range of pH and A1 concentrations in soft water (8 mg Ca L^?1) to determine effect levels at various life stages. The tested pH levels ranged from 8.0 through 5.2 and inorganic monomeric Al from 15 through 60 μg L^?1. Reproductive processes including spawning, embryogenesis and early larval survival were more sensitive to acid stress than were juvenile growth and survival. Juvenile survival was significantly reduced at pH 5.2 + 60 μg Al L^?1 (P <0.05). Spawning success was reduced at pH 6.0 and 5.5 (P <0.10) and failed completely at pH 5.2, regardless of Al concentration. An apparant beneficial effect of added Al was observed during spawning at pH 7.5 + 35 μg Al L^?1, but this effect was not significantly greater than at pH 7.5 + 15 μg Al L^?1. A significant (P <0.05) decrease in larval survival occurred at pH 6.0 + 15 μg Al L^?1 and lower compared to the survival at pH 7.5 + 15 μg Al L^?1. Aluminum at 30 μg L^?1 provided protection resulting in short term increased embryo-larval survival at pH 5.5. The effect of parental exposure on progeny survival was assessed by an interchange of embryos from the spawning treatment to all tested exposure conditions. When reared at pH 8.0 + 15 μg Al L^?1 through 6.0 + 15 μg Al L^?1 or at pH 5.5 + 30 μg Al L^?1, parental exposure did not significantly influence progeny survival. However, survival was significantly reduced among progeny from brood fish reared at pH 5.5 + 15 μg Al L^?1 as compared to those spawned at pH 6.0 + 15 μg Al L^?1 and above, or at pH 5.5 + 30 μg Al L^?1 (P <0.05). Juvenile or 14 d larval growth effects were not detected under any exposure condition (P >0.05). Ultimately, fathead minnow young-of-the-year recruitment and production potential can be expected to diminish when environmental pH falls to 6.0, and to fail completely at 5.5 and lower.     

Volume regulation and accumulation of copper in whole and decapitated Hediste (Nereis) diversicolor under varying salinity — Copper regimes

Volume regulation (weight change) correlates with varying salinity — Cu regimes in whole worms. Decapitation removed this correlation. Regulation of volume and Cu ion uptake are not coupled. Whole worms when exposed to Cu levels of 0.15 to 0.45 mg L^?1 accumulated Cu which ranged from 48.9 to 145 μg g^?1 dry weight within four days. Decapitated worms exposed to similar doses of Cu accumulated from 77.3 to 405.4 μg g^?1 dry weight Cu within three days. Volume regulation appears to be both passive and active processes mediated by the nervous system.     

FLOWER ABSCISSION IN PEPPER PLANTS GROWN UNDER DIFFERENT REGIMES OF NITROGEN FERTILIZATION AND PHOTOSYNTHETICALLY ACTIVE RADIATION

The effect of nitrogen fertilization on flower abscission in pepper was studied under different growth regimes. The pepper plants were irrigated with 4, 9, and 14 meq L^?1of nitrate (N4, N9, and N14). The plants were grown in winter under a low level (639 mol m^?2) of cumulative photosynthetically active radiation (PAR) (L_PAR), and in spring under a high level (1074 mol m^?2) of cumulative PAR (H_PAR). The number of flowers and flower abscission were higher under H_PAR than under L_PAR. Flower abscission was higher in response to treatment N4, than in response to treatments N9 and N14, while the flower number was significantly lower. Flower abscission was strongly correlated with growth-related parameters as well as with the carbon or nitrogen contents in plants. Neither the sucrose fluxes nor the amino acid fluxes through the flower pedicels were affected by nitrogen supply. The sucrose fluxes were strongly correlated with air temperature.     

Aquatic mosses for the detection and follow-up of accidental discharges in surface waters

Aquatic mosses have been used to study four accidental discharges of the heavy metals Cd, Zn and Hg or the chlorinated hydrocarbons pentachlorophenol (PCP) and lindane in highly contrasting river types. Hg, PCP and lindane moss concentrations reached 880, 4500 and 350 ng g^?1, respectively. In the case of Cd and Zn, water samples and transferred bioindicators were taken simultaneously throughout an accidental discharge. The very high dissolved metal concentrations reached during this accident (9 mg L^?1 Zn, 90 μg L^?1 Cd) induced accumulation by the mosses of up to 28 mg g^?1 for Zn and 225 μg g^?1 for Cd. The increase in concentrations in the mosses was as rapid and substantial as in the water, the time lag due to accumulation kinetics being almost zero. On the other hand, the memory effect enabled mosses to retain marked evidence of Cd, Zn, Hg, PCP and lindane up to 13 days after the accident when difference from background levels can hardly be detected in the water. The four case studies, which killed fish, but not the mosses, show that the previously established scales of quality based on the analysis of aquatic mosses are well suited to estimating the potential damage to the aquatic ecosystem as a whole.     

An investigation of blood lead content and atmospheric lead levels in Bangkok

Experiments were conducted during a 5 mo period (September 1975 to January 1976) to determine the Pb concentrations in Bangkok streets and blood Pb levels of Bangkok's population. A total of 185 air samples and 222 blood samples was collected and analyzed. Street Pb levels are in the range of 6.16 to 22.48 μg m^?3 and blood Pb levels are in the range of 1 to 34 μg (100 g)^?1 of whole blood, with an average value of 12.3 μg (100 g)P^?1. The effects of various parameters on air and blood Pb levels are discussed in this paper. Air Pb levels are found to be closely related to traffic volume and proximity to the roads. Blood Pb levels are found to increase progressively with age, reaching a saturation value at about 40 yr of age. The average time spent daily on roads by the people and the distance of their residence/workplace from the main road are found to be major parameters, affecting the blood Pb levels. There is no evidence to show that blood and air Pb levels are directly related, at the present ambient exposure levels.     

Toxicity of heavy metals (Zn,Cu, Cd,Pb) to vascular plants

The literature on heavy metal toxicity to vascular plants is reviewed. Special attention is given to forest plant species, especially trees, and effects at low metal concentrations, including growth, physiological, biochemical and cytological responses. Interactions between the metals in toxicity are considered and the role of mycorrhizal infection as well. Of the metals reviewed, Zn is the least toxic. Generally plant growth is affected at 1000 μg Zn L^?1 or more in a nutrient solution, though 100 to 200 µg L^?1 may give cytological disorders. At concentrations of 100 to 200 μg L^?1, Cu and Cd disturb metabolic processes and growth, whereas the phytotoxicity of Pb generally is lower. Although a great variation between plant species, critical leaf tissue concentrations affecting growth in most species being 200 to 300 μg Zn g^?1 dry weight, 15 to 20 μg Cu g^?1 and 8–12 μg Cd g^?1. With our present knowledge it is difficult to propose a limit for toxic concentrations of Zn, Cu, Cd and Pb in soils. Besides time of exposure, the degree of toxicity is influenced by biological availability of the metals and interactions with other metals in the soil, nutritional status, age and mycorrhizal infection of the plant.     

Effects of Some Organic Nitrogen Sources and Antibiotics on Callus Growth of Indica Rice Cultivars

A factorial experiment based on a completely randomized design with three replicates was conducted to evaluate effects of sixteen different mixtures of organic nitrogen sources and antibiotics which were supplemented to an Murashige and Skoog (MS) medium containing 4 mg L^?1 2,4-Dichlorophenoxyacetic acid (2,4-D), 0.4 mg L^?1 benzyl-aminopurine (BAP), 30 g L^?1 sucrose, 8 g L^?1 Agar-agar on fresh weight and dry weight (assessed after three days of drying at 70°C) of calli and in vitro callogenesis from scutellum of four indigenous Iranian Indica rice (Oryza sativa L.) cultivars, including ‘Hashemi’, ‘Gerdeh’, ‘Hasani’, and ‘Gharib’. It was found that proline at 2.8 g L^?1 is the most effective source of organic nitrogen in enhancing growth, whereas asparagine at 0.75 g L^?1 inhibited the calli growth. Hygromycin at 50 mg L^?1, with slight differences between the cultivars, could effectively stunt the growth of untransformed calli. Mixture of cefotaxime (250 mg L^?1) and vancomycin (250 mg L^?1) did not have any significant effects on calli growth, although this treatment was slightly phytotoxic.     

Metal concentrations in the ground water of the Ouachita Mountains,Arkansas, U.S.A.

Ninety-one ground water samples (predominantly from springs) in two mineralized areas of the Ouachita Mountains in west-central Arkansas, were analyzed for Fe, Mn, Zn, Cu, Co, Ni, Pb, Hg, Sb, Sr, Ba, Ca, and Li. These areas contain Mn, barite, strontianite, cinnabar, stibnite and scattered Pb-Zn mineralization, Cumulative frequency curves were used to determine the threshold and anomalous concentrations for each element in the two areas. These values were, in general, higher in the ground water from the more mineralized area for several of the base metals, but most notably for Mn and Fe, the principal metals in the Mn oxide minerals. The United States Environmental Protection Agency (EPA, 1976) criteria for Fe (300 μg L ^?1) and Mn (50 μg L^?1) in drinking water were exceeded, respectively, in 34% and 30% of the springs in Area I, and 13% and 23% in Area II. One spring exceeded the EPA Hg criterion (2 μg L^?1) and 3 springs exceeded the 50 μg L^?1 criterion for Pb. In spite of the large number of anomalous Ba concentrations, the highest concentration of Ba was 930 μg L^?1 (EPA criterion 1000 μg L ^?1).     

Polluted precipitation and the geochronology of mercury deposition in lake sediment of northern Minnesota

Elevated Hg levels in game fish from wilderness lakes in northern Minnesota led to the present study of sediment cores from two lakes to ascertain the source and history of Hg deposition. Natural background levels of Hg were found to range from 0.03 to 0.06 μg g^?1, with cultural levels as high as 0.16 μg g^?1. Reconstructed geochronologies reveal a dramatic two-fold increase in Hg flux, from 0.008 to 0.017 μg cm^?2 yr^?1, occuring after the year 1880, suggesting an anthropogenic influence. No industrial or geologic source of Hg is found in the study watersheds. The entire historical increase in Hg flux can be accounted for by atmospheric loading provided that 1/5 of all the Hg presently supplied to the watershed via precipitation is ultimately deposited in lake sediment. Hg levels in fish are not correlated with Hg levels in lake sediment, although there is a link to acid-sensitivity of lake water, amount of acid-neutralizing geologic material exposed in the watershed, and watershed area/lake volume ratio. Thermal stratification of lake water and a complexation-adsorption mechanism are proposed to account for variations in Hg levels observed in sediment collected from different sites.     

Seasonal variations of oil residues in water of Shatt al-Arab river,Iraq

The distribution and seasonal variations of petroleum residues in the Shatt al-Arab water column have been determined spectrofluorometrically. Their concentrations were found to vary between 1.7 to 35.4 μg L^?1 Kuwait crude oil equivalents. The results suggested that petroleum hydrocarbons present in this river originated from diverse sources. Hydrocarbon amounts tend to be highest in winter (averaged 17.4 μg L^?1) and lowest in summer (averaged 3.1 μg L^?1).     

Behavior of Iodine in a Forest Plot,an Upland Field and a Paddy Field in the Upland Area of Tsukuba,Japan. Iodine Concentration in Precipitation,Irrigation Water,Ponding Water and Soil Water to a Depth of 2.5 m

In the course of a series of studies conducted to investigate the long-term behavior of ¹²⁹I (which has a half-life of 16 million years) in the environment, the concentration of stable iodine (¹²⁷I) in precipitation, irrigation water and soil water to a depth of 2.5 m in a forest plot, an upland field and a paddy field in the upland area of Tsukuba, Japan, was determined. In the forest plot, the mean iodine concentrations in soil water at all the depths ranged from 0.13 to 0.21 μg L^?1, about one-tenth of the values recorded in precipitation (weighted mean 2.1 μg L^?1). This finding suggests that the major part of iodine in precipitation was sorbed onto the surface soil horizon under oxidative conditions. In the upland field, the mean iodine concentration in soil water was 2.2 μg L^?1 at a depth of 0.2 m and it decreased to 0.34–0.44 μg L^?1 at a depth of 0.5 m or more; these concentrations were about one-fifth of that in precipitation. This suggested that the major part of the iodine derived from precipitation was sorbed onto the subsurface soil horizon (at depths between 0.2 and 0.5 m). In the paddy field, during the non-irrigation period, the mean iodine concentrations in soil water at all the depths ranged from 1.8 to 4.8 μg L^?1, almost the same values as those recorded in precipitation. During the irrigation period, the mean iodine concentrations at depths of 0.2 and 0.5 m were 18.8 and 16.7 μg L^?1, values higher than the 10.9 μg L^?1 value recorded in irrigation water and the 11.8 μg L^?1 value recorded in ponding water. However, at a depth of 1.0 m or more, the mean iodine concentrations in soil water rapidly decreased from 7.3 to 1.8 μg L^?1. These data suggested that a significant amount of iodine flowed out from the paddy field by surface runoff and a considerable amount of iodine that leached to a depth of 0.5 m was retained onto the mildly oxidative soil horizon (2Bw) that lay at depths between 0.5 and 1.0 m. At a depth of 2.5 m in the paddy field, the mean iodine concentration in soil water decreased to 1.8 μg L^?1, but this level was much higher than those in the forest plot and upland field at the same depth, which suggested that a significant amount of iodine had leached into the groundwater-bearing layer. There was a negative correlation (r=-0.889) between the E_h of soil and the iodine concentration in soil water (0.2 m depth) of the paddy field. Particularly, when the E_h of soil fell below approximately 150 mV, the iodine concentration rapidly increased to above 10μg L^?1. As for the chemical forms of iodine in precipitation, irrigation water, ponding water and soil water during the winter irrigation period in the paddy field with oxidative conditions, 58–82% of iodine consisted of IO^? ₃ and 17–42% of iodine consisted of I^?. In the soil water during the summer irrigation period in the paddy field under reductive conditions, 52–58% of iodine consisted of I^?, and 42–47% consisted of IO^? ₃.     

PHYSIOLOGICAL AND BIOCHEMICAL CHANGES IN CATHARANTHUS ROSEUS L. IN RESPONSE TO BORON NUTRITION

Catharanthus roseus L., a medicinally important plant was grown till maturity at varying levels of boron (0.033, 0.066, 0.33 and 3.3 mg B L^?1) supply. Optimum yield was observed in plants receiving 0.33 mg B L^?1. Plants receiving deficient boron showed growth reduction and visual symptoms such as chlorosis and cupping of young emerging leaves and apical tip necrosis. The number and size of the flowers, pods and seeds formed and the pollen viability of the boron deficient plants was markedly reduced. The threshold values for deficiency and toxicity were 57 and 79 μg B g^?1 dry weight for vegetative growth and 60.4 and 68.9 μg B g^?1 dry weight for reproductive growth, respectively, and is reported for the first time in periwinkle. An increase was observed in reducing and non-reducing sugars and in activity of acid phosphatase and ribonuclease in boron stressed plants.     

Inducing waterlogging tolerance in cotton via an anti-ethylene agent aminoethoxyvinylglycine application

Increased ethylene biosynthesis in cotton tissues have been associated with accelerated fruit abscission and yield losses in waterlogged cotton. In a series of glasshouse and field experiments, we investigated the effect of various application rates (0, 50, 100 and 150 [active ingredient, ai] ha^?1) and time (pre- and post-waterlogging) of an anti-ethylene agent, aminoethoxyvinylglycine (AVG) on the growth and yield of cotton. The glasshouse study suggested that AVG (100–150 g [ai] ha^?1) applied 24 h prior to waterlogging can increase growth and fruit retention (FR) of waterlogged (WL) and non-waterlogged (NWL) cotton. The positive effects of AVG were further validated in two years of field studies, suggesting that AVG (125 g [ai] ha^?1) applied at an early reproductive phase of cotton can significantly increase cotton yield under WL (13%, averaged over two years) and NWL (9%, averaged over two years) environments. Yield increase in AVG-treated cotton was associated with increased number of bolls, boll weight and FR. On the other hand, no further improvement in cotton yield under higher AVG concentration (150 g [ai] ha^?1) indicated the saturation of AVG on ethylene inhibition. Thus, appropriate AVG concentration and application timing may help overcome waterlogging-induced yield losses in cotton production systems.     

Water Column and Sediment Phosphorus in a Calcareous Lowland River and Their Differential Response to Point Source Control Measures

Phosphorus control measures at two major (>10000 people equivalent, p.e.) sewage treatment works (STWs) were installed in the lowland calcareous basin of the River Wensum (England). In-stream phosphorus concentrations were monitored seasonally from subcatchments with different levels of phosphorus impacts, as well as before and after phosphorus control, above and below the two major STWs. Point source effluents raised in-stream soluble reactive phosphorus (SRP) concentrations from 9–15 μg L^?1 (agricultural sub-catchments) to 580–3270 μg L^?1. This was accompanied by an increase of the SRP relative to total phosphorus from 27% to 80–90%. The phosphorus content of the suspended sediment was high (0.2 to 7.7%). Molybdate unreactive phosphorus (1–29 μg L^?1) was surprisingly not affected by point source effluents. The river bed sediment bioavailable phosphorus concentrations were higher (4–18 μg g^?1 wet weight) downstream from the main effluents, compared to upstream (2–6 μg g^?1 wet weight). Phosphorus control at the STWs in 1999 has allowed to reduce in-stream soluble reactive concentrations to 140–280 μg L^?1 but has had no significant impact on bioavailable phosphorus in the sediment by 2001, suggesting that either net sediment desorption did not occur or that it is a much slower, longer term response. The relative contribution of the diffuse sources increased from 10% to 27% of the total phosphorus loads at Fakenham. The management of these rivers is therefore problematic.     

Pre-industrial atmospheric deposition of mercury: Uncertain rates from lake sediment and peat cores

Lacustrine sediment cores from depositional areas have frequently been used to estimate pre-industrial rates of atmospheric Hg deposition. However, this approach tends to result in overestimates, partly because of Hg inputs from the catchment, partly because of a horizontal redistribution of sediments within lakes. Peat core studies may suffer from a vertical migration of Hg due to water table fluctuations. A natural Hg deposition rate around 2 μg m^?2 y^?1 is suggested to be more realistic than values of 3 to 12 μg m^?2 y^?1 reported from recent studies. The anthropogenic impact on the present Hg deposition may have been underestimated accordingly.     

Natural Mercury Levels in Geological Enriched and Geological Active Areas: Case Study of Katun River and Lake Teletskoye,Altai (Siberia)

Natural geological Hg deposits control the Hg levels inthe upper Katun river. Very high levels of total Hg areobserved in the watercolumn (up to 20 ng L^-1) and thesediments (up to 244 μg g^-1) close to the depositarea, but almost normal levels (1.8 ng L^-1 in the watercolumn and 0.14 μg g^-1 in the sediments) are reached60 km downstream of that zone. In general, low dissolvedmethylmercury (MMHg) concentrations were found (0.04–0.05 ngL^-1) due to unfavourable methylation conditions. The MMHgconcentrations in the sediments vary from 23.3 ng g^-1, inthe vicinity of the geological Hg deposits, to 0.17 ng g^-1 60 km downstream.Total Hg levels in Lake Teletskoye (a geological activearea) are slightly increased (1.1–1.8 ng L^-1) compared toLake Baikal and fairly constant alover the Lake, suggestingmultiple sources. High mercury concentrations in springs andsoils coincide with high radon concentrations in the samecompartments as well as high soil exhalation fluxes. Theseresults in combination with the fact that Lake Teletskoye islocated in an active fault zone suggest that the Rn and Hgsources may be fault aligned spring waters and deep seatedgases escaping through open cracks. Methylmercuryconcentrations in the Lake (0.03–0.1 ng L^-1) werecomparable to the concentrations found in Katun river butrelative to the total Hg burden this means a higher percentage.     

Evaluation of nanosilicon dioxide and chitosan on tissue culture of apple under agar-induced osmotic stress

In vitro, applications of nanosilicon dioxide (SiO₂) and chitosan were investigated for their effects on growth and proliferation of apple (Malus domestica Borkh. ‘Gala’) explants under osmotic stress induced by agar to simulate drought stress and under non-stressed conditions. The experiment included five levels of SiO₂ (0, 25, 50, 100, and 200 mg L^?1), two levels of chitosan (0 and 40 mg L^?1), and two levels of agar (7 g L^?1 and 9 g L^?1) added to Murashige and Skoog medium. Under non-stressed conditions (7 g L^?1 agar), application of SiO₂ at 50 or 100 mg ^?1 increased proliferation of apple explants. Use of 50 or 100 mg L^?1 SiO₂ or 40 mg L^?1 chitosan increased growth of apple explants under osmotic stress (9 g L^?1 agar). This research suggests that use of SiO₂ or chitosan may improve plant growth and tolerance to stress.     

Selenium Behavior in Open Bulk Precipitation, Soil Solution and Groundwater in Alluvial Fan Area in Tsukui, Central Japan

A monitoring study was carried out in an alluvial fan area in Tsukui, Central Japan during the study period of 1999–2003, in order to explain selenium (Se) behaviors in ecosystem combined with air, soil and groundwater. Monthly Se concentrations in open bulk precipitation (rainfall+aerosol, gaseous deposition and etc.), soil solution (collected by porous ceramic-cup) and groundwater ranged from 0.1 to 1.4 μg L^?1 (volume-weighted average: 0.34 μg L^?1), 0.21 to 1.0 μg L^?1 (0.48 μg L^?1) and 1.6 to 2.4 μg L^?1 (2.2 μg L^?1), respectively. Se concentration in open bulk precipitation was negatively correlated with the rainfall amount. Se concentration in soil solution significantly increased with DOC concentration in soil solution. Besides, despite atmospheric Se input and rainfall to the grassland study area, Se concentration in soil solution and groundwater received no significant effect from the rainfall amount, pH, Se, DOC, SO₄ ^2?, NO₃ ^? and EC in rainfall. Even though Se concentrations in groundwater were significantly correlated with soil solution volume, Se, DOC and NO₃ ^? and groundwater level, the result of multiple regression analyses (MRA) indicated that the groundwater Se was negatively influenced by groundwater level, which depended on groundwater recharge. Se was transported into the groundwater through the groundwater recharge that largely increased in this alluvial fan study area after heavy rain.     

Effects and relative toxicity of heavy metals on Cuscuta reflexa

The effects of four concentrations (0.5, 1, 5 and 10 μg mL^?1) of the heavy metals Hg, As, Pb, Cu, Cd, and Cr on some senescence variables of Cuscuta reflexa Roxb. were studied. All of the treatments, except 0.5 μg mL^?1, decreased Hill reaction activity, chlorophyll and protein contents and dry matter percentage in biomass and increased tissue permeability over control data. The harmful effects of the metals were best visible at 10 μg mL^?1. The general order of sensitivity was As > Cd > Pb > Hg > Cu > Cr (absolute metal concentration). The data suggest that Cuscuta reflexa shows tolerance to the heavy metals tested up to 0.5 μg mL^?1.