Urinary arsenic,cadmium, manganese,nickel, and vanadium levels of schoolchildren in the vicinity of the industrialised area of Asaluyeh,Iran

Asaluyeh is one of the most heavily industrialised areas in the world where gas, petrochemical, and many downstream industries are located. This study aims to survey the biomonitoring of four metals and one metalloid in children living in the vicinity of Asaluyeh area. To do this, we analysed the creatinine-adjusted urinary levels of arsenic (As), cadmium (Cd), vanadium (V), manganese (Mn), and nickel (Ni) in 184 elementary schoolchildren (99 boys and 85 girls) living in Asaluyeh and compared them with a reference population. The comparisons were done for two seasons (spring and fall). The results showed that in the case area (Asaluyeh), the levels of As, V, Mn, and Ni were significantly higher and that of Cd was not significantly higher than the reference city for both seasons. The mean concentration of metal(loid)s in Asaluyeh (case) and Sadabad (reference) area as μg g^?1 creatinine was As 2.90 and 2.24, V 0.06 and 0.03, Mn 0.28 and 0.25, Ni 0.54 and 0.29, and Cd 0.31 and 0.28 in spring and As 3.08 and 2.28, V 0.07 and 0.03, Mn 0.30 and 0.26, Ni 0.91 and 0.30, and Cd 0.36 and 0.31 in the fall. Seasonal variations played a key role in determining urinary metal(loid) concentration, as we saw the significant level of As, Cd, V, and Ni in fall than in spring. With regard to the impact of gender on the absorption and accumulation of urinary metal(loid)s, boys showed higher levels of the studied elements, especially for As, than girls as outdoor activities are more popular among boys. Due to the values being lower than those reported in literature, more research is needed on various population groups and other exposure sources in order to judge whether living in the vicinity of the gas and petrochemical industries in Asaluyeh is a threat to nearby residents.     

Methylmercury, fish consumption, and the precautionary principle

This paper considers several broad issues in the context of probabilistic assessment of the benefits of curtailing mercury (Hg) emissions from U.S. coal-fired power plants, based on information developed from recent literature and epidemiology studies of health effects of methylmercury. Exposure of the U.S. population is considered on the national scale, in large part because of recent questions arising from survey and experimental data about the relative importance of local deposition of airborne Hg. Although epidemiological studies have provided useful information, safe levels of Hg exposure remain uncertain, in part because of other dietary considerations in the populations that were studied. For example, much of the seafood consumed in one of the major studies was also contaminated with polychlorinated biphenyls, as are fish taken from some U.S. fresh waters. The primary epidemiological approach involves cross-study comparisons in relation to mean exposures, rather than detailed critiques of individual effects reported in each study. U.S. exposures are seen to be well below the levels at which adverse health effects are reported. This analysis supports the conclusion that unilateral reduction of Hg emissions from U.S. coal-fired power plants alone is unlikely to realize significant public health benefits.     

Formulation factors that can reduce the formation of the phytotoxic impurity, N,N'-dibutylurea, from benomyl

Fungicide benomyl is easily decomposed to carbendazim (MBC) and butyl isocyanate (BIC) in formulation, BIC is further hydrolyzed to butylamine. The BIC also reacts with butylamine to form N,N'-dibutylurea (DBU), a phytotoxic compound. The purpose of this study was to investigate the effects of selected additives and the manufacturing method of benomyl water dispersible granules (WG) on reducing DBU content in benomyl formulations. The manufacturing methods studied were granulation by extrusion, fluid bed spray, and spray dry. For the extrusion method, each benomyl powder formulation was homogenized by kneading with 20% v/w of 95% ethanol instead of water. After granulation, the percentages of the active ingredient benomyl and its degradation product carbendazim in each formulation were determined. For the fluid bed spray method, two formulations of wettable powders were formed. The first sample was granulated using 5% Na(2)SO(4) as the binder solution; the second sample used 2% urea. Changes in the active ingredient content after granulation were determined for each sample. For the spray dry method, four basic formulations of 70% benomyl, 5% sodium dodecyl sulfate (SDS) and 10% or 20% sodium sulfate were prepared, to study the effects of HMTA, urea and dispersant on reducing DBU formation in formulation. The DBU content of each formulation was measured for the fresh samples and after 1 year of storage. The results showed that urea had a stabilizing effect on benomyl, and reduced DBU formation. BIC increased benomyl yield during manufacturing, which reduced DBU content in fresh samples but allowed a greater potential for future DBU formation since it did not stabilize the extra benomyl. HMTA was found to reduce DBU in both aqueous BIC and prepared formulations. The study discusses how each of the selected constituents affected DBU formation and how commercial formulations can be improved to reduce DBU formation. From this study, it is clear that a safer benomyl formulation can be developed.     

Population-level toxicity of the insecticide, spinosad and the nonylphenol polyethoxylate, R-11, to the cladoceran species Ceriodaphnia dubia Richard

The effects of the natural insecticide, spinosad, and the agricultural adjuvant, R-11, were evaluated on populations of the water flea, Ceriodaphnia dubia after chronic 8-day exposures. The number of individuals used to start the chronic exposure studies (founders) and the number of offspring/surviving female were significantly reduced after exposure to spinosad concentrations ≥ 2.5 μg/L. The final number of individuals was significantly reduced after exposure to spinosad concentrations ≥ 1.0 μg/L. Population growth rate was significantly reduced after exposure to spinosad concentrations ≥ 1 μg/L. Extinction occurred (defined as negative population growth rate) after exposure to spinosad concentrations of 10 μg/L. Therefore, negative effects were observed in C. dubia after exposure to spinosad at a concentration near the chronic expected environmental concentration (EEC) of 2.3 μg/L. R-11 was much less toxic to C. dubia than spinosad. The number of founders was not significantly reduced until C. dubia were exposed to 12,000 μg/L. The number of offspring/surviving female, final number of individuals, and population growth rate were significantly reduced after exposure to R-11 concentrations ≥ 5,000 μg/L. Extinction occurred after exposure to R-11 concentrations of 12,000 μg/L which was above the EEC of 790 μg/L. These results indicate that spinosad and R-11 both have lethal and sublethal effects on C. dubia. However, spinosad appears to affect C. dubia at or near the EEC while R-11 does not negatively affect this species until concentrations are much higher than the EEC.     

Polychlorinated biphenyls in the Kupa River, Croatia, Yugoslavia

The presence of polychlorinated biphenyls (PCBs) was investigated in samples of water, suspended particles, sediments and fish from the Kupa river, Croatia, Yugoslavia, along a river stretch extending up to 10 km upstream and 200 km downstream of the primary contaminated karst region. Contamination was due to improper disposal of industrial waste discharge. The PCB levels detected in the samples collected downstream ranged from 1 to 52 ng 1⁻¹ for water, from 50 to 190 μg kg⁻¹ for suspended particles and from 8 to 39 μg kg⁻¹ for the sediment. A wide range of PCB concentrations, from 0.1 to 42.3 μg g⁻¹, which were measured in edible portions of different fish confirmed a long-term contamination of the river with PCBs. As the Kupa may be classified among low to moderately contaminated waters, it is essential that the investigations of the presence and behaviour of PCBs in the river and its environment be continued.     

Levels of polychlorinated biphenyls, organochlorine pesticides, mercury, cadmium, copper, selenium, arsenic, and zinc in the harbour seal, Phoca vitulina, in Norwegian waters

Residue levels of the chlorinated hydrocarbons polychlorinated biphenyls (PCBs), total DDT, alpha-, beta- and gamma-hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), and oxychlordane in blubber, and the elements mercury, cadmium, copper, selenium, arsenic, and zinc in liver, of 82 harbour seals, Phoca vitulina, were determined. The seals were found dead or dying in Norwegian waters during the disease outbreak caused by a morbilli virus in 1988. Of the chlorinated hydrocarbons, the highest concentrations were found of PCBs, which were 2-4 times higher than the total DDT concentrations. P,p'-DDE was the main contributor to the total DDT, and constituted about 80%. The PCB and total DDT concentrations ranged from 0.4-38 and 0.1-8.8 mg kg(-1), respectively. The mercury concentrations ranged from 0.1-89 mg kg(-1). Significantly higher mean levels of PCBs (13 mg kg(-1) and mercury (16 mg kg(-1)) were found in blubber and liver, respectively, of seals from the Southern coast of Norway, as compared to the corresponding mean levels in seals from the Oslofjord (8.8 and 4.1 mg kg(-1)), and at the Northwestern coast (5.8 and 7.9 mg kg(-1)), respectively. A significant positive correlation was found between the concentrations of selenium and mercury. When the seals were grouped according to sex and age, females of ageclass > 1 and pups of both sexes had significantly lower PCB and total DDT levels than males ageclass > 1. Significantly higher hepatic mercury levels were found in seals ageclass > 1 as compared to pups. Only low levels of the other organochlorines, cadmium and arsenic, were found. Copper and zinc were considered to be present at normal physiological levels. The present organochlorine and heavy metal concentrations gave no support to suggestions that organochlorines and heavy metal pollution may be directly involved in the observed seal deaths.     

Bioaccumulation of toxicants in the zebra mussel, Dreissena polymorpha, at the Times Beach Confined Disposal Facility, Buffalo, New York

This study consisted of a site characterization followed by biomonitoring the zebra mussel, Dreissena polymorpha, at the Times Beach Confined Disposal Facility (CDF), located in Buffalo, New York. Concentrations of selected contaminants, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and metals -arsenic (As), chromium (Cr), barium (Ba), mercury (Hg), cadmium (Cd), lead (Pb), selenium (Se) and silver (Ag)-were at or below detection limits in the water column. Sediment contaminant concentrations, recorded as dry weight, were as high as 549 mg/kg for total PAHs, 9 mg/kg for PCB Aroclor 1248 and 54, 99, 6, 355, 637 and 16 mg/kg for the metals As, Ba, Cd, Cr, Pb and Hg, respectively. To predict contaminant bioavailability, elutriate and whole sediment toxicity tests were performed utilizing the cladoceran, Daphnia magna. Whole sediment tests indicated significant impact. Control survival was 84%, while sediment treatment had survival ranging from 1 to 7%. Mean control reproduction was 86.8 neonates, whereas treatment reproduction ranged from 1.4 to 9.0. Zebra mussels placed both in the water column (Upper) and at the sediment level (Lower) survived the 34-day exposure. Contaminants that significantly accumulated in zebra mussel tissue (wet wt mg/kg) were total PAHs (6.58), fluoranthene (1.23), pyrene (1.08), chrysene (0.98), benzo(a)anthracene (0.60), PCB Aroclor 1248 (1.64), As (0.97), Cr (2.87) and Ba (7.00). Accumulation of these contaminants in zebra mussel tissue represent a potentially realistic hazard to organisms (i.e. fish and birds) that feed on them.     

Lead in the diet and body tissues of dunlins, Calidris alpina, from the Bristol Channel, UK

Lead concentrations were determined in the organs of a shorebird, the dunlin, in its main invertebrate prey, and in sediments collected from five sites in the Bristol Channel. The highest sediment concentrations were found in the Taff Estuary (97 microg g(-1) dry mass). The highest concentrations in invertebrates were found in the upper Severn Estuary (45 microg g(-1) dry mass in Nereis diversicolor). In dunlins, the highest concentrations were found in the sternum (25 microg g(-1) dry mass in males), followed by the beak, legs, kidney, liver and pectoral muscle. Adult males contained significantly higher concentrations (ca 20%) than adult females, and in some cases adults had significantly higher concentrations than first year birds (36% higher in the case of the sternum). Lead concentrations tended to increase throughout the winter, being 37-115% higher in the spring. Birds were able to purge themselves of a substantial portion of their body lead burdens, probably during the autumn moult.     

Toxicity assessment of the maize herbicides S-metolachlor,benoxacor, mesotrione and nicosulfuron,and their corresponding commercial formulations,alone and in mixtures,using the Microtox® test

The Microtox® test, using the prokaryote Vibrio fischeri, was employed to assess the toxicity of the maize herbicides S-metolachlor, benoxacor, mesotrione and nicosulfuron, and their formulated compounds: Dual Gold Safeneur®, Callisto® and Milagro®; alone and in mixtures. For each compound we obtained original IC₅₀ values, with consistent higher toxicities for formulated compounds compared to active ingredients alone. Mixtures of the four herbicides, prepared according to application doses encountered in agriculture, were found to be toxic at a lower concentration than single molecules. Mesotrione and nicosulfuron mixture appeared to be highly toxic to V. fischeri, however, this recommended post-emergence combination for maize crops got its toxicity decreased in formulated compound mixtures, suggesting that chemical interactions could potentially reduce the toxicity. Data comparisons to theoretical models showed a good prediction of mixture toxicity by Concentration Addition concept. Results seemed to exclude any synergistic effects on V. fischeri for the tested herbicide mixtures. Additional work coupling these bioassay data to ecosystemic level studies (aquatic and soil compartments) and data on additives and degradation products toxicity, will help to fill the gap in our knowledge of the environmental impact of these xenobiotics and in the choice of a more sustainable use of pesticides.     

Deltas,freshwater discharge,and waves along the Young Sound,NE Greenland

A wide range of delta morphologies occurs along the fringes of the Young Sound in Northeast Greenland due to spatial heterogeneity of delta regimes. In general, the delta regime is related to catchment and basin characteristics (geology, topography, drainage pattern, sediment availability, and bathymetry), fluvial discharges and associated sediment load, and processes by waves and currents. Main factors steering the Arctic fluvial discharges into the Young Sound are the snow and ice melt and precipitation in the catchment, and extreme events like glacier lake outburst floods (GLOFs). Waves are subordinate and only rework fringes of the delta plain forming sandy bars if the exposure and fetch are optimal. Spatial gradients and variability in driving forces (snow and precipitation) and catchment characteristics (amount of glacier coverage, sediment characteristics) as well as the strong and local influence of GLOFs in a specific catchment impede a simple upscaling of sediment fluxes from individual catchments toward a total sediment flux into the Young Sound.     

Nature and COVID-19: The pandemic,the environment,and the way ahead

The COVID-19 pandemic has brought profound social, political, economic, and environmental challenges to the world. The virus may have emerged from wildlife reservoirs linked to environmental disruption, was transmitted to humans via the wildlife trade, and its spread was facilitated by economic globalization. The pandemic arrived at a time when wildfires, high temperatures, floods, and storms amplified human suffering. These challenges call for a powerful response to COVID-19 that addresses social and economic development, climate change, and biodiversity together, offering an opportunity to bring transformational change to the structure and functioning of the global economy. This biodefense can include a “One Health” approach in all relevant sectors; a greener approach to agriculture that minimizes greenhouse gas emissions and leads to healthier diets; sustainable forms of energy; more effective international environmental agreements; post-COVID development that is equitable and sustainable; and nature-compatible international trade. Restoring and enhancing protected areas as part of devoting 50% of the planet’s land to environmentally sound management that conserves biodiversity would also support adaptation to climate change and limit human contact with zoonotic pathogens. The essential links between human health and well-being, biodiversity, and climate change could inspire a new generation of innovators to provide green solutions to enable humans to live in a healthy balance with nature leading to a long-term resilient future.     

An assessment of the chronic toxicity of the synthetic pyrethroid, fenvalerate, to Daphnia galeata mendotae, using life tables

The effects of chronic exposure to fenvalerate, a synthetic pyrethroid insecticide, on the cladoceran Daphnia galeata mendotae were evaluated under laboratory conditions. The daphnids were exposed for their entire life cycle to concentrations ranging from 0.005 to 0.1 microg fenvalerate litre(-1). The parameters used to determined toxicity were survival, time to first reproduction, reproductive frequency, number of young per brood, cumulative brood size, intrinsic rate of natural increase (r(m)), generation time (T) and net reproductive rate (R(0)). A concentration of 0.005 microg fenvalerate litre(-1) resulted in an increase in longevity but a decrease in production of young. Higher concentrations caused a decrease in survival. Studies of shorter duration than the complete life cycle of the organisms would not have detected toxicity at such low levels. The intrinsic rate of natural increase, r(m), was not affected by fenvalerate until concentration reached 0.05 microg litre(-1) and r(m) decreased to 0.113 from 0.238. A concentration of 0.01 microg litre(-1) caused the net reproductive rate, R(0), and the generation time, T, to decrease to 73.2 offspring per female and 17.3 days from 125.9 offspring per female and 20.3 days, respectively.     

Exposure,epidemiology, and mechanism of the environmental toxicant manganese

It has become increasingly apparent that global manganese (Mn) pollution to air and water is a significant threat to human health. Despite this recognition, research is only beginning to comprehend the detrimental effects of exposure. Mn, while essential, is particularly harmful to the central nervous system, and overexposure is symptomatic of several neurological disorders. At-risk populations have been identified, but it is still unclear whether typical exposure levels have any long-term consequences. Those at an elevated risk have diminished intellectual function, learning and memory, and mental development. While the overall mechanism of toxicity is undetermined, Mn has been found to induce oxidative stress, exacerbate mitochondrial dysfunction, dysregulate autophagy, and promote apoptosis, ultimately enhancing neurodegeneration. Extrapolation of this in vitro and in vivo data to humans is difficult. There is a definite need to correlate epidemiological studies with causative effects. It is imperative that research efforts endure, so threats are appropriately identified and exposure properly regulated.     

A review of the occurrence, analyses, toxicity, and biodegradation of naphthenic acids

Naphthenic acids occur naturally in crude oils and in oil sands bitumens. They are toxic components in refinery wastewaters and in oil sands extraction waters. In addition, there are many industrial uses for naphthenic acids, so there is a potential for their release to the environment from a variety of activities. Studies have shown that naphthenic acids are susceptible to biodegradation, which decreases their concentration and reduces toxicity. This is a complex group of carboxylic acids with the general formula CnH(2n+Z)O2, where n indicates the carbon number and Z specifies the hydrogen deficiency resulting from ring formation. Measuring the concentrations of naphthenic acids in environmental samples and determining the chemical composition of a naphthenic acids mixture are huge analytical challenges. However, new analytical methods are being applied to these problems and progress is being made to better understand this mixture of chemically similar compounds. This paper reviews a variety of analytical methods and their application to assessing biodegradation of naphthenic acids.     

A global perspective on the use, sales, exposure pathways, occurrence, fate and effects of veterinary antibiotics (VAs) in the environment

Veterinary antibiotics (VAs) are widely used in many countries worldwide to treat disease and protect the health of animals. They are also incorporated into animal feed to improve growth rate and feed efficiency. As antibiotics are poorly adsorbed in the gut of the animals, the majority is excreted unchanged in faeces and urine. Given that land application of animal waste as a supplement to fertilizer is often a common practice in many countries, there is a growing international concern about the potential impact of antibiotic residues on the environment. Frequent use of antibiotics has also raised concerns about increased antibiotic resistance of microorganisms. We have attempted in this paper to summarize the latest information available in the literature on the use, sales, exposure pathways, environmental occurrence, fate and effects of veterinary antibiotics in animal agriculture. The review has focused on four important groups of antibiotics (tylosin, tetracycline, sulfonamides and, to a lesser extent, bacitracin) giving a background on their chemical nature, fate processes, occurrence, and effects on plants, soil organisms and bacterial community. Recognising the importance and the growing debate, the issue of antibiotic resistance due to the frequent use of antibiotics in food-producing animals is also briefly covered. The final section highlights some unresolved questions and presents a way forward on issues requiring urgent attention.     

Carboxylic acids in the troposphere, occurrence, sources, and sinks: A review

Carboxylic acids are ubiquitous and important components of the troposphere; they are currently measured in different environments. They are thought to have several sources comprising primary biogenic and anthropogenic emissions, hydrocarbons gas-phase oxidations, and some carbonyl compounds aqueous-phase oxidations. In the present review we make a synthesis of the concentrations of low molecular weight carboxylic acids in tropospheric aqueous and gaseous phases and in aerosol particles for different environments. We also successively examine the major sources of carboxylic acids and discuss their relative contribution to tropospheric concentrations for various environments as well as the principal sinks of these compounds.     

Modeling the competitive effect of phosphate, sulfate, silicate, and tungstate anions on the adsorption of molybdate onto goethite

The mobility of Mo in soils and sediments depends on several factors including soil mineralogy and the presence of other oxyanions that compete with Mo for the adsorbent's retention sites. Batch experiments addressing Mo adsorption onto goethite were conducted with phosphate, sulfate, silicate, and tungstate as competing anions in order to produce competitive two anions adsorption envelopes, as well as competitive two anions adsorption isotherms. Tungstate and phosphate appear to be the strongest competitors of Mo for the adsorption sites of goethite, whereas little competitive effects were observed in the case of silicate and sulfate. Mo adsorption isotherm from a phosphate solution was similar to the one from a tungstate solution. The charge distribution multi-site complexation (CD-MUSIC) model was used to predict competitive adsorption between MoO(4)(2-) and other anions (i.e., phosphate, sulfate, silicate and tungstate) using model parameters obtained from the fitting of single ion adsorption envelopes. CD-MUSIC results strongly agree with the experimental adsorption envelopes of molybdate over the pH range from 3.5 to 10. Furthermore, CD-MUSIC prediction of the molybdate adsorption isotherm show a satisfactory fit of the experimental results. Modeling results suggest that the diprotonated monodentate complexes, FeOW(OH)(5)(-0.5) and FeOMo(OH)(5)(-0.5), were respectively the dominant complexes of adsorbed W and Mo on goethite 110 faces at low pH. The model suggests that Mo and W are retained mainly by the formation of monodentate complexes on the goethite surface. Our results indicate that surface complexation modeling may have applications in predicting competitive adsorption in more complex systems containing multiple competing ions.     

Toxicity of synthetic pyrethroid insecticides to the grass shrimp,Palaemonetes pugio,parasitized with the bopyrid isopod,Probopyrus pandalicola

The grass shrimp, Palaemonetes pugio, plays a large role in the marine ecosystem, serving as a vital link in the food web between many other species. Marine parasites such as the bopyrid isopod, Probopyrus pandalicola, reduce shrimp growth and reproductive output and may also cause P. pugio to be more vulnerable to the lethal effects of contaminants. The purpose of this study was to determine the toxicity of resmethrin and bifenthrin on the grass shrimp, P. pugio, infected with the bopyrid isopod, Probopyrus pandalicola. A 96-h static renewal test was conducted to determine the toxicity of the pyrethroid insecticides resmethrin and bifenthrin to grass shrimp, Palaemonetes pugio, parasitized with the bopyrid isopod, Probopyrus pandalicola. The results were then compared to similar tests utilizing unparasitized P. pugio. Parasitized P. pugio had lower 24-h LC₅₀ (1.08 μg/L) and 96-h LC₅₀ (0.43 μg/L) values for resmethrin than unparasitized P. pugio. However, LC₅₀ ratio tests found that there was no significant difference between parasitized and unparasitized shrimp when affected by resmethrin (p = 0.1751 and 0.1108, respectively). In contrast, an LC₁₀ ratio test indicated that there was a significant difference between parasitized and unparasitized P. pugio after 96 h (p < 0.0001). When subjected to bifenthrin, parasitized P. pugio had a higher 24-h LC₅₀ (0.049 μg/L6) than unparasitized P. pugio. The LC₅₀ ratio test established that the effects of bifenthrin on parasitized P. pugio when compared to unparasitized P. pugio were significantly different at 24 h (p = 0.0065). However, there were no significant differences between parasitized and unparasitized after 96 h (p = 0.4229). In conclusion, both resmethrin and bifenthrin are toxic to the grass shrimp, P. pugio, regardless of parasite presence, and parasitized shrimp may be more susceptible to lower doses of resmethrin (when exposed in the field).     

Lake eutrophication at the urban fringe,Seattle region,USA

Nutrient pollution and associated eutrophication of freshwaters threaten the ecological integrity and the services provided to humans by lakes. We examined how human residential development influenced the level of lake eutrophication in the Seattle, WA, USA, region. We surveyed 30 lakes and measured 3 indicators of eutrophication: concentrations of chlorophyll-a and phosphorus, and the proportion of algae that are inedible to zooplankton. We classified lakes based on the waste-treatment method for shoreline homes: septic, sewer, and undeveloped lakes. Septic lakes occurred along the urban-rural fringe while sewer lakes occurred near urban centers. Septic lakes were more eutrophic than sewer lakes and undeveloped lakes, as indicated by higher levels of phosphorus and chlorophyll-a. These results suggest that septic systems contribute to the high levels of eutrophication in lakes at the urban-rural fringe. Lakes at the urban-rural fringe represent an opportunity for proactive management of urban expansion to minimize lake eutrophication.