Showing papers in "Reviews of Environmental Contamination and Toxicology in 2006"

Ecotoxicological Evaluation of Perfluorooctanesulfonate (PFOS)

Abstract: Based on available toxicity data, protective screening-level concentrations of PFOS were calculated for aquatic and terrestrial organisms. Using the Great Lakes Initiative, water concentrations of PFOS were calculated to protect aquatic plants and animals. The screening plant value (SPV) protective of aquatic algae and macrophytes was calculated as 2.3 mg PFOS/L. The secondary chronic value protective of aquatic organisms was 1.2 microg PFOS/L. The screening-value water concentrations less than or equal to 1.2 microg PFOS/L would not pose a potential risk to aquatic organisms. Because the aquatic benchmark is based on the most sensitive species, this benchmark should also be protective of other aquatic organisms, including amphibians. The tissue-based TRV for fish was determined to be 87 mg PFOS/kg ww. For terrestrial plants, a screening benchmark was determined to be 1.3 mg PFOS/kg soil ww or 1.5 mg PFOS/kg soil dw, whereas for soil invertebrates such as earthworms the benchmark value was 39 mg PFOS/kg dw soil or 33 mg PFOS/kgww soil. For avian species, dietary, ADI, and egg yolk-based benchmarks were determined as 0.28mg PFOS/kg diet, 0.021mg PFOS/kg bw/d, and 1.7 microg PFOS/mL yolk, respectively. Benchmarks for serum and liver for the protection of avian species were 1.0 microg PFOS/mL and 0.6 microg PFOS/gww, respectively. However, no-effect levels in laboratory studies suggest actual population-level effects would not be expected to occur until a concentration of 6.0mg PFOS/kg in the diet, 5.0 microg PFOS/gww in the liver, or 9.0 microg PFOS/mL in the serum was exceeded, thus indicating the conservative nature of the benchmarks.

Sulfonamides in the environment as veterinary drugs.

Abstract: SAs, a structurally related group of antibiotics containing a similar 4-aminobenzene sulfonamide backbone, are used in agriculture, aquaculture, animal husbandry, and also as human medicines. Competing with p-aminobenzoic acid in the enzymatic synthesis of dihydrofolic acid, SAs inhibit the growth and reproduction of bacteria. Once released to the environment, SAs distribute themselves among different environmental compartments, along with their degradation products, and are transported to surface water and groundwater. The physicochemical properties, the dosage applied and the nature of the environmental components with which they interact, govern the whole process. SAs, as a class, are less sorptive, impersistent, and leachable. They cannot be characterized as readily biodegradable. Their adsorption to soil increases with the aromaticity and electronegativity of functional groups attached to the sulfonyl phenyl amine core. Preferential flow in clay soils has been identified as a mechanism responsible for surface water contamination by SAs.

Adsorption of Ionisable Pesticides in Soils

Abstract: Pesticides are intensively used in agriculture, and much effort is expended to manage and reduce possible deleterious effects on the environment.The soil compartment has a major influence on the fate and behaviour of pesticides applied to crops preemergence or early postemergence or chemicals subject to washoff from crop surfaces. Once in the soil, pesticide molecules partition between the aqueous and solid phases, which affects many other aspects of their behaviour: sorption can be rate limiting to volatilization, bioavailability (and thus efficacy and biodegradation rate), and subsurface transport. Understanding the fate of a pesticide in soil is fundamental to the accurate assessment of its environmental behaviour and vital in ensuring the safe use of new and existing products. It is also necessary to develop and validate computer simulation models for use as predictive tools in future environmental fate assessments.

Earthworm biomarkers in ecological risk assessment.

Abstract: Earthworms are important components of the soil system, mainly because of their favorable effects on soil structure and function (Paoletti 1999; Jongmans et al. 2003). Their burrowing and feeding activities contribute notably to increased water infiltration, soil aeration, and the stabilization of soil aggregates. In addition, earthworms help to increase soil fertility by formation of an organic matter layer in topsoil. These features, among others, have led to the popularity of earthworms as excellent bioindicators of soil pollution (Cortet et al. 1999; Lanno et al. 2004). These organisms ingest large amounts of soil, or specific fractions of soil (i.e., organic matter), thereby being continuously exposed to contaminants through their alimentary surfaces (Morgan et al. 2004). Moreover, several studies have shown that earthworm skin is a significant route of contaminant uptake as well (Saxe et al. 2001; Jager et al. 2003;Vijver et al. 2005).

Marine Halogenated Natural Products of Environmental Relevance

Abstract: Polyhalogenated compounds have been used for industrial and agricultural applications for some 50 years.Variations in the degree of halogenation can change their properties in almost any desired direction, so that their application fields were diverse and production rates were high. However, the other side of the coin provided evidence that the polyhalogenated xenobiotics are serious environmental contaminants. Their detection in the environment along with the linking of their presence to adverse affects observed in the living environment was an important step toward the recognition that there is a thorough need of environmental protection.

Heavy Metals Remediation of Water Using Plants and Lignocellulosic Agrowastes

Abstract: Metals in the environment arise from natural sources or directly or indirectly from human activities such as rapid industrialization, urbanization, and anthropogenic sources, threatening the environment and human health (Nriagu 1979). Mining and metallurgical activities produce wastewaters that can be considered as the major source of heavy metal contamination of natural waters (Schalcsha and Ahumada 1998; Reddad et al. 2002a). In the United States alone, more than 50,000 metal-contaminated sites await remediation, many of them Superfund sites (Ensley 2000). They are potential hazards to aquatic, animal, and human life because of their toxicity and bioaccumulative and nonbiodegradable nature (Zuane 1990). Nonessential metals such as Hg, Cd, Cr, Pb,As, and Sb are toxic in their chemically combined forms as well as the elemental form (Manahan 1993).Acute metal poisoning in humans causes severe dysfunction in the renal, reproductive, and nervous systems, and chronic exposures even at low concentrations in the environment can prove to be harmful to human health (Wyatt et al. 1998).

Behavior of pesticides in water-sediment systems.

Abstract: Many kinds of pesticides and their metabolites have been detected in various water bodies and bottom sediments even under normal agricultural practices (USEPA 1997; Gilliom 2001; Martin et al. 2003). Pesticides can potentially enter surface water by several routes and be partitioned to bottom sediments even if they are appropriately used for crop protection in accordance with good agricultural practices. Spray drift, surface runoff, and field drainage are relevant routes of exposure, and contamination via groundwater discharge may occur. The direct application of pesticides to water occures either for rice protection in a paddy field or for control of undesirable emergent vegetation of weeds and algae.

Terminology of Gonadal Anomalies in Fish and Amphibians Resulting from Chemical Exposures

Abstract: During the past decade, the scientific community and the public have become increasingly aware that some chemicals have the potential to interfere with endocrine systems in both vertebrate and invertebrate wildlife species (WHO 2002; Ankley et al. 1998). One aspect of these effects has been the observation of gonadal abnormalities in fish, amphibians, reptiles, birds, and mammals, including humans (Kavlock et al. 1996). To date, most research in this field has focused on demasculinization or feminization effects on male animals (Sumpter et al. 1996; Gimeno et al. 1998a,b; Crain et al. 1999; Jobling et al. 1998; Kloas et al. 1999; Hayes et al. 2002). Evidence for this estrogenic or antiandrogenic type of “endocrine disruption” has come largely from studies of teleost fish, either in controlled laboratory experiments where they have been exposed to specific chemicals or in the wild where organisms have been exposed to mixtures of compounds (Jobling et al. 1998; Harries et al. 1999; Minier et al. 2000; Hecker et al. 2002; Matthiessen et al. 2002). More recently, attention has shifted toward other groups of animals living in or closely associated with aquatic environments, such as alligators (Crain et al. 1999) and amphibians (Kloas et al. 1999; Hayes et al. 2002; Hecker et al. 2004).

Ecological risk assessment of contaminated soil.

Abstract: This review has described three cases of ecological risk assessment. The cases include two heavy metals (Cu and Zn) and an anthropogenic organic chemical (DDT). It concludes that there are at least two major constraints hampering the use of laboratory tests to predict effects under natural field conditions. One key issue is bioavailability, and another is suboptimal conditions or multiple stresses in the field such as climatic stress (drought, frost), predators, competition, or food shortage. On the basis of the presented case studies, it was possible to answer three essential questions often raised in connection to ecological risk assessment of contaminated sites. 1. To what extend does soil screening level (SSL) estimate the risk? The SSL are generally derived at levels corresponding to the lowest observed effect levels in laboratory studies, which often is close to the background levels found in many soils. In the cases of zinc and especially DDT, the SSL seemed quite conservative, whereas for copper they resemble the level at which changes in the community structure of soil microarthropods and the plant community have been observed at contaminated sites. The SSL correspond as a whole relatively well with concentrations where no effects or only minor effects were observed in controlled field studies. However, large variation in field surveys can often make it difficult to conclude to what extent the SSL corresponded to no-effect levels in the field. 2. Do bioassays represent a more realistic risk estimate? Here, there is no firm conclusion. The zinc study in UK showed a better relationship between the outcome of ex situ bioassays and field observations than the SSL. The latter overestimated the risk compared to field observations. However, this would be species dependent, as the sensitivity to metals may vary considerably between recognized test species, even within the same group of organisms, such as Folsomia candida and Folsomia fimetaria or Eisenia fetida and Lumbricus sp. Furthermore, it was demonstrated that bioassays were not useful for predicting general species diversity in the field as they are strongly influenced by natural variation and other factors not related to contamination. In the case of copper, bioassays with springtails and black bindweed seemed to underestimate the risk compared to the Cu concentrations at which significant changes in the community structure of soil microarthropods and plants have been observed at the contaminated site, and this was also the case for the DDT-contaminated soils. Here, bioassays with DDT-contaminated soils showed generally very low toxicity, with EC10 values considerably higher than the levels where clear effects on single species as well as community structure have been detected in the present field study. 3. Is it possible to make sound field surveys or do we lack suitable reference situations? Large natural variation caused by other factors than contaminants were observed in most cases, and this may have particularly hampered the conclusions made in the field surveys. These factors included pH, private and military traffic, age of vegetation, shading effects, and variations in light insensitivity as well as quantity and quality of organic matter. It was therefore concluded that field studies should always be interpreted in concert with similar data from a reference situation. Conclusions should therefore be made with caution in situations where important soil conditions vary between control plots and the contaminated sites. The cases also showed that indices focusing on species richness were unreliable. Estimates of evenness or dominance were recommended instead, and most authors concluded that multivariate analysis of community structure was a sensitive and useful method superior to single-species field data. This review concludes that there is a need for a tiered approach in ecological risk assessment of contaminated soils. Generic soil screening levels are needed as a first tier. Higher tiers of ecological risk assessment should, however, contain some kind of site-specific assessment. It is furthermore important to organize the various studies in a framework or decision support system that is transparent and useful for all stakeholders. A weight of evidence approach may be an obvious choice to deal with these uncertainties. The TRIAD approach, which incorporates and categorizes information in a triangle - chemistry, toxicology, and ecology - is an appropriate tool for handling conceptual uncertainties.

Health Risks of Enteric Viral Infections in Children

Abstract: Children are at a greater risk of infections from serious enteric viral illness than adults for a number of reasons. Most important is the immune system, which is needed to control the infection processes. This difference can lead to more serious infections than in adults, who have fully developed immune systems. There are a number of significant physiological and behavioral differences between adults and children that place children at a greater risk of exposure and a greater risk of serious infection from enteric viruses. Although most enteric viruses cause mild or asymptomatic infections, they can cause a wide range of serious and life-threatening illnesses in children. The peak incidence of most enteric viral illnesses is in children <2yr of age, although all age groups of children are affected. Most of these infections are more serious and result in higher mortality in children than adults. The fetus is also affected by enterovirus and infectious hepatitis resulting in significant risk of fetal death or serious illness. In addition to the poliovirus vaccine, the only vaccine available is for hepatitis A virus (HAV). A vaccine for rotavirus has currently been withdrawn, pending review because of potential adverse effects in infants. No specific treatment is available for the other enteric viruses. Enteric viral infections are very common in childhood. Most children are infected with rotavirus during the first 2yr of life. The incidence of enteroviruses and the viral enteric viruses ranges from 10% to 40% in children and is largely dependent on age. On average, half or more of the infections are asymptomatic. The incidence of hepatitis A virus is much lower than the enteric diarrheal viruses. There is no current evidence for hepatitis E virus (HEV) acquisition in children in the U.S. Enteric viral diseases have a major impact on direct and indirect health care costs (i.e., lost wages) and amount to several billion dollars a year in the U.S. Total direct and indirect costs for nonhospitalized cases may run from $88/case for Norwalk virus to $1,193/case for enterovirus aseptic meningitis. Direct costs of hospitalization ran from $887/case for Norwalk virus to $86,899/case for hepatitis A. These costs are based on 1997-1999 data. Generally, attack rates during drinking water outbreaks are greater for children than adults. The exception appears to be hepatitis E virus where young adults are more affected. However, pregnant women suffer a high mortality, resulting in concurrent fetal death. Also, secondary attack rates are much higher among children, probably because of fewer sanitary habits among this age group. Overall, waterborne outbreaks of viral disease have a greater impact among children than adults. To better quantify the impact on children, the literature hould be further reviewed for case studies of waterborne outbreaks where data are available on the resulting illness by age group. The EPA and/or Centers for Disease Control should attempt to collect these data as future outbreaks are documented.

Human Nails as a Biomarker of Element Exposure

Abstract: Human nails are extensively employed for monitoring exposure to excessive levels of elements. Nails can be studied easily and economically in subjects of residential areas and industrial workers and patients, and sometimes may indicate that high concentrations of elements are related to various illnesses. Deficiency of certain elements (Se and Fe) can also be determined with use of nails of subjects with specific or unknown deficiencies. Although nails are different from other biological samples in bioaccumulation, physiological activities may be partially due to chemical properties of the elements. Comparison of multielements between nails and other samples is relevant and found significant, because of the status of chronic exposure to high levels of elements. However, comparison of multielements between nails and other samples results in inconsistencies when exposure to elements is acute or unpredictable, or the subject is deficient in the elements being measured. Studies associated with elemental speciation, supplementation, interaction, and deficiency of essential elements (Zn, Cu, Mn, Mo,etc.), although rarely available, may enhance the growing use of nails. In many other research fields nail levels of elements and other associated factors or parameters are being investigated for further expansion of their application.

Ecotoxicological Assessment of the Highly Polluted Reconquista River of Argentina

Abstract: The situation of most of the Argentine rivers is very serious due to the amount and range of pollutants, principally as a consequence of industrial development with an inadequate regulatory framework and a deficit of decades in matters of sanitary substructure and waste treatment.

Human Exposure to Lead in Chile

Abstract: Lead is a very toxic environmental pollutant that affects people living or working in contaminated areas or ingesting this element. Since the beginning of lead use, it has left evidence of lead poisoning with dramatic effects on the destiny of ancient civilizations. It was recently proposed that this toxicity can also contribute to the decline of current societies through lead-induced impairment of intelligence, increased tendency to abuse of drugs, psychological and behavioral changes, and increase in delinquent behavior.

Pyrethroid illnesses in California, 1996-2002.

Abstract: This survey summarizes California's recent experience with illnesses related to pyrethroid exposures and augments the data available on pyrethroid inhalation exposure and residue dissipation. We reviewed California Department of Pesticide Regulation (DPR) Pesticide Illness Surveillance Program (PISP) data and DPR Pesticide Use Reporting (PUR) data for 13 pyrethroids used during 1996-2002 and identified 317 illnesses associated with exposure. PUR found a total of 4,629,852 pound (2,100,068 kg) of the 13 active ingredients were applied during the 7 yr. Type II pyrethroids accounted for 1,979,352 (897,820 kg) and 42.7% of the total pounds applied and 220 (69.6%) of the reported illnesses. Cyfluthrin was associated with 122 cases (55% of illnesses related to type II pyrethroids and 38.4% of all pyrethroid illnesses). Agricultural uses accounted for 118 (37.3%) of the reported illness cases, with 116 cases associated with employment. For the 199 cases (62.8%) associated with nonagricultural use, 132 (66.3%) were occupationally related. Overall, approximately equal numbers of illnesses resulted from individual exposures (167 cases) and group exposures (150 cases). The symptom arrays associated with the pyrethroid illnesses included irritant effects or pares- thesias of the eye, skin, or respiratory tract in 269 cases (84.9%). Type II pyrethroids were more frequently associated with isolated irritant symptoms (107 cases) than the type I pyrethroids (26 of 97 cases). Systemic symptoms were reported in 184 illnesses (58% of cases). Isolated systemic effects occurred in 48 cases (15.1%), but systemic effects were also present in 136 (50.6%) of the 269 cases with irritant symptoms. Residue exposures accounted for 158 illnesses (49.8%). Single or multiple violations of pesticide use regulations contributed to exposures in 90 of the 317 illnesses (28.4%); 76 were related to nonagricultural pyrethroid use. We also report results of DPR Worker Health and Safety Branch (WHS they are 11 and 32d, respectively. The third investigation involved an illness episode in which 11 raisin harvesters developed acute respiratory irritation symptoms when they were exposed to residues of lambda-cyhalothrin, propargite, and sulfur. Gas chromatography analyses of eight dislodgeable foliar residue (DFR) samples verified mean residues of lambda-cyhalothrin (0.43 +/- 0.10 microg/cm2), propargite (0.35 +/- 0.11 microg/cm2), and sulfur (0.31 +/- 0.28 microg/cm2) on the grape leaves. Subsequent investigation confirmed that the lambda-cyhalothrin product, which was not registered for use on grapes, was mistakenly mixed and applied 45 d earlier at 35 times the highest legal rate for any crop. The effects of exposure to average lambda-cyhalothrin DFR levels of 0.43 microg/cm2 have not been previously documented.

Does pesticide risk assessment in the European Union assess long-term effects?

Abstract: Current methods would allow reasonable predictions of long-term effects of pesticide application if three changes were instituted. First, more population-based laboratory studies should be applied in predictive pesticide risk assessment. Second, ERA should include as much effort on collating and integrating ecological knowledge into the assessment in Tier 1 as is currently expended on gathering chemical and toxicological information on exposure and effects. Production of a formal conceptual ecological risk assessment model for each product or active substance for which authorization is sought would provide an appropriate framework for integrating and applying such knowledge. Third, in acknowledgment of the uncertainties in the predictive risk assessment process, more postauthorization monitoring should be done.

Pesticide exposure monitoring databases in applied risk analysis.

Abstract: Faced with the need to evaluate under what conditions chemicals can be used with “reasonable certainty of no harm” to workers and consumers, industry and government agencies have embraced quantitative risk analysis as a science-based approach for product development, regulatory evaluations, and associated risk management decision making. Beginning in the 1990s, a variety of industry-sponsored task forces have been formed to develop exposure-related data to support safety evaluations for pesticide chemicals used in agricultural, industrial, institutional, residential, and other settings. Human exposure assessment and the underlying data (e.g., personal exposure and biological monitoring measurements, media-specific residue measurements, product use, and time—activity information) represent a critical component of the risk assessment process and a rapidly advancing science. While task forces have been created to develop databases for supporting the continued safe use of products, the development of these databases has served to advance general understanding of the basic principles underlying exposure assessment methodology and thereby provide the basis for improved science-based risk management by both industry and government. Given that developing chemical-specific data for every product use pattern and associated worker or consumer exposure scenario (e.g., professional mixer, loader and applicator activities associated with the use of a low-pressure sprayer, consumer residential lawn application via a ready-to-use hose-end sprayer product) is prohibitively expensive and time consuming, alternative approaches have been developed based upon meta-analyses and generalizations derived from databases of exposure monitoring studies for multiple chemicals, sorted by significant exposure covariates such as formulation type, method of application, amount of active ingredient applied, site of application, protective equipment and clothing, and task or activity. These generalizations can be used for predictive exposure analyses and have clearly demonstrated the value of “generic databases.” Although data in these databases and associated generalizations are subject to interpretation, e.g., during the regulatory decision-making processes, and may be used in conjunction with additional considerations or assessment methods that result in conservative biases, the role of generic databases for risk management decision making, and advancing the science of applied exposure analysis continues to be realized.

Using soil health to assess ecotoxicological impacts of pollutants on soil microflora.

Abstract: The ecotoxicity testing approach allows for an overall evaluation in the measurement of pollutant impacts on soil life. Ecotoxicological evaluation takes into consideration the complexity of the contaminant mixture as well as the multiple interactions that condition bioavailability and the level of exposure to living species.The measurement of ecotoxicity is generally performed using single organisms or species. The observed toxic effects can vary in gravity and extent depending on whether they affect survival, growth, or reproduction. However, this standard method cannot easily be used to evaluate pollutant ecotoxicological impacts on a soil microbial ecosystem. Indeed, soil is a complex living system in which a microbial community is intricately related with the chemical, and physical soil components (Avidano et al. 2005). Moreover, the soil biological content is in itself a relatively unknown elaborate structure. Its ecotoxicological evaluation goes beyond the individuals or species responses to the presence of pollutants (Kools et al. 2005).

Paper Manufacture and Its Impact on the Aquatic Environment

Abstract: The pulp and paper manufacturing industry generates large quantities of wastewater and has been described as a significant pollutant of the aquatic environment for many decades. The majority of pulp mills are located in the U.S. and Canada, and these countries are therefore subject to the greatest environmental impact. Some form of toxicity following exposure to mill effluent has been documented in numerous species, both aquatic and terrestrial, and the compounds present in effluents can affect multiple physiological processes, including hepatic mechanisms, reproduction and development, and endocrine function. Although the effects of PME on wildlife have been known for some time, the detection of chlorinated organic compounds generated substantial concern to humans because of the potential risk of exposure to these highly toxic compounds through environmental persistence and bioaccumulation. Government regulations were imposed on the pulping industry in an effort to prevent further contamination and reduce the toxic potential of pulp mill effluent to both humans and wildlife.