Critical loads of acidity for surface waters in China

Various types of partition coefficients have been used to facilitate the prediction of the concentration of pollutants in different phases in the environment. Many thousands of chemicals may exist in our environment which makes prediction work difficult or impossible due to a deficiency of knowledge of those unfamiliar compounds. In this study, the correlation between an octanol-water partition coefficient (Kow), water solubility (S) and a normalized soil/sediment partition coefficient (Koc) was investigated though the examination of 148 model chemicals. These model chemicals were classified into five major categories for easier adoption in future use. They are aliphatic compounds, aromatic compounds, pesticides, herbicides and polyaromatic hydrocarbons (PAH). Linear models are developed to correlate these partition coefficients in each category. The prediction of unfamiliar chemicals in the same category becomes possible if the fundamental properties of these chemicals (such as solubility) are previously known.     

Beyond REACH: Roadblocks and shortcuts en route to integrated risk assessment and management of chemicals

This paper addresses obstacles and opportunities for the development and application of novel methods for integrated assessment of cumulative risks from chemicals, exemplified by the REACH legislation of the EU, in the context of multiple stressors and of chemicals policy. We examine the role of such methods in connection with REACH by models of integration and innovation of risk information in multi-actor risk governance; analyses of key documents on REACH; and interviews with EU regulators and stakeholders. We first explain the emergence of REACH as a response to tensions in EU chemicals, environmental and other policies. We then analyze the present configuration of REACH particularly in relation to key dimensions of risk integration: across stressors; exposed organisms; and impacts. Among the policy aspects of integrated risk information, we focus on its interaction with management and the contesting framings and interpretations of assessment. Avenues and barriers are identified for integrated treatment of risks under REACH and with other instruments. We emphasize how bounded, formal and static assessments interact with open and informal approaches that have more flexibility in integrating risks in new ways. We conclude with a generalizing discussion on the role of novel methods of integrated risk assessment in the development of reflexive and participatory governance under REACH and beyond.     

Chemicals and biological products used in south-east Asian shrimp farming, and their potential impact on the environment — a review

A wide variety of chemicals and biological products are used to treat the water and sediment of ponds in semi-intensive and intensive south-east Asian shrimp farming. These products are also often used in shrimp hatcheries and to disinfect equipment for shrimp pond management. In spite of the size and importance of the shrimp farming industry in several south-east Asian countries, documentation of the quality and quantity of chemicals and biological products used during farming is scarce. This paper is a compilation of the literature available on substances used in shrimp farming, and the possible environmental effects of these products are analysed to the extent allowed by the limited information. The role of shrimp farm managers, the chemical industry, governments, inter-governmental organisations and scientists in the development of a sustainable practice is discussed. It is concluded that shrimp farmers should reduce the use of chemicals and biological products because of the risks to the environment, human health and to production, and also, because many chemicals and biological products used in pond management have not been scientifically shown to have a positive effect on production. Clearly, the use of some chemicals, i.e. certain antibiotics, poses a risk of danger towards human health. Some chemicals used in shrimp farming, such as organotin compounds, copper compounds, and other compounds with a high affinity to sediments leave persistent, toxic residues, and are likely to have a negative impact on the environment. However, to assess the reality of these risks, substantial new information about the quantity of chemicals used in marine south-east Asian shrimp farming is needed.     

Chemicals and biological products used in south-east Asian shrimp farming, and their potential impact on the environment--a review.

A wide variety of chemicals and biological products are used to treat the water and sediment of ponds in semi-intensive and intensive south-east Asian shrimp farming. These products are also often used in shrimp hatcheries and to disinfect equipment for shrimp pond management. In spite of the size and importance of the shrimp farming industry in several south-east Asian countries, documentation of the quality and quantity of chemicals and biological products used during farming is scarce. This paper is a compilation of the literature available on substances used in shrimp farming, and the possible environmental effects of these products are analysed to the extent allowed by the limited information. The role of shrimp farm managers, the chemical industry, governments, inter-governmental organisations and scientists in the development of a sustainable practice is discussed. It is concluded that shrimp farmers should reduce the use of chemicals and biological products because of the risks to the environment, human health and to production, and also, because many chemicals and biological products used in pond management have not been scientifically shown to have a positive effect on production. Clearly, the use of some chemicals, i.e. certain antibiotics, poses a risk of danger towards human health. Some chemicals used in shrimp farming, such as organotin compounds, copper compounds, and other compounds with a high affinity to sediments leave persistent, toxic residues, and are likely to have a negative impact on the environment. However, to assess the reality of these risks, substantial new information about the quantity of chemicals used in marine south-east Asian shrimp farming is needed.     

A methodology for ranking and hazard identification of xenobiotic organic compounds in urban stormwater

The paper presents a novel methodology (RICH, Ranking and Identification of Chemical Hazards) for ranking and identification of xenobiotic organic compounds of environmental concern in stormwater discharged to surface water. The RICH method is illustrated as a funnel fitted with different filters that sort out problematic and hazardous compounds based on inherent physico-chemical and biological properties. The outcomes of the RICH procedure are separate lists for both water phase and solid phase associated compounds. These lists comprise: a justified list of compounds which can be disregarded in hazard/risk assessments, a justified list of stormwater priority pollutants which must be included in hazard/risk assessments, and a list of compounds which may be present in discharged stormwater, but cannot be evaluated due to lack of data. The procedure was applied to 233 xenobiotic organic chemicals (XOCs) of relevance for stormwater. Of these 233 compounds, 121 compounds were found to be priority pollutants with regard to solids phases (i.e. suspended solids, soil, or sediments) when stormwater is discharged to surface water and 56 compounds were found to be priority pollutants with regard to the water phase. For 11% of the potential stormwater priority pollutants the screening procedure could not be carried out due to lack of data on basic physico-chemical properties and/or data on bioaccumulation, resistance to biodegradation, and ecotoxicity. The tiered approach applied in the RICH procedure and the focus on the phases relevant for monitoring or risk assessment in the aquatic environment refines the list of "compounds of concern" when compared to the outcome of existing classification schemes. In this paper the RICH procedure is focused on effects in the aquatic environment exemplified with xenobiotic organic compounds (XOCs) found in urban stormwater, but it may be transferred to other environmental compartments and problems. Thus, the RICH procedure can be used as a stand-alone tool for selection of potential priority pollutants or it can be integrated in larger priority setting frameworks.     

Quellen und Vorkommen kurzkettiger Alkylphenole (SCAP)

A literature research and own data on Short Chain Alkyl Phenols (SCAP) in the environment indicate that treatment of solid fossil fuel materials and the production of chemicals from various industries have common potenzial anthropogenic sources of SCAP compounds in the environment. Potenzial natural sources of SCAP in the environment are solely from petroliferous rocks. A wide range of SCAP applications for different industries is summarized here briefly. Many process-based inputs to the environment have been identified. Contaminations have specific “fingerprints”, (unique types of SCAP compound occurrences). This enables the identification of SCAP sources. Furthermore, unique environmental properties among the variety of SCAP compounds, facilitates characterisation of contaminated sites. Knowledge of the unique SCAP “fingerprints” in conjunction with the environmentally predictable relationships of the various SCAP compounds is the basis for the use of these substances in process and flow characterisation within aquifers.     

Municipal landfill leachates: A significant source for new and emerging pollutants

Landfills have historically remained the most common methods of organized waste disposal and still remain so in many regions of the world. Thus, they may contain wastes resulting from several decades of disposal and decomposition with subsequent release of organic compounds that may have environmental, wildlife and human health consequences. Products containing different types of additives with unique beneficial improvement properties are in daily use. However, when these products are decomposed, additives are release into the environment, some of which have been shown to have negative environmental impacts, resulting in the ban or at least restricted application of some chemicals. New and emerging compounds are continuously discovered in the environment. Herein, we report qualitative and quantitative data on the occurrence of new and emerging compounds with increasing environmental and public health concern in water- and particle phase of landfill leachates. Under normal environmental conditions, several of these chemicals are persistent high-volume products. Identified chemicals in the leachates at nanogram (ng) or microgram (μg) per liter levels include — chlorinated alkylphosphates such as tris(1-chloro-2-propyl) phosphate (TCPP), N-butyl benzensulfonamide (NBBS), the insect repellent diethyl toluamide (DEET) and personal care products such as the non-steroidal anti-inflammatory drug ibuprofen and polycyclic musk compounds. Among new and emerging contaminants, perfluorinated compounds (PFCs) were measured in the water phase at concentrations up to 6231 ng/L. Compared with the other chemicals, PFCs were primarily distributed in water phase. An effective removal method for PFCs and other polar and persistent compounds from landfill leachates has been a major challenge, since commonly used treatment technologies are based on aeration and sedimentation. Thus, the present study has shown that municipal landfill leachates may represent a significant source of concern for legacy, new and emerging chemicals in groundwater.     

Risk assessment of "down-the-drain" chemicals: search for a suitable model

Legal and regulatory authorities around the world generally require that risk assessments are undertaken for the licensing of new and existing substances that present high risk to the environment or the human health. This applies to 'down-the-drain' chemicals that are usually found in household products, such as detergents, that are mainly discharged into rivers via sewer systems. However, the data available for these chemicals is often limited due to cost constraints: in particular, concentration time series for works effluent are generally unavailable, even load data for specific works is often scarce. Although a wide range of models are available, there is a general lack of knowledge on their suitability to model the fate of down-the-drain chemicals at the catchment scale. Several models are presented in this review. The models selected are: the Mackay models, EUSES, Mike 11, QUAL2E, TOMCAT and GREAT-ER. Various applications of these models were investigated to investigate their strength and weaknesses. It appears that, where the availability of data is limited, multimedia fate models such as the Mackay models and EUSES may best be applied to estimate the global risk within each media. However, for site-specific risk assessment the GREAT-ER in-stream water quality model was considered to be more appropriate for modelling down-the-drain chemicals, because it accounts for both spatial and temporal variability, while its data requirements are lower than for models such as Mike 11 and QUAL2E.     

Risk assessment of “down-the-drain” chemicals: Search for a suitable model

Legal and regulatory authorities around the world generally require that risk assessments are undertaken for the licensing of new and existing substances that present high risk to the environment or the human health. This applies to ‘down-the-drain’ chemicals that are usually found in household products, such as detergents, that are mainly discharged into rivers via sewer systems. However, the data available for these chemicals is often limited due to cost constraints: in particular, concentration time series for works effluent are generally unavailable, even load data for specific works is often scarce.Although a wide range of models are available, there is a general lack of knowledge on their suitability to model the fate of down-the-drain chemicals at the catchment scale. Several models are presented in this review. The models selected are: the Mackay models, EUSES, Mike 11, QUAL2E, TOMCAT and GREAT-ER. Various applications of these models were investigated to investigate their strength and weaknesses. It appears that, where the availability of data is limited, multimedia fate models such as the Mackay models and EUSES may best be applied to estimate the global risk within each media. However, for site-specific risk assessment the GREAT-ER in-stream water quality model was considered to be more appropriate for modelling down-the-drain chemicals, because it accounts for both spatial and temporal variability, while its data requirements are lower than for models such as Mike 11 and QUAL2E.     

Household hazardous waste in municipal landfills: contaminants in leachate

Household hazardous waste (HHW) includes waste from a number of household products such as paint, garden pesticides, pharmaceuticals, photographic chemicals, certain detergents, personal care products, fluorescent tubes, waste oil, heavy metal-containing batteries, wood treated with dangerous substances, waste electronic and electrical equipment and discarded CFC-containing equipment. Data on the amounts of HHW discarded are very limited and are hampered by insufficient definitions of what constitutes HHW. Consequently, the risks associated with the disposal of HHW to landfill have not been fully elucidated. This work has focused on the assessment of data concerning the presence of hazardous chemicals in leachates as evidence of the disposal of HHW in municipal landfills. Evidence is sought from a number of sources on the occurrence in landfill leachates of hazardous components (heavy metals and xenobiotic organic compounds [XOC]) from household products and the possible disposal-to-emissions pathways occurring within landfills. This review demonstrates that a broad range of xenobiotic compounds occurring in leachate can be linked to HHW but further work is required to assess whether such compounds pose a risk to the environment and human health as a result of leakage/seepage or through treatment and discharge.     

Partition coefficients for the trihalomethanes among blood, urine, water, milk and air

Chloroform, bromodichloromethane, chlorodibromomethane, and bromoform comprise the trihalomethanes, a group of widespread and mildly lipophilic compounds that result from water chlorination and other sources. Many animal studies show the chronic toxicity and carcinogenicity of these compounds, and recent work has demonstrated the importance of both ingestion and inhalation exposure pathways. This study presents partition coefficients describing the equilibrium among biological compartments (air, water, blood, milk, urine) for the four THMs based on results of headspace gas chromatographic analyses performed under equilibrium conditions and at 37 degrees C. The calculated partition coefficients ranged from 2.92 to 4.14 for blood/water, 1.54-2.85 for milk/blood, and 3.41-4.93 for blood/urine, with the lowest being chloroform and the highest being bromoform. Both human and cow milk were tested, with similar results. The available samples of human milk may not fully account for differences in lipid content and possibly other factors that affect estimates of partition coefficients. Simultaneous measurements of milk and blood in exposed individuals are suggested to confirm laboratory results. Partition coefficients are predicted using the octanol-air partition coefficient, also measured in this study, and the octanol-water partition coefficient. Results are similar to literature estimates for liquid/air partitioning of chloroform and chlorodibromomethane, but they differ from predictions based on hydrophobicity and lipid content. High correlations between the derived partitioned coefficients and the molecular structure (number of Br atoms) and physical properties (molecular weight and boiling point) are found for these analogous chemicals. In humans, THMs are both stored and metabolized with relatively rapid clearance rates. The derived partition coefficients can help to interpret results of biological monitoring and predict the potential for the accumulation and transfer of chemicals, specifically by the application of physiologically-based pharmacokinetic models. THM exposures to potentially susceptible populations, e.g. nursing infants, can be predicted using either such models.     

Potential Endocrine Disrupting Substances from Materials in Contact with Drinking Water

At present, there is much interest in the potential effects of chemicals on the endocrine systems in animals and man. Chemicals with endocrine-disrupting potential include (a) various phthalates, (b) compounds based on bisphenol A and F, (c) compounds based on alkyl phenols, and (d) the antioxidant butylated hydroxyanisole. However, the potency of these chemicals in comparison with natural hormones appears to be very low. Although there is some evidence for activity in animals, high doses are usually necessary, and there is controversy and uncertainty in the interpretation of some positive findings. In addition to consideration of potential hazards, the level of exposure through leaching of these chemicals into drinking water is an important component of risk assessment. The present approval processes ensure that such exposure is very low. The paper suggests a strategy for the future continued assurance of an adequate safety margin for human exposure to such substances through drinking water.     

Exposure to endocrine disrupting compounds via the food chain: Is packaging a relevant source?

Contamination of foodstuffs by environmental pollutants (e.g. dioxins, metals) receives much attention. Until recently, food packaging as a source of xenobiotics, especially those with endocrine disrupting properties, has received little awareness despite its ubiquitous use. This article reviews the regulations and use of endocrine disrupting compounds (EDCs) in food packaging and discusses their presence within the context of new toxicology paradigms.I focused on substances known to be legally used in food packaging that have been shown to exhibit endocrine disruptive effects in biological systems. I compiled a list of 50 known or potential EDCs used in food contact materials and examined data of EDCs leaching from packaging into food, with a focus on nonylphenol. I included recent advances in toxicology: mixture effects, the developmental origins of adult disease hypothesis, low-dose effects, and epigenetics. I especially considered the case of bisphenol A. The core hypothesis of this review is that chemicals leaching from packaging into food contribute to human EDCs exposure and might lead to chronic disease in light of the current knowledge.Food contact materials are a major source of food contaminants. Many migrating compounds, possibly with endocrine disruptive properties, remain unidentified. There is a need for information on identity/quantity of chemicals leaching into food, human exposure, and long-term impact on health. Especially EDCs in food packaging are of concern. Even at low concentrations, chronic exposure to EDCs is toxicologically relevant. Concerns increase when humans are exposed to mixtures of similar acting EDCs and/or during sensitive windows of development. In particular, non-intentionally added substances (NIAS) migrating from food contact materials need toxicological characterization; the overall migrate of the finished packaging could be evaluated for biological effects using bioassays. The widespread legal use of EDCs in food packaging requires dedicated assessment and should be updated according to contemporary scientific knowledge.     

Identifikation NSO-heterocyclischer Prioritärsubstanzen zur Erkundung und Überwachung Teeröl-kontaminierter Standorte

The German Federal Soil Protection and Contaminated Sites Ordinance (BBodSchV) requires the monitoring of NSO-heterocyclic hydrocarbons without specifying the extent of such analysis. An assessment procedure for the identification of NSO-heterocyclic priority substances was thus created within the “KORA” project (“Natural Attenuation: Retention and Degradation Processes Reducing Contaminations in Groundwater and Soil”) funded by the German Federal Ministry of Education and Research (BMBF). This assessment includes physicochemical properties, biodegradability, toxicity, and groundwater propagation of these substances at creosote-contaminated sites. In addition to unsubstituted compounds, the derived list of 20 priority NSO-heterocycles also contains substituted derivatives as well as relevant transformation products.     

The fate of xenobiotic organic compounds in wastewater treatment plants

The effective operation of wastewater treatment plants plays an important role in minimising the release of xenobiotic compounds into the aquatic environment. Considerable effort has been expended in developing models to quantify the overall removal and fate of these compounds in biological treatment plants. A synthesis and modification of these approaches has been made and a generalised fate model for organic compounds in an activated sludge plant is presented. The influence of the different removal mechanisms, such as sorption, volatilisation and advection for chemicals with different physico-chemical properties is investigated and the important role of biotransformation is discussed. The effect of some operating parameters has been found to have an important influence upon the concentration of xenobiotic released in the sludges and final effluent. This may have significance for a wide range of ecotoxic compounds and in particular the class of compounds increasingly recognised as having the potential to disrupt endocrine activity in some aquatic vertebrates.     

Red-List Substances: Selection and Monitoring

The conference of Ministers representing North Sea littoral states, held in November 1987, agreed certain initiatives to reduce inputs of potentially dangerous substances to the North Sea from land-based sources. The UK Government has responded by proposing reductions of substances on a 'red list', selected on the basis of ecotoxicity, persistence, potential for bio-accumulation and estimated concentration in the environment.
This paper describes the approaches which have been used in selecting candidate substances for the red list and other priority-setting exercises, highlighting the difficulties presented by the lack of data for individual chemicals and the use of default values.
The estimation of input loads via rivers and direct discharges is discussed, with particular reference to monitoring requirements and analytical performance criteria.     

Occurrence and removal of priority pollutants by lamella clarification and biofiltration

This study investigates the occurrence of all priority substances (n = 41) listed in the Water Framework Directive and additional substances (n = 47) in raw sewage, as well as the removal performance of lamella clarification and biofiltration techniques. Once the efficiency of both types of techniques has been assessed for typical wastewater parameters, the differences in each technique's ability to remove pollutants becomes obvious; nevertheless, pollutant removal in quantitative terms still depends on the physico-chemical properties of the compounds used and operating conditions within the selected facility. For lamella clarification, the removal of organic chemicals was found to be primarily correlated with their sorption potential and, hence, strongly dependent upon log K_ow of the compound under study. Compounds with a strong hydrophobic character (log K_ow > 4.5) are removed to a significant extent (approx. 85%), while hydrophilic compounds (log K_ow < 3.5) are poorly removed (<20%). For biofiltration, the removal of chemicals appears to be compound-dependent, although this outcome involves several mechanisms, namely: i) physical filtration of total suspended solids, ii) volatilisation, iii) sorption, and iv) biotransformation of substances. Even if the complex processes within a biofilter system do not yield an accurate prediction of pollutant removal, two groups of chemicals can still be clearly identified: i) hydrophobic or volatile compounds, for which moderate to high removal rates are observed (from 50% to over 80%); and ii) hydrophilic, non-volatile and refractory compounds for which a low removal rate would be expected (<20%).     

Persistency of organic contaminants in groundwater,lessons from soil pollution incidents in the Netherlands

Based on an inventory of the presence of halogenated substances in raw water of 232 groundwater pumping stations and on the study of a number of soil pollution incidents in The Netherlands a compilation of more than 100 organic substances identified in contaminated groundwater is discussed. Subsequently the reason why a number of these substances are very persistent under the circumstances prevailing in the soil is analysed. Water solubility is shown to be a major parameter determining the occurrence in groundwater of frequently used chemicals and controlling to a large extend the persistence in groundwater of non-degradable organic chemicals. A list of 12 pollutants, mainly hydrocarbons and chlorinated hydrocarbons, which are of a major concern due to their widespread use, transportability and persistence observed in groundwater in The Netherlands.