A critical assessment of the European Commission's proposals for the risk assessment and registration of chemical substances in the European Union

In May, 2003, the European Commission published detailed proposals relating to its 2001 White Paper--Strategy for a Future Chemicals Policy. The White Paper described a new registration system called the REACH (Registration, Evaluation and Authorisation of Chemicals) system, for both new and existing chemicals. Subsequently, these detailed proposals were available for an eight-week consultation period for stakeholders to voice their views and concerns. In this paper, we describe our reactions to the Commissions more-detailed proposals. These include the creation of a European Chemicals Agency to implement the REACH system in conjunction with Competent Authorities (CAs) in Member States and the Commission itself. Unfortunately, many of our concerns and suggestions, previously voiced and shared with several other key stakeholders, remain unanswered, but are as relevant as when the White Paper was published. In particular, we are concerned about the lack of a clear and coherent strategy. There is no guidance for registrants on intelligent testing to maximise the use of non-animal approaches to safety testing, based on a combination of factors for estimating exposure levels, rather than mainly on production volumes. We are also concerned about the absence of a clear programme for the development, improvement and validation of new alternative methods, in conjunction with the Commissions own unit, the European Centre for the Validation of Alternative Methods, as well as other organisations with relevant expertise and experience, including FRAME. Finally, we explain why such measures should be introduced, together with clearer guidelines for the respective roles of the Agency, the CAs and the Commission in implementing and harmonising the REACH system at the European Union and Member State levels. A series of recommendations are made, to improve the situation and to improve the risk assessment process.     

A critical assessment of the European Commission's proposals for the risk assessment and registration of chemical substances in the European Union

In May, 2003, the European Commission published detailed proposals relating to its 2001 White Paper - Strategy for a Future Chemicals Policy. The White Paper described a new registration system called the REACH (Registration, Evaluation and Authorisation of Chemicals) system, for both new and existing chemicals. Subsequently, these detailed proposals were available for an eight-week consultation period for stakeholders to voice their views and concerns. In this paper, we describe our reactions to the Commission's more-detailed proposals. These include the creation of a European Chemicals Agency to implement the REACH system in conjunction with Competent Authorities (CAs) in Member States and the Commission itself. Unfortunately, many of our concerns and suggestions, previously voiced and shared with several other key stakeholders, remain unanswered, but are as relevant as when the White Paper was published. In particular, we are concerned about the lack of a clear and coherent strategy. There is no guidance for registrants on intelligent testing to maximise the use of non-animal approaches to safety testing, based on a combination of factors for estimating exposure levels, rather than mainly on production volumes. We are also concerned about the absence of a clear programme for the development, improvement and validation of new alternative methods, in conjunction with the Commission's own unit, the European Centre for the Validation of Alternative Methods, as well as other organisations with relevant expertise and experience, including FRAME. Finally, we explain why such measures should be introduced, together with clearer guidelines for the respective roles of the Agency, the CAs and the Commission in implementing and harmonising the REACH system at the European Union and Member State levels. A series of recommendations are made, to improve the situation and to improve the risk assessment process.     

Whole‐genome sequencing approaches for conservation biology: Advantages,limitations and practical recommendations

Whole‐genome resequencing (WGR) is a powerful method for addressing fundamental evolutionary biology questions that have not been fully resolved using traditional methods. WGR includes four approaches: the sequencing of individuals to a high depth of coverage with either unresolved or resolved haplotypes, the sequencing of population genomes to a high depth by mixing equimolar amounts of unlabelled‐individual DNA (Pool‐seq) and the sequencing of multiple individuals from a population to a low depth (lcWGR). These techniques require the availability of a reference genome. This, along with the still high cost of shotgun sequencing and the large demand for computing resources and storage, has limited their implementation in nonmodel species with scarce genomic resources and in fields such as conservation biology. Our goal here is to describe the various WGR methods, their pros and cons and potential applications in conservation biology. WGR offers an unprecedented marker density and surveys a wide diversity of genetic variations not limited to single nucleotide polymorphisms (e.g., structural variants and mutations in regulatory elements), increasing their power for the detection of signatures of selection and local adaptation as well as for the identification of the genetic basis of phenotypic traits and diseases. Currently, though, no single WGR approach fulfils all requirements of conservation genetics, and each method has its own limitations and sources of potential bias. We discuss proposed ways to minimize such biases. We envision a not distant future where the analysis of whole genomes becomes a routine task in many nonmodel species and fields including conservation biology.     

A multiple in silico program approach for the prediction of mutagenicity from chemical structure

We have conducted an evaluation of three of the most widely used commercial toxicity prediction programs, Toxicity Prediction by Komputer Assisted Technology (TOPKAT), Deductive Estimation of Risk from Existing Knowledge (DEREK) for Windows (DfW) and CASETOX. The three programs were evaluated for their ability to predict Ames test mutagenicity using 520 proprietary drug candidate (Test set 1) and 94 commercial (Test set 2) compounds. The study demonstrates that these three commercially available programs are useful, with limitations in their ability to predict mutagenicity over a wide range of chemical space, i.e. global predictivity. Individually, each of the programs performed at an acceptable level for overall accuracy, i.e. the ability to predict the correct outcome. However, analysis of the predictions indicates that the overall accuracy figure is heavily weighted by the ability of the programs to correctly predict non-mutagens, whereas none of the programs individually performed well in the prediction of novel mutagenic structures, i.e. Ames positive compounds. The performance of these programs' in predicting Ames positive mutagens appeared to be independent of the chemical utility of the compound, i.e. industrial, agricultural or pharmaceutical. The combination of program predictions provided some improvement in overall accuracy, sensitivity and specificity.     

Utilization of data obtained in pilot acute experiments for practical hygienic assessment of a chemical substance

A large number of the chemical substances and preparations (compositions) that are incorporated into the national economy cannot be subjected to long-term and detailed testing for toxicity and safety. There are simple methods on the acute experimental level which can serve as a basis for working out the necessary prophylactic measures in introducing new substances into the industry. Determination of LD50 upon intragastric administration, intravenous administration (model of rapid penetration into the organism), static inhalatory treatment under saturated concentration, determination of the primary local effect of the skin and mucous membranes, together with careful observation of the behaviour of the experimental animals, signs of their intoxication and their death, as well as comparison of the physico-chemical properties of the substance and its already familiar structural analogues may serve as the ground for predicting the biological significance of the new substance even at longer terms of contact with the organism and making toxicological and hygienic assessments under concrete technological conditions.     

Economical factors in the assessment of various cellulosic substances as chemical and energy resources.

Economic factors in the assessment of various cellulosic substances as chemical and energy resources are many and complex. No substrate nor conversion process can be singled out as significantly advantageous. Agricultural wastes appear to have the best volume and availability characteristics. If glucose is to be the end product, then it will probably have to compete with corn syrup. If SCP is to be the end product, then productivities of 2-4 g/liter-hr must be achieved and the protein demand be such that the product can sell for at least $225/ton. If alcohol is to be the end product, then an intermediate product stream of glucose and other sugars must be obtained for 1-3cent/lb of fermentable sugars.     

中国国家公园体制试点进展、问题及对策建议

建立国家公园体制是我国生态文明建设的重要内容,是实现自然生态保护领域治理体系和治理能力现代化的重要举措.2015年我国启动了国家公园体制试点工作,旨在为建立国家公园体制改革提供实践经验.为评估5年多来试点改革成效,基于对10个国家公园体制试点开展的深入调研,发现:国家公园体制试点工作稳妥有序推进,在国家公园顶层制度设计...     

Control of infection in general practice: a survey and recommendations.

Twenty general practices in four areas in Britain were surveyed to establish their needs for and practices of sterilising and disinfecting equipment. Of the 327 items of equipment and instruments examined in the survey, 190 were satisfactorily decontaminated, 100 were treated in a way judged to result in doubtful decontamination, and in 37 cases treatment was considered unsatisfactory. Decontamination apparatuses (autoclaves, hot air ovens, and hot water disinfectors) were generally in good working order, but the use of chemical disinfectants was often inappropriate. Recommendations were made on appropriate methods of decontamination for various items in common use in general practice. By virtue of the large numbers of patients treated by general practitioners there is a substantial possibility of transmitting infection; having appropriate methods for decontaminating instruments and equipment is therefore imperative.     

A practical concept for the ecological assessment of aquatic ecosystems: application on the River Dore in France

The ecological assessment of freshwater ecosystems necessitates to consider (i) the operational biological classification for defining a range of ecosystem alterations, (ii) operational biomonitoring tools fulfilling the requirements of the classification, (iii) ecological quality objectives to be preserved or restored. The development of this biomonitoring approach was illustrated by the study of the River Dore. Four biological qualities were defined with their related bio-indicators: (1) general biological quality (invertebrates), (2) biological sediment quality (oligochaetes), (3) biological water quality (diatoms) and (4) biological fish quality (fish communities). The selected bio-indicators were adjusted to an ecological classification model, based on a range of 8 ecological qualities, from `pristine' (S0) to extreme toxicity (S7). The model allows to use numerical index values as well as methods without index calculations, and to assess the general ecological quality of the river and its time-dependent evolution. At the sites downstream of industrial discharges, an improvement of the general ecological quality was observed from 1983 to 1995 in relation to sewage-treatment actions. A general ecological quality objective is proposed for each site of the river, taking into account the past and present ecological evolution of the river. The relevance of the approach greatly depends upon the accuracy of bio-indicator adjustment to the classification model and would be enhanced by taking into account other biological characteristics, like trophic status and hyporheic biocenoses.     

Emergency admissions to a general medical unit: A survey of the accompanying letters,with recommendations

Letters of referral accompanied 166 out of 188 emergency admissions to a general medical unit over a four-month period. Of these, 129 contained useful information concerning past medical history, emergency treatment given, drugs taken, and provisional diagnosis. It is suggested that general practitioners should adopt some format based on essential criteria when writing letters of referral, so that important information is not overlooked.     

Feedforwards and global system failure: A general mechanism for senescence

Although senescence is almost a ubiquitous property of organisms, it remains one of the most poorly understood of biological phenomena. The many mechanisms which have been proposed to account for senescence, however much they differ in detail, are alike in regarding senescence as a kind of system failure arising from local failures in specific subsystems. If senescence is indeed identified with system failure, then we must consider the possibility that there exist modes of failure which do not arise from local subsystem failures. We show that any system manifesting a feed-forward mode of control will in general exhibit such a non-local failure; or more generally, that any property of such a system will be temporally spanned. Since physiological systems are replete with feedforward loops, it is suggested that the temporal spanning arising in this way is responsible for senescence. A number of suggestive results are drawn from this argument, bearing on the possibility of system “rejuvenation”, and on the inability of experimental techniques entirely concerned with local sub-system behavior to bear directly on senescence mechanisms.     

A new biological assay, utilizing parasitic protozoa, for screening carcinogenic substances which induce bladder cancer in man and other mammals

Injections of aromatic amines (β-naphthylamine, benzidine, O-dianisidine or N-2-fluorenyl acetamide), tryptophan metabolites (3-hydroxyanthranilic acid, xanthurenic acid or LD-kynurenine sulphate), oestrone, and nicotine, which are known bladder carcinogens in man and some other mammals induced sexual reproduction (encystation) in Opalina sudafricana when injected into its host Bufo regularis. This may be used as a new biological assay for screening substances which induce bladder cancer in man and some other mammals. It is speculated that the metabolites of the injected carcinogenic substances used in this work are excreted in the urine of the host, hydrolysed by the hydrolytic enzymes and become carcinogenic. These carcinogenic metabolites reach the parasites in the rectum of the toads and induce them to divide mitotically to form small forms which eventually encyst. It is speculated that the presence of cysts in the rectum of the injected toads is indicative that a carcinogenic effect took place in the parasites. Oestrone is the only carcinogenic substance which induced encystation in the opalinids in vitro. Urine of toads injected with β-naphthylamine, benzidine, O-dianisidine, N-2-fluorenyl acetamide, 3-hydroxyanthranilic acid, xanthurenic acid, DL-kynurenine sulphate, oestrone and nicotine induced cyst formation in the parasites in vitro.     

Classification according to chemical structure, mutagenicity to Salmonella and level of carcinogenicity of a further 42 chemicals tested for carcinogenicity by the U.S. National Toxicology Program

This paper is an extension and update of an earlier review published in this journal (Ashby and Tennant, 1988). A summary of the rodent carcinogenicity bioassay data on a further 42 chemicals tested by the U.S. National Toxicology Program (NTP) is presented. An evaluation of each chemical for structural alerts to DNA-reactivity is also provided, together with a summary of its mutagenicity to Salmonella. The 42 chemicals were numbered and evaluated as an extension of the earlier analysis of 222 NTP chemicals. The activity patterns and conclusions derived from the earlier study remain unchanged for the larger group of 264 chemicals. Based on the extended database of 264 NTP chemicals, the sensitivity of the Salmonella assay for rodent carcinogens is 58% and the specificity for the non-carcinogens is 73%. A total of 32 chemicals were defined as equivocal for carcinogenicity and, of these, 11 (34%) are mutagenic to Salmonella. An evaluation is made of instances where predictions of carcinogenicity, based on structural alerts, disagree with the Salmonella mutagenicity result (12% of the database). The majority of the disagreements are for structural alerts on non-mutagens, and that places these alerts as a sensitive primary screen with a specificity lower than that of the Salmonella assay. That analysis indicates some need for assays complementary to the Salmonella test when screening for potential genotoxic carcinogens. It also reveals that the correlation between structural alerts and mutagenicity to Salmonella is probably greater than 90%. Chemicals predicted to show Michael-type alkylating activity (i.e., CH2 = CHX; where X = an electron-withdrawing group, e.g. acrylamide) have been confirmed as a structural alert, and the halomethanes (624 are possible) have been classified as structurally-alerting. To this end an extended carcinogen-alert model structure is presented. Among the 138 NTP carcinogens now reviewed, 45 (33%) are non-mutagenic to Salmonella and possess a chemical structure that does not alert to DNA-reactivity. These carcinogens therefore either illustrate the need for complementary genetic screening tests to the Salmonella assay, or they represent the group of non-genotoxic carcinogens referred to most specifically by Weisburger and Williams (1981); the latter concept is favoured.     

Classification according to chemical structure, mutagenicity to Salmonella and level of carcinogenicity of a further 39 chemicals tested for carcinogenicity by the U.S. National Toxicology Program

This paper is an extension of compilations published previously in this journal. (Ashby and Tennant, 1988; Ashby et al., 1989). A summary of the rodent carcinogenicity bioassay data on a further 39 chemicals tested by the U.S. National Toxicology Program (NTP) is presented. An evaluation of each chemical for structural alerts to DNA-reactivity is also provided, together with a summary of its mutagenicity to Salmonella. Chemicals with an aliphatic nitro group (-C-NO2) have been added to the composite structure of DNA-reactive sub-groups. The 39 chemicals were numbered and evaluated as an extension of the earlier analysis of 264 NTP chemicals. The activity patterns and conclusions derived from the earlier studies are followed by these 39 chemicals, albeit a detailed analysis of the total database of 301 chemicals is reserved for the succeeding paper.     

Automated metaphase finding: an assessment of the efficiency of the METAFER2 system in a routine mutagenicity assay

The efficiency of the automated metaphase finding system METAFER2 is assessed in a routine mutagenicity assay using an aneuploid rat liver cell line treated with various promutagens. Data sets generated by automated and manual selection of metaphases are compared. It is demonstrated that METAFER2 routinely allows an efficient automatic identification of metaphases not only in lymphocyte preparations, but also in preparation from mammalian cell lines with varying chromosome numbers. Although larger slide areas are required for automated compared to manual metaphase scanning, the automatic system is faster by a factor of about 5. The interactive visual elimination of metaphases of insufficient quality is an easy and fast procedure.METAFER2 allows an unbiased selection of metaphases irrespective of their appearance as homogeneously stained first or harlequin-staines second division cells. Random selection of metaphases is neither influenced by various structural chromosome changes nor by increased frequencies of sister-chromatid exchanges.     

Micronuclei in lymphocytes with preserved cytoplasm: A method for assessment of cytogenetic damage in man

The micronucleus method for studying cytogenetic effects in lymphocytes in man was modified. The cells were analyzed with preserved cytoplasm, which allowed a more precise identification of micronuclei. The method was tested on 58 individuals 38 of whom were exposed to styrene. Higher frequencies of micronuclei were obtained in 96-h cultures than in 72-h ones. In cells X-rayed in vitro a culture time of 80–88 h gave a maximal frequency of micronuclei. There was a very close correlation between the results of cultures from whole blood and from ‘buffy coat’ (r = 0.99). There was also a good correlation between two observers (r = 0.95), but a systematic difference of about 30% existed between the two sets of observations. The method error (variation coefficient) was 11 and 6% in preparations with mean micronuclei frequencies of 4 and 38%, respectively. The styrene-exposed group displayed weak but statistically significant correlations between frequencies of micronuclei and numerical chromosome aberrations. There were statistically significant effects of age, smoking and low levels of styrene exposure but these factors explained only 12–24% of the total variance.