Comparing Injury and Illness Risk Assessments for Occupational Hazards

One common framework for describing the evaluation and assessment of hazards in the workplace includes the four steps of hazard identification, exposure assessment, exposure-response modeling, and risk characterization (NAS, 1983). We discuss hazards for occupational injury and illness in light of this framework, and we contrast the evaluation of injury hazards with the evaluation of illness hazards. In particular, the nature of the hazards, typical exposure patterns, quantification of exposure, and the attribution of outcome to exposure are discussed. Finally, we discuss the management of occupational illness and injury hazards and issues encountered when evaluating efforts designed to mitigate the effects of occupational hazards.     

Occupational exposures and reproductive health: 2003 Teratology Society Meeting Symposium summary

Assuring reproductive health in the workplace challenges researchers, occupational safety and health practitioners, and clinicians. Most chemicals in the workplace have not been evaluated for reproductive toxicity. Although occupational exposure limits are established to protect 'nearly all' workers, there is little research that characterizes reproductive hazards. For researchers, improvements in epidemiologic design and exposure assessment methods are needed to conduct adequate reproductive studies. Occupational safety and health programs' qualitative and quantitative evaluations of the workplace for reproductive hazards may differ from standardized approaches used for other occupational hazards in that estimates of exposure intensity must be considered in the context of the time-dependent windows of reproductive susceptibility. Clinicians and counselors should place the risk estimate into context by emphasizing the limitations of the available knowledge and the qualitative nature of the exposure estimates, as well as what is known about other non-occupational risk factors for adverse outcomes. This will allow informed decision-making about the need for added protections or alternative duty assignment when a hazard cannot be eliminated. These policies should preserve a worker's income, benefits, and seniority. Applying hazard control technologies and hazard communication training can minimize a worker's risk. Chemical reproductive hazard training is required for workers by the Occupational Safety and Health Administration's Hazard Communication Standard. The National Institute for Occupational Safety and Health (NIOSH) has formed a National Occupational Research Agenda Team to promote communication and partnering among reproductive toxicologists, clinicians and epidemiologists, to improve reproductive hazard exposure assessment and management, and to encourage needed research.     

Quantitative microbiological risk assessment: principles applied to determining the comparative risk of salmonellosis from chicken products

Since causal links have been established between food-borne illness and particular microorganisms, it has been possible to assess the public health risks of their presence in foods and propose measures to ensure the safety of customers. Effective control measures for food safety have been based on knowledge of the resistance of pathogenic microorganisms to the treatments used for preservation (e.g. acidification or reduced water activity) or decontamination (e.g. pasteurisation or sterilisation). Using this principle, food safety has been managed informally and successfully within the food industry for many years. Recently, formal risk assessment schemes, for example from Codex Alimentarius, have developed and placed the elements of decision-making on suitable control measures into a formal framework with clearly identifiable stages. The output of the four stages of a formal risk assessment (hazard identification, hazard characterisation, exposure assessment and risk characterisation) provides the basis for decisions on actions needed to control the identified hazard. There are many difficulties in ensuring that risk assessments are realistic and accessible to potential users, in many cases their value is limited by the data available. The study reported here on control of Salmonella in poultry products illustrates that it is possible to produce a comparative risk assessment based on published data. This study is not a full quantitative risk assessment, but provide useful pointers for a risk manager. Differences are discussed between the exposure assessment data needed to propose controls for infectious or toxigenic pathogens. For infectious pathogens, the presence of viable and infectious microorganisms is itself the hazard, but for toxigenic microorganisms, absence or destruction of viable cells at ingestion does not in itself ensure the absence of toxin. For toxin hazards, exposure assessment needs to consider previous conditions that may have led to toxin formation and persistence, rather than just the level of microbes at ingestion.     

Health risk assessment via consumption of Pb and Cd contaminated vegetables collected from fresh markets in the lower north of Thailand

This study aimed to investigate the Pb and Cd contamination and health risk assessment for population via consumption of vegetables sold in fresh markets around the lower north of Thailand. The concentrations of Pb and Cd in various vegetables such as root/tuber, stem, inflorescence, fruit, and leaf vegetables were analyzed using an atomic absorption spec-trophotometer. Human health risks of these metals in vegetables were assessed based on target hazard quotient (THQ). The results indicated that more than 80% of the Pb and Cd in almost all vegetable samples exceeded the maximum allowable concentration by National Food Institute criteria with an average range of 0.96–3.39 and 0.48–1.40 mg/kg, respectively. The estimated daily intakes (EDI) of Pb and Cd via dietary consumption of vegetables were between 0.001–0.010 and 0.002–0.008 mg/kg/d, respectively. All EDIs of Pb contaminated vegetables were higher than the reference dose recommended by the USEPA except for leaf edible vegetables, while all EDIs of Cd contaminated vegetables were higher than the reference dose recommended by the USEPA. THQ indicated that the consumption of Pb contaminated root/tuber, stem, inflorescence, and fruit edible vegetables and Cd contaminated leaf vegetable for the local population in the lower north of Thailand could be a severe health risk problem.     

The sterile insect technique and the Mediterranean fruit fly: assessing the utility of aromatherapy in large field enclosures

The sterile insect technique (SIT) is widely used in integrated programs against tephritid fruit flies, particularly the Mediterranean fruit fly, Ceratitis capitata Wiedemann (Diptera: Tephritidae). Unfortunately, the mass‐rearing procedures inherent to the SIT often lead to a reduction in the male mating competitiveness. One potential solution involves the prerelease exposure of males to particular attractants. In particular, male exposure to ginger root oil [Zingiber officinale Roscoe (Zingiberaceae); hereafter GRO], has been shown to increase mating success dramatically in field cage trials. To evaluate more rigorously the effectiveness of GRO exposure, we here describe two projects that compared levels of egg sterility or pupal yield, respectively, following the release of wild flies and either GRO‐exposed (treated) sterile males or GRO‐deprived (control) sterile males in large field enclosures. In both projects, sterile males from a genetic sexing strain were exposed as adults to GRO for 24 h while held in large storage boxes. In Hawaii, we dissected eggs from fruits to determine the percentage of egg hatch at four overflooding ratios, ranging from 5 : 1 to 60 : 1 (sterile : wild males), and found that, at all four ratios, the proportion of unhatched (sterile) eggs was significantly greater in enclosures containing GRO‐exposed males than control males. In Guatemala, we allowed larvae to develop in fruits and counted the number of pupae produced. At the only overflooding ratio tested (25 : 1), pupal yield was approximately 25% lower for enclosures containing GRO‐exposed males than control males, although this difference was not statistically significant. An explanation for the differing outcomes is proposed, and the implications of these findings for the SIT are discussed.     

Intake of fruits and vegetables,and risk of endometrial cancer in the NIH-AARP Diet and Health Study

Background: Fruits and vegetables contain a wide variety of phytochemicals which may have anti-carcinogenic effects. Although the results of case–control studies have suggested a possible protective effect of fruit and vegetable intake on the risk of endometrial carcinoma, few cohort studies have examined this association. Materials and methods: We used data from the NIH-AARP Diet and Health Study to assess the association of fruit and vegetable consumption, as well as intake of specific botanical groupings of fruits and vegetables, with endometrial cancer risk among 112,088 women who completed a food-frequency questionnaire at baseline, in 1995–1996. During 8 years of follow-up 1142 incident cases of endometrial cancer were ascertained. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI). Results: After adjustment for covariates, HRs for the highest compared to the lowest quintile of total fruit and total vegetable intake were 1.30 (95% CI 1.04–1.61, P for trend 0.05) and 1.09 (95% CI 0.90–1.33, P for trend 0.55), respectively. No inverse associations were observed for intake of any of 13 botanical groupings of fruits and vegetables. Conclusions: Results from this large prospective study do not support a protective role of a high intake of fruits or vegetables on the risk of endometrial cancer in older women.     

Non-target organism risk assessment of MIR604 maize expressing mCry3A for control of corn rootworm

Abstract:  Event MIR604 maize expresses a modified Cry3A protein (mCry3A), for control of corn rootworm. As part of the environmental safety assessment of MIR604 maize, risks to non-target organisms of mCry3A were assessed. The potential exposure of non-target organisms to mCry3A following cultivation of MIR604 maize was determined, and the hypothesis that such exposure is not harmful was tested. The hypothesis was tested rigorously by making worst-case or highly conservative assumptions about exposure, along with laboratory testing for hazards using species taxonomically related to the target pest and species expected to have high exposure to mCry3A, or both. Further rigour was introduced by study designs incorporating long exposures and measurements of sensitive endpoints. No adverse effects were observed in any study, and in most cases exposure to mCry3A in the study was higher than the worst-case expected exposure. In all cases, exposure in the study was higher than realistic, but still conservative, estimates of exposure. These results indicate minimal risk of MIR604 maize to non-target organisms.     

Mechanism and effectiveness of safflower oil against female Queensland fruit fly Bactrocera tryoni

Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), infests many horticultural fruit crops in the eastern part of Australia. Farmers usually apply synthetic insecticides to control this pest. Little is known on the use of plant products especially vegetable oils for fruit fly control although they are considered to be safer than synthetic insecticides. In this study, safflower oil was investigated for its mechanism and effectiveness against female B. tryoni. In a laboratory test, safflower oil treatments (2.5 and 5.0 ml l^?1) reduced the number of fly punctures on treated artificial fruits, no matter whether pre‐punctures were present or absent. Safflower oil treatments also reduced the number of fly landings and eggs laid, but only when the treated artificial fruits were without pre‐punctures. These results confirmed that safflower oil is active against female B. tryoni mainly by preventing this fruit fly from making oviposition punctures, not by discouraging them from depositing eggs or by repelling them. The slippery nature of safflower oil is considered to be responsible for a reduction in the susceptibility of artificial fruit to fruit fly punctures. Further investigation using fruit‐bearing tomato plants (a no‐choice test) in a glasshouse situation revealed that safflower oil application at concentrations of 10 and 15 ml l^?1 reduced the number of oviposition punctures but failed to reduce the number of eggs laid. To increase efficacy of safflower oil under field conditions, multiple tools may be needed to reduce fruit fly populations and oviposition behaviour, such as the addition of trap‐crops, provision of artificial oviposition sites, or mixing the insecticides with the oil.     

番茄吸收和积累Cd能力的品种间差异

旨在筛选和利用在受污染土壤中可食部位污染物积累水平在食品卫生标准允许范围内的农作物品种(pollution-safecultivar,简称为PSC),以降低水土环境污染物经食物链危害人类健康的风险。研究对象为番茄,探讨了在一定Cd污染土壤中其果实Cd含量低于国际食品法典委员会(CAC)Cd最高限值的品种(Cd-PSC)存在的可能性。通过盆栽试验研究了36个番茄品种(包括普通番茄和樱桃番茄两个变种)不同器官在受不同程度镉污染的土壤中吸收和积累Cd能力的差异。结果表明:(1)在土壤Cd重度胁迫(13.3mg.kg-1)和轻度Cd胁迫(1.1mg.kg-1)下,番茄所有器官Cd含量的变异在统计学上均存在极显著意义(p<0.01),其中果实Cd含量的范围分别为0.08~0.33mg.kg-1和0.00~0.09mg.kg-1,变异系数分别达到28.5%和77.9%;(2)在重度胁迫下,所有供试品种的果实Cd含量均超出CAC标准,而轻度胁迫下的Cd含量超标率达到19.4%,说明番茄是易受Cd污染的农作物种类,其中樱桃番茄的受污染风险特别高,在轻度胁迫下6个供试品种中有5个超标,而30个普通番茄品种仅1个超标。因此,仅在轻度胁迫条件下,存在着番茄的Cd-PSC,其中有5个普通番茄品种的果实中未检出Cd,属于比较安全的PSC,包括品种No.121、6、24、35和No.36,可以推荐在土壤Cd污染程度略超国家三级标准或具有潜在受污染风险的区域应用;(3)尽管大多数情况下各营养器官的Cd含量间均呈显著的正相关,但营养器官与果实Cd含量间均无明显的相关性,推测Cd在番茄营养器官间和营养器官与果实间的转运途径是不一样的。组织中Cd含量的显著相关性说明该特性可以作为农作物品种的种性特征;(4)与轻度胁迫相比,重度胁迫下的所有供试品种平均果实生物量上升了7.5%,一半以上的品种表现出较强的耐Cd能力,这一特性可能导致因不易察觉土壤的Cd污染状况而增加番茄产品受Cd污染风险。     

Environmental Health Risk Perception of a Nationwide Sample of Taiwan College Students Majoring in Engineering and Health Sciences

The present study aims to characterize Taiwan college students’ risk perception on 26 environmental health hazards, and to identify influential factors contributing to their perceived risk. A total of 1218 nationwide college students and 35 professors participated in the study. Despite their varying demographic background, the students on average show very similar perceived relative risks, particularly for hazards of high-rank risk. Aggregate-level data analyses show that the perceived risk of a hazard increases with its increasing dreadfulness, but decreases with its increasing unknown to the participants. On the other hand, the factors contributing to the perceived risk by an individual are more complex. The dread component is the dominant factor affecting both the students’ and professors’ perceived risk. However, unlike the students, the professors’ perceived risk is also strongly driven by considerations for the exposure characteristics, the uncontrollable nature, and the newness of a hazard. It is notable that, for certain hazards, the perception gaps between the students and professors are substantial, thus highlighting areas of interest for additional risk communication efforts.     

Spatial distribution of rainstorm hazard risk based on EW-AHP in mountainous scenic area of China

Rainstorm hazards seriously affect the lives of residents and activities of tourists in rainstorm harder-hit scenic areas. The assessment of rainstorm hazard risk has a great significance in the area. Based on the disciplines of geography and tourism, an assessment system has been constructed by using the Entropy Weight-Analytic Hierarchy Process and exponential model. Finally, the Huayang Ancient Town Scenic Area in China has been taken as study area, and its rainstorm hazard risk and spatial distribution have been evaluated. The results indicate the following: The rainstorm hazard risk areas are mainly concentrated along rivers, valleys, or roads; The specific spatial distributions are: rainstorm hazard risk of the Huayang Old Streets is high, that of the Red Cliff Valley and both sides of the Mandarin Duck River are higher, that of the Golden Monkey Valley and the Macaque Park are lower, that of the Tangluo Ancient Road is low, and the risks of other areas are medium; The main influencing factors of rainstorm hazard risk are elevation, terrain, gap and width of river, distance to river, building density, tourist flow and tourism activity; People's awareness, system of monitoring and early warning, emergency plan, facilities and equipment for rainstorm hazard prevention and mitigation need to be continuously improved.     

Approaches to Ecological Risk Characterization and Management: Selecting the Right Tools for the Job

Chemical-specific hazard quotient (HQ) risk characterization in ecological risk assessment (ERA) can be a value-added tool for risk management decision-making at chemical release sites, when applied appropriately. However, there is little consensus regarding how HQ results can be used for risk management decision-making at the population, community, and ecosystem levels. Furthermore, stakeholders are reluctant to consider alternatives to HQ results for risk management decisions. Chemical-specific HQs risk characterization should be viewed as only one of several approaches (i.e., tools) for addressing ecological issues; and in many situations, other quantitative and qualitative approaches will likely result in superior risk management decisions. The purpose of this paper is to address fundamental issues and limitations associated with chemical-specific HQ risk characterization in ERA, to identify when it may be appropriate, to explore alternatives that are currently available, and to identify areas that could be developed for the future. Several alternatives (i.e., compensatory restoration, performance-based ecological monitoring, ecological significance criteria, net environmental benefit analysis), including their limitations, that can supplement, augment, or substitute for HQs in ERA are presented. In addition, areas of research (i.e., wildlife habitat assessment/landscape ecology/population biology, and field validated risk-based screening levels) that could yield new tools are discussed.     

Natural hazard threats to pollinators and pollination

Natural hazards are naturally occurring physical events that can impact human welfare both directly and indirectly, via shocks to ecosystems and the services they provide. Animal‐mediated pollination is critical for sustaining agricultural economies and biodiversity, yet stands to lose both from present exposure to natural hazards, and future climate‐driven shifts in their distribution, frequency, and intensity. In contrast to the depth of knowledge available for anthropogenic‐related threats, our understanding of how naturally occurring extreme events impact pollinators and pollination has not yet been synthesized. We performed a systematic review and meta‐analysis to examine the potential impacts of natural hazards on pollinators and pollination in natural and cultivated systems. From a total of 117 studies (74% of which were observational), we found evidence of community and population‐level impacts to plants and pollinators from seven hazard types, including climatological (extreme heat, fire, drought), hydrological (flooding), meteorological (hurricanes), and geophysical (volcanic activity, tsunamis). Plant and pollinator response depended on the type of natural hazard and level of biological organization observed; 19% of cases reported no significant impact, whereas the majority of hazards held consistent negative impacts. However, the effects of fire were mixed, but taxa specific; meta‐analysis revealed that bee abundance and species richness tended to increase in response to fire, differing significantly from the mainly negative response of Lepidoptera. Building from this synthesis, we highlight important future directions for pollination‐focused natural hazard research, including the need to: (a) advance climate change research beyond static “mean‐level” changes by better incorporating “shock” events; (b) identify impacts at higher levels of organization, including ecological networks and co‐evolutionary history; and (c) address the notable gap in crop pollination services research—particularly in developing regions of the world. We conclude by discussing implications for safeguarding pollination services in the face of global climate change.     

Cause‐Specific Cumulative Incidence Estimation and the Fine and Gray Model Under Both Left Truncation and Right Censoring

Summary The standard estimator for the cause‐specific cumulative incidence function in a competing risks setting with left truncated and/or right censored data can be written in two alternative forms. One is a weighted empirical cumulative distribution function and the other a product‐limit estimator. This equivalence suggests an alternative view of the analysis of time‐to‐event data with left truncation and right censoring: individuals who are still at risk or experienced an earlier competing event receive weights from the censoring and truncation mechanisms. As a consequence, inference on the cumulative scale can be performed using weighted versions of standard procedures. This holds for estimation of the cause‐specific cumulative incidence function as well as for estimation of the regression parameters in the Fine and Gray proportional subdistribution hazards model. We show that, with the appropriate filtration, a martingale property holds that allows deriving asymptotic results for the proportional subdistribution hazards model in the same way as for the standard Cox proportional hazards model. Estimation of the cause‐specific cumulative incidence function and regression on the subdistribution hazard can be performed using standard software for survival analysis if the software allows for inclusion of time‐dependent weights. We show the implementation in the R statistical package. The proportional subdistribution hazards model is used to investigate the effect of calendar period as a deterministic external time varying covariate, which can be seen as a special case of left truncation, on AIDS related and non‐AIDS related cumulative mortality.     

Lethal and behavioral sublethal side effects of thiamethoxam on the predator Harmonia axyridis

Thiamethoxam (TMX) is one of the most effective neonicotinoid insecticides for the control of green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), and various side effects can be expected in its natural enemies. The multicolored Asian lady beetle or harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is an important predator against M. persicae in greenhouses and fields. In this study, we evaluated the toxicity of TMX to H. axyridis and the effect on the functional response of this predator to M. persicae through three routes of exposure. Acute toxicity bioassays indicated that LC₅₀ values of TMX on H. axyridis through direct residual contact (‘contact’), systemic application (‘systemic’), and leaf‐dip treatment (‘leaf‐dip’) were 18.99, 21.26, and 15.39 mg a.i. l^?1, respectively. The hazard quotient indicated a potential hazard of this agrochemical regardless of the exposure routes. The mortality caused by the lowest rate, 2 mg a.i. l^?1, was not significantly different compared with the control group. For the three routes of sublethal TMX exposure, the type‐II functional response was a good fit to the prey consumption of H. axyridis. Predation was most affected by leaf‐dip treatment, followed by contact and systemic treatments, which had similar effect. For all exposure routes, the predation capacity of the predator recovered quickly after transfer to untreated cabbage leaves. Thiamethoxam applied systemically was the least toxic to H. axyridis and did not affect the functional response of the predator. However, the sublethal effects of TMX through both contact and leaf‐dip application may reduce the population growth of H. axyridis and consequently impair the biological control of M. persicae by this predator. These results illustrate that the assessment of potential effects of TMX on H. axyridis is crucial to develop effective integrated pest management programs for M. persicae in China.     

Efficacy of extracts of Melia azedarach L. callus, leaves and fruits against adults of the sweetpotato whitefly Bemisia tabaci (Hom., Aleyrodidae)

Bioassays with extracts of callus, fruit and leaves of the Chinaberry tree, Melia azedarach L., were performed against adults of Bemisia tabaci (Gennadius). Tissue culture of M. azedarach was carried out in Murashige and Skoog (MS) medium supplemented with indole butyric acid and benzyl adenine. Fresh and frozen leaves or fruits and the callus product were extracted in water or methanol at a ratio of 1 : 5 (w/v) for 48 h. The aqueous and methanol extracts were applied on tomato plants to determine their effect on B. tabaci adults and their corresponding oviposition and consequent adult emergence in comparison with the control, distilled water. Results have shown that extracts of callus and different age classes of M. azedarach leaves and fruits have shown significant repellent activity of 58.9–67.7% and have significantly decreased the oviposition rate of the insect without affecting the adult whitefly emergence in comparison with the control. Aqueous and methanol extracts have shown comparable effects against adult whiteflies indicating a similar efficacy of the two solvents in extracting the bioactive components of Melia . Extracts of frozen samples were found to be as effective against the pest as fresh samples, thus allowing storage of Melia parts to be used in case of shortage. This is the first report of the use of M. azedarach callus against B. tabaci; the M. azedarach callus, leaf and fruit extracts seem to present a potential source for management of B. tabaci .     

Risk Assessment: Replacing Default Options with Specific Science

The history of approaches to evaluating the hazards and risks of chemicals is briefly reviewed. The role of default options (generic approaches based on general knowledge in the absence of specific knowledge to the contrary) is discussed as a part of the risk assessment paradigm advanced by the National Academy of Science/National Research Council in 1983 and 1994. Examples are given of the impact of acquiring specific science to replace default options. An argument is made for developing specific science that would reduce uncertainty in risk assessments. Research on specific science would be guided by identified sources of uncertainty in the risk assessment process. The importance of using a research strategy that builds on human data is emphasized for validating new molecular and cellular biological assessment methods. The paper closes with a discussion of the tension between a hazard-based approach versus quantitative risk assessment in guiding risk management decisions. The former requires limited data, is qualitative, and easy to communicate, while the latter requires substantial data and is difficult to communicate. However, quantitative risk assessment provides a more rational basis for decisions on the allocation of both public and private resources for actions that will effectively minimize overall health risks to the public.     

Reflections on the implications of thresholds of mutagenic activity for the labelling of chemicals by the European Union

During the course of the safety evaluation and regulatory control of chemicals it is important to distinguish between "potential hazard" and "actual risk" of exposure to toxins. In the case of DNA reactive chemicals, it has been prudent to assume that hazard is expressed as risk at low exposure concentrations. However, analysis of the dose-response relationships of both DNA reactive and non-DNA reactive genotoxins (e.g., aneugens) indicate that there are exposure concentrations below which protective mechanisms such as DNA repair activity and the presence of multiple targets may lead to the prediction of no risk until threshold concentrations are achieved. Current European Union management procedures for mutagenic chemicals are based predominantly upon hazard assessment rather than assessment of actual risk under likely exposure scenarios. As our knowledge of protective mechanisms increases, the time is now appropriate to undertake a re-evaluation of European Union criteria and to base the clarification mutagenic chemical more firmly upon the basis of actual risks to the human population and to the environment.     

A framework for the identification of hotspots of climate change risk for mammals

As rates of global warming increase rapidly, identifying species at risk of decline due to climate impacts and the factors affecting this risk have become key challenges in ecology and conservation biology. Here, we present a framework for assessing three components of climate‐related risk for species: vulnerability, exposure and hazard. We used the relationship between the observed response of species to climate change and a set of intrinsic traits (e.g. weaning age) and extrinsic factors (e.g. precipitation seasonality within a species geographic range) to predict, respectively, the vulnerability and exposure of all data‐sufficient terrestrial non‐volant mammals (3,953 species). Combining this information with hazard (the magnitude of projected climate change within a species geographic range), we identified global hotspots of species at risk from climate change that includes the western Amazon basin, south‐western Kenya, north‐eastern Tanzania, north‐eastern South Africa, Yunnan province in China, and mountain chains in Papua‐New Guinea. Our framework identifies priority areas for monitoring climate change effects on species and directing climate mitigation actions for biodiversity.