Science topic

Hazard Assessment - Science topic

Explore the latest questions and answers in Hazard Assessment, and find Hazard Assessment experts.
Questions related to Hazard Assessment
  • asked a question related to Hazard Assessment
Question
39 answers
I am looking for collaboration in writing a research paper; if anyone working in occupational safety, workplace accidents, Process safety, and nature of injuries & severity related areas please drop a message
Regards
Relevant answer
Answer
If am not late, please consider me.
  • asked a question related to Hazard Assessment
Question
10 answers
It will be great if you can help me with the links of free satellite imagery for natural hazard assessment
Relevant answer
Answer
Vuk Gajić Thank you very much.
  • asked a question related to Hazard Assessment
Question
1 answer
Hi Everyone
I am using R-CRISIS for seismic hazard map creation. I know how to use the given attenuation model in R-CRISIS but I want to use an attenuation model from a published article. How to make such an input file? Also, I would like to know, how to find out suitable spectral ordinate parameters for each zone for R-CRISIS? (It will be so helpful if you explain the later one in detail)
Hope Somebody can help me with this.
Relevant answer
Answer
About your first question :
You have to create a text file according to the desired attenuation model and change the format of this text file from txt to ATN. Then, you should import the defined text file through R-CRISIS ( attenuation data>add user model) and then you have to assign this attenuation model to the desired seismic source. It should be noted that this method is for CRISIS2007 which is also applicable for R-CRISIS.
The mentioned text file should be look like the attached file. I think that Kramer's book explains how to make this text file. I have attached a manual which is in Persian.
About your second question:
The hazard curves often obtain based on Peak Ground Acceleration (PGA) and also most attenuation models are based on this spectral parameter.
  • asked a question related to Hazard Assessment
Question
4 answers
Looking for a case study where severe influx and loss events were experienced even when a MPD system is installed and active. Interested in the sequence of events and mitigation steps.
A real well example, not theoretical discussions. A big shout out to the petroleum engineers, drilling engineers, MPD experts and wellsite folks.
Thanks in advance.
Relevant answer
Answer
Hi, Souvik Sen I did a quick search on onepetro.org and found some interesting papers. Kindly check through and see if you can extract some data from it.
Best regards
  • asked a question related to Hazard Assessment
Question
32 answers
Hazardous waste from incinerator plant
Relevant answer
Answer
The solid residues from gas cleaning of municipal solid waste incineration, in particular, the fly ashes, are in most countries classified as hazardous waste because of their high inventory of soluble salts, especially chlorides of alkali metals, leachable heavy metals, and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs).
  • asked a question related to Hazard Assessment
Question
7 answers
I have a two step reaction that I would like to make a one pot reaction, but I'm worried whether or not commercially bought 33% HBr/AcOH (hydrobromic acid in acetic acid) is compatible with molecular sieves (4 angstrom).
In the first reaction (diazoketone formation using TMS-protected diazomethane), I use molecular sieves in the flask to keep the reaction dry, which I then filter off through a sintered funnel. I then treat the filtrate with a small volume (few mL's or less) of my HBr/AcOH solution.
Ideally, I would like to add the HBr/AcOH directly to the flask containing both the diazoketone product and molecular sieves, as this would spare me the filtration of a hazard solution in addition to quenching the fatal TMS-CHN2 reagents. My only concern with making this is two-step/one pot reaction is that the HBr/AcOH will somehow not be compatible with the sieves.
Does anyone have experience doing this? I suppose I could try treating activated sieves in an empty flask with HBr/AcOH, but I'm mostly worried about the formation of some sort of toxic byproduct.
Relevant answer
Answer
Grant, now that I more details about your synthetic scheme I can see the potential difficulties that certain other routes to your bromomethyl ketone derivatives may have. I presume that you have done the necessary literature search covering the preparation of the desired products and will make no suggestions. It always helps to account for all the reaction products in the reaction scheme. As far as the sieves are concerned I don't see a problem as they are inorganic zeolites (see the molecular sieve entry in Fieser and Fieser Vol 1) so adding HBr/AcOH should be a nonissue, but it is a good idea to check. What is the reaction solvent?
  • asked a question related to Hazard Assessment
Question
10 answers
Hello everyone,
this is the second draft of my Question, I'll keep refining it until it becomes readable, coherent and goes to the point. Thanks for the entries and the suggestions already offered. This is part of my Ph.D. studies, dealing with remote sensing techniques and numerical modelling of deforming slopes. The question popped out once I completed a run of simulations using a combination of 2D and 3D trajectory analysis software (Rocfall and Rockyfor3D, and I'm planning to add RocPro3D to the recipe as well).
In a Ritchie's video (from Ritchie 1963, see attached image for reference, I do actually love it), on the CD that comes with the book ROCKFALL, Characterization and Control (TRB), he says how angular momentum, and increased rotational velocity, is one of the most important factor controlling the run-out of falling blocks, if a rock stays close to the slope, and start to roll faster and faster, is very likely to end up further away from the bottom of the slope, even compared to other geometrical/physical properties. And he mentions also how falling rocks tend to rotate perpendicular to their major axis, which is a minor issue for equidimensional blocks (spheres, blocks) but it can be fundamental for elongated blocks (e.g. fragments of columnar basalt).
The real case scenario I'm testing the models with, is a relatively small rockfall. Its vertical drop is about 15 m in a blocky/columnar weathered granite, the transition zone is resting at approximatively 45 degrees, covered in medium sized blocks (10 cm to 1 m across section), the deposition zone is about 25 m away from the vertical wall, confined by a 3 m height crushed rock embankment. The energy line for this event is extremely high (around 80 degrees), because is constrained by the rocktrap. I'll add some maps, maybe some screenshots, to hide some sensible information.
In the simulations that I have run (in ecorisQ's Rockyfor3D) it looks like the column-like boulders (having a very evident major axis, the base is .4 m x .8 m, while the height is 1.8 m) travel farther than any other class of rocks (I got 3 classes, small spheres 50 cm in diameter, large cubes 1 m by side, and column-like), even the ones larger in dimension and volume/mass, but with all 3 axis of comparable length. You can observe the results in the maps attached to the question. Img02 has been computed with cubical blocks. Img03 with elongated block.
The value of the pixels farther away from the bottom of the slope, the ones that overtopped the rocktrap, upon investigation, in GIS, show a value of indicatively 0.05 (%). Following some consideration in the ecorisQ manual they should be considered outliers, and practically tolerable.
My question is: how do I have to interpret this effect? Is it due to the rigid body approach? If everything else stay the same, mass should be the primary factor for controlling the horizontal travel distance right? Why I do find smaller block travelling farther? It might be a negligible difference given the extremely low likelyhood for those blocks to get there, but does it tell me something I don't get about how the numerical model works?
Is there a way to visualise angular momentum/rotational velocity in that software? AND, most importantly, is the way the problem has been formulated valid?
I really appreciate any help and any idea you can share about it. I'm very appreciative of the time you will spend regarding my problem. I'll probably keep adding details as they are needed. Thanks again
Kind Regards,
Carlo Robiati, PhD student in Camborne School of Mines, UK
Relevant answer
Answer
as observed by Matthew:
"At 3:36 in the video is states "the only shape that has a marked effect upon the way a rock rolls is demonstrated by this elongated piece of columnar basalt. Its length gives it eccentric action." By this I think they mean it inhibits its ability to roll. If you have ever tried to roll a fireplace sized log down a natural slope, you will have observed the difficultly that is being referred to."
An elongated rock (or log) is unable to change direction as easily as the natural slope changes aspect which cause it to wobble or bounce and slow its momentum. Not sure how/if you can model that effect.
Elongated rocks also have more of a tendency to break apart as they travel down a slope.
It is fortunate that the rockfall trap is effective for each of your simulations and not dependent on this issue.
good luck
Dave
  • asked a question related to Hazard Assessment
Question
3 answers
Inform about upcoming workshop/training programs in Landslide hazard assessment.
Relevant answer
Answer
Besides the LARAM School, which I personally attended and was a great experience for me, I recommend the iRALL school on Large Landslides which is held every year in October in Chengdu, China. The LARAM and the iRALL are open to both PhD students and young doctors. Both of them are short (2 weeks) intensive training courses.
More info here:
Regards,
Gianvito
  • asked a question related to Hazard Assessment
Question
10 answers
Generally landslide inventories are used to assess the landslide hazard.Where landslide datas are not available ,LSZ or LHZ maps are used for this.So how to estimate the future probability (temporal) of landslides ?
Relevant answer
Answer
Dear Rajesh,
The inventory data is important not just to the assessment of landslide hazard but also to validate the result. However, I think you can do that qualitatively (expert base) then you can transfer the qualitative information to quantitative values through a method such as AHP or Fuzzy-AHP.
  • asked a question related to Hazard Assessment
Question
3 answers
It is well known that directivity effects cause pulse-like ground motions in near-fault region and increase the seismic hazard and risk. These effects depend on the source to site geometry parameters and in some recent ground motion models have been accounted for their impacts in seismic hazard assessment.
Relevant answer
Dear Dr
Please clear subject
  • asked a question related to Hazard Assessment
Question
11 answers
Mostly, landslides are mapped using aerial photographs, satellite images and other higher remote sensing techniques. Field based mapping is next approach in mapping the landslides. While we generate landslide susceptibility or hazard model using the inventory, we have to validate the model. This can be done by randomly partitioning data in training and testing data-sets (for success and prediction rate). ROC plots/AUC can be used to validate the model.
Is it MUST/NECESSARY to verify each and every landslides (in the inventory) in field? How to deal with this shortcomings in the quality of inventory maps?
Relevant answer
Answer
Depending on the size of your inventory, it might be impossible to check them all. But it is important to get a feeling for the quality of your data. Are the landslides mapped as polygons or as points? If polygons, then you should check for instance if the entire landslide was mapped or just the part that has moved (without the crown). If points, it is important to check where the points are located. For susceptibility modelling is may seem rather useless if they are right in the middle of the landslide - you should prefer points at the headscarp.
And please do not only pay attention to the ROC value for estimating the quality of your statistical output. It should also make sense from a geomorphological point of view and should delineate high susceptibility where this is really the case.
  • asked a question related to Hazard Assessment
Question
8 answers
Our Health & Safety team on site is trying to convince us to work with the Glove Box in under pressure. Our normal work is Li ion battery assembly in 2 and 3 electrode configurations with metallic lithium used regularly and with standard organic battery electrolyte. How can I convince them that working in over pressure is a standard procedure in this type of activity?. Thanks!
Relevant answer
Answer
As mentioned by Sebastian safety issues in working with glove boxes is definitely with slight over pressure.
Being also responsible for chemical lab safety I guess it might be a misunderstanding of your Health & Safety department because chemical labs where our glove boxes are being used, of course run in under pressure environment avoiding gases etc. reach the offices and floors.
  • asked a question related to Hazard Assessment
Question
3 answers
I use Atkinson and Boore (2011), Chiou andd Yaungs (2008), Campbell and Bozorgnia (2008) eauations for seismic hazard assessment.
some parameters at these equations like type of faulting, dip angle, rupture width, depth to top of rupture... are identified for linears sources, however, sources of my zone are area sources.
would you please let me know how to use those parameters for area sources using attenuation equations?
does anyone please know to help me?
Relevant answer
Answer
The depth of earthquake events are the crucial problem in use an area- source model. Therefore you can estimate the depth with appropriate estimation. The other parameters you can input directly to the ground motion prediction equation that you use
  • asked a question related to Hazard Assessment
Question
7 answers
I need any handbook for "GIS systems in engineering geology" and/or "GIS systems in natural hazard assessment" and unfortunetelly.
If anyone can help me, I'll be very thankful.
Relevant answer
Answer
მირიან, ვიცი შენც გაქვს წვდომის რაღაც საშუალებები, მაგრამ მაინც გიგზავნი ამ წიგნებს, თამრიკო
  • asked a question related to Hazard Assessment
Question
2 answers
I would like to develop or at least attend external field trips that explore processes of modern carbonate sedimentology but my organization has been denying approval due to safety concerns. If anyone knows of a good safety plan, risk register, and/or hazard assessment related to snorkeling and using small boats, please point me in the right direction! 
Relevant answer
Answer
As a former Navy Deep Sea Diver I would include the following steps before you allow a student to go snorkling.
1) Swim test 300 yards
2) Practice of mask and snorkle in pool include clearing out the mask and snorkel.
3) Ensure the mask, fins and snorkel fits the person
4) Establish a buddy system and each team trail a Floatable Diver Down flag with them for visibility
5) Chase boat crew must be alert and plan ahead how they would appoach swimmers so they don't run over them or another team.
  • asked a question related to Hazard Assessment
Question
7 answers
I have found concentration of Arsenic and other metals less than LOQ of AAS. But, for the calculation of Hazard Quotient (HQ) do I need to calculate for the values that are less than LOQ?
Also, if I calculate the value it will be like (<2.30 or like this). Then for HI (which is the sum of individual HQ) how can I include that value in calculation?
Can you help me to get out of this situation?
Relevant answer
Answer
You have choices here. Less than the Limit of Quantification is not the same as zero, so assuming zero concentration would conflict with the principle of being conservative in health risk assessment. To be appropriately conservative, I recommend assuming that the concentration is half the distance between zero and the LOQ (0.5 x LOQ). Another possibility would be to use a different fraction, such as the fraction of samples in which the substance was detected; for example, if detected in 75 percent of samples, assume 0.75 x LOQ for all samples in which the substance was not detected.
I hope this helps. If you have further question, please feel free to contact me.
  • asked a question related to Hazard Assessment
Question
4 answers
Damage and loss got exaggerated due to liquefaction effects as this has been witnessed in several large magnitude earthquakes in India and Abroad. In NatCat modeling for Insurance/ reinsurance purpose, would you suggest to consider its effects in earthquake hazard ground notion or in loss assessment through additional vulnerability functions.
Relevant answer
Answer
Dear Ana
Thanks for the response. If i assume you are right! then at location of liquifaction site there should be higher ground motion recorded, for example, PGA or Spectral acceleration. So far, i have not come across any strong ground motion measurement records having higher recorded ground motion at the liquifaction site than at the same distance another non-liquifaction site.
While it is well known and observed that a building on liquifiable soil suffers higher damage and loss.
Looking forward to hear more views, especially of earthquake risk modeling experts.
  • asked a question related to Hazard Assessment
Question
7 answers
I am developing a medical device (orthopedic prosthetic), during application I want to use UV curable adhesive for fixing and cavity filling. for that I am planing to use High power UV led light having peak wavelength of 365 nm and intensity is ~100mw/cm2. I coulden't find any confirmed data on safety study over skin. exposure is one time and it would last for 3-4 minutes.
Should I go ahead with above UV LED light ?
Would you please help me to find safety study for this ?
Relevant answer
Answer
for general and occupational UV exposure limits see ICNIRP:
there a monochromaltic exposure limit of 270 kJ/m2 to eyes and skin is set at 365 nm, but also an overall limit of 10 kJ/m2 to UVA irradiation (315-400 nm). Because of thermal effects the exposure rate should not exceed 10 kW/m2, especially for the eye.
All these exposure limits do not pertain to medical applications. The question apparently relates to fixation of a prosthetic, which to me is a borderline case. Considering UVA1 therapies in dermatology, there should not be a problem with a skin exposure of 240 kJ/m2  @ 365 nm for this application.
It is also not necessarily true that 405 nm would be any safer, e.g. if we consider oxidative effects
  • asked a question related to Hazard Assessment
Question
3 answers
Previous evaluations of regional liquefaction hazards identify several geologic and hydrologic factors that influence the susceptibility of a deposit to liquefaction, including (1) the age and depositional environment of the deposit; (2) the relative consolidation of sands and silts; and (3) the local depth to ground water
Can you outline these procedures in preparation of liquefaction hazard map? If you have developed relationship in each stage stated clearly?
What are the procedure for preparation of liquefaction susceptibility map?. 
Relevant answer
Answer
To prepare a susceptibility map to liquefaction you need  Geological, hydrogeological and geotechnical data:  (1) You need a detailed (1/5000- 1/1000) geological map where non compacted recent geological units should appear on the map (ancient compacted deposits are not liquefiable, (2) You need a detailed geotechnical map based on in situ and laboratory tests, mainly the granulometry of the deposits (liquefiable deposits should be fine sand with less 20% of clay), (3) You need the hydrogeological map of the area (liquefaction occurs only if the table water is at depth of less than 12m). See also the following references: Youd and Perkins (1978), Youd (1998).
  • asked a question related to Hazard Assessment
Question
6 answers
Good morning every one
I am doing a PhD in computer sciences and Risk analysis. My major goal is aggregation of data in order to build an indicator that would assess the consequences of a given scenario of industrial accidents on biodiversity.
In the case of a scenario in which a big volume of an acid or basic solution would be lost in the environment (for exemple Ajka accident, Hungary, 2010) and if we could predict the modification of pH in the surrounding environment (that would go back to 7 after two or three days). Would it be possible to assess "how bad it would be for the biodiversity". I have been told that, for a 7 +- 1.5 pH, almost everything dies. Could we say for example "with a 7+- 1 pH there would be a big impact but with a 7+-0.5 pH almost nothing happens"?
Thank you for your help
Tom
Relevant answer
Answer
7+- 1.5 may be there is change in biodiversity but no to death.
but it may be different from each organism to another, but I belive for juveniles or larvea this could some mortality,
but for 7+-0.5 I think it is the same.
but the question how could you design this pH system in the environment?
how could you control it ?
I think it is not possible
regards
  • asked a question related to Hazard Assessment
Question
3 answers
I am interested to use InSAR data and techniques in the Himalaya and Karakoram Ranges to identify geohazards like landslides and to make further hazard assessment, analysis to mitigate the georisk. Thanks for valuable comments and suggestions.
Regards
IJAZ
Relevant answer
Answer
ESA's Sentinel-1 acquires SAR data in Interferometric Wide Swath Mode that can be obtained for free from the ESA Sentinel Data Hub.
ALOS-PALSAR and PALSAR-2 have acquired some interferometric pairs but the SLC images are only available by submitting a proposal for data access to JAXA.
TanDEM-X is a single-pass InSAR constellation and provides the highest resolution, but again you need to request access to free data from DLR in Germany.
COSMO-SKYMED by ASI has similar capability but is commercial.
My opinion is that Sentinel-1 (C-band SAR) and its precursors ENVISAT-ASAR, ERS-1 and 2 are your best data source. There is still the problem that the method will likely not work very well in very rough terrain such as the Karakoram Range. But it may be worth a try. Perhaps you get good results for some parts of the study area at least.
  • asked a question related to Hazard Assessment
Question
4 answers
I am combining multiple studies on mortality in CKD per different categories of 25(OH)D. One study have reported Hazard Ration per 1 unit standard deviation increase in 25(OH)D  and some reported Hazard Ratios (HR or relative risk). what is the difference between HR/SD and HR? Is there any possibility to convert HR/SD to HR? Assuming both types of study measure mortality, can both be combined together? Thank you.
Relevant answer
Answer
HR per 1 standard deviation reveals that they have standardized that predictor before entering into model. Namely they used standardized values instead of its ordinary values. A unit increase in HR per SD should be interpreted as an SD unit increase in ordinary HR. So you can revert back to HR using HR/SD if you know SD.
Take log of HR/SD and divide by SD. Then exponentiate it. This way you will get HR.
  • asked a question related to Hazard Assessment
Question
4 answers
what data sets and algorithms can be used? you can attach a soft copy of a report, journal or pdf on the same question?
  • asked a question related to Hazard Assessment
Question
4 answers
I want to know if there is any heath hazard in using Titanium Dioxide as disinfectant . for the one who work with it for long term of time 
Relevant answer
Answer
Dear Saifeldin,
The following publication fully covers the answer to your question and I found it very important:
Nano Titanium Dioxide Technical Information Sheet
Nanomaterial Health Hazard Review: Health effects of titanium dioxide nanoparticles
Industrial nanomaterials (also called nanoparticles) are defined as substances that are intentionally produced, manufactured or engineered to have specific properties and one or more dimensions typically between 1 and 100 nanometres. Most industrial nanomaterials come in varying sizes, shapes, and in some cases surface coatings. 
Titanium dioxide (TiO2) nanoparticles, like the regular/bulk form of TiO2, exist in three crystalline structures or polymorphs: rutile, anatase and brookite. They can vary in size and shape, can form agglomerates or aggregates and be coated with other materials. Brookite TiO2 is less common than rutile or anatase TiO2. Samples of TiO2 nanoparticles may contain more than one polymorphic form.
All polymorphs of TiO2 have low water solubility. Hazards and biological activity of TiO2 nanoparticles may vary with its:
crystalline form (e.g. anatase TiO2 is considered more reactive than rutile TiO2);
particle size;
particle shape;
agglomerate/aggregate status;
surface properties; and
type of coating.
Industrial uses
TiO2 nanoparticles are reported to be widely used in cosmetics and paint. Rutile TiO2 nanoparticles are often used in sunscreens as ultraviolet absorbers, and anatase TiO2 in photo-catalytic and sensing applications. In Australia, responses to NICNAS Calls for Information on the use of nanomaterials (2006 and 2008) reported the use of TiO2 nanoparticles in cosmetics, secondary sunscreens and surface coatings. The 2006 responses also indicated use in water treatment and domestic products, but these uses were not reported by industry in 2008.
Hazard profile
The information below is a summary of national and international reviews and journal articles published up to July 2012, which are based on a limited number of studies on specific particle sizes of various TiO2 polymorphs. The information sheet was updated in late 2013 to include important national and international reports published after July 2012.  Detail and references for all of the studies considered in this review are included in the Appendix under corresponding headings.
It is possible for TiO2 nanoparticles to be manufactured in various forms and sizes. As particle size and polymorph structure are important determinants of the properties of TiO2, the data summarised below may not represent health effects for all polymorphic forms and/or sizes of TiO2 nanoparticles.
Toxicokinetics—Systemic availability
Studies in rodents showing systemic absorption of TiO2 nanoparticles through the gastrointestinal tract, based on doses ~5000 mg/kg bw, are not likely to reflect realistic human exposures.
Repeated dose oral studies indicated bioavailability through the gastrointestinal tract, although the extent of absorption/bioavailability was not quantified. Studies on rats reported accumulation in the liver, spleen, lung and peritoneal tissues for 500 nm particles. For particles <50 nm, accumulation occurred in the liver and heart. Information on the adverse effects of this accumulation in repeated dose oral studies was limited.
Inhaled TiO2 particles (20–30 nm and 200–250 nm) were found to deposit in the lung of rats, with a small fraction translocated to local lymph nodes and interstitial spaces. However, smaller particles tended to have a longer retention time in the lung and greater interstitial translocation compared with larger particles. Pulmonary clearance and responses to deposited nanoparticles varied with different test species, doses and particle sizes. Following inhalation of particles, clearance from the lung can be dependent on physical/mechanical processes which can be impaired under particle overload conditions.
Acute toxicity
The available data indicate low acute oral toxicity in rats and mice (LD50 >5000 mg/kg bw) for particles ranging from 5 to ~100 nm.
The current weight of evidence for dermal penetration studies indicates that TiO2 nanoparticles do not reach viable skin cells. No acute dermal toxicity data are available to derive an LD50 value. Given that there is no significant dermal penetration, acute dermal toxicity in uncompromised skin is expected to be low.
The available data indicated low acute inhalation toxicity in mice for particles of 5 and 21 nm (LC50 >7.35 mg/m3/4h).
Skin irritation and sensitisation
TiO2 nanoparticles did not cause skin irritation or sensitisation in rodents.
Eye irritation
TiO2 nanoparticles caused mild eye irritation in rodents.
Repeated dose toxicity
A no observed adverse effect level (NOAEL) of 62.5 mg/kg bw/day is reported for anatase TiO2 (~5 nm) in female mice following oral gavage administration for 30 days. Serious damage to the liver (including increased enzyme activities, triglycerides and cholesterol) was observed at doses 125 mg/kg bw/day and above.
Two studies investigated the effects of intragastric administration of anatase TiO2 (~5 nm) in mice for 60 days. In the first study, accumulation of particles in the liver led to fatty degeneration, necrosis, inflammatory cell infiltration and hepatocyte apoptosis at 10 and 50 mg/kg bw/day. The hepatotoxic effects were considered to be due to alterations in gene expression levels and proteins which caused suppressed immunity in mice. Decline of neurobehavioural performance and morphological signs of brain damage in mice were reported in the second study, starting at 5 mg/kg bw/day. The effects at 10 and 50 mg/kg bw/day were attributed to the disturbances in the homeostasis of trace elements, enzymes and neurotransmitters in the mouse brain. The lowest observed adverse effect level (LOAEL) was reported as 5 mg/kg bw/day.
There are several short-term inhalation (4–13 weeks), or instillation studies in rodents with conflicting results. Two recent studies reported no inflammatory effects in mice and rats after inhaling TiO2 nanoparticles (20 nm anatase and brookite mixture and 35–60 nm rutile TiO2) for four weeks. There was evidence that chronic inhalation exposure of rats to high concentrations of TiO2 particles of both nano and non-nanoscale particles could lead to impaired pulmonary clearance due to particle overload. The associated adverse effects could include chronic inflammation, pulmonary damage, fibrosis, and lung tumours.
No repeated dose dermal toxicity studies were available.
Genotoxicity
Conflicting results have been reported in genotoxicity studies. Genotoxic effects secondary to inflammatory response and/or oxidative stress have been observed in both in vitro and in vivo studies.
Carcinogenicity
The International Agency for Research on Cancer (IARC) has classified TiO2 as possibly carcinogenic to humans (Group 2B), based on increased reports of lung tumours in rats under conditions of impaired lung clearance. The studies reviewed by IARC used a range of crystalline structures and particle sizes of TiO2. Therefore, it is not clear whether the lung tumours were due to size, crystalline structure or other differences. A 2-year inhalation toxicity study with ultrafine TiO2 (10–50 nm) in rats reported lung tumours at a dose of 10 mg/m3 (equivalent to the NOHSC recommended exposure standard for inspirable dust in general) compared with 250 mg/m3 for fine TiO2. This suggests that the nanoparticles may be causing overloading effects at a lower dose compared with fine particles. Further studies are necessary to investigate lung overload versus non-overload conditions in various animal species to make a conclusion on carcinogenicity from inhalation exposure.
Reproductive toxicity
Several reproductive/developmental studies in mice were available. Three reproductive/developmental studies in mice indicated very low translocation/accumulation in the placenta following inhalation of 21 nm coated rutile TiO2. Considerable translocation/accumulation in the placenta was observed following subcutaneous injections of 25–70 nm anatase TiO2, which caused adverse effects in the genital and cranial nervous system of male offspring. These studies indicated that translocation and accumulation of TiO2 nanoparticles into reproductive organs and/or placenta are necessary in order to exert any adverse effects.
Exposure and health effects
Reported uses of TiO2 nanoparticles in Australia are similar to the overseas uses — cosmetic and sunscreen products and surface coatings such as paint.
The size range for TiO2 particles is determined by the intended use. Pigment-grade TiO2 is optimised for visible light scattering, with particle size typically around 300 nm (Kroschwitz & Howe-Grant, 1997), although incidental presence of particles below 100 nm has been shown to occur. For transparent sunscreens, TiO2 particles in the nanoscale, which are too small to scatter visible light, are used. Anatase TiO2 and TiO2 mixtures containing anatase TiO2 at 85% have shown high photo-catalytic activity compared to rutile TiO2 or TiO2 mixtures containing less than 5% anatase TiO2 (SCCS, 2013). In many applications, particles are coated to reduce photo-catalytic effects and to aid dispersion in formulated products by reducing agglomeration. Coatings such as amorphous silicon dioxide may affect toxicological properties, by reducing production of reactive oxygen species. There is limited information indicating that aluminium hydroxide coated nanoparticles are generating free radicals under experimental conditions when exposed to sunlight in the presence of water containing chlorine. Further research is required to assess whether there is a risk to human health (TGA, 2013).
Cosmetics and sunscreens
Cosmetics and sunscreens used by the public will allow exposure through dermal (e.g. body lotions) and inhalation (e.g. cosmetic powders) routes. Limited incidental oral exposure is also possible.
The current weight of evidence suggests that TiO2 nanoparticles applied to the skin do not reach viable skin cells, but remain on the outer layer of the skin (TGA 2009; EPA 2010) and unlikely to cause harm when used as an ingredient in sunscreens (TGA, 2013). On this basis, health concerns are not expected from TiO2 nanoparticles in cosmetics and sunscreens under normal use conditions. However, data are limited on long-term use of sunscreens containing nanoparticles on hairy, damaged or aged skin, or flexural creases.
If photo-catalytic TiO2 nanoparticles (e.g. anatase TiO2) are present in a sunscreen, they can generate reactive oxygen species (ROS) following exposure to ultraviolet light (SCCS, 2013). The interaction of modern sunscreen formulations with surface coatings was investigated using 35 commercial sunscreens in Australia (Barker and Branch, 2008). Testing of ten samples with key compositional variations indicated that five out of these 10 samples contained TiO2 at 2.5 to 9% concentration, with four of these containing anatase and rutile mixture at 3:1 ratio.
Species-specific pulmonary inflammation is reported in animals following inhalation of all forms of TiO2. While IARC has classified TiO2 as 'possibly carcinogenic to humans' based on inhalation studies in rats with particle overload, inhalation exposure levels from use of cosmetic powders containing incidental TiO2 nanoparticles are expected to be low. Therefore, use of cosmetic powders containing TiO2 nanoparticles is not anticipated to cause lung overload, and consequently unlikely to pose adverse health effects in humans. A recent study reported that nanoparticles in cosmetic powders are in a highly agglomerated state and therefore, as would be expected based on the size of primary particles, the predominant deposition will occur in the tracheobronchial and head airways, and not in the alveolar region. However, considering the inflammatory responses observed in repeated dose inhalation toxicity studies in animals, the SCCS does not recommend the use of nano TiO2 in products that may have significant inhalation exposure (e.g. powders or sprayable products).
The incidental oral exposure is not expected to cause adverse health effects given the likely low exposure and low acute oral toxicity.
Based on the hazard information available, there are no significant concerns at this time from the use of TiO2nanoparticles with low photo-catalytic activity in cosmetics and sunscreens.
Surface coatings
Dermal exposure to TiO2 nanoparticles in surface coatings is not expected to pose significant systemic exposure due to the film-forming nature of surface coating formulations.
Inhalation exposure may occur during spray application of surface coatings. In occupational settings, spray applications need to be carried out in accordance with the Safe Work Australia National Guidance Material for Spray Painting [NOHSC (1999)]. Workplaces are required to maintain airborne concentrations of TiO2 below the exposure standard (10 mg/m3over an eight hour period).
On these grounds, additional control measures are not required for the use of TiO2 nanoparticles in surface coatings.
Current regulatory status in Australia
TiO2 (CAS 13463-67-7), rutile TiO2 (CAS 1317-80-2) and anatase TiO2 (CAS 1317-70-0) are:
listed in the Australian Inventory of Chemical Substances (AICS); and
not listed in the Standard for the Uniform Scheduling of Medicines and Poisons (SUSMP).
TiO2 (CAS 13463-67-7) is:
listed in the Hazardous Substances Information System (HSIS) with no risk phrases but with an exposure standard of 10 mg/m3 time weighted average (TWA).
TiO2 nanoparticles are not listed separately in any of the above, therefore there are no nanoparticle-specific regulatory requirements in place for TiO2. However, all regulatory requirements applying to regular/bulk TiO2, will apply to TiO2 nanoparticles.
Hoping this will be helpful,
Rafik
  • asked a question related to Hazard Assessment
Question
3 answers
I am combining multiple studies on mortality in mental health. Some studies report standardized mortality ratio (SMR) and some report Hazard Ratios (HR or relative risk). Assuming both types of study measure mortality, can both be combined together? Is SMR effectively just HR but deaths vs general population expectations? Or is there some mathematical difference which means they cannot be pooled. Thank you.
Relevant answer
Answer
I have pooled SMR and HR/RR after having seen that done previously in related literature.  Here's the meta-analysis that I looked at:
RoereckeM, Rehm J. Alcohol use disorders and mortality: a systematic review and meta-analysis. Addiction. 2013;108(9):1562-1578
  • asked a question related to Hazard Assessment
Question
1 answer
In Zn Phosphate process, how can we increase the bath life of the Activation bath and when and what is the indication other than pH for bath discarding?
Relevant answer
Answer
there is a chance for carbonation.add accelerators and use the bath. All chemicals are in reduced concentration ; do analysis and add salts
  • asked a question related to Hazard Assessment
Question
10 answers
 Identifying assets is the primary, and most critical step in threat modeling, because assets are essentially threat targets. 
So, How we could determine that the list of assets is complete and be sure that we have not overlooked relevant assets? 
Relevant answer
Answer
In addition to the above great feedbacks, you should also take in consideration all dependencies(1st, 2nd, etc... Order Levels) that each asset leverages and how many assets may share common dependencies. 
  • asked a question related to Hazard Assessment
Question
4 answers
The model in which hazard rate is constant called negative exponential model.
Relevant answer
Since the shape parameter (B) depends on the standard deviation of the response variable Y (Sigma(y)), [where Y=ln(-ln(R(t))=b0+Bx] and on the standard deviation of the logarithm of the analyzed lifetime data (Sigma(x); [x=ln(t)], then B=1 (exponential case) ocurs only when Sigma(x) equals Sigmal(y). Please observe that ones the sample size n was determined sigma(Y) is constant. (the relation of B with sigma(y) and Sigma(x) is given in equation (14) of my paper "Weibull accelerated life testing analysis with several variables using multiple linear regression" .
On the other hand,iIn practice it occurs when the analyzed component presents several competitve  failure modes (electronic divices), thus, the component fails randomly for any of the failure modes. 
Finally, found that B=1 when the scale parameter eta is far away of the designed time t (eta is several times higher than t). It is to say, to constant R(t) index, say R(t)=0.96, with a desired design time t, say t=1500hrs, then with B=1, eta=24.4966*1500. Clearly higher the difference between eta and t, higher Sigma(x), and thus, from the mentioned equation (14) B<1 ocurs only when Sigma(x)>Sigma(y) implying that specific factors are causing the failures.
  • asked a question related to Hazard Assessment
Question
1 answer
Recent deliveries of 10 x TBE solution from Life Technologies have had a label attached to the bottles which states:
"Contains TRIS Base, Boric Acid      Danger
causes skin irritation
causes serious eye irritation
May damage fertility, May damage the unborn child"
While the available MSDS for the powdered TBE mix does carry similar warnings, the MSDS for 10 x TBE states that there are no special measures required and that generally there is no irritation risk.
Is anyone aware of changes to the hazard status of 10 x TBE solution and are special precautions/personal protection required when handling it ir the 1 x and 0.5 x dilutions in use in the lab?
Relevant answer
Answer
Boric acid is the main hazard. Avoid eye and skin contact, use goggles, gloves and an apron.
-Daniel Beckwitt
  • asked a question related to Hazard Assessment
Question
8 answers
I prepared physical and social vulnerability maps of Seoul and Busan megacities. But I could not find the methods to validate those maps.
Relevant answer
Answer
I do not work with social modelling, but I would use old data and analyse them against the predictor variables (environmental and others). And based on this statistic I would create a predictive models and then used a second old dataset to validate, or rather evaluate, the predictive model. But that requires that the data used for happening is within the range of the data used for creating the model, if not you can not trust the predictive model if you  do not fully trust the interpolation that is made.
  • asked a question related to Hazard Assessment
Question
2 answers
All ethoxylated materials are said to contain trace amounts of EO and 1, 4 Dioxane. If my product contains well bellow .1% of ethylene oxide, does this need to be mentioned in the SDS in order to be compliant with California Prop 65? 
According to The Office of Environmental Health Hazard Assessment (http://oehha.ca.gov/prop65/crnr_notices/admin_listing/requests_info/092013ChangeBasis.html) regarding Prop 65 and ethylene oxide.
Prior to June 1, 2016, employers may use the following legend in lieu of that specified in paragraph (j)(2)(i)(A) of this section:
“DANGER ETHYLENE OXIDE CANCER HAZARD AND REPRODUCTIVE HAZARD AUTHORIZED PERSONNEL ONLY ”
“1910.1047(j)(2)(ii)(A)
The employer shall ensure that labels are affixed to all containers of EtO [ethylene oxide] whose contents are capable of causing employee exposure at or above the action level or whose contents may reasonably be foreseen to cause employee exposure above the excursion limit, and that the labels remain affixed when the containers of EtO leave the workplace. For the purposes of this paragraph (j)(2)(ii), reaction vessels, storage tanks, and pipes or piping systems are not considered to be containers.”
"Action level" means a concentration of airborne EtO of 0.5 ppm calculated as an eight (8)-hour time-weighted average (https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=standards&p_id=10070).
So here's my math:
.5/1,000,000= 0.0000005
0.0000005 x 100=0.00005%
I can't find a clear answer, or if there's a new regulation concerning EO. Many of our products would only contain trace amounts, if any at all since EO is extremely volatile and they were not required to be reported before, but the UN's Global Harmonizing System or California may have changed the rules.
Relevant answer
Answer
Hello,
Proposition 65 is specific to California. This is sometimes considered a "right to know" regulation and is separate from OSHA or other occupational regulations, and is independent from the federal government.
Proposition 65 requires that a clear and reasonable warning be provided on a product that contains a chemical known to the State of California to cause cancer or birth defects (ethylene oxide is listed as both) IF the exposure from using the product would be above what is called a "Safe Harbor Level (SHL)."  It is complicated because the SHL is in units of micrograms/day instead of as a concentration.  For ethylene oxide there is a cancer endpoint SHL of 2 microgram/day and a developmental toxicity endpoint SHL of 20 microgram/day. http://oehha.ca.gov/prop65/pdf/safeharbor081513.pdf
For a volatile substance, you could calculate workplace exposure by determining how much might be released into the breathing space of the worker (convert to a unit of microgram/cubic meter and then multiply that by the amount of air that someone would breath in during an 8 hour work day (m3/hr x 8 hr/day) using the product.  If the result you get (microgram/day) using reasonable conservative assumptions (e.g., high activity job) is greater than the SHL then a prop 65 warning would be required.  If there is potential for skin contact and hand to mouth indirect ingestion that would also need to added to the exposure amount.  Often you can find proposition 65 warnings on section 15 (other regulatory information) of an MSDS.  However, note that OEHHA which is responsible for Proposition 65 is currently working on updating the requirements for what constitutes a "clear and reasonable warning".  Any changes should be posted to their website
Best Regards
Lois Haighton
  • asked a question related to Hazard Assessment
Question
5 answers
I am planning on creating flood hazard maps of coastal regions.I would like to achieve that without using any numerical model even if it is an open-source.
If anyone could suggest me some papers with methodologies it would be great.
Relevant answer
Answer
You might want to take a look at the DSS tool produced under the Theseus Project (http://www.theseusproject.eu/)
  • asked a question related to Hazard Assessment
Question
8 answers
Hazard is any factor or situation that has an adverse effect on man's health while risk is the probability of an unfavorable event occurring on someone. So does this imply that hazard is a dormant risk? What then is the threshold (ceiling) for hazard to be converted into risk?
Relevant answer
Answer
Dear Jia,
It's all about definitions I guess... Hazard is an intrinsic property of an object, substance or situation. Hazard only becomes a risk when you are exposed to it (sharks can be very hazardous, but as long as you stay away from the water, you're not at risk). The risk level depends not only on the hazard, but also to the level of exposure to it and your (quantitative) definition of both hazard and risk. I think how you translate hazard to risk, once you're exposed, is therefore very case specific...
  • asked a question related to Hazard Assessment
Question
4 answers
We're developing a hazard perception test for young cyclists. We collected a lot of videoclips with hazardous events. The next step would be to create a time frame in which participants can respond to the hazard by clicking on a button. At the end of the clip a score (based on the timeframe in which te hazard develops over time) should be given to the participant. Which software can I use?
Relevant answer
Answer
Hi,
Thanks for the fast responses! Psychtoolbox 3 looks very promising. Tomorrow we'll take a look at the other possibilities.
  • asked a question related to Hazard Assessment
Question
17 answers
Usually an Internet search would return billions of results when the following keywords are looked up, 'disaster statistics' or 'natural hazard statistics'. Further exploration reveals official and unofficial numbers. To complicate matters there are various news reports which  furnish unverified  figures. Although I believe it may not be that easy to come to a consensus on putting a numerical figure on the losses but still where does one look for the right sources.
Having said that, I would appreciate if I can get some help in identifying the legitimate sources. It doesn't matter if it is at the International, national, regional or even local level.
Relevant answer
There are no reliable data about disasters, as all sources have both (avoidable and unavoidable) technical problems, scope, and not least self interest in manipulating the information (political, financial or otherwise). In addition, you have serious problem of aggregation across events, countries and over time when, especially but not only, using panel data. As long as you are aware of these deep failures, you can entertain some loose thought experiments. But my recommendation would be that you should be extremely careful from reading, let alone interpreting, too much from available data. Have a look at my 2013 book (Routledge) “Disasters and the Networked Economy” (especially Chapter 1: The Problem with Quantitative Studies).
  • asked a question related to Hazard Assessment
Question
10 answers
For meta-analysis: Can hazard ratios and odds ratio be used interchangeably in meta-analysis? If not how can I convert hazard ratio to odds ratio?
Relevant answer
Answer
Dear Mohammed Ali
The answer to your question is no - hazards and risks or odds are not interchangable! Regardsing the specific statistical differnces you would have to consult a statistician. But i can try to give you a lay-physician explanation.
Risks refer to absolute numbers of an event (i.e. disease) in a popualation - we have no consideration of time in a risk.
Hazards refers only to the "speed" of specific events in a population. A hazard is therefore a time to event estimate and will never reflect the absolute risk of an event in a population.
Hazard risk and risk ratios are therefor two different measures of events in a population. They are based on two different infernential statistics and most likely also based on two different types of studies (propesctive cohort vs. interventional studies). The statistical question asked in a hazard rate is "does a specific exposure cause outcome quicker than to not being exposed" where the question in a risk ratio is "does exposure cause outcome more often compared to not being exposed".   
My advice to you is therefore not to include hazard ratios if you are making a meta analysis based on risks or odds ratios.  
  • asked a question related to Hazard Assessment
Question
11 answers
Computer vision syndrome (CVS) is a temporary condition resulting from focusing the eyes on a computer display for protracted, uninterrupted periods of time. Some symptoms of CVS include headaches, blurred vision, neck pain, redness in the eyes, fatigue, eye strain, dry eyes, irritated eyes, double vision, vertigo/dizziness, polyopia, and difficulty refocusing the eyes. These symptoms can be further aggravated by improper lighting conditions (i.e. glare  or bright overhead lighting) or air moving past the eyes (e.g. overhead vents, direct air from a fan). [Source: Wikipedia]
With the increasing access to digital devices, Computer Vision Syndrome is becoming a common ailment
Nowadays ours eyes do not get adequate rest as most of the time we are either on our computer, laptop, i-pad, mobile or watching television. Eye strain caused by excessive use of computer is called Computer Vision Syndrome or digital vision syndrome. It manifests as tiredness, inability to work for long hours, blurring of vision, double vision, watering, redness, itching and pain in eyes. These symptoms will be present in 95 per cent of people who use the computer for more than three hours a day.[Source: The Hindu]
Some Excerpts from the second article:
What To Do
Posture and Exercises
Good posture and regular exercises of back and cervical muscles are a must if you use the computer for more than three to four hours a day.
Lighting
The room should be well illuminated with the light source positioned in a way that light does not fall directly on your eyes or on the screen The light source should be behind the screen or on the ceiling and partially covered. anti-glare screens and spectacles can also help.
Dryness
Normally we blink 10 to 12 times a minute. When we watch TV our blink rate is 5 to 6 a minute and while working on the computer it further goes down to 3 to 4 times a minute. Reduced blinking causes evaporation of tears thereby increasing the osmolarity (concentration) of the tears. The hyperosmolar tears induce inflammation and tear film instability which in turn cause increase reflex lacrimation. In other words, the dry eye caused by Computer Vision Syndrome may present not only as dry eye but may present as watering and inflamed eye.
To overcome this, it is better to have the computer screen 20 to 40 degrees below the eye level. This causes partial closure of the eyes by the lids thereby decreasing the evaporative surface.
Your comments and views are welcome. Muchas Gracias !!
Relevant answer
Answer
According to the National Institute of Occupational Safety and Health, CVS affects approximately 90% of the people who spent three hours or more at day looking at a computer. The lighting, air quality, and the time spent focusing on a screen are the main factors that could bring about CVS. Taking breaks by closing your eyes or focusing on objects far away could help give the overused muscles a necessary time out. If giving your eyes a little breather is hard to remember you could set a reminder or timer. Some other variables to consider that could contribute to eyestrain is the environment.  If the room is really bright you could consider tinted glasses or maybe a certain pair of glasses just for computer use. If there is a lot of airflow that is drying out your eyes, some lubricating eye drops might help. Also make sure your settings are so that the font and screen lighting can be read with ease.
  • asked a question related to Hazard Assessment
Question
5 answers
I am interested in suggestions for verbal anchors that may be used for different levels of severity (such as minor, moderate, severe...) and definitions for each level.
Relevant answer
Answer
Hi Donald - I would like to add that I have found it very useful in practice to make the steps between ratings (both on likelihood & consequence scale) to be a factor of 10 bigger. I have included a couple of old slides to show you want I mean. See attached  - I hope !!
This was a recommendation that I saw years ago in Royal Society Risk guidance publication (1977). Ironically it is very contemporary idea as it fits into the concept that risk is emergent property from a complex system and therefore the spread of risks should follow a power law.  
In a practical sense it is useful to make the scale grades big enough to really make people think about the range. You adjust the values of $impact or frequency (T) or injury to suit your own situation.  If you were a multinational then $V would be millions but for a corner shop a loss of $100 might hurt.  Likewise if you are planning a school trip a broken ankle might be a serious event but if you were planning an invasion of  a country then several hundred loss of life might not be that serious.   Hope that helps 
  • asked a question related to Hazard Assessment
Question
3 answers
For example, when we are trying to use Cox proportional hazard regression model to analyze the hazard ratio (HR) of medication A on disease B. Another medication C is known to increase the risk of B, and that medication C is often but not always prescribed in those patients receiving medication A. Let's assume that medication A do in fact increase the risk of B, will there be "overcorrection" when we add medication C into the covariates and make the HR of A become statistically insignificant?
If so, how could we deal with this problem and have a better analysis to reveal the true effect of A on the risk of B?
Relevant answer
Answer
Overcorrection occurs when the proposed model includes factors that share common causes that link them to the outcome of interest. 
When we suspect that the link between an exposure and an outcome is influenced by a third factor, we then need to include an interaction term in the model. This will then make it possible to test the association of the exposure of interest in the presence and absence of this third factor.
However, we have to preplan the analysis and make sure the sample size is large enough to maintain the requested power to detect interaction before concluding anything (Brookes et al. 2001).
In the provided example, you would have to construct the model in the following way: landa(t|X) = landa0(t) + b1medA + b2medC + b3(medA*medC)
The effect of the medication A on the condition B in the absence of medication C will be provided by the coefficient b1, and the effect of medication A in the presence of medication C will be provided by summing the coefficients b1 and b3. Most statistical software do this automatically and you need to look up at "interaction" or "effect modifier".
Brookes ST, Whitley E, Peters TJ, Mulheran PA, Egger M, Davey Smith G: Subgroup analyses in randomised controlled trials: quantifying the risks of false-positives and false-negatives. Health Technol Assess 2001, 5(33):1-56 
  • asked a question related to Hazard Assessment
Question
7 answers
In univariate case hazard rate, my interest is of bath tub form.
Is there anything like bath tub shaped hazard function in bivariate case?
Relevant answer
Answer
Hopefully the link should appear this time.
  • asked a question related to Hazard Assessment
Question
8 answers
Academia provides scientific knowledge; governments provide regulations, enforcement, and financial support; organizations bring parties together, advocate and promote participation, etc.; and private sectors innovation and technical support.
Relevant answer
Answer
Ultimately, the Community involvement is the key. Building a resilient society with appropriate coping mechanisms is the basic principle behind any DRR. And the other stake holders are like the Local Government and other competent authorities like National disaster Management Authority;  the NGO Networks; Volunteer Groups; the Financing Institutions; private/business ; the media; Red Cross society; hospitals and fire Fighting and other services; academic community; UN bodies. Timeliness is the essence in DRR and how quickly these stake holders act and work together is important ultimately. Each stakeholder has his/hr own responsibility in different phases of  Disasters ( such as Disaster Prevention, Preparedness, Response, Relief and Mitigation )
  • asked a question related to Hazard Assessment
Question
26 answers
How can land use change reveal the frequency and magnitude of natural hazards occurrences? I want to find the relation between these two. I need also some methodology to evaluate a possible relationship.
Relevant answer
Answer
i just published a paper about land use change and in particular change in the artificial drainage network and an example of the changes in network saturation, as an example of the possible effects on flood risk...we anyway focused on the changes in the network due to urbanization and how to detect the changes in the network drainage density and water storage... 
  • asked a question related to Hazard Assessment
Question
3 answers
I have culture microbes with hydrocarbon substrate to detect biodegradation hydrocarbon activity, I used N-hexane to extract the residual compound before GC-MS analysis. Should I decrease pH solution before extraction? What is the function of decreasing pH?
Relevant answer
Answer
Hi,
Before extraction of biodegraded or biotransformed hydrocarbon you should take into consideration that what type of hydrocarbon you are using for degradation then consider its solubility in different solvents like polar mid polar and non polar solvents.
then through literature survey try to predict that after degradation or transformation what type of compounds will formed depending on that you should change your pH, temperature, slvent system etc etc
Regards