Hi Surya,

First have a glance to the concepts of ADI and NOAEL on Wiki + links

https://en.wikipedia.org/wiki/Acceptable_daily_intake

Then you'll find more informations for chlorpyrifos on

http://npic.orst.edu/factsheets/archive/chlorptech.html

And many other official sites for food safety

Dear Surya Prakash,

Please check the following ResearchGate link and PDF attachment.

https://www.researchgate.net/publication/313876622_Chlorpyrifos_poisoning_and_its_implications_in_human_fatal_cases_A_forensic_perspective_with_reference_to_Indian_scenario

Good luck!

https://www.epa.gov/ingredients-used-pesticide-products/chlorpyrifos

https://www.epa.gov/ingredients-used-pesticide-products/revised-human-health-risk-assessment-chlorpyrifos

http://www.who.int/whopes/quality/Chlorpyrifos_WHO_specs_eval_Mar_2009.pdf

https://www.efsa.europa.eu/en/efsajournal/pub/3640

Thanks for the responses. They are helpful.

The values of LOAEL/NOAEL for Chlorpyrifos are clear from different sources. Even different studies have found LD50 values for animals like rats, rabbits etc.

Is there any reference that roughly states (or say predicts) an approximate LD50 value for humans?

If not, can we assume LD50 values of a certain animal (eg: rat) to be close to humans ? If so, which animal is best suited ?

Hi Surya,

For safety reasons, and because human experimentation is obviously not possible, LD50 values obtained on animal (else) is considered as valid for humans.

Moreover, ADI takes into account a security inter-species parameter (typically 1/100 of NOAEL) which guarantees in theory the transfer from animal to humans of the data obtained in animal experimentation.

Is there a limit? Yes. For any response up to death, there will be a limit beyond which poisoning symptoms progress to the next level.

There are typically governmental requirements for personal protective equipment designed to minimize exposure risk. Failure to follow regulations may result in fines or suspension of pesticide applicator's license in addition to whatever effect the pesticide might have.

Does not cause harm: Yes and No and depending on if you are interested in acute or chronic effects. Yes there is a limit for acute effects, however long before that limit is reached there are a range of sublethal effects. These effects may be present only in sensitive individuals, or may only be detectable in experiments with huge sample sizes (hundreds or hundreds of thousands). Think about designing an experiment to detect the effect of a pesticide exposure that will decrease the life expectancy by 4 days. An individual that would normally have died on their 78th birthday will now die 4 days before that. Another way to answer would be to say yes, but only because your experimental design is such that you create a threshold. If I test at 10ppm and 100ppm and 1000ppm, then I might find a threshold between 10 ppm and 1000ppm. Yet looking closer I cannot find a value of 347ppm below which there is no effect on any individual and above which all individuals will respond.

mg/kg to ppm conversion: This is not possible. If I have a dose of 2mg/kg and a 50kg person, then I will need 100mg to get a response. I can dilute that in 1 liter of water to get a 100ppm solution, or I can dilute it in 100 ml to get a 1000ppm solution. Overall this does not work because the dose is time sensitive. The 100mg dose might be lethal if diluted in 1 ml that can be consumed in 1 second, yet have no effect if diluted in 5 l where it will take several days to consume the entire dose.

The volume of solid and/or liquid which separates shall not be more than 0.3 ml

Read this article written by:

Adel Mashaan Rabee*, Yaaroub Faleh Al-Fatlawy*, Abd-Al-Husain Najim Abd own** and Mustafa Nameer**Department of Biology,

College of Science, University of Baghdad. **Ministry of Science and Technologyle written by

not an easy answer now because of many issues on regulations, politics, and lawsuits. The answer is "it depends" on where you live.

It is generally accepted that the No Effect of 1 mg/kg/day on blood ACE was established many years ago. The question becomes, how many safety factors do you add. There have been studies on human subjects, but those studies are not allowed to be used to assess risks to humans according to policy.To your original question - there is no conversion of the established No Effect level and PPM, It goes inthe other direction. Based on food consumption, activity levels, etc it is possible to compare the exposure (ppm as mg/kg * food consumption in kg/day=mg/kg bwt/day) to the established regulatory exposure limit. As an example you can find my paper on acute exposure to chlorpyrifos that was published 16 years ago Article Refinements in Acute Dietary Exposure Assessments for Chlorpyrifos

Pesticides mg/L 0.01

https://en.wikipedia.org/wiki/Chlorpyrifos

https://en.wikipedia.org/wiki/Chlorpyrifos

Check this it will be ok

Yes, there is a limit. Often times a universal threshold is declared for this substances but each society can have its own minimal and maximum according to the level of control achievable at each given period. I once worked on the LD50 of lead in water using universal(WHO) standard but in couple of Months the benchmark had changed. Moreso, conversion from units depends largely on the size of the particulate you are working on, sometimes mg/kg can be the same with your ppm or ppt or pph. It's just a matter of ratio. To get recent updates please refer to the journal of Environmental Toxicology and Assessment.