Environmental Indexes by Amit Joshi

Purpose Assess the potential risks posed by releases from industrial sources Conduct preliminary impact assessment Tool for screening analysis

Classification Abiotic Indexes Health-Related Indexes Ecotoxicity Indexes

Abiotic Indexes Global Warming Stratospheric Ozone Depletion Acid Deposition Smog Formation

Health-Related Indexes Inhalation Toxicity Ingestion Toxicity Inhalation Carcinogen Toxicity Ingestion Carcinogen Toxicity

Ecotoxicity Indexes Fish Aquatic Toxicity

Global Warming Index Ratio of cumulative infrared energy capture from the release of 1 kg of a green-house gas relative to that from 1 kg of carbon dioxide (IPCC,1991) a i is the predicted radiative forcing of the gas i (Wm -2) Ci is its predicted concentration in the atmosphere (ppm) n is the number of years over which the integration is performed

Global Warming Index (contd..) The product of GWP and the mass emission rate of the greenhouse chemical gives the emission in terms of CO 2 (the benchmark compound) I GW =  (GWP i * m i ) For the, organic compounds, with atmospheric reaction residence time less than ½ a year, an indirect GWP is defined (Shonnard and Hiew, 2000) Nc is the number of carbon atoms in the chemical MWi is the molecular wt.

Global Warming Index (contd..) Factors affecting GWP 1) Chemical’s tropospheric residence time 2) The strength of its infrared radiation absorbance

Ozone Depletion Index Ratio of the predicted time- and height- integrated change  [O3] in stratospheric ozone caused by the release of a specific quantity of the chemical relative to that caused by the same quantity of a benchmark compound, tricholorofluoromethane (CFC-11,CCL 3 F) (Fisher et al., 1990)

Ozone Depletion Index (contd..) The product of ODP and the mass emission rate of the greenhouse chemical gives the emission in terms of CFC-11, the benchmark compound. I OD =  (ODP i * m i )

Acid Rain Index The number of H + created per number of moles of the compound emitted as shown in the following equation X   H where, X is the emitted chemicals substance initiating acidification and  is a molar stoichiometric coefficient. H+ created per mass of substance emitted (  i,H + moles/ kg i)  i =  i __ MW i MWi is the molecular weight of the emitted substance (moles i /kg i )

Acid Rain Index (contd..) ARP i = __  i __  SO2 expressed in terms of benchmark compound SO2 The product of ARP and the mass emission rate of the chemical gives the emission in terms of SO2 (the benchmark compound) I AR =  (ARP i * m i )

Smog Formation Index Incremental reactivity (IR) for evaluation of SWP Definition: The Change in moles of ozone formed as a result of emission into an air shed of one mole of the VOC (Carter and Atkinson,1989) VOC IR is proportional to NOx level relative to reactive organic gases (ROG)

Smog Formation Index (contd..) Maximum Incremental Reactivity (MIR)- Most relavent scale for comparing VOCs. MIR occurs under high NOx conditions when the highest ozone formation occurs (Carter,1994) SFP i = __MIR i __ MIR ROG MIRROG is the average value for background organic gases, the benchmark compound for this index

Smog Formation Index (contd..) The product of SFP and the mass emission rate of the chemical gives the emission in terms of background ROG, the benchmark compound I SF =  (SFP i * m i )

Toxicity Potentials Toxicity : Complex function of dose and response Dose: Depends on complex series of steps involving 1) manner of release 2) environmental fate and transport of chemicals 3) uptake mechanisms Response: Response by the target organ in the body is a complex function of 1) chemical structure 2) modes of action

Toxicity Potentials (contd..) Types of Toxicity 1) Carcinogenic Toxicity: defined in terms of Benzene 2) Non-Carcinogenic Toxicity : defined in terms of Toluene Dominant exposure routes for human contact with toxic chemicals in the environment 1) Inhalation 2) Ingestion

Toxicity Potentials (contd..) Non-Carcinogenic Toxicity controlled by threshold exposure i.e., doses below the threshold value do not manifest a toxic response whereas the doses above this will do. Key parameters for chemicals Ingestion : reference does (RfD(mg/kg/day)) : lethal dose (LD 50 ) Inhalation: reference concentration (RfC(mg/m 3 )) : lethal concentration(LC 50 ) RfCs and RfDs are not available for all chemicals so LD 50 and LC 50 are used

Toxicity Potentials (contd..) Non-Carcinogenic Ingestion Toxicity Potential Ingestion Toxicity Potential Inhalation Toxicity Potential C w,i and C w,Toluene are the steady- state concentrations of the chemical and the benchmark compound in the water compartment C a,i and C a,Toluene are the steady- state concentrations of the chemical and the benchmark compound in the air compartment

Toxicity Potentials (contd..) Non-Carcinogenic Ingestion Toxicity Potential (contd..) The product of I * ING i and the mass emission rate of the chemical gives the emission in terms of Toluene, the benchmark compound I ING =  (I * ING i * m i ) The product of I * INHY i and the mass emission rate of the chemical gives the emission in terms of Toluene, the benchmark compound. I INH =  (I * INH i * m i )

Toxicity Potentials (contd..) Carcinogenic Toxicity Ingestion Toxicity Potential Inhalation Toxicity Potential HV is the hazard value for carcinogenic health effects

Toxicity Potentials (contd..) Carcinogenic Toxicity (contd..) The product of I * CING i and the mass emission rate of the chemical gives the emission in terms of Toluene (the benchmark compound) I CINGi =  (I * CING i * m i ) The product of I * INHY i and the mass emission rate of the chemical gives the emission in terms of Toluene (the benchmark compound) I CINHi =  (I * CINH i * m i )

Toxicity Potentials (contd..) In non-carcinogenic toxicity indexes, RfDs and RfCs can also be used if available instead of LD 50 and LC 50. In carcinogenic toxicity indexes, Slope Factor (SF) can be used instead of hazard values for chemicals. Slope Factor : Known as a cancer slope potency factor. It is obtained using the excess cancer versus administered dose data

Ecotoxicity Index Fish Toxicity Index LC 50 - the 4-day rodent or fish lethal dose (mg/l) which causes 50% mortality in a test population. Benchmark compound: PCP - pentachlorophenol

Summary

Summary (contd..)