Abstract:
The increased awareness of the importance of environmental protection and assessment of the
GHGS emission, and the possible impacts associated with products both manufactured and
consumed, has led to the development of life cycle assessment (LCA) methods to better
understand and address impacts which assists in identifying opportunities to improve the
environmental performance of products at various points in their life cycle. A representative
leather tannery industry in Bangladesh has been studied from an environmental point of view.
Life Cycle Analysis (LCA) methodology from cradle to gate has been used for the
quantification and evaluation of the impacts of two representative leather articles namely fullchrome
and chrome retanned crust leather production systems as a basis to analyze, compare
and propose further improvement actions. The functional unit chosen is 1 square meter crust
leather. The effects of the resource use and emissions generated are grouped and quantified
into a limited number of midpoint impact categories (human toxicity, respiratory inorganics,
respiratory organics, ionizing radiation, ozone layer depletion, aquatic ecotoxicity, terrestrial
ecotoxicity, aquatic acidification, aquatic eutrophication, terrestrial acidification/nitrification,
land occupation, global warming, nonrenewable energy consumption, mineral extraction) and
these are finally grouped into four endpoint damage categories (human health, ecosystem
quality, climate change, and resources). To characterize and assess the effects of the
environmental burdens identified in the inventory, impact assessment was conducted based on
impact 2002+methodology. In doing so, life cycle inventory data were linked to the midpoint
categories. In few cases, like electricity, transportation, packaging energy from generator and
diesel combusted in boiler processes have been taken as proxy processes. The obvious
advantage of using proxies is that they facilitate the impact estimation when a full assessment
would be too costly. The use of proxy data sets is the quickest and easiest solution for bridging
data gaps. The results indicate that significant environmental impacts were caused during the
tanning as well as the transportation for raw material, imported chemicals and delivery of crust
leather; electricity production and packaging materials required in the life cycle. Damages to
human health, ecosystem quality are mainly produced by the chrome tanning, acid wash,
Rechroming and neutralization processes. Transport and electricity also contributed
moderately. The control and reduction of chromium and ammonia emissions are the critical
points to be considered to improve the environmental performance of the process. Technologies
available for improved management of chromium tanning were proposed. The carbon footprint
of the two systems found to be 0.721 and 0.731 Kg CO2 eq per m2 of full-chrome and chrome
retanned crust leather respectively. Environmental hotspots found for production processes were tanning, rechroming, neutralization, deliming-bating and acidwash. Supply chain
hotspots are transport for raw hides and chemicals, electricity. Slaughtering, the cradle
considered for carbon footprint analysis of leather contributed minor amount to the impact
categories. Production processes mainly contributed to non-carcinogens, aquatic ecotoxicity,
aquatic acidification and aquatic eutrophication midpoint categories which finally contributed
much to damage categories human health and ecosystem quality. Supply chain processes
mainly contributed to midpoint categories global warming, carcinogens, ionizing radiation,
ozone layer depletion, terrestrial ecotoxicity, terrestrial acidification/nutrification, respiratory
organics, respiratory inorganics, land occupation, mineral extraction and non-renewable energy
which finally contributed much to damage categories climate change, resources and human
health. Full-chrome crust leather has 5 times higher impact on aquatic ecotoxicity, 4.53 times
higher on non-carcinogens and 2.53 times higher on ecosystem quality. In addition, aquatic
acidification of full-chrome system is greater than chrome retanned system but chrome
retanned crust leather has marginally higher value of aquatic eutrophication. Comparing all
impact categories, full-chrome crust leather had higher environmental burden than chrome
retanned crust leather.