A composition for preparing a geomembrane liner for a containment system, wherein said composition is of: 1) a master batch; and 2) a base resin and wherein said composition comprises: i) 8-10 wt% of a master batch composition comprising a) 70 to 80 wt% of a Linear Low Density Polyethylene (LLDPE), Medium Density Polyethylene (MDPE), High Density Polyethylene (HDPE), or Polyethylene of Raised Temperature (PERT) resin carrier has density from 0.910 to 0.955 g/cm3. b) 1 to 3 wt% of a primary antioxidant, wherein said primary antioxidant comprises 1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4- hydroxybenzyl) benzene; c) 0.1 to 0.5 wt% of a secondary antioxidant, wherein said secondary antioxidant comprises pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); d) optionally, 0.1 to 0.5 wt% of tris (2,4-di-tert-butylphenyl) phosphite; e) 1 to 3 wt% of a UV stabilizer, wherein said UV stabilizer comprises a high molecular weight hindered amine light stabilizer; f) 0.1 to 0.5 wt% of an acid neutralizer; and g) 20 to 30 wt% of a carbon black, wherein said carbon black is a furnace carbon black, and wherein the percentages by weight add up to 100% and are based on the total weight of the master batch composition; and ii) 90 to 92 wt% of a base resin composition comprising Polyethylene of Raised Temperature (PERT) base resin, wherein the percentage by weight is based on the total weight of the geomembrane composition. i) 8-10 wt% of a master batch composition comprising a) 70 to 80 wt% of a Linear Low Density Polyethylene (LLDPE), Medium Density Polyethylene (MDPE), High Density Polyethylene (HDPE), or Polyethylene of Raised Temperature (PERT) resin carrier has density from 0.910 to 0.955 g/cm3. b) 1 to 3 wt% of a primary antioxidant, wherein said primary antioxidant comprises 1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4- hydroxybenzyl) benzene; c) 0.1 to 0.5 wt% of a secondary antioxidant, wherein said secondary antioxidant comprises pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); d) optionally, 0.1 to 0.5 wt% of tris (2,4-di-tert-butylphenyl) phosphite; e) 1 to 3 wt% of a UV stabilizer, wherein said UV stabilizer comprises a high molecular weight hindered amine light stabilizer; f) 0.1 to 0.5 wt% of an acid neutralizer; and g) 20 to 30 wt% of a carbon black, wherein said carbon black is a furnace carbon black, and wherein the percentages by weight add up to 100% and are based on the total weight of the master batch composition; and a) 70 to 80 wt% of a Linear Low Density Polyethylene (LLDPE), Medium Density Polyethylene (MDPE), High Density Polyethylene (HDPE), or Polyethylene of Raised Temperature (PERT) resin carrier has density from 0.910 to 0.955 g/cm3. b) 1 to 3 wt% of a primary antioxidant, wherein said primary antioxidant comprises 1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4- hydroxybenzyl) benzene; c) 0.1 to 0.5 wt% of a secondary antioxidant, wherein said secondary antioxidant comprises pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); d) optionally, 0.1 to 0.5 wt% of tris (2,4-di-tert-butylphenyl) phosphite; e) 1 to 3 wt% of a UV stabilizer, wherein said UV stabilizer comprises a high molecular weight hindered amine light stabilizer; f) 0.1 to 0.5 wt% of an acid neutralizer; and g) 20 to 30 wt% of a carbon black, wherein said carbon black is a furnace carbon black, and wherein the percentages by weight add up to 100% and are based on the total weight of the master batch composition; and ii) 90 to 92 wt% of a base resin composition comprising Polyethylene of Raised Temperature (PERT) base resin, wherein the percentage by weight is based on the total weight of the geomembrane composition. <EOS>