During this era, adsorption-driven remediation using natural and low-cost adsorbents such as peat, wood, silica, and agricultural by-products became a central, cost-effective strategy for removing dyes and color from effluents. Meanwhile groundwater and landfill leachate remediation emphasized plume fate under redox-controlled conditions, with pump-and-treat approaches and redox zoning shaping contaminant trajectories. Bioremediation and microbial degradation emerged as primary mechanisms for hydrocarbon cleanup, complemented by attention to heavy metals in sludge and soils and to ecotoxicology and bioavailability linking contaminants to wildlife exposure. Influential Works: Prominent cross-period works include Accumulators and excluders (1981), which introduced the hyperaccumulator versus excluder framework and catalyzed phytoremediation research. Key works such as Microbial Degradation of Hydrocarbons in the Environment (1990) and Microbial Degradation of Petroleum Hydrocarbons: An Environmental Perspective (1981) outlined microbial pathways and community-level biodegradation concepts that underpinned later biotechnological approaches. Foundational assessments like Quantitative assessment of worldwide contamination of air, water and soils by trace metals (1988) and Speciation of Heavy Metals in Soils and Sediments (1993) established global inventories and standardized extraction methods to guide risk assessment and remediation targeting.