Abstract: Aimed to explore the correlations between land use pattern and water quality in heterogeneous landscapes, Taihu Lake basin was taken as a case, and was divided into 13 hydro-ecological units based on topography, land use pattern, and flow direction of major hydrological systems. The correlation analysis on the area proportions of different land use/cover types and water quality grade across the hydro-ecological units showed that the coefficient of variation of the water quality grade had a positive correlation with the area proportion of woodland, but a negative correlation with the area proportions of farmland and settlement, being significant for that of the settlement in non-flood season, which suggested that different land use types had different effects on water quality, i.e., woodland could improve water quality more effectively than farmland and settlement. The water quality grade of the hydro-ecological units was significantly positively correlated with the area proportion of farmland and of settlement in the flood season and non-flood season, respectively, but negatively correlated with that of woodland. There was a weak negative correlation between the water quality grade and the area proportion of wetland in the non-flood season, but a weak positive correlation in the flood season and in the whole year. The effect of the four major land use types in improving water quality in the flood season was in the order of woodland > wetland > settlement > farmland, and that in non-flood season was woodland > farmland > wetland > settlement, suggesting that woodland had the greatest positive contribution to the water quality, while farmland and settlement had the greatest negative contribution to the water quality in the flood season and non-flood season, respectively.

Key words: Toxicity identification evaluation (TIE), Daphnia magna, Industrial effluent treatment, Toxicant, Removal efficiency