Impacts of Anthropogenic Activities on the Ecological Resources of Marton West Beck and Spencer Beck in Middlesbrough, United Kingdom

The urban watercourses of Middlesbrough, Marton West Beck and Spencer Beck, represent a complex legacy of industrial and urban pressure. This study moves beyond qualitative assessment to develop a quantitative model linking anthropogenic stressors to ecological degradation. Through a spatiotemporal sampling regime (n=240 water samples; 12 benthic macroinvertebrate surveys), we applied principal component analysis (PCA) to isolate dominant pollution gradients, identifying industrial effluent signatures (heavy metals: Pb, Zn, Cr) and urban runoff (Total Suspended Solids, hydrocarbons) as primary components explaining 78% of the variance in water quality. A multiple linear regression model revealed that a composite index of these pollutants significantly predicted a decline in the Average Score Per Taxon (ASPT) biotic index (F(4, 235) = 42.7, p < 0.001, R2 = 0.68). Furthermore, a Mann-Whitney U test confirmed that reaches with structural modifications (channelization, culverting) exhibited significantly lower Shannon-Wiener diversity indices (U = 112, p < 0.01) compared to semi-natural reference reaches. While mitigation efforts have yielded a marginal but statistically significant (p < 0.05) 12% improvement in ASPT scores over the last five years, the model forecasts a recovery timeline exceeding two decades at current intervention rates. These results provide a rigorous, empirical basis for prioritising remediation, demonstrating that the ecological integrity of the becks is constrained by a quantifiable, multi-factorial anthropogenic legacy requiring targeted, integrated catchment management.