Water quality
Sewer overflows spike chemicals in marine harbours
Open access · cc by · source: Europe PMC
In two protected English harbours, CSO discharge days raised mixed chemical burdens 25- to 43-fold above a dry-spring baseline, with imidacloprid exceeding PNEC.
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In two protected English harbours, CSO discharge days raised mixed chemical burdens 25- to 43-fold above a dry-spring baseline, with imidacloprid exceeding PNEC.
Evidence for the claim as stated.
Study at a glance
- Design
- Other — Targeted chemical profiling of harbour water and pooled biota against combined-sewer-overflow records
- N
- N=21 · 21 harbour sites; 339 water samples in some summaries, with four CSO-near sites resampled
- Population
- Surface water and biota in two protected English marine harbours
- Outcome
- CSO discharge days raised mixed chemical burdens 25- to 43-fold above a dry-spring baseline, with imidacloprid exceeding PNEC
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Inspect source passages
Sewer overflows spike chemicals in marine harbours
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67 pharmaceuticals detected; 22 at more than 50% of sites
Of all 67 pharmaceuticals detected, 22 were detected at more than 50 % of the sites.
March mean concentrations ranged from 0.12 ng/L to 129 ng/L (citalopram)
Mean concentrations of chemicals in samples from March ranged from 0.12 ± 0.06 ng L -1 (propamocarb) up to 129 ± 108 ng L -1 (citalopram), with cumulative mean concentrations for all compounds across all replicates reaching up to 995 ng L -1 ().
Key findings
March means ranged 0.12–129 ng/L (citalopram high); 22 of 67 compounds were at >50% of sites. At Site 16, daily means rose from 6.6 ng/L in March to 281 ng/L on an August CSO day (25–43×). Cocaine (~15×) and benzoylecgonine (~20×) tracked overflows; imidacloprid RQs averaged 3.9 (March) and reached 9.3. Spikes returned toward baseline within 24 h.
Methodology
Authors sampled 21 harbour sites in a dry March, then resampled four CSO-near sites through wetter August/November, quantifying 67 pharmaceuticals/pesticides/markers in water (and pooled biota) against event-duration-monitoring overflow records.
Limitations
Four intensively resampled sites cannot represent all UK harbours. Biota were pooled, so individual organisms are not dose-mapped. PNEC exceedances are screening-level, not measured ecological damage.
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