STUDYING why Sussex oysters are refusing to change sex could be the key to tackling harmful pollutants, researchers say.

University of Brighton experts are part of a new EU project aiming to tackle potentially harmful chemicals called endocrine disruptors polluting the environment.

These pollutants can interfere with humans’ hormone systems, causing birth defects and cancerous tumours.

The project aims to develop quick tests to determine whether chemicals in products are likely to interfere with human or animal hormones.

Experts say this will tackle the problem at the source.

But the key to fighting the pollutant could be studying the overwhelmingly male European oysters in Chichester Harbour, says Brighton project lead Dr Corina Ciocan.

“The sex ratio is 11 males to every one female,” said the researcher.

“Oysters can change sex. The fact they’re stuck in the male states suggests the environment isn’t very friendly.

“It takes a lot of energy to change into the female state and develop eggs.

“We know endocrine disruptors can alter the reproductive systems of molluscs.”

The researchers will look for “biomarkers” - early signals which can predict a change in hormones when organisms are exposed to the pollutant.

Endocrine disruptors are difficult to detect in the environment without expensive state-of-the-art equipment.

The EU project will focus on six specific endrocrine disruptors which can leak into the environment from many different sources.

Previous studies have revealed how chemicals from birth control pills have leaked into rivers and feminised fish. Other potential endocrine disruptors include homosalate, found in some sun creams.

“The aim of the project is to develop quick tests to show that those chemicals have an environmental effect on reproductive systems,” said Dr Ciocan.

“In three years’ time we want to have tests which can be done by laboratories.”

The project involves four universities from Britain and France, as well as French lab firm Toxem and the Chichester Harbour Conservancy, which looks after the harbour.