Weak environmental regulations in Texas have led to a big influx of industrial livestock operations that are hazards to public health and the environment, says a report issued yesterday by local offices of the Sierra Club and Consumers Union. Although other states have strengthened such regulations or even placed moratoriums on the construction of new livestock operations, the report contends that Texas under Gov. George W. Bush (R) has restricted the ability of residents living near the smelly operations to contest new permits and expansions. Texas tops the nation by producing 220 billion pounds a year of animal waste, causing 338 miles of streams and more than 23,000 acres of lakes to become polluted, the report says.